Thorn Cycles Forum
Technical => General Technical => Topic started by: onebikeoneworld on January 04, 2018, 01:31:03 pm
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I've been considering changing out some bolts that look a bit worn, and was wondering about the idea of changing to Titanium ones. They're certainly not cheap (http://tibike.co.uk/shop/ seem to have them at about £3 a go) and a quick glance at the bike suggests there are north of 50 bolts.
Has anyone does this? What precautions should be taken? Would the interface on Titanium bolts be less prone to rounding from Hex keys than on stock bolts? Is it just a way to spend £200 to save 100g on a Thorn Raven which weighs a silly amount.
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Well thinking about this I vaguely remember some of the properties of titanium. It is a poor conductor, it is less dense than steel and thus lighter, more ductile and has a much higher elongation rate, and superior tensile strength. Now that is off the top of my underpowered head - so double checking might be in order, and I wonder myself how that would play out.
Normally if you go to theoretical extremes, all the differences except weight can be seen as either good or bad thing depending on the over-all design objectives, but I feel that it's similar to the idea of what one bicycle salesman told me once, how an ahead stem is stronger than a quil stem. I asked him was "under which conditions, where are you measuring the various forces, and what sort of numbers did your testing show?" He responded - well everyone knows this and left - which was a desirable outcome for me.
I don't think it matters except as a good topic on a rainy day, inside a warm pub, with some of one's drunk friends, where it becomes very important as the beers are put away. On a real bicycle it does not make any sort of difference, I'm sure. I mean if one worries about the strength of a quill stem not being enough, where it would take forces that would shear your arms off at the shoulders, before shearing the stem. Better to not use carbon fiber handlebars instead, or even avoid aluminum perhaps rather that worry about the stem. I dunno, it all seem like a lot of marketing driven fetishism. And so too with titanium versus steel bolts on a bike.
But we are "guys", and thus I highly recommend titanium bolts. If there is a mountain somewhere, it must be climbed. Titanium bolts will allow for almost three Cliff Shot energy gells to be carried without a weight penalty and due to the superior melting point of titanium, in the case of a nuclear war they will be the last thing to melt, potentially saving time and money on the rebuild.
I've never pondered this before - but now I realize that I too need titanium bolts. The bigger question gnawing on me now however is - the benefits of titanium rims and tireless tubes.
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I can't imagine why you would want Titanium bolts. If you want the corrosion resistance, use stainless. Almost all of the bolts on my bikes are stainless. I am not sure what the shear strength is on Titanium bolts, but I do know that my stainless bolts are good enough.
I do not know how much weight savings there would be from switching to Titanium from stainless, but I would not be surprised if I could achieve even more weight reduction if I cleaned the dirt off of my bike, especially under the fenders (mudguards) where dirt accumulates.
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I can't imagine why you would want Titanium bolts. If you want the corrosion resistance, use stainless. Almost all of the bolts on my bikes are stainless. I am not sure what the shear strength is on Titanium bolts, but I do know that my stainless bolts are good enough.
I do not know how much weight savings there would be from switching to Titanium from stainless, but I would not be surprised if I could achieve even more weight reduction if I cleaned the dirt off of my bike, especially under the fenders (mudguards) where dirt accumulates.
That is a common mistake to call that "dirt". It is in fact "UV protection" and I make sure I never remove it from my bike - the way my wife thinks "UV protection" should be removed from bicycles and cars. It also saves me hours each week, now that I've become more enlightened.
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I can’t work out where there would be 50 bolts (Which by the way will almost definitely be screws)
Is your bike made from Meccano?
IMO The weight saving will be so minimal as to be worthless. If you have any screws just plugging spare threaded holes, you could swap them for nylon screws, which will be lighter than ti.
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I can’t work out where there would be 50 bolts (Which by the way will almost definitely be screws)
Well, let's see...
On my Nomad (for example):
Fork:
4- racks
2- mudguard stays
1- headlight
2- dynamo clamp adapter mount
1- underside fork crown mudguard mount
2- v-brake bosses
Stem:
4-clamp
1-headset preload bolt
Frame:
6- water bottle mounts
2- upper rack mounts
2- lower rack mount
2- mudguard mounts
2- disc brake mounting tab
2- M8 eccentric bolts
1- seat collar pinch bolt
1- underside seatstay bridge mount for mudguards
1- chainstay bridge mount for mudguards
1- v-brake bosses
Then, we have components:
2 - external BB crank pinch bolts or main crank bolts if internal BB
4 or 5- chainring bolts and sleeve nuts
(4-nuts on v-brakes...don't count 'cos nuts not bolts)
2- Thorn Exp mudguard stay mounts on rear rack
2- cross-brace on Thorn Low-Loader Mk V front racks
2- brake lever mounting clamp bolts
2- crosstop brake lever mounting clamp bolts
2- v-brake cable clamp bolts
1- saddle rail clamp on seatpost
(8 draw bolts and nuts for mudguard stay mounts...no Ti equivalent, so don't count)
...unless I missed something, that's it. [No, it isn't...I lost count. ??? There's four more bolts in a Thorn EXP rear rack]
Total on frame/fork: 37 unless I've lost count
Total on components: 18 22
Grand total: 55 59
All the best,
Dan.
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yeah .... but what about those titanium rims? it would get me to my touring destination 34 seconds a day earlier on the average 70 mile (112 km) day .... every day. How's that not an amazing thing?
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...but what about those titanium rim
Because titanium is more dense than aluminum and therefore heavier (though still lighter than steel), you would likely be slower on a course that required frequent starts/stops or uphill. On a flat course with steady-state pedaling, you would likely be about the same speed overall once you had reached cruising speed.
All the best,
Dan.
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The OP asked...
Would the interface on Titanium bolts be less prone to rounding from Hex keys than on stock bolts?
To get around the problem, I have replaced some of my socket head/Allen bolts with hex-head bolts. The surface area is larger, the span across the fastener is greater, and of you only have an open-end wrench with you, you have three shots/face-pairs for removal (though I prefer box-end wrenches).
I installed mine on my rack mounts. They make removal much easier over time as the interface ages.
Similarly, I sometimes thread a longer bolt clear through a rack braze-on and secure the rack with a locking nut. In the event the bolt fractures, it makes removal an easier task. I know Andy Blance does this also.
Best,
Dan.
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34 seconds a day earlier on the average 70 mile (112 km) day
34 seconds is maybe a bit optimistic for a 100g shaving, but even half that, 17s a day, 220 days a year, say, is definitely worth $200. That's over an hour, and back in the day my time was charged at very much more than that.
It's not difficult to conceive of many other circumstances in which 17s in 70m would be worth much more. At Le Mans for instance, 17s in every five laps would be a crushing margin at the end of the 24h race of nearly 14 minutes, for which Audi or Porsche or Toyota would be happy to pay tens of millions.
All of that said, I have only one ti screw on my bike, and that was given to me by Julian (Julk) with a double-saddle-rail to micro-adjustable seatpost adaptor and, IIRC, was all that would fit. All the rest are stainless, because that is the optimum rustfree choice as George says.
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Expensive enough to find stainless screws in all the required sizes and lengths (which is why you should prefer bike manufacturers and component makers who supply stainless screws as standard), near impossible to do it in ti. In addition, the wider availability of stainless sizes/lengths makes fitting longer screws and self-locking nuts in selected locations (where you have to disassemble/reassemble the component or assembly often, and therefore you don't want to use Loctte) so much more likely and consequently your life so much easier when you're trying to assemble your bike on the busy sidewalk in front of an airport building.
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Since we are on the topic of bolts, ...
Just a quick recommendation for blue Loctite on all rack bolts. I also use it on kickstand bolts (Thorn recommends against kickstands). Since I lost a shoe cleat bolt last summer, I now use it on those bolts too. After Dave (SJS Shop) commented on dissimilar metal corrosion, I also use it on my Rohloff drain plug screw.
Thorn/SJS has a specific recommendation for which loctite is recommended but I think that it uses a model number specific to UK vendors. I am in USA, sometimes I use a competitor product instead of genuine loctite branding. The version of loctite you want says on the package that the bolts are removable, you do not want something that is permanent, you only need to guard against vibration causing them to fall out.
Other bolts like water bottle bolts, seatpost bolt, stem cap bolt, I instead use grease instead of loctite. Grease is a viscous liquid, that high viscosity will reduce the likelyhood of a bolt falling out compared to a dry bolt that has come loose. But they can still come loose, so carry a few spares on a bike tour. On my Thorns that had a tab on the front fork to mount a bottle dynamo, I carry my spare bolts threaded into that tab.
On my seatpost bolt, I have cut a small slot in the end of the bolt. That way if I torque it too much and break the bolt, I should be able to extract it with a small screwdriver.
I met a biker in Iceland, we were over 100 km from any form of retail establishment. He had used up all of his spare bolts, so he was obsessive about making sure his bolts were tight every day. And he went so far as to wrap tape around the bolt and frame on each of his rack bolts to make sure that if the bolt started to come loose, the tape would prevent it from coming all the way out. After talking to him, I was so glad I used some blue loctite.
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Just a quick recommendation for blue Loctite on all rack bolts. I also use it on kickstand bolts (Thorn recommends against kickstands). Since I lost a shoe cleat bolt last summer, I now use it on those bolts too.
Boy! I sure agree with you, George.
Just one caution when torquing lubed bolts (and Loctite is like a lubricant while it is wet):
http://thorncyclesforum.co.uk/index.php?topic=11655.msg85102#msg85102
On my Thorns that had a tab on the front fork to mount a bottle dynamo, I carry my spare bolts threaded into that tab.
Me too. It is a good place to store a spare pair of SPD shoe cleats, too. The threads are the same M5 x 0.8mm.
Best,
Dan.
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But is it still a proper adventure if one does not lose any bolts at the worst possible time?
I use thread compound on every nut and bolt on both my bicycles and motorcycles. Contrary to what some may first think it helps things stay put (preload) as well as to take off.
I wonder if there is any galvanic action between Titanium and the Steel in Thorn tubes in that sea air of Britain?
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Onebikeoneworld,
Go for it - then both the bike and your wallet will weigh less!
You will also be creating a family heirloom for the distant future.
I found http://www.torontocycles.com/Selling/Titanium_Bolts.html (http://www.torontocycles.com/Selling/Titanium_Bolts.html) has a large choice and not too pricey.
I really really tried to find a longer M7 ss bolt for the clamp on my Nitto S84 seatpost, but nothing suitable emerged from my internet efforts. My Brooks saddle has rear springs and this alters the angle of the clamp making a longer bolt a safer full thread fastening at the front end. The supplied Nitto bolt was a couple of threads short in my setup.
I must admit a have a bit more titanium on my Bromptons…
Julian.
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I wonder if there is any galvanic action between Titanium and the Steel in Thorn tubes in that sea air of Britain?
Did you buy the Titanium bolts after all?
I still think you want steel bolts.
Attached photo shows a steel rack bolt and steel fender bolt on my Titanium frame. (If you are tempted to give me a hard time for showing a non-Thorn in the photo, I bought the XT hub and the Spyre disc brake unit from SJS.)
Titanium is highly reactive to Oxygen, a Titanium Oxide coating develops on the bare metal. But the Titanium Oxide coating that develops on it is very corrosion resistant which is one reason that Titanium frames are often unpainted, I would expect that you would not have any problem with having Titanium in direct contact with other metals.
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Mickeg ... how do you find the Titanium frame compared to a steel frame? It certainly looks good unpainted and from what I've read the ride is supposed to be comfortable. Is there a list of pro's and cons you'd share with us, in the titanium vs steel choice?
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It really depends on how it is constructed. The bike in the photo is a touring bike, it is intended to be ridden with a load of camping gear. But the frame was still quite light, the frame without fork is lighter than my rear wheel with tire (XT M756A hub, 36 Wheelsmith DB-14 spokes, Velocity Dyad rim, Hutchinson Globetrotter 37mm wide 700c tire). But regarding weight, it still is a touring bike and it weighs a bit over 15 kg. I suspect that the Titanium cut maybe a kg of weight compared to a steel bike. I have a steel fork on it, the manufacturer of the frame does not make Titanium forks. For touring I did not want a Carbon fork.
I was not specifically planning on building up a Titanium bike, but I got lucky and got that frame new for less than half of the manufacturers list price. I had a bunch of parts that were looking for a new home (new frame) so I was just watching for something in 700c that looked interesting. I bid on that (on Ebay) and won the auction. It is not used, I still have manufacturers warranty.
I suspect many of you know how that goes, you suddenly have a higher end new frame that you were going to put a bunch of old parts on. Suddenly those old parts did not look so good anymore, suddenly new parts looked a lot better. So, it became a more expensive project than I planned, but I am still quite happy I built it up. I think my total cost for the bike when I factor in the cost of the parts that I already had to put on it was about the same as the manufacturers list price for just the frame without fork. And I put an SP dynohub and Luxos U on it, so I did not scrimp on parts.
How does it handle? Handles like a touring bike, it has very large diameter headtube and downtube for stiffness, these tubes are fatter than on my Nomad. Rear stays are also pretty big, but they are round and untapered, unlike the tapered and shaped stays on my Nomad. But if is not as hard a ride as I suspect an Aluminum bike would ride. And with 37mm wide tires, it is not going to have that hard ride that you would get from high pressure skinny tires.
I have read that Titanium is roughly in between steel and Aluminum for ride characteristics, I would not disagree with that.
Because of the high cost for Titanium bikes, the vast majority of them have high end components, skinny tires, and are built for speed. There also are a number of mountain bikes made from Titanium, these are often more performance oriented. I do not expect to see a lot of Titanium bikes being built for touring for that reason, as it does not make much financial sense to put 20 kg of camping gear on an expensive bike that would have been a lot more affordable if it weighed one kg more like a steel bike would have.
So, for touring I have the following:
- Thorn Nomad for heavy touring, also has S&S couplers to make shipping by airplane less costly if I am willing to take the time to pack and later reassemble it.
- Thorn Sherpa for medium duty touring, fitted with eight speed cassette (Sram 11/32), bar ends and a triple with half step plus granny (46/42/24), have used this on several tours and I like it for that purpose.
- The Titanium bike I expect to use more for on-pavement only (on-tarmac only) type of touring with lighter weight loads. It has the same drivetrain as the Sherpa (eight speed, bar ends and triple with the same exact gearing). But the final drive ratios are slightly higher with the larger diameter 700c wheel. I did a five day tour with four panniers and handlebar bag on it, was very happy with it.
I also have an Airnimal Joey (folding bike with 24 inch wheels) that I might try to tour on some day, but have not found a reason to do that yet.
I think most of the historical experience that riders describe about Titanium is based on racing bikes. Titanium was the thing to have before Carbon became big. I do not know if it is true, but I have heard that (the now disgraced) Lance Armstrong during his first year of Trek sponsorship insisted on riding on a Titanium bike of a different manufacturer, thus they repainted that other bike to match the Treks and let him race that Titanium bike, but after that first year he conformed and rode Treks.
I am not concerned about corrosion, those of you near salt air might be more concerned. Titanium has great corrosion resistance. But I put a coating of frame saver inside my Nomad frame before I built that up to protect the steel. Such protection on a Titanium frame is unnecessary.
I suspect some of you were puzzled by the odd looking disc mount. That manufacturer makes both a post mount (as pictured) and a flat mount for the newer flat mount disc brakes, either mount can be fitted to the rear chainstay with three bolts. This was my first disc brake bike. I had a non-disk fork that I wanted to use to cut costs, that fork was for rim brakes. Thus, the bike is rim brake on front wheel and disc on rear. That mix works quite well, I think my rim brakes (with Koolstop Salmon pads) outperform the disc.
I think I covered all the topics, let me know if you have specific questions. But, bear in mind that the forum is hosted by a steel frame bike manufacturer, so if you have specific questions, lets handle those by private message.
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Great write-up. Thanks. You are right that saving a kilo makes much less sense on a touring bike, especially for someone such as myself, where comfort, especially for sleep, is the top priority over weight and reliability/simplicity is next. Still, it sure is a nice looking bike, judging by that one photo. I'm surprised to hear you tell that the tubes are fatter than on the Thorn.
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I'm surprised to hear you tell that the tubes are fatter than on the Thorn.
You might find this interesting
https://www.ibiscycles.com/support/technical_articles/metallurgy_for_cyclists/the_titanium_advantage/
Steel is heavier but stiffer, tubes of the same dimension would be half the weight but impractically flexible, as the above article says
steel and titanium are roughly comparable when it comes to the stiffness-to-weight ratio
I'm a bit sceptical that mickeg frame saves a kg, IMO that won't be the case if it's a like for like comparison.
I've just replaced a Ti frame (With a failed weld) with a Mercury, they're no identical but pretty similar, the Merc frame is 190g heavier (Though I've reclaimed that with a lighter EBB and fork)
Photo
https://www.flickr.com/photos/phbike/5592766517/in/album-72157626312048871/
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I can’t work out where there would be 50 bolts (Which by the way will almost definitely be screws)
Well, let's see...
On my Nomad (for example):
....snip....
Total on frame/fork: 37 unless I've lost count
Total on components: 18 22
Grand total: 55 59
All the best,
Dan.
I hadn't taken into account changing the bolts on components, simply because it isn't something I'd do, I'd assume fittings for the likes of stems and brakes had been tested as part of the overall component and would have to be sure of what I was doing before replacing.
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And please will people stop calling screws bolts
https://mechanical-engg.com/blogs/entry/534-difference-between-boltscrew-and-stud/
If you're bolting stuff together it'll require a nut on the other side, if you're screwing it together it is, not surprisingly, a screw ;)
You can of course sometimes use one for the other, but it's usually best to use the fastener intended for the purpose.
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I hadn't taken into account changing the bolts on components, simply because it isn't something I'd do, I'd assume fittings for the likes of stems and brakes had been tested as part of the overall component and would have to be sure of what I was doing before replacing.
And, for the same reason, if you're replacing a bolt or a screw with a damaged head or for any other reason, don't just replace it with something from your local hardware store of the same size and thread: get the real thing from the OEM (original equipment manufacturer) or his authorized agent, and if you can't, on any critical component (steering, brakes, seat post collar, around the pedals) replace the whole component because it will come with new screws/bolts/studs of the correct tensile rating. Not all threaded items were created equal! And that also gives you a hint to why you shouldn't willy-nilly fit fasteners of different materials to those originally specified to critical components unless, of course, you're a materials engineer who sleeps with Timoshenko under his pillow. Note that there can be situations where a nominally higher spec of fastener can be undesirable, for instance where the native "stretch" in a material has been calculated into the operation of the component, or where part of a component is expected to be removed and refitted multiple times in normal service, in which case steel is hard to beat.
On the other hand, many OEMs sell aftermarket sets of correctly specified stainless screw sets for those who must have the bling. If nylock nuts are included buy spares of these -- yep, you got it, not supposed to be reused. A way round the nylock nut waste is to get two half-nuts for each threaded fastener, torque the first one up to spec, and lock the second one against the first by friction. Works a treat and isn't wasteful.
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Jan Heine has posted a cogent piece on the uses of titanium on bikes, weight savings, and design appropriateness here:
https://janheine.wordpress.com/2018/01/09/myth-2-titanium-is-lighter-than-steel/
Best,
Dan.
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Thaqnks for that link, Dan. I find Jan heine's blog to be useful on all sorts of issues, and generally well-written.
My own experience with titanium is limited to the past few years, and is varied, but not expensive:
> I have a couple of ti implants in my lower left jaw, adorned with two trick ceramic crowns. These are about 8 years old now. They replace teeth lost to inadequate dental care a half-century or so ago. Everything seems fine, and half the cost was tax-deductible :) No reason not to use ti in that setting, so far as I can tell. Its non-oxidizing properties seem very appropriate.
> My experience with my ti frame on my light-touring Eclipse has been mixed. The frame is well made and nicely finished, and of course shows no signs of rust :) Dimensionally, it fits me well. The bike is about 2 kgs lighter than my Raven, when both have similar specs for fenders, etc., though the Raven has slightly wider rims & tires. The feel of the two bikes is quite different, the Eclipse being much nippier, but the lighter weight of the Eclipse makes little appreciable difference its its speed over the road when I'm riding, because so many other factors are at play. Notably, the Raven fits me much better, as a result of various tweaks I've made to its spec, drawing on a decade of experience with the Eclipse. The better fit makes the Raven both more comfortable and thus (I think) more efficient.
> The matter of utility of the two bikes is affected by other considerations, too. My Eclipse originally came with carbon forks, which had no provision for fenders, nor for a front rack. I used clip-on fenders, which were OK but no more than that, and I used a front rack fixed at the bolt bosses and the skewer. I refreshed the bike a couple of springs ago, replacing the CF forks with a nice Surly steel fork, and that's been brilliant: dead steady on fast downhills, with nice fitting for a smart VO alloy fender and a light rack, if I wanted to fit one.
> And, of course, the Raven has a Rohloff, while the Eclipse is a derailleur bike. I had a decade of headaches with the drivetrains on the Eclipse, which we don't need to dwell on here because it is a Bad Vibe for me.
Conclusion: The Eclipse is a nice bike for rides of a few hours or less, and looks very spiffy indeed. I'm not taking it to 'Straya next week, however, because (i) the airborne sand on Gold Coast roads wrecks chains and cogsets, and the Raven has a 'glider; (ii) the Raven's gearing will let me spin up the 15% grades in the NSW border ranges much more easily than the 11-32 x 24T low ring on the Eclipse; and (iii) I think that the Marathon Supremes I have on the Eclipse will manage the Queensland debris better than the M'thon Racers on the Eclipse.
And on ti bolts, etc.: stick with quality stainless, Pavel -- use marine grade if need be.
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Jan Heine has posted a cogent piece on the uses of titanium on bikes, weight savings, and design appropriateness here:
https://janheine.wordpress.com/2018/01/09/myth-2-titanium-is-lighter-than-steel/
Best,
Dan.
Thanks for posting. Nice brief writeup.
Regarding his discussion of fitting a crankset, I found that interesting as the right side chainstay on my bike is in part a solid piece of Titanium instead of entirely tubular. Photo attached, you can see the chainstay aft of the chainrings becomes tubular but in front of that is solid. I did not have to use a wider bottom bracket, normal crank and bottom bracket fit just fine.
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https://janheine.wordpress.com/2018/01/09/myth-2-titanium-is-lighter-than-steel/
How apt! "Vélocio, the editor of the French magazine Le Cycliste..."