Replacing worn rims

[rugbyleaguebiker]

I have just picked up a pair of mavic x517 rims with hope hubs and Michelin tyres and tubes for a tenner, the bearings are smooth but the rims are a little concave. How much is too concave? And how difficult of a job is replacing rims. Google throws up taping old rim to a new one and swapping spokes over then tightening them all an equal amount, surely it cannot be that straightforward?? Anyone any experience in this or know how much a wheel builder might charge?

 

[kingbling]

If your unsure of rebuilding your wheels do as the google post suggests but leave the spokes loose then take them to your LBS to finish off which should be in the region of £15 - £20 depending how long they take. If you do swap rims your self don't for get to oil the spoke nipple threads before refitting.

EDIT Price Per Wheel

 

[ishaw]

I've done the rim swap a few times and it's not quite as simple as tightening all the spikes up the same amount. You need to get the spoke tension correct and also dish the wheels so that they sit in the middle of the frame and fork. Spoke tension on the rear is different per side as well.

What I tend to do is get them as close as I can, if I'm happy with the result, ride. If not, I take them to a bike shop for a true.

 

[02gf74]

As ishaw says. Move spoke over at a time and do up by same amount.

Then fit in forks to takes out side to side and getting the dishing. Radial adjustment i find more difficult but i got it within 1 mm.

Having done this at leasy twice on a set of wheels using original spokes and nipples, never had problrmd.

Tensioning, grab pair of spokes on a good wheel then compare. If zlavk, go round giving yet nipples a 1/4 turn, vheck side to side t, afjust, check tension adjust until happy.

 

[mattr]

Don't oil the spoke threads.
It's not needed. And *can* in some cases make the wheel unreliable and likely to come out of true. Makes them a bugger to build as well. Something like linseed oil will be ok as it sets. Chain lube would be a nightmare.
Do however give them a clean with an oily rag or something.

It's also worth getting a bag of spare nipples, as if the wheel is old and well used enough to have concave breaking surfaces I'd be wary of seized or damaged nipples.

 

[hamster]

Good point - if the nipples are aluminium they will doubtless crumble or round off. Use a set of brass nipples which last better and are easier to use.

 

[kingbling]

When it comes to oiling nipples it's horses for courses some say don't, some say do. The natural corrosive properties of a brass nipple will help lock the spoke in place a bonus because it keeps the wheel tight, but make if hard to retrue if the nipples become fully corroded. If you do its best to use light oil like 3in1 for all purposes especially for nipple to rim bed contact were friction is greatest this can prevent equal tension when friction causes the nipple from turning. Oiling threads was also proved useful to prevent spoke wind up which can happen when using old nipples.

 

[rugbyleaguebiker]

Re:

Thanks for the input fellas, much appreciated. Can anyone recommend rims to look out for, I don't want to spend much bearing in mind I may have to have them trued anyway. Durability is as important as performance, I'm willing to sacrifice quite a few grass if it means wheels that will last

 

[RadNomad]

Re:

If you select a different rim brand or model you may find the spokes are the wrong length due to varying rim depth across different designs. You only have a few milimeters of leeway on spoke length. Be aware of this. Measure the candidate new rim if possible and compare with the original Mavic.

Always oil or grease spoke threads and nipple seats regardless brass or alloy nipples. It is good engineering practice and rumours of them coming loose due to lubrication are unfounded.

As for how much rim concavity is acceptable on an old rim, this is difficult to answer as rim wall thicknesses vary. Some minor concavity is ok but the day will come when a desperately worn rim will fail. If you are familiar with bikes and are worried about the rims in your possession that should probably tell you something. I never experienced a failed rim but have read a couple of stories on here and aparently it can happen quite suddenly and unexpectedly while riding. Several inches of alloy rim suddenly cracking free, inner tubes suddenly poping out sideways and jamming in the fork, that kind of thing. Better safety first..

 

[dyna-ti]

Undo each spoke nipple a 1/4 turn and continue going around till theyre all very loose.

Use masking take to attach one rim to the other, making sure its aligned around the way you want it and one at a time swop the spokes to the new rim.
Placing a thumb over the end of the spoke as you put it in saves from scoring the inner rim surface.

Deliver the effectively 1/2 built wheel to a shop for completion or try it yourself