Rear Wheel appears off centre

Ramon518 · Post by **Ramon518** » Wed Jun 18, 2003 4:24 pm

Walking away from my G80S I noted with some alarm that the rear wheel appears to be off centre

The brake Base Plate is very close to the (LH) Jampot suspension unit (1/4 " ish), the chain even closer.
I have checked the external spacers etc. they are OK - could it be that the set up of the wheel centre bearings and locating parts are off centre.

Under the Mudguard, the Tyre also is closer to that side by about half an inch. - HELP!!

Biscuit · Post by **Biscuit** » Wed Jun 18, 2003 11:10 pm

Having checked my bikes ('56 G11 and '54 G3) I find the brake backplate is a lot closer to the jampot than a 1/4".I can't understand the remark regarding the chain, as it is inboard of the backplate, how can it be closer to the jampot?. I would suspect that the wheel has been re-built with an incorrect amount off offset.

Ramon518 · Post by **Ramon518** » Thu Jun 19, 2003 12:16 am

Sorry Alan, I mean't Chainguard.
However its a comfort to know that your bikes have their backplates similarly close to the Jampot.

This dimension is controlled by a loose bush that fits between the brake face plate and the swing arm.

Question is - how do I move wheel on spindle ( to the right) when the afore mentioned spacer keeps the 1/4"ish gap constant?? on the left.

I have looked closely at the swing arms and they are both just tucked nicely inside the bracket each side, definitely not off centre.
Is it possible that the spacer between the bearings might be too short - ie from another wheel type seem a likely answer do you or anyone else know if these spacers vary in length ( like the B52 clutch operating rod )
Thanks for your interest
Ray

Biscuit · Post by **Biscuit** » Thu Jun 19, 2003 10:40 am

Hi Ramon, Should you attempt to move the wheel to the right by varying the spacer dimensions, then of necessity the brake drum and backplate will follow suit and the extended portion of the backplate will not engage with the abutment on the left hand fork leg. The swinging arm is not symmetrical, the pivot, be it the earlier aluminium casting or the later forging, is offset to the right, which would place the wheel rim closer to the left hand fork leg than the right. Placing a straight edge along the brake backplate the distance to the rim is 2 3/8" in the case of the G11 and 2 7/16" on the G3. The difference is possibly due to the fact that the G11 plate is flat whereas the G3 has a raised portion around the outer edge. I am still inclined to the theory that the wheel has been built incorrectly.

Ramon518 · Post by **Ramon518** » Thu Jun 19, 2003 10:54 am

Morning alan
I will check those dimensions on my machine. Have you looked at the rear of your two (lucky man) bikes to see if the centre line of the Tyre is in line with the centre line of the Mudguard/No plate in each case.

Biscuit · Post by **Biscuit** » Thu Jun 19, 2003 12:15 pm

Morning again Ray, Have checked my two bikes, the G3 mudguard is dead centre to the tyre, the G11 mudguard was biassed to the left, but slackening the bolts for the tailpiece and hoicking (technical term that!) it over, left it also dead centre. I think the straight edge/ rim measurement will prove crucial. I used a piece of 1/2" mild steel, laid under the brake lever and pointing horizontally to the rear. Just remembered, the swinging arm is not symmetrical to allow the left hand boss to clear the primary chaincase.

silverarrow · Post by **silverarrow** » Thu Jun 19, 2003 1:15 pm

It strikes me that two things are important - that is chain alignment and wheel alignment. Both can be checked using straight edges. If one but not both align then the wrongly built wheel theory kicks in. Using whatever spacers are necessary to achieve both together is OK.
Les Smith

Biscuit · Post by **Biscuit** » Thu Jun 19, 2003 2:03 pm

Sorry Les, but tinkering with the spacers must be a no-no. Ray needs to shift the wheel by 1/2", where would that place the backplate stay and it's abutment?

silverarrow · Post by **silverarrow** » Thu Jun 19, 2003 4:59 pm

Did I miss out on the ½inch (12mm) bit? I thought we were talkings smidgeons (another nice techno word) here? I still think it wise to check the chai allignment and then see where the rim is if that is OK. Humble apologs for talking out of cinque. les Smith

Biscuit · Post by **Biscuit** » Thu Jun 19, 2003 5:59 pm

All is forgiven Les, well nearly all MILLIMETRES! go gargle - anyway did you mean 12.7 mm. Checking the chain alignment is a wise move, although the proximity of the brake backplate to the jampot would point to the fact that this appears to be ok. Ray does'nt give us the year of his bike, ie does he have the QD wheel or the 'cotton reel' hub with bolted on brake drum. If the latter he could have a missing/sheared key for the r/h snail cam. (Scraping the barrel now!)