Wheel balancing nightmare.

[steve452]

Bought a Wheel-balancing stand from Bikers Toolbox and have managed to get different readings spaced up to 180 degrees apart. Have tried it with and without the cones, in four different positions in and out of the garage and with the cone Allen screws secured 180 degrees away from each other (because the kit axle rod is 11.97mm OD but the cones are 13.07mm ID so there is an offset). I've added a pic of the latest attempt outside the garage (the base of the balancer rocks on a glass plate ..so this is the only place it doesn't rock). The last measurement is at 12 o/clock. The previous two are at 4 and 7ish. Any ideas what I'm doing wrong?

[Kwackman]

Is it possible that the wheel IS balanced?

[zapo]

Is it possible that the wheel IS balanced?

+1

[steve452]

Doh! The penny drops (or does it? see further on). Central Wheels stated they were happy to tension, true, and fit tubes and tyres and the rear wheel grippers but would not balance "wheels fitted with rim locks". I've been trying to balance a wheel NOT fitted with rim locks (the front) which I'm now assuming they were happy to balance from the start. The only problem with this is there are no visible wheel weights! All that I've done since picking the wheels up from them is add the disc rotors to the front (LH disc is my original with 22,000 odd miles on it, RH disc is new pattern as I've gone for Z-Power's twin disc conversion). I've now tried the wheel-balance stand with the rear and it has stopped in EXACTLY the same place on three runs. I've now successfully balanced the rear so the stand was a useful investment for the future. So, back to the front. Unless they've balanced it with invisible weights or fitted them inside the rim, the only conclusion is that by pure chance the wheel has achieved near perfect balance by the grace of god and good old British blitz spirit. Unless any of you can explain this I'll put it down to Z-Pixies.

[CAT3]

In order to balance a wheel the balancer must be on a flat, level surface. If your balancer does not have adjustable feet you could fit four M8 bolts in the base to act as feet. You could then use these feet to level the balancer before you start trying to balance a wheel. Fitting a "bulls-eye" bubble level to the balancer base greatly helps this levelling process.

Is the red dot on the tyre sidewall, (indicating the light spot of the tyre & should always be next to the valve, in theory the heaviest point on the wheel) positioned next to the valve ?

You need to make sure the support rod is straight & true as well. Rolling it on a sheet of glass or even you kitchen unit work surface will give a fairley accurate indication of trueness.
Also, check the two cones are the same, square & the tapers are the same as best as you can.

Make sure the four bearings that the rod rests on are free to rotate smoothly & with no tight spots.

If the cones have o-rings in their bores to hold them in place on the rod you may find that as the wheel rotates the weight of the wheel can push the cones apart & obviously that makes getting accurate readings very difficult. I find if I rotate the wheel slowly & then push the two cones firmly into the wheel bearings they usually stay put for that check. Repeat this process each time you rotate the wheel before leaving it to stop at the heavy spot.

To be honest I only ever bother with balancing my front wheels. I really don't believe that a bike like ours gets used to the level that requires the rear balancing. I've never had an issue with any of my bikes because the rear wheel was not balanced. The front yes, but the rear no.

I'm not sure if I've misunderstood you, but if your rear wheel has stopped three times in exactly the same spot then it is not balanced.

[CAT3]

Forgot to say your locking tabs look a bit of a mess !!

There has to be a knack of tightening those bolts without them gripping the tabs & twisting them up like yours.
Have you tried putting a tiny bit of grease unter the bolt head prior to tightening ? Or filing a chamfer on the underside of the bolt heads to stop the edges gripping the tab washers ?

[steve452]

I think you may have misunderstood me! My point is that with the same stand I could not get the front to stop in the same place on multiple tries and in multiple positions. As soon as I put the rear on it did indeed keep stopping in the same place and as a result I was able to balance it. This is what I expected as Central Wheels had said they would not balance a wheel with rimlocks fitted. The fact that I could not get the front to stop consistently in the same spot would suggest that CW did in fact balance the front (as no rimlocks fitted) as Kwackman pointed out. The mystery is that there are no visible weights fitted.
With regard to the lock washers I agree they look a mess and my next order to Z-Power (I'm about to start on the engine rebuild so will probably need more bits) will include some replacements. Surprisingly I managed to get the RH side bolted down without the LW's rotating. I think I had done the bolts up a hard finger tight before I torqued them and that might have done the trick.
Many thanks for your advice anyway. It is very much appreciated.

[CAT3]

I think you may have misunderstood me!

Yes, I think you're right
Sometimes I guess you can get a wheel/tyre set-up that isn't too far out balance wise. Your picture looks like the wheel has a metal dust cap fitted. If it is metal, you could maybe try removing the dust cap & see if it affects the balance at all.