Wheel trueness - why is it important?

Krypton

Hi,

Just got a new wheel-set for my Sirrus. I fitted them easier than I thought (just had to adjust brakes) and had a great first ride out on them yesterday.

I did notice, however, when I span the wheels by hand that there was a very slight wobble on the front of maybe 1mm or less (wheel got nearer and farther away from brake block by a tiny amount). Similar story for the rear.

I didn't check the set I was replacing so can't say whether they were better, the same, or worse.

My question, I suppose, is does it matter?

What are the negatives associated with a wheel that doesn't spin absolutely true?

Are all wheels a little bit "out"?

Cheers,
Shaun

--
Stopped smoking, saved a fortune. Started cycling, spent it all! - PS, don't <b>CLICK THIS LINK!!</b>

The Bosscp

Rim wear due to the brakes will be uneven.
Is more likely to go more out of true quicker.

Check they're definitely seated in the dropout correctly however.


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simbil1

If new, they should be absolutely true - I'd take them back.
As The Boss says, the rim wear will be uneven once they are untrue. They will not be as efficient either and depending on the cause of the defect can carry on getting more out of shape.

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Uncle Phil

The other problem is that to avoid having the brakes dragging on the rims, you'll have to adjust them with more clearance between the blocks and rims. With only a millimetre of wobble it's no big deal, but small wobbles often go on to become big wobbles, and then the brakes have to be so slack that by the time you've got the blocks onto the rim, the lever's hit the handlebar.

You know those nasty full suspension moutain bikes that hoodied young chavs ride along pavements? The ones that always have the V brakes disconnected? The reason they're disconnected is that the wheels are so wobbly that the brakes would drag all the time if they weren't.

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Mister Paul

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by The Boss</i>

Check they're definitely seated in the dropout correctly however.
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This wouldn't cause any change in distance between brake pad and rim on each rotation. It would just mean that the rim was possibly closer to one pad.

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monty_dogcp

Whilst it might be acceptable for pootling about, having out of true wheels on fast descents or for rapid stops can be scary - the brake can snatch, making braking and handling erratic. It's very hard to get smooth. progressive braking when the wheel is out of true. Wheel rims will wear through quicker to as all braking effort is confined to certain points.

008

I once went to my lbs as I noticed the front wheel was slightly out of true... probably the same as yours Krypton... ever so slight and not rubbing on the brakes blocks. Anyway, lbs told me it wasn't a problem but if it got worse then bring it back in.

That's the thing I like about my lbs, he keeps sending me away instead of fleecing me. He could easily have made ever so minor adjustments and charged me for it... but didn't![:)]


I saw a guy the other week whos back wheel was horrendously out of true... looked like a clowns bike the way it was wobbling round. I was going to tell him about it (just in case he wasn't aware) but noticed the back brakes disconnected... so left him to it.

Krypton

Thanks for the replies.

I've done about 50+ miles on them now and re-checked them last night.

There's no change from initial fitting, but I think I'll ask the LBS to true-up the back wheel as that has a more noticable wobble, and just keep an eye on the front one as it's very minor.

Does feel faster with the new wheels and skinny tyres though, and it seems to pull away from lights much better! [:D]

--
Stopped smoking, saved a fortune. Started cycling, spent it all! - PS, don't <b>CLICK THIS LINK!!</b>

pauluscp

If the rear wheel goes out of true on either side it will put the spokes on the opposite side to the loose ones under more pressure,(tightness),which could lead to spokes snapping and then the wheel having to be rebuilt or scrapped altogether.

So many roads, so little time!!!

008

Krypton - Just out of interest... what wheel set and tyres/size did you get?

Krypton

I got the Shimano R550 wheelset with Spesh Armadilo 23s - a harsher, but slightly faster ride than the stock Alex rims and 28s.

--
Stopped smoking, saved a fortune. Started cycling, spent it all! - PS, don't <b>CLICK THIS LINK!!</b>

ysarn

Ironic when you talk about rim wear that cheap pinned rims tend to have wear indicators. Is this because pinned rims are more likely to go out of true, so get faster brake wear, whereas better welded rims hold true longer so brake wear is better...