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Wheel Help - Replace Spoke or Rebuild

www.richtreen.co.ukwww.richtreen.co.uk Posts: 245
edited January 2012 in Workshop
Hi All

Looking for some quick rear wheel advice/opinions.

Hope Pro (3 I think) Hub with Ambrosio Excellence Rim - 32 Hole with Sapim spokes. I Snapped a spoke at 2000 odd miles on the non drive side, had it replaced with no further problems apart from it went very slightly out of true. Got the LBS to true it a few weeks ago. Went to ride the bike this evening on the Turbo but couldn't - the wheel was majorly out of true and jamming against the brakes - hopped of to have a look and saw the reason, another broken spoke. The wheel had done 1500 miles since the last one broke.

Both have broken non drive side at the J bend where it enters the hub. Should I be looking at just replacing the 1 spoke again or is there another underlying reason why they keep breaking and is a total rebuild the best plan ?

I need the wheels to be reliable for commuting in the summer months. When the first one snapped it was still rideable without even opening the brake quick release, but even that would not have worked this time it was that much out of true. At least it was only an excuse not to do a turbo session tonight !

Cheers

Rich

Posts

  • rakerake Posts: 3,281
    sounds like tensions too low and fatigue has got them.
  • Hi Rich - I broke a non drive side spoke on my rear about 3 weeks ago (broke on the threaded section). A local lbs fixed it and trued the wheel but about two weeks later I broke a drive side one (same part broke). My bike is only four months old or so and the place I bought it are dealing wiht it under warranty. I know it's not exactly the same as your case but the advice I got from both lbs, dealer and manufacturer was consistent that the wheel needed to be rebuilt so I think you would be wise to do the same.

    I read around a lot when it happended and it seemed to be that repairing just one spoke is very tricky and if more than one goes it's best to rebuild to ensure even tension etc
  • Monty DogMonty Dog Posts: 20,614
    I would suggest replacing all the drive side spokes, perhaps with plain gauge ones too. Non-drive side should be OK as they are not as highly stressed.
    Make mine an Italian, with Campagnolo on the side..
  • Yes, fatigue got the best of them... shame as they are near new... did you get them built by a respectable builder or your shop? I suggest rebuild, as your rims and hubs are top quality. If your LBS is the same that did the fix the first time round, I suggest you do not contact them.
    If you fail to find someone local, PM me
  • Most spoke failures occur on the left-hand side of the rear wheel, where a lower spoke tension is unavoidable because of the asymmetrical geometry of the wheel... Gerd Schraner: The Art of “Wheelbuilding”

    He also advises the use of washers at the spoke head if there is any detectable play between the spoke and the spoke hole in the hub flange. You didn't mention which Sapim spokes - less than 2mm at the head prob needs washers.

    So, check the drive side tension is high enough - in the order of 1000N or above. This dictates the maximum tension you achieve on the NDS due to dishing. And check if there’s any play at the spoke hole, if in doubt use washers.
    I may be a minority of one but that doesn't prevent me from being right.
    http://www.dalynchi.com
  • Most spoke failures occur on the left-hand side of the rear wheel, where a lower spoke tension is unavoidable because of the asymmetrical geometry of the wheel... Gerd Schraner: The Art of “Wheelbuilding”

    He also advises the use of washers at the spoke head if there is any detectable play between the spoke and the spoke hole in the hub flange. You didn't mention which Sapim spokes - less than 2mm at the head prob needs washers.

    So, check the drive side tension is high enough - in the order of 1000N or above. This dictates the maximum tension you achieve on the NDS due to dishing. And check if there’s any play at the spoke hole, if in doubt use washers.

    Indeed, however no builder I know, except myself, actually uses the brass washers... they do really help, I have yet to have a spoke failure on a wheel I built
  • Thanks for the replies all.

    The shop that trued the wheel a few weeks ago and replaced the first broken spoke is not the same shop that built the wheels as it was near work which was ideal as they fixed the spoke so I could ride home.

    I could either entrust them to rebuild the wheel, go to the place that built it originally (20 miles away) and get them to redo it or try and find somewhere else local to do it.

    Was the initial build bad for the wheel to have broken a spoke in the first place ?
  • racingcondorracingcondor Posts: 1,434
    32 spoke (3 cross?) with a relatively solid rim and a decent hub should be very tough indeed. You don't say what you weigh or what you use them for but with that build I'd expect it to last almost whatever you throw at it.

    If the wheel was poorly built in the first place (seems likely unless you've been abusing them a whole lot) I wouldn't be surprised to find several spokes are fatigued and just replacing the one that breaks won't fix it for long. Alternatively the shop that replaced the spoke didn't check the tensions and gave you back a wheel that was prone to breaking (my money is on the original build).
  • Cheers.

    392178_10150408090801653_609051652_8819243_2006319708_n.jpg

    Picture of said wheel.

    I weigh 81-82 Kg depending on the time of the week. Just used on the road and my turbo. No abuse as far as I know, do my best to avoid potholes etc !
  • To build a wheel properly, it takes time, as tensions need to be checked several times, destressing, as well as the final truing... most shops are happy just truing them so that they look OK, but the problem remains... in your case you need a rebuild of the rear wheel, the front is probably OK, they always are. I wouldn't trust a LBS, they are rushed for time and can't spend 2 hours to do one wheel properly. A builder would do the same job much quicker and better. They are nice wheels and deserve to be built well
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