Rear wheel alignment/chain rubbing primary chaincase

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stevewhitt
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Rear wheel alignment/chain rubbing primary chaincase

Post by stevewhitt »

Evening all,

I have spent the last 2 days struggling to sort the rear wheel alignment/rubbing chain. Here is the story...

When I got the bike, and took the rear wheel out I noticed that in addition to the spacers, washers and nuts I expected to find, there were also 2 quite large round washers on the spindle of the drive side; the spindle was also fitted the wrong way round. So I corrected this and put it back together per specification. It was immediately obvious that the lower part of the drive chain was just catching the inside bottom edge of the primary chain cover. So, I then spent a few hours checking the alignment of the front/rear wheels. Corrected, it now means the but only by 0.5mm clearance. The top of the chain has a much healthier clearance of about 2mm.
I have attached some pictures for reference.
My questions are:
1) Is the brake anchor bar the correct way around; it fits the other way round but fouls the lower frame bar.
2) Is it normal for the large flat rivet on the brake plate to sit against the frame bar?
3) Should the brake adjuster spindle be hidden behind the upright frame bar?
4) Does the configuration of spacers and nuts look correct?

I am now wondering if the 2 large washers were used to bias the chain line to the centre of the bike by approx. 4mm, to avoid the issue of the chain fouling the primary chain cover. If that is the case, should I put them back, although I would want to understand why before doing so.

Looking forward to your thoughts and comments.
Attachments
IMG_1448.JPG
IMG_1450.JPG
IMG_1449.JPG
IMG_1453.JPG
IMG_1451.JPG
will_curry
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by will_curry »

The only thing in your pictures which looks wrong to me is
the brake anchor bar. The one fitted to my bike is considerably
thicker, is rounded at both ends and will only fit on one way round.

If yours is the wrong length the location of the brake adjuster and the
actuating arm will be wrong as well.
Adz.F
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by Adz.F »

I would say the same, I just purchased the correct one for mine from drags. Here it is mocked up to show you the relative position of the adjuster. Mine looks orientated forward compared to yours..
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by Adz.F »

Here it is..
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20221115_200451.jpg
stevewhitt
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by stevewhitt »

Thanks for the pictures and advice, mine is definitely wrong and I will purchase a replacement soon.

Just out of interest, how much clearance is there between the lower part of the chain and the edge of the primary chain case cover?
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by stevewhitt »

Sorry Adz, daft question for you....
Adz.F
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by Adz.F »

I will take a look after work tomorrow and get back to you in the evening!
will_curry
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by will_curry »

Mine has about 1/16" clearance top and bottom for the chain against
the primary chaincase but it does have alloy cases.

I've not had any dealings with tin chaincases but the alloy ones can be
adjusted somewhat using washers between the case and the frame
lug under the clutch dome.
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simon.holyfield
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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by simon.holyfield »

Heres a picture of my lower chain guard - the chain should run under the cast channel that's fed from the primary case, which you can just see at the front of the chain guard.

You might want to look at the bolt that acts as the brake pedal stop. It retains the primary case to the frame but is usually fitted with a spacer - the primary case is usually something like 1/2" away from the frame lug.

A missing spacer will pull the primary case too close to the chain.
IMAG5920.jpg
cheers

Simes

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Re: Rear wheel alignment/chain rubbing primary chaincase

Post by Simon.Gardiner »

Steve - bear in mind that the secondary chain runs close enough to the back of the chaincase for the makers(!) to recommend fitting the spring clip with the 'spring' in the inside, away from the chaincase, to avoid the rubbing.

The chaincases will flex a bit, I've had to add an additional washer between the chaincase and the frame before now to get the case right (if it's too much in the wrong place, one way or another, the clutch chainwheel usually rubs on one of the inside faces).

SG
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