Wheel Alighnment/Run out

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scottbc

Member
I'll post this here as I'm working on my EXC 450, but this question should apply to any bike. I needed to change my front tire so I thought that it would be a good time to lube the spoke nipples and check the spoke tension ect.

I started by removing the nipples one at a time, cleaning, lubing and re tightening. After wards I thought that I should check the wheel run out. I found the run out to be around 1mm to 1.5mm. Is this normal? What is acceptable run out on a dirt wheel?

Thanks, Scott
 
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Shuswap

Member
No info on the EXC, but my rough n ready DRZ400 has a run out service limit of 2.0 mm axial and radial. Personally, it could be more, I'll bet mine is, and I wouldn't worry.
 
SouthPoint

SouthPoint

Member
I am going to do some wheel truing this winter. Everything I have read says you should try for about 0.020" which is about 0.5mm. I'm not sure how realistic (or necessary) that is on a dirt bike wheel. I guess it depends on how much highway travel you do.
 
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scottbc

Member
If I had been thinking I would have checked what it was before I started. It's not that easy without a truing stand and a dial indicator or an adjustable pin. I mounted the wheel on the bike and used a bar between the forks with reference marks at the wheels furthest deflections. Then adjusted to keep the wheel centered between the marks. The problem that I see with this is that I am checking at the part of the wheel that is most likely to be bent or out of true. Black wheels don't help either, it's harder to see the variations.

Scott
 
SouthPoint

SouthPoint

Member
I'd probably just do the best with what you have, put it back together and see how it feels. Pick up a cheap dial indicator and a truing stand for next time. Neither are that expensive. You can buy both for about $125.
 
O

old trials guy

Guest
My secret trick is to use a sharpy marker. I just start by holding the marker close to the rim and spin it. Works best if you start at one of the "high" spots. If you place it lightly against the rim you should get an intermittent line on the rim. Adjust the spokes and repeat. After a couple of passes you should get a line around the rim. This line might get thicker and thinner and you can fine tune it until you get a consistent thichness which should be a very true rim. You can also see the axial runnout with this techique. You can do front rims right on the bike and rears as well, just take off the chain so the wheel can spin freely.

What is so handy with this method is you can see the high and low spots and it makes it super easy to adjust.

All for the price of one Sharpy marker. Solvent or WD 40 will remove the marker ink.

otg
 
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Phoenix

Phoenix

New member
When I replaced my front rim earlier this year I found it to be a perfect excuse to buy more tools. I bought the dial indicator and started to use it but switched to OTG's method as it was easier than trying to read the dial and left me with a definite indication of where I needed to tighten and loosen spokes. My final run out variation was within a millimeter or so and have had no problems all season with test runs at high speed. I won't mention the speeds but it's in the triple digits. Also my lesser quality rim had a natural variation at the weld which threw me off when trying to use a dial indicator.

Cheers, Alex.
 
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caribooster

Member
A quick and dirty method that I have used in the past is positioning a zip tie on each side for markers. They are stiff yet flexible and work well as a guide for your wheel.
 
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scottbc

Member
Thanks guys for all the good advice. What started as a preventative maintenance project to avoid seized spoke nipples has become a larger project. Tom, thanks for the link, that's a great article.

Scott
 
SouthPoint

SouthPoint

Member
Last weekend I had a go at truing my front wheel as it had an annoying hop, which I confirmed was not a tire problem when I put it in the truing stand.

I loosened all of the spokes and lubed them. I then mounted the wheel in the truing stand and used a wire pointer to tighten the spokes and get the wheel reasonably true. I then fine tuned it using a dial indicator. Nice thing about using the dial is that you can tell exactly which spokes need to be adjusted. It didn't take long before I had the run-out down to 0.025" side to side and 0.035" up and down.

The larger up and down movement was due (I think) to a bit of a defect in the wheel in one spot about an inch long. Except for that one spot, the rest of the wheel had about 0.020" run-out up and down.

Depending how good you want your wheels to run, I think it is well worth using a truing stand and a dial indicator.
 
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