Failing Rim?

[mgarl10024]

Morning all,

Hope you are all well?

Having cleaned my bike recently, I noticed that the back wheel rim has little cracks in it around where the spokes are. Some have little splits radiating out from either side of the spoke, and some have little splits around the spokes. To the untrained eye, it appears as if the spokes are pulling through from the rim. I've attached the best couple of pictures I have - but my camera doesn't really like doing closeups.

The bike is a 2010 Marin San Anselmo Deore (http://www.marin.co.uk/2010/bikepage.php?ModNo=10AN) with WTB Dual Duty, Double Wall, 36 Hole with CNC Side Walls rims. She's about two years old and has done 3200 miles, mainly commuting on roads or cyclepaths (no offroading). I am reasonably heavy at about 17.5st, and do carry panniers to work.

What I want to know is
- is this normal wear? Does everyone's bike have it and I've only just noticed it?
- is this a sign that a new back wheel is required? (disappointing if so, given age/distance).
- is it safe to use, or should I immediately stop?
- am I unnecessarily concerned? It has just come out of the LBS for something else and they didn't mention it.

Thanks,

MG

 

[martint235]

It's a bit difficult to tell from the pics but if they are real cracks rather than just cracks in the black paint, I'd stop riding it now and order a new wheel. I've had it once but I can safely say it was almost certainly my fault as it was just after the very first time I'd played with a spoke key.

 

[PpPete]

Difficult to tell from the pictures. Could just be the paint cracking?
Is it alternate spokes? The ones coming from the cassette side?

If you are concerned I'd ask the shop to check the spoke tensions are correct, but mostly the problem on factory wheels is that tensions are too low rather than too high.

 

[mgarl10024]

Thanks for the very quick replies.

It is alternate spokes that are affected - and yes, all seem to be on the cassette side. How did you know that?

I've attached two new pictures which I hope will be clearer.
The first picture is of the worst spoke. To me, they look like real cracks. There are two other spokes that are like this, but this one is by far the worst.
The second picture is of the horizontal cracks. I've about 8 spokes like this. It's difficult to tell whether they are cracks or just paint cracks.

When the bike last went in for a service, I had noticed that the wheel was out of true, so I asked the chappy to true it. I wonder if he went a bit overzealous with his key, and that's why 3 of these spokes seem a bit mangled.

I guess if it is only 3 out of 36, I could carry on running the wheel and see how things go?

If I did want to order a new wheel, I guess I need someone to build it for me? There's nothing wrong with the cassette or hub?
Or do most people just buy new wheels complete and ditch the old hub?

Thanks once again,

 

[martint235]

If it was 3 dodgy spokes I might risk it however it's not the spokes that are the problem here it's the rim itself. Judging by that first picture, I would not ride that wheel again. I'm a bit paranoid about structural integrity so a spoke breaking is one thing, a spoke being pulled out and leaving a whole in the rim is be dodgier.

It does look exactly the same as what I did years ago and it may well be the guy in the shop got a bit overzealous. The spokes being alternate and on the same side suggests he just overtightened that one area. I doubt the shop will accept fault though.

Keep the hub and cassette (and possibly the spokes) and ask someone to build you a new wheel with a new rim (although possibly not the same guy that did this work )

 

[PpPete]

Thanks for the very quick replies.

I guess if it is only 3 out of 36, I could carry on running the wheel and see how things go?

Based on those new pics - I'd agree with Martin. Do not ride it again. Whoever tightened the spokes that far wants taking out and shooting, and quickly, before he damages anyone else's bike.

It is possible, but unlikely IMO, that he had to tighten them beyond what the rim could stand to get it true, but if that was the case he should have told you that the rim was shot.

 

[andrew_s]

It's OK to ride on in the short term, but you should think about getting a new wheel.

What will happen is that the nipples will pull through the cracked spoke holes a little, the wheel will go out of true, and you won't be able to get it trued up again on anything other than a temporary basis. The cracks are on alternate spokes because they are all gear side spokes in a rear wheel, and gear side spokes are under twice the tension of the non drive side spokes because of the dish.

Hard anodised rims are meant to be more prone to cracking, so a silver rim may be better, or look at a different model that's stronger.

 

[I like Skol]

I had this same problem towards the end of 2011. Similar bike use and mileage, mainly commuting with a lightly laden pannier. As the bike was only 11 months old the wheels were changed under warranty. The wheels had not had any attention prior to this and I only noticed because I had a puncture and spotted the cracks while swapping the innertube. I had noticed that the wheel had gone out of true a few days before this but just assumed it was 'normal'

 

[mgarl10024]

Hi all,

Thank you for your excellent replies.

I sent the picture to the local bike shop and the manager phoned me back. He said that the wheel should not be used any more, and that if it was that I risked "catastrophic failure" of the aluminium. I ordered a replacement wheel and will shortly be back to cycling.

I then had a long chat with the bike shop manager (who had originally sold me the bike) about the old wheel. He was convinced that the wheel was showing signs of "classic wheel rim failure" and that this was just a symptom of a failing fatigued wheel. I reminded him of the age and usage of the wheel (under 2yrs, around 3200 miles) and he explained that the bike came with factory wheels (not hand-built) and these generally don't last as long. He said that two years was "about average" and that these things do "just happen", but that because it was out of the 1yr warranty provided by the manufacturer that I was unlikely to get much joy from contacting them.
I explained that the point of buying a £650 bike and not a £150 Halfords one was that I hoped to get a better quality machine, and not one where the "average expected life" of the wheel was about 2years. I asked what price bike I would need to purchase to get better wheels and he said "over £1000". I clarified that I could buy a £1000 bike from him, and that he would not be surprised if a wheel failed after under 2 years, and he said "yep".
I did then cheekily point it out to him that perhaps he should include it in his sales pitch - as someone expects with a new bike to have to periodically purchase new tyres and chains, but perhaps not new wheels every two years! He responded that it was unrealistic of me to expect unlimited life from components just because they were not listed in his sales patter as needing replacement (not what I was suggesting at all!).

I put it to him that the damage could have been caused 6mths ago when the bike was serviced and the wheel was trued, and that it was not detected because (frankly) the bike was a bit grubby during the Winter and was only recently cleaned. He said that if the spokes had been overtightened, then the wheel would have been impossible to true and would have failed long ago. He was adamant that the truing was unconnected, wheels just fail, and this one had recently done just that.

So, I'm after honest advice.
Do factory built and supplied-with-a-£650-bike wheels really have such a short life as that? If so, how come I see such ancient Halfords bikes still kicking around?
How often do wheels fail?
Do wheels "just fail" like mine did? or 9/10 is it overtightening of the spokes?
Is it possible to tell why my wheel failed? i.e. could the manufacturer or some other expert tell the difference between a fatigued wheel and one that had been damaged by overtightening of the spokes whilst being trued?

The last question is particularly key, because if it can be proved, I will be trying to take it further with the shop in question.

All advice appreciated, and sorry for the long post but there was a lot of detail to get in.

Thanks again,

MG

 

[I like Skol]

My wheel failed exactly that way without ever having had a visit from Mr Spoke Key, so yes in answer to your question, factory wheels do/can fail prematurely purely from fatigue.

Funnily enough I think the RRP for my bike was around £650-700. Do I think this level of quality on a bike that price is acceptable? Resoundingly NO!

 

[snorri]

I also had a factory built wheel on a new Trek bike develop cracks similar to those in your pics., they appeared within months of purchase (less than 3K miles). Due to some more pressing isues in my life at the time I did not chase it up with the supplier, and the cracks got no worse, not that I am recommending continued use in your case.

 

[Smut Pedaller]

Usually the rim spoke bed is reinforced with more aluminium or an eyelet to prevent cracking. Under normal circumstances when properly built the rim would typically fail by wearing through the brake tracks not by the spoke bed cracking. Even factory built wheels will last a long time, much much longer than 3200miles.

 

[kevin_cambs_uk]

I had a cracked rim on my Bontrager Race X Lite. After only 5,000 miles as well and 8 months. It would not stay true, and so on closer inspection, the rim was cracked around the spoke nipple.

Bontrager wheels are guaranteed for 2 years, and after a little wait for it to be delivered got a brand new wheel ! Well done Bontrager