Did my Rohloff break my TI frame?

[Andre Jute]

In retrospect, I think I had an extra bit of backup on my ti frame: My LBS in Québec from which I bought it, Pecco's, ordered their frames from Germany.

I hate to bring bad news to a nice guy, John, especially after you've been so flattering about my humble powers, but I had a profile Porsche on a welded-in-Germany titanium space frame. It never finished a single race, and I didn't dare drive it further from Johannesburg than Pretoria unless I had my welder sitting beside me and his gas cylinders and other gear on the shelf behind the seats. Ti welding is better understood today, I suppose, and bonding is a possibility already proven in ali-monocoque car frames (Jaguar and Audi have the best ones), but you'll still have the fundamental problem of the nature of ti. It just isn't as forgiving as correctly proportioned mild(ish) steel.

Something else that bicyclists are apt to overlook: if titanium, which is a very cheap raw material, not rare or wonderful at all, could be made a reliable repetitive multi-directional load-barer with a slowly progressive failure mode, the major motorcar manufacturers with their huge research departments would long, long since have chosen it -- but in fact it isn't even chosen for racing cars these days, and in racing cars was an expensive and fraught gambit never repeated by even the only successful gambler on ti. The godfather of British fast car designers, Arthur Mallock's mouth twisted when I once mentioned titanium space frames to him; the Major didn't think much of the idea; I changed the subject in a hurry because I wanted a favour (a super mini-chapter by him explaining some tricky math in weight transfer between the axles in my DESIGN AND CONSTRUCTION OF SPECIAL CARS).

I would guess we are not far off the time when ti bikes will be spoken of nostalgically. "Granddad, if you had a titanium bike like Super CADence, you know, the hero in my comics, why are you leaving me your steel bikes?"

Has it ever struck you that this forum seems to be the home from home for cyclists who make components last an inordinately long time -- you with your aged ti frame, the OP with his 100,000km ti frame, all kinds of high mileage chains and tyres, a very high proportion of the high-miler's HGB par excellence, the Rohloff, etc.

[John Saxby]

Thanks, Andre.  Your point about racing car applications--or not, to be precise--is well taken.  I remember that in the mid-60s, Jeff Smith was riding a BSA 500 in motocross with a ti frame. The hope was that the weight saving would give a small-but-valuable edge.  Um, it didn't:  the thing kept breaking at inopportune times, and couldn't be welded in the pits between races, as it required a special closed-chamber wotsit. So, the factory dropped the whole thing.

I asked Pecco's about the issue, citing Jeff Smith, BSA 500, international motocross, etc.--after all, it was only about 35 years earlier.  They looked at me, wide-eyed in bemusement ("Who is this relic? What is he on about?") and said that, in their experience, the German welding was better than the Taiwanese equivalent, tho' they did use the latter for their alloy frames.

Funny thing, five years ago I switched out the original carbon forks on my Eclipse as a precaution against disastrous fracture on the rough roads of W Qué.  A Surly Check steel pair now adorns the front end.  Maybe I'll just avoid those scenic bumpy downhills entirely, and stick to smoother terrain with the Eclipse.  I use nice compliant 700 x 35 Supremes, and those help greatly as well.

Cheers,  J.

An added PS:  be interesting to hear the experience of makers of ti-framed touring bikes, such as Spa Cycles and Lynskey.

[leftpoole]

I had a custom TI frame built 11 years ago, with sliding dropouts to accommodate the Speedhub.  Recently, the bottom-left seatstay completely cracked in two while riding, for no apparent reason.  (Luckily, I was going slowly uphill at the time, so it didn't causes a crash.)  It has over 100,000 km on it.  The repair guy said he needed to "reinforce" the frame after the initial repairs to accommodate the Rohloff.  (Not sure exactly how its "reinforced," I still haven't gotten it back.)  I know there is the torque arm available, but from what I understood from the manual, this is only needed on standard frames (without sliding dropouts).   Was I supposed to have the torque arm on my bike, despite it having sliding dropouts?  Was that the reason my frame broke?  (BTW, if I ever get another frame, it will definitely be steel . . . at least when it breaks, its a lot cheaper to repair/replace, and it can be recycled!)

My feeling is that I must have been out of the room and missed something here.
Is not the whole idea of a Titanium frame, to actually assist in weight saving for those with the desire?
To me, fitting a heavy lump such as a Rohloff results in simply (?) more money spent for no actual gain.

[PH]

you'll still have the fundamental problem of the nature of ti. It just isn't as forgiving as correctly proportioned mild(ish) steel.

Maybe you'd like to elaborate on just what those fundamental problems are?  It doesn't sit well with anything I've read or what I know about it's use in the aviation industry (Most of which come from those who work for RR here in Derby)  Back down to earth, I haven't seen a single picture of a ti failure on a bike frame that didn't start within the weld or HAZ, would that not indicate the problems are in fabrication rather than material?

Something else that bicyclists are apt to overlook: if titanium, which is a very cheap raw material,

Not wishing to split hairs - It's a very common element, though it's extraction can be expensive as it isn't found in such concentrated locations as many elements.  It's also an expensive process to turn it from an element to a material.

I would guess we are not far off the time when ti bikes will be spoken of nostalgically

Quite possibly, but that with be due to the increasing popularity of carbon fibre, rather than the alternatives.

[Andre Jute]

you'll still have the fundamental problem of the nature of ti. It just isn't as forgiving as correctly proportioned mild(ish) steel.

Maybe you'd like to elaborate on just what those fundamental problems are?  It doesn't sit well with anything I've read or what I know about it's use in the aviation industry (Most of which come from those who work for RR here in Derby)  Back down to earth, I haven't seen a single picture of a ti failure on aåç bike frame that didn't start within the weld or HAZ, would that not indicate the problems are in fabrication rather than material?

The answer is contained in your question. RR Aerospace deal in cost-no-object research and fabrication of components and assemblies with rigorous manufacturing and test and inspection protocols in use all the way to replacement, with as required short service life to replacement by distinctly counted cycles operated or age. That doesn't however describe a bicycle made of ti. Hell, if I could afford to buy and replace a ti bike made by your chums at RR under those conditions and schedules, I'd have a ti bike too.

What I meant by "the fundamental problem of the nature of ti" was precisely what you mean, the difficulty of controlling the manufacture to resist these well-known cyclical breakages. Does anyone except the OP actually have a well-used ti bike without any problems to tell us about? John Saxon has changed the fork on his ti bike for steel, and who is willing to say that wasn't a wise decision by an experienced tourer?

Seems to me that ti has had enough time to prove whether the production problem on bike-size and -price components can be overcome, and the problem has proven both general and insuperable.

Be interesting to know whether any of your RR chums would buy a ti bike and how long they would expect its service life to be.

[pakcyclist]

My feeling is that I must have been out of the room and missed something here.
Is not the whole idea of a Titanium frame, to actually assist in weight saving for those with the desire?
To me, fitting a heavy lump such as a Rohloff results in simply (?) more money spent for no actual gain.
[/quote]

My reasoning for TI had nothing to do with weight savings.  (With the hub it weighs about 25 lbs.)  Again, I was apparently under the mistaken impression that TI "lasted a lifetime,"  that it was the most durable material.  (I know it at least doesn't rust.)  Guess I learned my lesson the VERY long and expensive was . . .

[PH]

ion. RR Aerospace deal in cost-no-object research and fabrication of components and assemblies with rigorous manufacturing and test and inspection protocols in use all the way to replacement, with as required short service life to replacement by distinctly counted cycles operated or age. That doesn't however describe a bicycle made of ti. Hell, if I could afford to buy and replace a ti bike made by your chums at RR under those conditions and schedules, I'd have a ti bike too.

What I meant by "the fundamental problem of the nature of ti" was precisely what you mean, the difficulty of controlling the manufacture to resist these well-known cyclical breakages. Does anyone except the OP actually have a well-used ti bike without any problems to tell us about? John Saxon has changed the fork on his ti bike for steel, and who is willing to say that wasn't a wise decision by an experienced tourer?

Seems to me that ti has had enough time to prove whether the production problem on bike-size and -price components can be overcome, and the problem has proven both general and insuperable.

Be interesting to know whether any of your RR chums would buy a ti bike and how long they would expect its service life to be.

What you appear to be saying is there's a fundamental problem with the application rather than the material, maybe there's some truth in that but it's far from the whole story.  There are some well established ti cycle manufacturers, offering lifetime guarantees, and honouring them.  I know of breakages with them all, but it's a long way from being with every frame, a don't know what percentage of replacements a business could stand but I doubt it would be very high.  You still haven't given any explanation for these "well-known cyclical breakage" they're certainly not well known by me, what causes a cyclical breakage?  It's not hard to look up the tensile strength, elasticity and fatigue resistance of ti tubing, they all compare favourably with steel, so what other factors are causing it? 

John Saxon has changed the fork on his ti bike for steel

He's changed his carbon fork for steel, not sure what you think that has to say about ti?

Be interesting to know whether any of your RR chums would buy a ti bike and how long they would expect its service life to be.

Ha, they make up about half one of the local cycling clubs, the half with the best bikes, RR are the most prestigious local employer.  Not many of them are riding cheap anything, most on hi end carbon, a couple of custom steel, and a few on ti, including one on a Linskey Sportive that was originally mine 12 years ago.  I have had this discussion about ti with some of them, it partly forms the opinions I'm expressing here, that is choosing who makes your frame is of far more importance than the material it's made from.

[mickeg]

I had a custom TI frame built 11 years ago, with sliding dropouts to accommodate the Speedhub.  Recently, the bottom-left seatstay completely cracked in two while riding, for no apparent reason.  (Luckily, I was going slowly uphill at the time, so it didn't causes a crash.)  It has over 100,000 km on it.  The repair guy said he needed to "reinforce" the frame after the initial repairs to accommodate the Rohloff.  (Not sure exactly how its "reinforced," I still haven't gotten it back.)  I know there is the torque arm available, but from what I understood from the manual, this is only needed on standard frames (without sliding dropouts).   Was I supposed to have the torque arm on my bike, despite it having sliding dropouts?  Was that the reason my frame broke?  (BTW, if I ever get another frame, it will definitely be steel . . . at least when it breaks, its a lot cheaper to repair/replace, and it can be recycled!)

Yeah, you needed the torque arm.

The sliding dropouts served one purpose, a way to adjust your chain tension without a couple extra pulleys like you see on derailleurs or on some IGH bikes.  Or, Thorn uses an eccentric bottom bracket to adjust the chain.  The sliding dropouts did not make the frame stronger.

The Rohloff can put a huge amount of torque on the non-drive side dropout.

I cannot see on your photos if this is a disc brake bike or not, disc brake bikes have a much stronger frame to withstand the torque than a rim brake does.  Some people use the disc brake unit mounting points to take the torque from the hub. 

But it sounds like you took a rim brake frame and put a Rohloff on it without any extra reinforcing for the torque.

You see a lot of IGH bikes that do not have a very wide gear range that have an axle with two flat sides on it and perhaps a special washer that keeps the axle from spinning in the dropout, but those hubs do not put a lot of torque on the frame.  My folding bike has a Sram Dual Drive rear hub that is a three speed hub with a cassette, that three speed gearing is a fairly tight range and a special washer is more than adequate to keep the axle from spinning in the frame.  The Roholoff hub has a much wider range, puts much more torque on the frame.

I have one aluminum frame (folding bike), one titanium frame (touring bike) and several steel frames (touring, randonneuring, road). 

I see nothing wrong with using a titanium frame with a Rohloff provided that the frame is designed for the torque.  I built up my titanium frame as a derailleur bike, but I probably could have fitted a Rohloff on it and used the disc brake mounts for the Rohloff torque.

I will never put the distance on any bike that you put on yours, but I am confident that each of my frames is capable of the distance that you have ridden, and that includes my Thorn Nomad (with Rohloff) and my titanium bike.

[PH]

For anyone who hasn't quite grasped the torque from the hub that has to be resisted by by some method of securing it, there's a clear explanation from Rohloff, including a chart at the bottom of the page,  here
https://www.rohloff.de/en/service/handbook/speedhub/assembly/torque-anchoring

In the most common gears it's less than 20% of the crank torque, rising to nearly 100% if first gear.  The OEM2 plate which a lot of frames use without issue (Including if you fit a Rohloff to Thorn's current Audax model) is a short arm and the fitting is a slot in the plate around a 6mm set screw in the frame.  Maybe just think about that for a moment before suggesting this torque snaps frames - Rohloff say a 6mm set screw a few cm away, in sheer, is enough to resist it.
As for the idea that the weight of the hub securely fitted between the dropouts is relevant, it's pretty insignificant compared to the weight of the lump bouncing around above it in the saddle.  What other points of the frame do you think that weight transfers to the ground via?  Or maybe some riders really do believe they float.

EDIT - The first photo in that link is a clear one of the type of dropout used by the OP

[mickeg]

...
An added PS:  be interesting to hear the experience of makers of ti-framed touring bikes, such as Spa Cycles and Lynskey.

My Lynskey Backroad is derailleur, can't provide any pertinent input here.  I have seen a photo of a total of only one Backroad with a Rohloff on it.

Keep in mind that most Lynskey frames stay in North America, and Rohloff hubs are pretty rare in USA.  So, that combination will be quite uncommon. 

My Lynskey drivetrain in the photo, 2017 frame, a 1990s rear derailleur, eight speed Sram cassette, Campy square taper crankset.  But the crank is half step plus granny, not the normal road triple.

[Andre Jute]

... choosing who makes your frame is of far more importance than the material it's made from.

Perhaps 15 years ago I was on a bicycle tech conference with a fellow who had ti frames made in Taiwan which he sold to anyone who wanted to buy one. He was very well reputed for standing behind his product with an extended guarantee generously applied. Members had lots of stories of how he would give them a new frame. His frames were defended on the grounds that he used the very best Taiwanese factory to make them. Gradually I started noticing that none of the engineers whose resumes, in some cases of bicycle component innovation, I found impressive had bought his frames, and they were strangely silent about them. It was clear to me that a substantial proportion of his customers had frames replaced. A few years later he was no longer on the conference, and his fan club faded away into the carbon frame boosters club.

From this, plus earlier adverse experience with small thin wall ti tubes welded into a sportscar space frame, I formed the opinion that a) who mitres and welds your titanium bike matters, as does the equipment and adherence to standards in the facility they do it in, and b) if the best facility in the bicycle-frame price bracket cannot deliver a frame that is as invariably reliable as a steel frame, there is something "wrong" with the material. For a bicyclist making a decision influenced by opportunity cost right now it doesn't matter whether that "something" is a parameter that science is yet to discover, or simply that ti is impossible to weld in a permanent manner as with steel.

Not everything in materials is dreamt of in Timoshenko.

But my conclusion wasn't mystical; it was just practical. There are too many superb materials one can choose for single-material obsessions to make sense, so I moved on. Note that I basically arrived at the same conclusion as your knowledgeable chums and you; I just went one step further on hand of the consistency of anecdotal evidence. (And it wouldn't surprise me if your mates, with their different experience and expectations, arrive at a different conclusion or even a preference for titanium frames.)

The case with composite plastic bike frames is exactly the same as with titanium frames -- we just avoid discussion of carbon frame unsuitability by a general implicit agreement not to mention the elephant in the carbon fibre bicycle frame room, that in bicycle weights the material has a shorter service life than steel or aluminium.

***
Sorry about the confusion about the material of the fork John Saxby replaced on his ti bike. It comes from not writing out the order of my logic, which I hope I've now made comprehensible in the shorter-service-life connection between ti and CRF described in the par immediately above.

[John Saxby]

George, I like the mix in your Lynskey: Trick Modern Frame Material harnessed to decades-old components which have proved their worth over time.  Nicely done.

Cheers,  John 

[Andre Jute]

For anyone who hasn't quite grasped the torque from the hub that has to be resisted by by some method of securing it, there's a clear explanation from Rohloff, including a chart at the bottom of the page,  here
https://www.rohloff.de/en/service/handbook/speedhub/assembly/torque-anchoring

Grand job on the torque reaction, Paul.

I would just add that the long torque arm isn't as superior a solution as it would seem at first glance: it feeds the load into the stay in a tangent mix of bending and lengthwise stresses, whereas all the other options feed the load into the end of a stay or, if there is a bending component, into the stay pretty near a junction with several load paths.

That last option, "a junction with several load paths", leads to tricky design options because, if two or more load paths are not designed to share the load equally, one of the members will tend to develop a fracture. This isn't just a ti requirement, it applies to all materials. It is because of this consideration that doubled stays, one to each side of the rear wheel, are made thinner than the bottom or top tubes, so that two stays carry the same stress as the larger tube. In ti, by experience the tolerance in scaling the tubes is clearly smaller than in steel.

[Tiberius]

I have two Van Nicholas TI bikes - one running a standard derailleur and the other a Rohloff. The Rohloff bike is not a Rohloff specific frame, I use a Monkeybone/OEM2 plate with a chain tensioner, the whole thing fits together and works really well.

After reading through this thread I looked into the VN warranty situation and it APPEARS very straight forward and remarkably unambiguous for a modern day warranty..

The gist - As long as the frame is registered with them when you buy it (mine were) then they will cover any  defect in materials or manufacturing for the 'life cycle' of the bike - 'life cycle' being defined as 25 years. Interestingly they won't repair anything. If there is an issue then they simply replace the frame.

My derailleur bike is 5 years old, the Rohloff bike is 1 year old and I'm 63 years old. I like the odds.

[leftpoole]

George, I like the mix in your Lynskey: Trick Modern Frame Material harnessed to decades-old components which have proved their worth over time.  Nicely done.

Cheers,  John

I bought a Lynskey Vialle frameset. Built into what looked a lovely bike. Rode it twice Dreadful ,sluggish and I dismantled and sent it back. Subsequently I heard from the importer’Fat Birds’ who told me it was out of line!