Thorn Cycles Forum
Technical => General Technical => Topic started by: kingoftheworld on October 18, 2022, 11:54:03 am
-
Dear fellow cyclists,
I am the very, very, proud owner of a 2009 Thorn EXP (Thanks AndyB).
Attached is my spec.
This year I cycled the Southern trail USA & noticed for the first time that the "Old Girl" was starting to struggle a little , two front spokes broke and more worrying I got a slight chain rub onto my steel frame (see pic) that I solved by adding a washer between the cassette & back fork (any idea why I've lost the gap? ) and my eccentric bracket has seen better days, I am also worried about my carbide rims, I don't really know if they are worn or not. Next year I am planning to cycle across Australia, so it would be really important to have the bike in tip top condition. I live in Austria (not Australia) which makes things difficult to send to Thorn for repair (Brexit etc) I could buy all the spares and get a local good dealer here to work on the bike, but I am open to discussion if it should all be done by Thorn.
Appreciate any support on this topic.
Thanks
Simon
Keep On Cycling.
-
Welcome back, nice of you to pop in between mega tours to make some of us jealous!
Carbide rim wear - I put a straight edge across the rim with a light source behind, so far there's only a paper thickness gap in the middle. If there's room you could move the brake blocks down if they're not already right on the edge. If/when there's considerably more wear than paper thickness, I'll borrow or buy the tool to measure. It's also worth removing the rim tape and having a look at the eyelets. I was thinking of selling a derailleur CSS wheel, but was surprised to find some of the eyelets rotting away.
Front wheel spokes - Have you an idea why they broke? It could just be fatigue, though I wouldn't expect that in the distance, if it is, it's likely to effect others. I don't know the answer, the disturbance from rebuilding with new spokes might do more harm than good. I'd either get a new wheel and keep that one for trips closer to home, or take a few spare spokes.
Chain rub - I'd check chain line at the BB. Could it be possible that the EBB or BB are not sitting square in the frame? If not that, I'd check the frame for trueness, it's steel, they do get bent, it doesn't take much and it's no big deal getting them bent back! Plenty of online guidance on how to do this yourself, bits of string, set squares, measuring and re-measuring... If you have a framebuilder or decent shop with a jig locally, save yourself the effort and get them to do in 10 min what it might take you all day (It does me!) If you get that done and it needs straightening, I'd recommend NOT watching, it's brutal, trust they know what they're doing.
Is there an issue with the EBB? I'm not sure what style it is on your bike.
That's it, good clean and lube, maybe remove, check and refit the bolt on bits, racks, bottle cages, etc. At 25,000 km I might be tempted to replace BB and headset bearings as a precautionary measure before a long tour, but if they're smooth and clean I wouldn't say it was required.
In my opinion there's nothing in what you describe that I would consider required sending back to Thorn for.
-
Hi PH,
Thanks for your quick reply and clear info on what needs to be serviced/checked.
I think the spokes broke as I was carrying too much weight on the front of the bike, otherwise no idea why they would break, luckily I was carrying spares.
Great tip on how to check the rims. The BB is sitting square I've checked it, I tend to feel that the frame has suffered a little, I'll ask at the dealers for them to check all that.
Regarding the eccentric bracket, I do have to check the two screws on a regular basis as they become loose, otherwise it seems ok.
Thanks once more PH :)
Cheers
Keep on Cycling
Simon
-
It might also be worthwhile pre-emptively replacing the Rohloff gear control cables/housings if you are still on the originals after 25,000 km, including the cable inside the internal gear change mechanism if you have that type. Setting up the Rohloff cables is a bit fiddly, and I would prefer not to have to do it on tour.
Personally, as well as PH's suggestion for checking brake track wear I would check the rims (front and rear) for cracks around the eyelets, which can occur on the carbide rims as well as on standard aluminium alloy rims.
And I would either rebuild the front wheel with all new spokes if the rim and hub are OK, or buy a new wheel (probably not carbide, as these do not seem to be manufactured any more).
I generally check all wheels that I haven't built myself, usually the spokes are not tensioned enough, which is a cause of spoke breakages later on.
The 3 wheels I bought from SJS cycles are an exception (two that came on my first Raven Tour and a Rohloff wheel for my Raven Sport Tour frame), I didn't need to do any tweaking on these.
-
I have no clue why you would have chain rubbing on the frame. If you have not touched up the paint on the frame, I would do that first. I use fingernail polish for that sort of thing, the brush being built into the cap makes it very convenient.
I agree with previous comments on the rims, my only additional comment would be to keep using them as long as you can, I have virtually no wear on my CSS rims and am very happy with them.
Front wheel spokes, it is very rare for a front wheel to break spokes, rear is much more common. And to break two, that suggests that the third and fourth broken spokes are coming soon. I do not know if you have a dynohub you want to keep or not, but I would suggest retaining your existing CSS rim, have a wheel builder replace the spokes.
If your front hub is a non-dynohub from Shimano, they were often skimpy on grease, would not be a bad idea to open it up and add grease.
You did not say where the spokes failed, if I recall correctly several years ago there were some bad Sapim spokes that failed by breaking in the middle and not on an end, if yours broke in the middle, I would most certainly replace them.
If you do not have a dynohub, but if you might want one some day, now would be the time to add it if you replace the front spokes. Dynohubs do not come with a skewer, retain your old one.
If you replace your front spokes, I would just buy a couple spare spokes and discard your old spare front ones.
If your next trip will put you far away from bike shops, after over a decade of use you should make sure that the bearings in your bottom bracket, pedals and headset feel as good as new, if unsure replace.
If you have Shimano pedals, a lot of their pedals can be disassembled with the TL-PD40 tool. If you have pedals that use that tool, as a preventative measure I would remove the spindle from teh pedal body and add some grease. But do a thorough cleaning first. The tool is very affordable, there are several good youtube videos that explain how to use it. I have found it very simple to remove the bearings, add grease and close it up again. I had two pairs of pedals that developed a clicking sound, but all they needed was additional grease.
https://www.youtube.com/watch?v=bVmSrsnVUGI
Side note: Park Tools have excellent youtube videos if you find you suddenly need to figure out how to fix something.
I do not know if your eccentric uses the same screws as my Nomad Mk II to keep the eccentric in place. If it does, I found it useful to put a couple of rubber bands between the two screws, that way they can't come lose and unthread from vibration. See photo. The rubber bands were cut from inner tube rubber, that seems to last longer than normal rubber bands. But I still carry a spare screw on tours, it is a very odd size and would be hard to replace.
-
Good morning fellow Thorn cyclists :)
Oooh brilliant info guys, I owe you all a round of drinks :)
Mick, very interesting point regarding the spokes, I had a Schmidt dynamo rebuild done about 5 years ago, the front spokes actually have been snapping in the middle (2 so far) and 100% agree, I need to change all the front spokes (the back wheel are the one's from Thorn 12 years ago fitted with Rohlhoff that have not broken (yet).
Let me re-cap on the maintenance steps based on all your feedback so far, feel free to throw in any comments.
1) Check carbide rims
2) Check eyelets for rust etc
3) Replace front spokes (dynohub) maybe also back ( Rohlhof)
a) Order extra spares
4) Either buy new wheels (if not carbide then what? ) or rebuild old wheels replacing spokes .Dynamo and rohloff will need to be re-fitted.
5) Get the frame checked for trueness
6) Check and refit, grease bolts (imperial or metric)
7) Replace Rohlhoff gear grip with new standard, cables,housings already replaced, 3x.
8) Buy fingernail polish, black, (for touching up the frame)
9)Replace bearings
a)Bottom bracket
b)Pedals (TL-PD40 tool)
c)Headset
10) Rubber bands ( to fix the eccentric screws)
11) Maybe order a couple of screws from SJS as back up
Regarding point 6, I seem to feel that 1/4 " threads, screws have beed used, any ideas if this is correct ? If so that will mean I'll just grease and lube all the screws although some could really do with replacing.
Once again, thanks for the feedback
Keep on Cycling
Simon
-
6 - Screws, most would be M5 or maybe a few are M6. I would be surprised if any are not metric.
I use blue removable threadlocker on some of my screws and bolts. One brand is Loctite, there are other brands. I am in USA so I probably see different brands than you. This is what I bought last time I bought any:
https://www.truevalue.com/6-ml-removable-blue-thread-locker-1
I use threadlocker on all my rack bolts, fender bolts, kickstand bolts (if fitted). I assume you have canti or V brakes, the bolts that hold the brakes into the frame mounts usually had blue threadlocker on the bolts before they were installed.
I use grease on water bottle cage bolts, the eccentric bolts (the ones you mentioned), seatpost bolt, stem bolts, brake lever bolts, threads on pedal spindles, and just about any other screws and bolts that I can think of.
Speaking of grease, I assume you know that a seatpost should be greased, that reduces the amount of rainwater that can get into the frame on a rainy day. And if the seatpost is not painted, the grease can reduce the chance of dissimilar metal corrosion.
Where I have nuts fitted, if practical I use nylock nuts.
But that is me, everybody does things a bit different.
I mentioned that I carry a spare eccentric bolt on tour, I also carry spare spokes, nipples, cables, nuts and bolts, spare Rohloff drain screw, etc. That is in additon to the standard inner tubes and patches. My spare Rohloff cable is pre-cut to length, I have a Nomad Mk II with EX box, thus do not have an internal gear cable.
If your seatpost bolt breaks (extremely rare, but if it happens, most inconvenient), if your stem cap bolt will not fit as a substitute, then a spare one of those too. I have cut a slot in the threaded end of mine so that if it broke I could use a tiny screwdriver to remove the stub that remains threaded into the frame.
I am not sure which version Rohloff you have, you might have a need for a T 20 wrench on a tour, that is not included on most multi-tools. Some of my B&M lights also use that wrench.
-
No mention of changing the rohloff oil, perhaps people assume you have done this on a regular basis? Regarding repacking the pedal bearings, it is good to have some ball bearings (3/32 I believe) on hand. Count them before removing (12 typically?), the little buggers love to scurry about on the floor to places unknown. My test for cleaning is to remove pedals and turn the shaft with my fingers to feel for grime, same with BB but removing cranks. All other suggestions really good as is always the case on this site.
-
Hi Hendrich,
Thanks for the feedback. Yes, I do change the Rohlhoff oil regularly, every 5.000km, honestly, if I leave it and try to go over the 5k I get a slight noise, but as soon as she has new oil in her cogs, no noise.
I'll do the ball bearing count and add that to my list thanks :)
Keep on Cycling
Simon
-
3) Replace front spokes (dynohub) maybe also back ( Rohlhof)
a) Order extra spares
4) Either buy new wheels (if not carbide then what? ) or rebuild old wheels replacing spokes .Dynamo and rohloff will need to be re-fitted.
If rebuilding the back wheel then add the Rohloff flange support rings https://www.rohloff.de/en/company/news/news/flange-support-rings. Once the spokes have been removed the support rings can be pushed onto the flanges using fingers and thumbs and will be held in place by the spokes.
-
Let me re-cap on the maintenance steps based on all your feedback so far, feel free to throw in any comments.
<SNIP>
That looks a very thorough service, it ought to put it back to excellent condition.
I like to use thread lock for those screws not intended to be frequently moved, second choice would be Copperslip, grease if that's all I have, but really the differences between the options is minor, the important thing is not to let them sit there dry.
The wheels are going to be a judgement call, I wouldn't touch the rear if the rim was OK and it hasn't given problems, there's no reason to think the spokes are weakened. The front is a bit of an oddity, spokes breaking in the middle is damage, fatigue or faulty. It's unlikely you'll damage a spoke without noticing, the distance shouldn't cause fatigue on a well built wheel and when it does it's more common at the bend, faulty spokes usually become apparent in a shorter time. Spaim did have some QC issues a few years back, though I can't remember if it would have coincided with your build. I have a reluctance to re-use rims, I've a feeling releasing all the tensions and reapplying with new spokes must have some effect, though I don't know if it's significant. Usually rims are cheap and available enough for that not to be a consideration, it's the CSS which complicates it!
I service my pedals every couple of years, I follow the PT video mickeg links too, I've never done a full strip and risked losing the balls, there doesn't seem any need, as the vid explains the new grease flushes out the old. I might strip it to replace balls, though if that needed doing it's probably already be too late and the advantage of periodic maintenance is not to let it get to that point.
-
I agree with Ph, if the rear wheel has not shown any reason to question the spokes, leave them be. And yes, add the rings if you replace spokes.
-
Another vote to not rebuild the rear wheel, unless you find cracks in the rim (usually around the eyelets).
After it was suggested on this forum, I cut screwdriver slots in the seatpost bolts on ALL family bikes with this type of bolt. And I put a spare bolt in my toolkit, it only adds a few grams.
Nobody has mentioned tyres. For a major tour, I would fit new ones, unless they have been changed recently.
If you are going to cross really remote areas it might be a good idea to carry a spare tyre in case you damage one beyond repair, I don't bother to do this myself with a large-wheel bike, as where I ride in France, Spain and Portugal I reckon I could always find some sort of 26" tyre within about 50 kms distance max.
But I do carry a spare when I tour on a Brompton, the 16" tyres are more fragile and not easy to find. The folding spare is also lighter and less bulky than a 26" tyre, and I have needed to use it once.
I don't think anyone has mentioned chains. If the current chain isn't relatively new I would put a new one on for the Australia tour, and keep the old one to use it up later on shorter trips. And maybe reverse the rear sprocket if it has significant wear.
Chain wear can be very rapid under certain conditions, I used up 3 chains on one tour, but that was "worst case" with a derailleur bike, a U-brake under the bottom bracket (sprays grit and water onto the chain) and quite a lot of riding on dry dusty tracks and wet sandy tracks. I carried one spare chain with me and bought 2 more during the tour.
With a hub gear there is less wear (chain further from the ground) and you can run a worn chain for much longer. Nowadays I just carry a few spare links and 2 quick connectors so I can repair a chain if a link plate breaks (this has happened twice in about 45 years). And I have Chaingliders on nearly all the large-wheel bikes, which reduce transmission wear significantly.
-
I over-tightened my seat post bolt on my Mk1 Nomad/ Brooks Conquest set up. Snapped the bolt and had a very uncomfortable and careful ride home; about 15miles. My fault obviously but I do wonder if the Conquest’s springs exacerbated things. Lovely saddle regardless.
-
I over-tightened my seat post bolt on my Mk1 Nomad/ Brooks Conquest set up. Snapped the bolt and had a very uncomfortable and careful ride home; about 15miles. My fault obviously but I do wonder if the Conquest’s springs exacerbated things. Lovely saddle regardless.
I can't see the springs making it worse. I have Conquest saddles on most of my bikes.
Seatposts are things that often slip and therefore often need a tighter bolt, in part because we always lube the post with grease to make it more likely to slip. I once bought a seatpost that I had trouble with slippage. Eventually I spray painted the part of the post that was inserted in the frame with a couple heavy coats of spray paint, let the paint dry and harden for a few weeks before inserting again. That extra thickness of paint was enough to make the post less likely to slip in the frame. That post was slightly undersized.
-
Since spare tires were mentioned, some tours I carry one and some I do not.
When I carry one, it is not a heavy bulky tire capable of replacing one of my tires, it instead is a light weight one that is more than adequate to get me to the nearest bike shop. It would be unlikely that I would put more than a couple hundred miles on my spare.
That said, 26 inch tires are getting more rare in bike shops, I may have to re-think this in a few more years, as I could imagine bike shops not having any in stock.
My tours are short enough that I do not wear out a tire on a tour, if I was doing a really long distance tour, I might bring a replacement tire as my spare.
-
Hi Guys,
To follow up on some of the points you have raised.
I will carry one extra folding tire, I use Schwalbe 26" x1.5 " Marathon Plus. They usually last around 10.000km (I'll be cycling around 5.5k).
Yes, you are right, strangely 26" tire has really become rare, 12 years ago it was THE standard it seems, but this year I struggled to find a 26" Schwalbe Marathon while on my tour in the states. So I will take a spare with me and 3-4 inner tubes. Plus a chain or at least a KMC missing link/connector set. I agree, the reversal of the rear sprocket is really important when connecting a new chain, I forgot to do that of course on my trip across the USA, I then had a rubbing sound for at least 10 days.
I have a brooks saddle, B17, I love it.
Agreed, I wont rebuild the back wheel if I don't have to. Never change a winning team :)
If anybody is interested, this is roughly the route I am hoping to cycle.
https://ridewithgps.com/routes/18777910
Keep On Cycling
Simon
-
Nice route, Simon.
I think my pal, Ed Pratt did it on his unicycle a few years ago.
He has some good clips on YouTube.
Best of luck.
Matt.
( One of Ed's mottos to get him through some tough times is, " It's not a problem until it is".
-
If anybody is interested, this is roughly the route I am hoping to cycle.
https://ridewithgps.com/routes/18777910
Looks like it is mainly tarmac. If the towns are not too far apart you could probably get away without a spare tyre. Marathon Plus are robust tyres and you are unlikely to wear one out on that distance. The same goes for the chain, a few spare links and connectors should be enough.
On good tarmac I would personally use lighter and faster tyres, but I don't know if there are "goathead" thorns in that part of Australia. In which case Marathon Plus are by far the best choice.
-
Just a note on flying with a Rohloff. I do not know about you but I seemed to have a lot of oil leakage after a flight. I used to do the oil flush, drain, and fill process before a trip and that meant before a flight. Thus flew with a hub that 15ml of oil in it. But starting with my last tour, I did not add oil to the hub until I arrived at my destination. I seemed to have less leakage when my hub was in a drained state during the flight. That meant bringing a small syringe, the oil tube and threaded fitting, and a small bottle of oil. Plus, I carry a spare drain screw in case I drop it and lose it.
There are a few Australians that have posted over the years at this forum. Perhaps one of them will be able to tell you where there are a few well stocked bike shops along your route that you could contact to see if they stock your desired tires, etc. At that distance you might be looking to buy another bottle of chain lube too.
If my recollection is correct, KMC has started selling Rohloff sprockets that are thicker than the standard Rohloff sprockets, they use single speed chains that are wider. I wonder if that would provide a longer chain and sprocket life? I am going to keep using the Rohloff sprockets and 8 speed chains, but I am not anticipating a trip like yours where a longer component life might be useful. If you use a chain glider (I do not), I have no clue if the wider KMC chain and sprocket is compatible.
-
Re flying with a Rohloff:
I've flown from UK to Tajikistan, Sri Lanka, Ethiopia & Morocco with my Raven Tour.
Oil changes have been done a few weeks before the flight.
I've never had an oil leak as a consequence of the flight.
( & I've never lowered the tired pressures )
Maybe I've been lucky.....
Best
Matt
-
If my recollection is correct, KMC has started selling Rohloff sprockets that are thicker than the standard Rohloff sprockets, they use single speed chains that are wider. I wonder if that would provide a longer chain and sprocket life?
And chainrings:
https://www.kmcchain.eu/10000km
They claim 10,000 kms lifespan. Compared to "standard" on their advert, their system is supposed to last 9 or 10 times longer. I suppose that means using all three KMC components together.
If you use a chain glider (I do not), I have no clue if the wider KMC chain and sprocket is compatible.
In theory, no.
In practice I have setups with Chainglider and wide 1/8" chain/sprocket and TA 1/8" chainring running on two family bikes without problems (one of them since 2012)