Thorn Cycles Forum
Technical => General Technical => Topic started by: steve216c on September 29, 2020, 11:31:09 am
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My baby-oiled, talcum powdered, Ikea-candled bike (see my other posts) is due for 5000km service. In fact more than just an oil change, I plan to replace bottom bracket, renew the gear shift rubber, replace the gear cable outers so I can use standard 'Shimano fit' gear cables and amongst other things, replace hub oil. Given that I will be swapping out the BB-UN55, removal of the existing chainguard fitting/support can be easily done at same time- so the opportunity to consider a chainglider raises its not so ugly head.
The candlewax dipped Wippermann Connex 808 is riding well- approx 500km between re-waxing intervals- but with winter rapidly approaching, I'm wondering about replacing the existing 'open' chain guard with a Hebie Chainglider as I suspect this will increase the waxing interval periods- given that 500km rewax is less than 3 weeks of commuting- so a reasonably frequent event for me.
I currently have a 42-16 set up, with rear cog being original pre-splined style. I reversed the sprocket on purchase of my 2nd hand bike, and after around 5000km is still not too worn to warrant a change of chain/sprocket just yet. My intention though is to replace it with a splined carrier 15 tooth (already purchased) at the point the current chain/sprocket needs replacing- making the bike go from 42-16 (unsplined) to 42-15 splined. Most likely in 2021.
There are forum posts about how the Hebie's wouldn't fit on the splined sockets when these were introduced. But do the existing Hebie offerings work on the splined?
The Hebie page is confusing me. I am English mother tongue speaker, but also speak fluent German. And neither German instruction 'eingespritzt=squirted or injected' or English 'moulded-in on the backside' clarify if the 350R S15 would work on BOTH splined AND ALSO old style sprokets.
'350R S15 Rohloff Steckritzel | Splined sprocket Nur wenn 15T-17T auf der Rückseite eingespritzt ist, kann dieses Heckteil auch mit dem Rohloff Steckritzel verwendet werden! Only if 15T-17T is moulded-in on the backside you can use the rear part with the Rohloff splined sprocket.'
Anyone have any experience of using that Hebie rear end on both old style and splined sprockets? Or will I need to purchase different rear end for current set up, and later change it for splined compatible?
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Hi Steve,
An at-best-partial answer to your query about the Hebie 350R-S15 x 42 'glider:
First, I don't have experience with both splined and unsplined sprockets: My current sprocket, a 17T item, is the old unsplined variant, still has ~5 - 6,000 km of wear remaining after being flipped, and then will be replaced with a brand new version. I use a 350R-S15 x 38 'glider, which I bought in 2014. The raised lettering on the back side of the frontmost part of the rear section (!!) says that it can take a 15 - 18T rear sprocket. Maybe the current rear section (15-17T) is fractionally smaller on the vertical plane?
Second, on the matter of splined sprockets and their fit on a 'glider: The issue, as I recall it, was that the first iteration of the splined carrier moved the chain outwards far enough to upset Rohloff's 54 mm chainline. The "slimline" version came later, and that meant a much smaller change in the chainline, no more than a mm or so. The former would have meant problems in fitting a 'glider; the latter, much less so.
Reading Hebie's "Info" PDF and their "Assembly Instructions", I'd assume that they apply to both splined (slimline) and unsplined sprockets. BUT, it may be worth a phone call or an email.
Third, even with the old unsplined sprocket or the slimline splined carrier, you may have some clearance problems between the forward section of the of the rear part of the 'glider, and the chainstay on your bike:
Have attached below a photo of the close fit betw the rear section of my 'glider and the chainstay on my Raven. You'll see that I have trimmed off the outer "shoulder" of the bump-up on the frontmost part of the rear section. That plastic surgery gives about 5 mm of clearance between 'glider and chainstay. That in turn ensures that my 'glider keeps its proper amount of fore-and-aft and up-and-down slop. My Raven measures 440 mm between BB axle and rear axle -- if your bike has longer chainstays, its seat stays may be far enough back that shoulder surgery is not required.
A good-quality exacto knife or something similar will do the trick, if needed.
Hope that's helpful, and good luck.
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Thanks John- I realize you have answered that you are not familiar with the splined variant- but if the fitting problem on splined carriers can be resolved by adjusting the clearance with the aforementioned plastic surgery- be that with scalpel, craft knife or other suitable implement, that might be the solution.
Actually, your explanation regarding the raised lettering now makes the PDF instructions make more sense. I thought they were referring to the actual Rohloff and its native accessories. But they are referring to the plastic injection molding of their sprocket cover from the chain glider. I think the penny dropped now for me why the instructions didn't make sense, but now seem to make sense.
But what is with the part number. Your non-splined version is 15-18 but seems to have same parts description as 350R-S15 as the 15-17 description I took from the online assembly instructions. It would have made sense for Hebie to use a different part number to distinguish old style from from the other.
I'll hang on to see if anyone else can add the benefits of their experience. If someone has done what I plan to do, it is good to know.
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I don't have the splined Rohloff sprocket. No Chainglider surgery needed to clear the chainstay on the 3 Chainglider equipped Raven Tour frames I own, but only one may be (partially) relevant :
- my Raven Tour with Rohloff and old-style 16T screw-on sprocket. This is a 587S size. As I have spare screw-on sprockets, when the splined sprockets were introduced I bought a spare Rohloff-compatible Chainglider rear part for this bike in case the new style version for splined sprockets is incompatible.
The other two frames (Raven Tour 612S and Raven Tour Step Through 390 S-T) have Shimano hub gears, on which the sprocket is closer to the centreline and therefore further away from the chainstay.
The more recent Thorn Raven (without the "Tour") frames will probably be different, but as your bike is ten years old I expect it will be a Raven Tour.
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The more recent Thorn Raven (without the "Tour") frames will probably be different, but as your bike is ten years old I expect it will be a Raven Tour.
Alas, not a Thorn at all. I'm here for the English language Rohloff community as an British ex-pat . But I'm riding a German Winora Labrador on the 'wrong-side-of-the-road' in Berlin. It was the right bike at the right price at the right time- albeit, other than having a Rohloff hub, not my dream bike. I was (and still am) recovering from a DVT and stroke last spring and desperately needed to motivate myself back onto 2 wheels to help lose weight, recover lost fitness and reduce the risk of relapse- but didn't want to spoil myself too much on a brand new bike because a) I have 2 good derailleur bikes that had not been ridden regularly in past 10 years and b) I didn't want to dig into savings for a brand new bike at a time when my wife/kids might have needed our savings if things had not progressed so positively, partially due to me riding bikes every day again.
Until I started following this online community, I was not even aware of Thorn as a brand :-[ but actually saw my first one while visiting my sister in Bath parked up outside her local Tesco. Having since become somewhat more aware since following the forum, it has made me more aware of brand options for possible future Rohoff bike purchases. (Still also quite fancy my Dad's old but reliable, comfortable and well ridden Dawes Super Galaxy. Shame that doesn't have a Rohloff hub though.)
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With the chainstay design on the Winora Labrador you shouldn't have clearance problems with a Chainglider.
There remains the problem of whether the recent Rohloff rear part will fit both the new splined sprocket and the old screw-on sprocket.
As you intend fitting a splined sprocket eventually, maybe just get the Rohloff rear Chainglider part for a splined sprocket and then see if it will fit the screw-on sprocket as well?
I am fairly sure that the Rohloff rear Chainglider part for a screw-on sprocket is not recommended with a splined sprocket, so if the recent Rohloff rear part doesn't fit screw-on sprockets you will either need both, or you will have to wait and fit a Chainglider when the current sprocket wears out.
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Steve, on other-than-sprocket matters -- good luck in managing the after-effects of your DVT. I had two clots, one in each leg, in 2001 and 2009. I've been able to maintain my cycling, and even ice hockey, tho' I stopped the latter a few years ago to protect my knees. Happy to share my experience, incl meds and fitness regimes. Send me a PM if that might be helpful.
Cheers, J.
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As you intend fitting a splined sprocket eventually, maybe just get the Rohloff rear Chainglider part for a splined sprocket and then see if it will fit the screw-on sprocket as well?
I am fairly sure that the Rohloff rear Chainglider part for a screw-on sprocket is not recommended with a splined sprocket, so if the recent Rohloff rear part doesn't fit screw-on sprockets you will either need both, or you will have to wait and fit a Chainglider when the current sprocket wears out.
So I ordered the 15-17 tooth splined Hebie rear end and it fitted fine on the non-spined rear sprocket. I gave the 5200km old chain a thorough clean followed by a fresh swim in molten wax before fitting. Last waxing lasted almost 900km without Hebie and mostly dry days. Since fitting last week I’ve not been so lucky with the weather but the chainglider is catching the crud the chain used to catch, so hoping this Hebie will extend time between chain lubrications.
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So I ordered the 15-17 tooth splined Hebie rear end and it fitted fine on the non-spined rear sprocket.
Thanks for the feedback.
For those of us who have a stock of them, useful to know the current Chainglider rear end will fit the old-style screw-on sprockets.
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Anybody tried fitting one to a fixed wheel machine? Could be beneficial upgrade for my wet and occasionally muddy winter commuting routes.
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Anybody tried fitting one to a fixed wheel machine?
Nooo, Brummie...but I recently finished making a chainguard for my own Fixie using my kitchen oven set to low heat, a plywood form, and a sheet of 2.3mm/0.09in smoked polycarbonate. A nice project during Covid downtime. It covers the chain run from just ahead of the sprocket all the way 'round to about 4 o'clock on the chainring. I'm nearly done getting it dialed in, but so far it appears it will work well for keeping the bulk of the rainwater off the top run of the chain and also the front of the chainring. I have a long mudflap on my front mudguard so there's almost no road spray that gets kicked onto the chain from below. I drilled a couple holes in the top which I covered with rubber plugs, the intention being to provide oiling from above without the need for removal.
I would have liked to have had it cover the sprocket also but that wasn't possible, given the chain is tensioned by moving the rear hub fore-aft in the ramped rear dropouts.
I shamelessly copied a BMX chainguard that was way too short for my needs and I remodeled a glass-filled nylon reflector bracket for the front mount and made a rear mount that ties into my Danneauxmade mudguard stay dropout adapter (the frame is from a 1970 road racing bike that had no dropout eyelets so I had to become creative, machining my own from aluminum billet and stainless steel). The 'guard mount so it is solid, safe and silent. I left extra clearance above the chain in case I ever want to fit larger chainring/sprocket sizes. I'm pleased with my present 38x16 combo for 64 gear-inches (I can hit 50kmh briefly with my hummingbird cadence), but I might want to go larger someday to reduce wear and I have the clearance to do so.
I was not prepared for the amount of finish work that would be required; the inside of the 'guard picked up every flaw in the plywood buck and required a lot of polishing to get to this point. Next time, I will use more care in preparing my mold. I'm glad I wore some undersized nitrile gloves to guide the heat-softened plastic over the mold, especially at the front. My first attempt with some samples showed the plastic also picks up fingerprints and those are permanent when cooled. I initially wanted to use clear plastic but wisely reconsidered when I factored in the molding flaws and oil spray/dirt and dust that could collect over time. The smoke color hides a lot of flaws.
Unfortunately, I think a Chaingliderlike floating case is beyond my capabilities. The key to their success is materials choice and a good, tight fit that is adjustable for application -- and a patent! Success on the Fixie project has me eyeing the Nomad for a Danneauxguard 2.0.
Best,
Dan.
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Anybody tried fitting one to a fixed wheel machine? Could be beneficial upgrade for my wet and occasionally muddy winter commuting routes.
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No, but I don't see why it shouldn't work, so long as the chainring/sprocket sizes are compatible, there are only a few options.
Hebie also specify maximum chainring, chain and sprocket widths but I have gotten away with using thick 1/8" chain, chainring and sprocket on two of my bikes with no noticeable drawbacks other than a rubbing noise for the first few hundred kms or so as the Chainglider wore slightly around the chainring. In my case, any extra drag caused by this rubbing was not detectable.
BUT - I think someone had excessive drag when using a thicker than recommended chainring, maybe his experience was due to a different chainring finish ? Mine are polished TA chainrings for 1/8" chain.
A good choice for a chainring for use in a Chainglider is the range of stainless-steel rings marketed by Surly. These are generally thinner than aluminium alloy rings and are supposed to last longer. They are also reversible, so they can be flipped to get even more use.
I would have liked to have had it cover the sprocket also but that wasn't possible, given the chain is tensioned by moving the rear hub fore-aft in the ramped rear dropouts.
This shouldn't be a problem with the Hebie Chainglider, as there are ridges to adjust the length. On my Thorn bikes, the chain is tensioned by moving the bottom bracket in the eccentric, which, as far as the Chainglider is concerned, comes to the same thing as moving the hub.
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This shouldn't be a problem with the Hebie Chainglider, as there are ridges to adjust the length.
Nice to know, Martin; thanks!
OTOH, it would be hard to beat the USD$10 invested in my homemade half-version. ;) ;D
All the best,
Dan.
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OTOH, it would be hard to beat the USD$10 invested in my homemade half-version. ;) ;D
As usual, a professionnal-looking project. It should protect the chain from the most important contribution of dirt.
Just after fitting my first Chainglider in 2012 I did a test ride in wet sand dunes to see what effect it had.
This test showed that the biggest contribution to dirt on the chain was just behind the chainring, where the tyre deposited stuff on the top run of the chain.
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Of course, this is only true if a ground-hugging front mudflap is also used.
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Anybody tried fitting one to a fixed wheel machine?
Nooo, Brummie...but I recently finished making a chainguard for my own Fixie using my kitchen oven set to low heat, a plywood form, and a sheet of 2.3mm/0.09in smoked polycarbonate. A nice project during Covid downtime. It covers the chain run from just ahead of the sprocket all the way 'round to about 4 o'clock on the chainring. I'm nearly done getting it dialed in, but so far it appears it will work well for keeping the bulk of the rainwater off the top run of the chain and also the front of the chainring. I have a long mudflap on my front mudguard so there's almost no road spray that gets kicked onto the chain from below. I drilled a couple holes in the top which I covered with rubber plugs, the intention being to provide oiling from above without the need for removal.
I have been considering doing something like this for our tandem timing chain (first) and then rear chain. I don't have a template, but will cut the wood to measurements. However, I was not sure which plastic to use, but thanks to you I now know. May I bug you with a few questions...
What plywood thickness, 3/4 in?
Did you cut the wood to match the BMX form and then cut the plastic leaving an extra border width of about 3 inch (or ?) to then bend over the plywood edge when hot?
Why did you decide to stop a 4 o'clock, rather than 6, perhaps concern about warping of plastic around chainring line?
What is the nominal distance between the chain and the inner guard surface (top and side clearance)?
Thanks again for any information, I now have a winter project! (Will open windows when heating plastic.)
Mike
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Of course, this is only true if a ground-hugging front mudflap is also used.
Home made?
Instructions please.
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Home made?
Instructions please.
Mudflap cut from an opaque white 5 litre plastique container as used for white spirit and other liquids. I use these on all my bikes, generally on both the front and rear mudguards. The one on the rear mudguard is "just" visible in the photo, on that I add two red reflective stripes to enhance visibility from the rear.
I generally prefer white, but on my touring Raven Tour I used black to match the frame, probably from a container that had held motor oil.
I curve the mudflap into the mudguard and fix it with either pop rivets or bolts, in both cases with flat washers to spread the load and avoid crushing the plastic too much.
The curve stiffens the mudflap, so that it stays in position and doesn't get deflected by strong winds. But the plastic is still flexible enough to bend if I pick up a twig or touch a rock.
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Thanks Martin, and Dan for your contributions. Food for thought.
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You guys know of course that the makers of the popular (or at least the best) Pxx mudguards sell aerodynamic deflectors for both the front and the back -- or top and bottom -- of their mudguards. These are small guides for air and water rather than mudflaps but they do a very good job on my P65 mudguards over 60mm Big Apples, so that I'm not joking when I say that twice a year I wipe some light dust off my Chainglider. It's been years since my shoes or trousers bottoms have gotten wet on my bike.
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Thanks, Martin, for the kind words and the time and trouble you took to illustrate the throw from spray and where it lands. Very helpful and much appreciated. That red bike is stunning with its matching bags.
And now some details for Mike; if too long for others, just skip...
Making this chainguard was something I've had in mind for some time and so I put a lot of advance planning into it. I think by sharing I can save you some time, so I'll do it in a tabular fashion:
1) When I said "I shamelessly copied a BMX chainguard that was way too short for my needs" I was referring to a broken one I recovered from a trash skip and used for inspiration. By looking closely at it, I was able avoid some initial pitfalls and I was also able to test-fit what was left of it to check basic clearances. It was too short for my chainstays and designed for a 34t chainring, so I needed to scale it up to fit my 38t 'ring and allow clearance for something larger in the future.
2) I made my "buck" (plywood form) from 3/4in labeled plywood that actually measured 11/16in thick. Make the plywood mold as smooth as possible to save yourself polishing later. The outside will take care of itself, but the inside will pick up every little imperfection in the wood mold and those flaws will set in the hardened plastic.
The polycarbonate I used was 2.3mm/0.09in, so pretty thin but sturdy enough, especially when "folded" over the mold (the 3-D shape helps stiffness). I sourced my plastic locally, but this link will give you a general idea as to thicknesses and availability: https://www.acmeplastics.com/cut-to-size-clear-polycarbonate-sheet
I initially set my oven to 175°F and kept the door closed until it was thoroughly warm, then opened it and placed the buck on the rack set on the lowest bracket until it began to soften and then adjusted the temperature. I really have no idea what the final temperature was because I kept opening the door and moving the plywood and plastic so it would form properly. I used leather gloves to handle the plywood buck and later, undersized nitrile gloves (no wrinkles) to do the final shaping outside the oven with the aid of my heat gun and a spackling spatula with a metal blade. If you do a longer chainguard, oven size might be a limitation.
3) I first drew what I wanted in profile using heavy cardstock and then trimmed it until I achieved the desired shape and transferred that to the plywood later. This pattern let me check clearances as well as serving as a final pattern to cut away the excess plastic -- and there was a lot of excess. It is necessary in order to achieve a good "drape" of the softened plastic over the plywood form. The final chainguard is about 1/3 of the total plastic I shaped over the mold. My initial pattern was a large rectangle of plastic from which I later carved a chainguard using my cardstock pattern as a template. I drilled some small holes so I could secure the rectangle of plastic sheet to the edge of the plywood mold; this kept it from shifting while the sides softened and draped; the nail holes became my oiling ports. A Dremel with a fresh/sharp spiral cutting bit set to medium speed (to prevent melting) did a nice job on the trimming. I polished the cut edge after as I did the whole chainguard. I used Blue Magic polish on a cotton buffing wheel set to low speed to avoid melting the plastic.
4) While it is easy to warp/wrap the softened plastic over the vertical top edge of the plywood mold, it is much more difficult to make the front wraparound for the chainring and this is why I stopped at 4 o'clock instead of 6 o'clock. The greater the curvature, the greater the distortion as you are working with three sides there. The plastic wants to wrinkle where it goes around the bend and more wrap can makes it worse. I used a dual-range heat gun to ease the plastic around and this helped a lot; a spackling spatula with a metal blade helps smooth/press/shape any distorting plastic against the plywood buck.
I too have a tandem and was mightily tempted to also make my first project a timing chain cover. I may yet, but there would need to be chainring curves at each end and a simple chainguard seemed the best first project. Also, making mounts would be more challenging and the longer distance could make it a challenge to fit in the oven unless it was made in two pieces. My tandem has a front eccentric to tension the timing chain so that would need to be taken into account as well.
5) I'm running a 1/8in chain on my Fixie, so it is 1/32in wider than the usual derailleur chain. I would say I have about ~5mm or roughly 3/16in between the chain pins and the inner side of the chainguard. Remember, the chainguard will never be narrower than your plywood buck, so it is best to choose the needed thickness when you make your mold. You will need to check the clearance between the crankset spider/chainring and the back side of the crankarm so you can avoid rubbing the chainguard as you pedal.
6) The mounts must be solid to impart rigidity as the chainguard which won't sag but can twist. As noted, I tied the steel rear mount into my dropout mudguard stay adapter so it is rigid but the front mount took more care. I used a glass-filled nylon reflector mount and used a Dremel to mill a small slot into it, sized to accept an M5 nut and drilled a lateral 5mm hole to accept a screw. I left a little flange on the inside of the chainguard and tapped it to M5x0.8 to accept an allenhead machine screw started from the inside. I used kneaded beeswax on the screw threads to hold the nut in position until it could be clamped in the bracket; in this way, I could adjust the offset and center the chainguard over the chainring simply by adjusting how far the captive nut screwed onto the screw. Mine was spot-on because I calculated the offset needed when I modified the bracket but thin washers could be used as spacers easily enough.
7) Yes, open the windows during the operation. I also wore my brazing mask fitted with charcoal cannister filters so I didn't smell the plastic until I removed it.
8 ) I sourced my plastic locally, but this link will give you a general idea as to thicknesses and availability:
https://www.acmeplastics.com/cut-to-size-clear-polycarbonate-sheet
9) As for mudflaps, I prefer the pre-made BuddyFlaps in "Regular" size from Portland, Oregon. They are a really nice size and I often use the longer "rear" flap on the front so the spray zone is kept well below the chain. They are cut from thick virgin vinyl and have enough mass to avoid being blown back at speed. See: https://buddyflaps.com/
I hope this answers your questions, Mike.
Best,
Dan.
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A very impressive job, Dan. It seems to me that your material is sturdy enough, and the rear mounting far enough back so that you could curl the chain guard round to 8 o'clock on the sprocket without problems. So what if the sprocket isn't centred in the imaginary circle of the the chain guard after you adjust for chain wear? However, I can easily see that the extra modelling, moulding, manufacturing and fettling work for this small extension of what you've done already will consume as much as, or even a multiple of, the time for all the rest to that point. The basic cheapness of working with mouldable plastics only works if you either don't count your own labour or will make tens or hundreds of thousands of units.
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A very impressive job, Dan. It seems to me that your material is sturdy enough, and the rear mounting far enough back so that you could curl the chain guard round to 8 o'clock on the sprocket without problems.
Thank you, Andre. The biggest problem I ran into trying to curl the chainguard further was the distortion it caused in the plastic. The 'guard has three sides at the front and it is a challenge to get it to wrap more without wrinkles. So what if the sprocket isn't centered in the imaginary circle of the the chain guard after you adjust for chain wear?
It is pretty well centered up front as I have no eccentric but would be a much bigger challenge on my Nomad. However, I left the rear open to allow for adjustment as I couldn't do like Hebie and fit an adjustable tailpiece. That is beyond my skillset and tools at present. ;) I can easily see that the extra modelling, moulding, manufacturing and fettling work for this small extension of what you've done already will consume as much as, or even a multiple of, the time for all the rest to that point. The basic cheapness of working with mouldable plastics only works if you either don't count your own labour or will make tens or hundreds of thousands of units.
Oh, yes! :D Due to the time and effort invested, I'll never get rich making them! However, it was a fun project during some downtime. ;)
All the best,
Dan.
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Dan,
Thanks much for your detailed reply. The part you folded over the wood was initially approximately 4 inch? 3/4 inch (wood thickness) + 3 inches, and then you trimmed the folded over piece. The extra length was for leverage in the bending process while hot?
Also, is it possible you plasticized the inside of your oven from the fumes? The stoker would have some very pointed, choice words if I damaged our oven. Is it conceivable to do all with only a heat gun?
There is something very satisfying in the construction of homemade stuff that becomes an essential part of the bike. To share, the picture shows a center bag for our bike that we designed and sewed.
Mike
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Hi Mike!
The part you folded over the wood was initially approximately 4 inch? 3/4 inch (wood thickness) + 3 inches, and then you trimmed the folded over piece.
I used 8 inches because... The extra length was for leverage in the bending process while hot?
Exactly! I would suggest you be generous with the overage as it makes the job easier and any embossed finger and spatula marks will be cut off, leaving a "clean" final product. The raw dimensions will depend on your final product. Side + side + top + overage at the wraparound front, side + top + overage at the rear. Also, is it possible you plasticized the inside of your oven from the fumes?
Possible but if so, I haven't noticed. Food baked in it still tastes and smells like food and not plastic. ;D There is no remaining odor; that cleared out immediately unlike some of my past paint-curing efforts. Remember, the idea is only to warm the plastic until it is ductile for forming, not to melt it or catch it on fire as it drips onto the lower element. Those two outcomes would be Very Bad Indeed for oven and plastic-bending stoker captain alike. :o There weren't many fumes apparent when I removed my mask. I believe it is possible to do this with only a heat gun but it will be a greater challenge to heat it evenly without getting thin spots or surface bubbling. Long sweeps with the heat gun blast would probably aid the effort. If you bend too quickly before the plastic is soft enough you will see stress marks form on the apex of the curves. There is a sort of natural flow to it you will see in practice. I suggest starting with some scraps first to get a feel for it. Remember, the plastic I chose is only 2.3mm thick so it will heat pretty fast. You'll need to combine general and localized heat in forming it 'round your plywood especially at the front. I keep a fire extinguisher and a bucket of cold water (stops melting) handy for such projects but have never needed them. There is something very satisfying in the construction of homemade stuff that becomes an essential part of the bike.
Indeed! 'Most of the reason I did this. I make a lot of other things for my bikes. To share, the picture shows a center bag for our bike that we designed and sewed.
Well done, Mike and stoker! The bag looks great and so does your tandem. Mounting a chainguard for your drive-side timing chain will be a challenge with the S&S coupled keel tube. Packing might be problematic with a timing-chain guard installed but I feel sure you can come up with a good solution. :)
Best,
Dan.
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Thanks,
I am also considering the hebie chainbar in picture as a base which provides a mount to the bike, and then forming/adding polycarbonate to further enclose the chain.
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I am also considering the hebie chainbar in picture as a base...
I think that's a good approach, Mike. :)
Best,
Dan.
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Hi All!
It has been a little over two years since I reported on my Fixie's homemade, partial chain guard, See...
http://thorncyclesforum.co.uk/index.php?topic=13951.msg103765#msg103765
...and...
http://thorncyclesforum.co.uk/index.php?topic=13951.msg103775#msg103775
I have been using the bike heavily in winter rains this year and the roads are periodically gritted to help with traction when temps fall below freezing.
My chainguard is proving the worth and value of keeping a chain even partly covered. As you can see, despite the bike being absolutely covered in road smut, the chain remains remarkably clean. The bike is often parked in the rain as well, and I find I my lubricant lasts much longer because it doesn't get washed off as quickly.
Two key takeaways: It really paid to wrap the 'guard around the front of the chainring for protection while underway and to combine it with a generously long mudflap on the front mudguard. Nice to find even the open lower run of chain remains cleaner as a result.
I would fit a Hebie Chainglider to my Nomad in a heartbeat if I could get one to fit my drivetrain combo.
Best, Dan.
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...Couple more pics...description in the titles.
Best, Dan.
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Looks like your home-made chainguard/low front mudflap do the majority of the job done by a Chainglider.
I reckon that you might be able to fit a similar chainguard to your Nomad - if you can work out a way of fitting the front part in the same relative position to the chainring you could fit an adjustable mount at the rear, perhaps just make a long slot in the plastic to mount the rear part.
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I am still happy with the Chainglider, I now have them on all but one of the "normal" bikes in the family.
Just overhauled my Thorn Raven Tour utility bike, taking out the eccentric, seatpost, forks, etc. I hadn't lubricated the chain in the 2,400 kms since I put it on the bike, it has been running on the original factory lubricant.
The chain had a small amount of surface grime and looked a bit dry, so I took it off, cleaned it (toothbrush and paraffin bath, rinse in clean paraffin) and relubricated it (hung up from the roof of the garage and "Oil of Rohloff" dripped on the top, process repeated until the oil comes off clean at the bottom. This flushes out at least some (if not most) of the grime and wear particles hidden inside the chain).
There was no measurable chain wear. Before using Chaingliders I would have expected at least 0.075 mm wear on my Rohloff chain gauge for a similar distance.
So instead of permuting chains to even out sprocket/chainring wear like I used to do, I put the same one back on.
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Another Chainglider tidbit : a while back I decided to put a Chainglider on my Raven Sport Tour. This currently has a 42T chainring and 19T sprocket, so I used the "standard" rear Chainglider part instead of the Rohloff-specific one.
Due to the large sprocket, there are no problems with the Chainglider rubbing on the hub shell, which was reported as a possible issue with smaller sprockets.
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I'm in my second winter of using an open Chainglider (because the Spa Cycles Elan frame needs a chain tensioner for the Rohloff hub). I think I commented elsewhere after the first winter that I reckon the open Chainglider is about 80% as effective in much protection as a full Chainglider (ie a similar conclusion to @Dannaux) and have also put an extra mudflap on the front mudguard (only slight increase in length but extra width). I don't expect to clean the chain during the winter but add a bit of wet lube if the chain starts to look dry. I'm using a KMC Z1 narrow chain which are remarkably cheap so it's less effort to replace the chain than to give it a thorough clean.
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Looks like your home-made chainguard/low front mudflap do the majority of the job done by a Chainglider.
With some delight...I think so, Martin! :) I was hopeful from the start but the evidence of its protection has exceeded all expectations.
I reckon that you might be able to fit a similar chainguard to your Nomad - if you can work out a way of fitting the front part in the same relative position to the chainring you could fit an adjustable mount at the rear, perhaps just make a long slot in the plastic to mount the rear part.
I agree, Martin, and it would surely be nice. Making these things is almost a labor of love because the process is so labor-intensive. Still, it does give a result in the end and it is "better" with than without, so I will think strongly about this as a summertime project.
I think in the Nomad's case with vertical rear dropouts and the front eccentric, I might try anchoring the rear solidly on a single bolt to allow it to pivot vertically and then slotting the front on its clamp so the clamp can move up and down the downtube as the 'guard is raised and lowered, all to accommodate the range of the eccentric. This might mean a somewhat awkward looking fit at the front, but so long as the 'guard provides similar coverage to the one on my Fixie, then I think I'd be okay. Hmm. This has started the creative juices flowing. I'm guessing I will have at least a paper pattern in the works well before Spring! ;) ;D
So pleased to hear your Chaingliders are still working well. As soon as it is possible for me, I will fit one as well.
Best, Dan.
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I'm happy to hear you men ride clean bikes -- presumably the ladies are so used to having clean bikes, they don't brag about it.
I'm perfectly happy with the Chainglider, and if I somehow broke mine, I'd fit another one. I don't think I'll wear it out; the one now on my bike has travelled north of 6K and doesn't show any signs of wear, and I'm keener after the Chinese virus to reacquaint myself with well-loved lanes than reaching for far horizons, so new dangers would be unlikely and extraordinary.
However, rereading this thread, a couple of ideas do occur to me:
A. A MACHINED PLASTIC GUARD
A common way for DIY makers of fountain pen barrels and colourful, distinguishing tool handles is to have their wives collect plastic bottles and containers, to melt them down in a rectangular cake pan, then give the resulting goo a small stir until it looks like marbled paper, and leave it to set. This recycled plastic is superb to saw, carve, lathe, mill, glue, paint, and wears remarkably well for a material so easy to machine. I haven't done the melting part myself, though I'm into fountain pens, because my skills on my toy lathe (of a size to make watch movements) aren't good enough to entrust expensive or irreplaceable pen components to, though I've made a couple of handles for doll's house size lathe tools. I just commission the parts I want from people who make them routinely. I think a long enough piece of this stuff could be machined out so that it is solid and, if supported in the middle, stiff enough even for a tandem. Maybe it won't in the most workable state last as long as a Chainglider, which I think has carbon fibre or hard rubber in it, but you could sacrifice some of the workability by putting a cotton cloth over a former and pouring the molten plastic across it, and then machine the outside, which will be easier to finish to an acceptable standard than Dan's hard work with the spatula and gloved hands on hot plastic. (! See below about a similar but less dangerous problem in cold molding wood !) This cloth plus plastic (or resin) material is called mikarta when it is made into knife handles for Real Men <TM>. Did I say cheap yet? Actually a saving, as you don't have to pay to have the surplus plastic packaging removed.
B. MOULDED WOOD, AN OVERLOOKED LIGHTWEIGHT STRUCTURAL MATERIAL
Back in the 1960s, after wrecking several transocean glassfibre yachts worth in today's money more millions than I'll ever see again, alas, it was suggested to me by an old racer, who wanted me to keep competing against him, that I build a yacht from wood ''if you don't want to drown." He was also in a position to give me as much superior quality naval wood of any type I could desire entirely free of charge, treated any way I wanted it, and expert advice with it. After speaking to several naval architects who'd already tried their level best to drown me, who anyway had the same initial reaction as I had, What the devil is this old chappie on about? but, unlike me, weren't willing to move on from reliance on the unproven material GRP (FRP for the Americans), I designed the yacht myself out of Hereshoff's book, and built it by parking a container load of beer (at the time my ad agency had lent me to a brewery) in the shed and telling my mates my shipbuilding experience was happy hour; you don't build a 68ft transocean racer and circumnavigator by your lonesome in any reasonable time, and mine had be built, outfitted and shaken down for a race at a fixed time only 11 months away. The hull itself was built over a mound of earth with the only solid wood in the entire thing on top (to mount the keel, the auxiliary engine and gennie, and to anchor the mast), covered diagonally with two layers of sacrificial laths of wood, and then we cold-molded overlapping 6in squares of wood veneer over the laths, tacking them down with electric window dressers' staplers using copper staples because, while we would later nip off the staples on the inside, with a tool I designed to nip and form the predetermined excess into a rivet head, the rest of the staple would be between layers and unreachable. When the underpart of the hull was finished, we turned the whole thing over with the aid of a helicopter, dropped it in a hole in the earth to brace it, and proceeded in the same way to make the deck integral with the lower shell. After that a couple of engineering chums from HP used FEA to calculate that even the biggest sea wouldn't ever flex it. Bulkheads for attaching stuff to rather than for strength were made the same way, all temporary support structures (some of it nothing more than foam) was pulled out and thrown away (and, trivia, the voids had to be filled with foam again when the ship was repurposed after its racing career as a luxury sunshine cruiser because the slightest slap of water on the hull was magnified into a tsunami in the voids, which was what much later made me think I could be a loudspeaker designer...). Because I'm a belt and braces man, and had already learned that the survivors in that sort of racing took care of every detail, we gave all parts of the hull regularly in contact with anything a couple of extra stepped layers on the inside, ditto all angles that would be under stress. Several engineers on the team thought I was crazy to add weight to a racing craft already so strong. The proof is in the pudding. The ship survived racing several times across the Southern Ocean, a rough sea at any season, multiple passages around Cape Horn, life at my floating dock in the rough sea where the Indian and Atlantic meet at Cape Agulhas, some notorious Indian Ocean monsoons, a decade or so as a luxurious rental in amateur hands, and is still providing solid security under junk rig for a family trading from Indonesia up into the South China Sea, not a place where you want to send amateurs in flimsy ships. I became a lifelong convert to the advantages of moulded wood. Or, if you guys want a British example, look up the wooden chasses under Jem Marsh and Frank Costin's early Marcos cars, of which many are still delighting drivers after 60 years or so. A chain guard (and how about mudguards to match?) would be a doddle in layers of wood veneer. In fact, an entire bike in layered wood veneer would need to be pretty incompetently designed and constructed to weigh more than a steel framed bike, and could easily be made both stronger and lighter than steel. The problem is of course that such intensive labour costs plenty. So about now, someone says, Yes, but what about compound curves?, and the answer is that you just work in smaller and smaller squares of veneer, diagonally overlaid, with vents cut into the veneer as if you're working with cloth; working diagonally across the curvature is in effect its own curve-fitting procedure. I regret to inform you that for cold molding you need to wear gloves or you'll lose the skin on your hands, which can be pretty painful.
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Darn you, Andre Jute! Now I have to try these methods in making future chainguards! ;) :D ;D
Might be a doddle compared to hot polycarbonate.
Mine is suspended above rather than floating on the chain so very forgiving of materials as no friction or contact involved. No glass-filled nylon required. So long as it was resistant to shock and vibration, I think other materials as you suggest could work well for the next DIY attempt.
Best, Dan.