Leaning bike, poor brake force, broken spoke

[napier]

If the following has been raised elsewhere, feel free to direct me to it! Here is the problem. I purchased a new rear wheel from a highly reputable wheel builder, I've had many from them before which have never let me down so I have complete faith in them. This particular wheel was made in 2016 and fitted to a road bike (audax style) for around two thousand miles and as far as I can remember, never caused a problem. I then fitted it to a new road frame made up with components from an accident damaged cycle. The wheel in question was not part of that accident. At around 3,500 total miles for the wheel I noticed that the bike was leaning markedly to the right during normal cycling. Attempts to make the bike stand straight caused it to track heavily to the left. This puzzled me greatly but then I noticed that the wheel was not sitting straight in the frame, it was visibly closer to the left chain stay.

I then spent some time "making" the wheel sit straight in the frame, it didn't want to but I was able to make it, just about. Then the bike was upright once more. Over time, the lean has returned and there has been a serious loss of brake force on the rear though until now I've not linked the two issues. I've tried new blocks (Ultegra), de-greasng the wheel rims, countless adjustment but all to no avail. It was beginning to feel unsafe as I was having trouble stopping quickly. Yesterday, I took the bike out for a ride and noticed the lean was back so I did the best I could to get the wheel sitting straight in the frame - it didn't like it much. The braking was horrible. After a 63 mile ride on the remote Scottish West Coast, I arrived back home and was opening the front door when there was a loud cracking noise, and I mean loud! The bike was leaning against a wall when this happened. It took me some minutes to work out that a spoke on the DS of the rear wheel had snapped just above the nipple and that the wheel had buckled so severely it was no longer possible to fully rotate it.

At this point the wheel had covered 4,513 miles from new, 2,478 on the original bike and 2,035 on the replacement. It is 700c and had been running a 700 x 25 Continental GatorSkin hard shell. Just prior to yesterday's ride I'd replaced this with a Schwalbe Marathon plus (I don't like punctures!) of the same size. The rim is H Plus On, hub is Ultegra. All brand new when the wheel was built. The front wheel is identical, was purchased at the same time and appears to be fine.

I've spent a lot of time trying to figure out what is going on here. I've used the string method to check the frame alignment and so far as I can tell it's pretty well ok, not perfect but within one mm I'd say. The wheel prior to the spoke breakage was true and I'd had not issues with the brake blocks rubbing, only that they didn't appear to work.

So, a wheel not sitting straight in the frame, a leaning bike, brakes scarcely working then a fairly violent spoke breakage. What could cause this? Frame alignment and/or wheel dish may be culprits but can a wheel lose it's dish but not be buckled?

Any ideas?

[pwa]

Did you try another wheel to see if it was a wheel or frame problem?

[napier]

That's the next step, problem is that the bike lives in northern Scotland and I live in southern England and I won't be going back for another three weeks. My plan is to take a different wheel with me but I'm trying to explore all possibilities before then so I can go as prepared as possible.

[Brucey]

trying another wheel makes good sense to me. If you don't have another wheel, as a test, try turning the one you have in the frame.

Possibly the brake cable needs fettling or replacing; bad cables are like little thieves that steal your brake force.

The Son archetype rim is stiff enough that a wheel will run fairly true even if the spoke tension is uneven; however an actual spoke breakage on the DS will throw the wheel well out of true. In a 130mm OLN wheel the NDS spokes will have about half the tension of the DS spokes. One of the things that can happen is that the NDS spoke nipples back out and this can result in a wheel that ends up with the wrong dish but without going wildly out of true in the meantime. The wheel reversal test will tell you if the wheel dish is really wrong or not. It is more or less essential to have the NDS spokes locked with threadlock in many modern wheels, especially if the rider is strong and/or heavy.

BTW if the wheel dish is wrong and/or the frame is out of track, centring the rim in the chainstays is not a case of 'two wrongs making a right' it is more a case of 'two wrongs making an even bigger wrong'.

cheers

[rjb]

Sounds like the wheel is not tight in the frame and the right drive side is being pulled forward. This can be caused by thin drop outs meaning the QR bottoms out on the axle before it tightens in the drop out. Do you have Chrome drop outs, it's not uncommon for these to cause issues with slippage, some riders use copper washers beneath the QR to counteract the problem. Couple more things to consider.

[531colin]

Let me see if I have understood all this correctly...….
The wheel moved closer to the left chainstay; not the driveside (right) chainstay?
If as Brucey suggests the NDS (non-driveside) spokes are backing off, wouldn't the rim get closer to the right chainstay?
If you have been pulling the wheel away from the left chainstay, you have been tightening the driveside spokes....is that the explanation for the driveside spoke failure?

[napier]

Thank you all for these comments, I'll attempt to answer the arising questions: Brucey, I'd thought about changing the brake cable, didn't mention it but yesterday before riding I reluctantly and with little expectation of an improvement, disconnected the rear brake cable and sprayed the inner with WD 40. My lack of optimism that it would make no difference proved well founded! I guess I've been trying to avoid having to remove perfectly good bar tape etc in order to change the cable or do you think it might only need the inner replacing? If indeed the cable is the problem?

The dropouts form part of the aluminium frame; I bought this mail order, it wasn't the most expensive, I found the wheel wouldn't fit in the drop-outs so on the advice of the frame builder (a reputable company) I gently filed away surplus paint to deal with this. So the drop outs are a part of the frame, no chrome. So far as I can tell (no specialist tools, just string) they are lined up OK.

And to confirm, the wheel when sitting where it wanted to unsecured, was closer to the left chain stay (NDS) as if you were standing at the rear of the bike facing forward. I did originally think it was being pulled across by pedalling forces acting against a weak QR but the skewer is Ultegra and was plenty tight enough. Besides, un-tightened the wheel was simply not resting straight - if that makes sense.

Riding style? I'm 11.5 stone and a high mileage plodding commuter/tourist - 200 miles a week at an average speed of 12/13 mph so probably not someone who will break a bike through brute force! Very little of that mileage is done on the bike in question though.

It's looking like I really need to get that spare wheel up to Scotland....

[pwa]

Dropout surfaces not parallel? Or parallel but pointing slightly left?

[531colin]

Vertical dropouts in a new frame?
Not much scope for the wheel to pull over?
String tests here....https://forum.cyclinguk.org/viewtopic.php?f=1&t=59332&hilit=string

[Brucey]

I guess I've been trying to avoid having to remove perfectly good bar tape etc in order to change the cable or do you think it might only need the inner replacing? If indeed the cable is the problem?....

IMHO it is always

a) worth pulling the inner back and forth both ways to see if it is draggy before doing anything much and
b) trying a new inner in the old housing first; it only takes five minutes to try this and as you say it can save a lot of time/expense.

but if you draw a blank then you will have to bite the bullet and fit a new cable.

cheers

[napier]

531 Colin, thank you for the link to the string tests - looks like they're worth a go. I tried a much simpler one I found on YouTube and that's what looked OK. I don't think it's my riding style as I've three other bikes and none of them have the "lean" problem, it'll be one of these that will lend it's wheel in three weeks time when I next go north. Brucey, the inner cable of the brake felt pretty smooth when I tried the WD 40 so I guess I'll be biting that bullet in due course.

[Brucey]

apologies if this is obvious but it only takes a tiny bit of chain lube on the rims to turn the braking bad too.

cheers

[foxyrider]

It sounds very much like the rear centres are not the same - even a millimetre would give the result of the wheel not sitting square and would be nigh on impossible to see by eye.
Whether the broken spoke is directly related I wouldn't like to speculate but i'm thinking that effectively the whole rear end of the bike is twisted and under stress when you've 'adjusted the wheel to square.
It should be sortable with a bit of fettling of the dropout.

[peetee]

Is the brake caliper working properly? Perhaps only one arm is reacting to the cable pull, forcing the rim over to meet the other pad and putting undue strain on the spokes and distorting the wheel. Can't quite get my head round the physics of it but if you relieve the tension on a set of spokes doesn't it produce a reaction on the other side of the wheel? (Which would be the road contact patch).

[9494arnold]

Broken Axle?