Stupid question

cm59 · Post by **cm59** » 16 Oct 2009 10:16

My front wheels not straight is this called out of true? When it goes round it rubs the brake block at a certain point.
How do i get this sorted? How much does it usually cost?

John Sanderson · Post by **John Sanderson** » 16 Oct 2009 10:36

Yes - that can be called 'out of true' - or some people say 'buckled'.

You can get this sorted by changing the tension in the spokes - which is achieved by twisting the spoke nipples - the small caps that sit in the rim of the wheel and which the spokes go into. If you Google the subject you'll find plenty of info. Ideally you'd do this using a wheel truing gauge, however it can also be done with the wheel in the frame - using the brake block as an indicator of where the wheel is 'out of true'.

However - messing around with wheels like this is something of a 'dark art' (or at least as far as i'm concerned it is!) so I always take the wheel to a bike shop and ask them to 'make it round again...'.

Cost? Depends on the shop - may be as little as £5 - some places might charge you as much as £20. I found that it is usually cheaper if you take just the wheel in, and remove the tyre and inner tube yourself - rather than taking the bike in and giving the shop the work of removing the wheel, etc...

George · Post by **George** » 16 Oct 2009 10:37

Yes, that's out of true.

A little blip can usually be corrected in minutes by fiddling with the spoke tension. You can do that yourself or get a good bike shop to do it. However, if the rim is seriously deformed the wheel will need rebuilding (i.e. taking apart and putting back together with a new rim and possibly new spokes). Whether that's worth doing depends on the quality and condition of the bits that are still serviceable; sometimes it makes more economic sense to simply buy a new wheel. The cost of a rebuild depends mainly on the parts you decide to use. Then there's obviously labour as well: a rebuild would take me half a day, but a skilled mechanic can probably do it in significantly less.

Post by **CakeStop** » 16 Oct 2009 10:41

Easy job for you local LBS. If you do it yourself just remember that to tighten a spoke you turn the nipple anticlockwise (looking at it from the hub) which can be a bit counter-intuitive, or at least it was for me last time I tweeked a wheel and couldn't understand why it was getting worse not better

GrahamGamblin · Post by **GrahamGamblin** » 16 Oct 2009 10:55

Hi Chris,
I had to do this yesterday - agree with the above, a small sideways wobble in the rim can usually be straightened out using a spoke key to tighten or loosen spokes. Identify where the wobble is, then use small adjustments (quarter of a turn at a time) of the adjacent spokes - if you tighten a spoke, it will pull the rim towards the side the spoke originates from at the hub. Make a small adjustment, spin the wheel and see whether you've made it better or worse. I turned my bike upside down and used the brake blocks as a guide for this.
I have to admit though that this scares me a bit, I worry about pulling the wheel out of shape, and if it was anything more than a little wobble I'd take it to the shop.

John Sanderson · Post by **John Sanderson** » 16 Oct 2009 11:31

I've always been reticent to tweak wheels as the tension of all the spokes is related to the tension of all the other spokes....

My understanding is that a wheel can be built and be round but be either under tensioned all round, or over tensioned all round - depending on how well it has been put together. So i've always envisaged that i'd start tweaking and probably not know where to stop - only to find out when the wheel either fell apart of pulled itself apart.....

Post by **CakeStop** » 16 Oct 2009 11:38

....and for each spoke you tighten slacken off the spokes either side so you minimise the adjustment to any single spoke.

Edit: John's is a good point. Depends how big the wobble is. If it's only slight (your brake blocks are close to the rim) I'd attempt it myself. If it's a big wobble I'd be concerned. If you tap the spokes with a screwdriver the sound coming from the spokes on either side for the rear or both sides for the front should be similar. If the adjustment means that some spokes will be much tighter than others it might be best to get it looked at.

George · Post by **George** » 16 Oct 2009 16:54

In an ideal world, the tension on all the spokes should be the same. Often, a wheel goes out of true precisely because the tension is not uniform (e.g. because a nipple has worked loose). Then, far from messing up the evenness of the tension by tinkering, you are restoring it. However, sometimes the wheel is out of true because the rim has a minor deformity, e.g. caused by hitting a stone. If that's the case, it's often a choice between, on the one hand, living with the wobble and, on the other, putting uneven tension on the spokes in order to compensate for the deformity. A wheel ought to be able to tolerate a bit of irregular tension, but the less even the tension becomes, the greater the risk of a spoke snapping while you are riding. Judging how far you can push your luck is just down to experience. You can gain that experience by initially limiting your tinkering to wheels that are only slightly out of true ... which is a good thing to do anyway, because it is often a case of 'a stitch in time'.

charlie · Post by **charlie** » 20 Nov 2009 23:21

Some wheels are built with the spokes too tight. When one breaks it usually results in quite a buckle in the wheel because of the tension. I used to slacken off all the spokes on a new wheel, although you have to be very careful whilst doing it.