How true should a wheel spin?

LancsRick

Ok, so the more I learn from these forums, the more attention I'm paying to setup details on my bike (Boardman Hybrid Comp).

The latest thing has been to check that brake rotors are true, and in doing so, also checking whether any wobble is down to the rotors or the wheel itself.

My front wheel is pretty damn good, when I spin it with the bike inverted, I can sight a "tremor" in horizontal wobble, but other than that it's sweet as a nut. The rear wheel though, has a definite wobble to it from true at one point, maybe 1-2mm deviation from eyeing it up. There is no slackness in the rotation, and I've checked that the wheel is fully set into the notches in the frame.

So my question - is this level of wobble acceptable, and if not, is there anything I can do without getting an LBS to check the wheel rim and adjust the spokes? I'm somewhat baffled given it's only a couple of months old with a couple of hundred miles on it!

Cheers in advance for any help.

LancsRick

Taken tyres and tubes off both, and both rims actually have a single wobble on them, the rear is just much more pronounced. I've been reading up on tweaking spokes myself, and to be honest, it looks like without at least making myself a crude jig I could make the problem worse rather than solving it.

My LBS has a truing stand and wants about £9 a wheel assuming it's just a spoke issue (there's no rim damage so I wouldn't expect any issues?) - to be honest I'm tempted to part with my £18 and get the job done properly.

My reading has led me to the conclusion that this isn't really anything to worry about, and is probably pretty normal for brand new wheels after they've been ridden a bit? Most people seem to advocate re-tensioning all the spokes on a new wheel soon after purchase from what I've seen?

Thoughts?

Monty Dog

The British Standard for new bikes allows something like 2mm lateral tolerance in the 'true' of the wheel but ideally there should be no visible deviation. A correctly built wheel will not usually go out of true as it will have been tensioned and de-stressed correctly. It's quite likely that your wheels won't get any worse and as you have disc brakes, will have little effect on ride performance. However, learning to true a wheel with a spoke key is a valuable skill - you don't need a workstand as your wheel is already mounted in a pretty handy jig (the frame)!

LancsRick

So although I might be worrying more than I should, tweaking it to be perfect is a) plain desirable and b) likely to last given they're new wheels and in decent nick? Probably going to let the shop do these, but when I ditch the old MTB next year I might learn to meddle with wheels on that, no impact if I foul up then! Cheers.

cycleclinic

For a disc brake wheel it will make little difference but if it were mine I would true it.

I had a small accident on my Trek that put the front wheel out well I thought it was out but by only 0.4mm. I suppose I am used to seeing wheels very straight. I thought it was more like 1mm so your wobble may not be as bad as you think.

When truing though so long as it within 0.5mm it will be fine. Just stress relieve after adjusting tension to remove any wind up as pinging when you are riding will throw it out again.

LancsRick

To be honest I tracked it down because my disc brake rubs in one little place, so I have to have the pads slacker than I normally would. Being the obsessive person I am, and because I like understanding how things work, I read up on truing disc rotors, only to lead myself to truing wheels and realised that was where my problem lay!

It's definitely more than 0.5mm out at the moment, so even if I'm likely to get away with it in the current state, there are clearly improvements to be had .

patrickf

LancsRick wrote:

To be honest I tracked it down because my disc brake rubs in one little place, so I have to have the pads slacker than I normally would. Being the obsessive person I am, and because I like understanding how things work, I read up on truing disc rotors, only to lead myself to truing wheels and realised that was where my problem lay!

It's definitely more than 0.5mm out at the moment, so even if I'm likely to get away with it in the current state, there are clearly improvements to be had .

Correct me if I'm wrong here, but if your disc brakes are rubbing then this is because the rotor is warped, not because the wheel may be out of true.

You may want to get a rotor truing fork instead of worrying about the rims?

LancsRick

It was a double whammy, both need tweaking. Already sorted the rotor with an adjustable spanner .