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View Full Version : Front wheel wobble data analysis!


Fallout
16-08-12, 10:40 AM
Ok, so Laurie lent me the front wheel from his gixxer last night and this morning I have been arsing around with various combinations and trying to determine what the hell is wrong with alignment.

First up, it worth mentioning I do not have fancy tools for measuring the movement in the brake disks. All I've been doing it holding a tape measure under the disc, resting my hand on the fork, winking like a pirate and spinning the wheel to see how far it moves.

The three components in play are the wheel, the spindle and the brake discs. Brake discs have always stayed on the same side as they were before, so Laurie's left disc was put on my wheel's left side etc.

Raw disc movement data | L = Laurie's stuff, S = Me stuff
1. L Wheel, L Spindle, L Discs -> Left 0 - 0.1 mm, Right 0.1 - 0.2 mm
2. S Wheel, S Spindle, S Discs -> Left 0.3 mm, Right 0.5 mm
3. S Wheel, L Spindle, L Discs -> Left 0.3 - 0.4mm, Right 0.8 -> 0.9mm
4. L Wheel, L Spindle, S Discs -> Left 0.1 mm, Right 0.2 -> 0.3mm

Stated tolerance for brake disc play in the manual is 0.3mm, so (1) Laurie's setup falls within that. (2) Mine is obviously on the limit on the left and way out on the right. This is probably my braking problem.

(3) The stat with Laurie's stuff on my wheel is very odd. Obviously this is not an exact science, especially squinting with a tape measure to measure it, so this reading could be out. Still, not good.

(4) Interestingly, my discs on Laurie's stuff was an ok setup, but perhaps suggests my discs are a little warped.

I think I do need to replace the wheel or somehow get it fixed though, since it seems to be the consistent issue, plus it has loads of weights on it. Laurie's has one medium sized weight on it to balance it. Mine has 4.

Any thoughts on all this info? I was hoping it'd be 1 really obvious issue, but it doesn't seem to be.

Sir Trev
16-08-12, 10:55 AM
Sounds like a trip to see Stewart is in order. He looked at my rear disk after an advisory on it's last MoT and after checking a few things said don't worry. He has a proper wheel balancer as well so will be able to clean up your weight issues*.



*inuendo likely to follow...

Fallout
16-08-12, 11:01 AM
I don't think balancing will help though. That would take out vibrations but wouldn't sort out the actual movement of the discs unless he has some special tools to accurately bend them or something.

Fallout
16-08-12, 09:07 PM
I've bought a second hand SRAD wheel for £60 delivered. Cheapest I could find on ebay which isn't described as fecked. Will report back if it helps. Otherwise I'll have a spare!