My mate has got.......

[chalky4]

an orange thing and has a problem. His back tyre is rubbing on the chain, chain all adjusted ok, suspension adjusted ok, the only thing we can come up with is the wrong size tyre.
His bike is a KTM 640 LC4 Super moto, and he is running a Bridgstone 160/60/17 on rear.
Any suggestions?

[Snaphappy]

He should be on

Tyres (Front) *120/70-17 Tyres (rear) *160/70-17
Doesn't seem much but chewing chain is not good

[Zenarchy]

Have you checked the back wheel alignment and straighness between the front and back wheels with a big straight stick or some chord? (if you've already done that forgive the dumb question but if things are out of alignment perhaps that could be a reason for it too).

[chalky4]

Not a dumb question and will check that he has looked at wheel alignment although having looked at his rear tyre the wear on it is very uniformed thinking about it now I'll also ask if he has got the correct spacers in assuming they have some.
I'll pass on info about tyre size but will the increase of 10?? depth make a difference on the tyre width. Am I correct in thinking the 1st figure is the width, 2nd the depth and 3rd diameter.
Thanks for replies...........keep telling him he should have got an XRV

[Snaphappy]

it could have its obviously just touching where as it should be just clearing

175 The tyre section width in millimetres (That is the width of the tyre tread) 70 The aspect ratio in % (the height of the sidewall divided by the tyre's width) R Denotes the tyre's construction type - in this case it's a radial 13 Rim diameter in inches 82 Load Index T Speed Rating

if the wheel spacers are fitted wrong this means the chain is also under side stress and will cause even more problems

[Sambamboo]

Its normal to get a little chain chaffe with a 160. but if its touching when statonary something's not quite right.

You get a lot of different rim setups for ktm's 4.25/5" wide, cush drive/non cush, and there are 1 or 2 different offsets. Check the part no's are correct for that year of bike.

[chalky4]

Originally Posted by Sambamboo

Its normal to get a little chain chaffe with a 160. but if its touching when statonary something's not quite right.

You get a lot of different rim setups for ktm's 4.25/5" wide, cush drive/non cush, and there are 1 or 2 different offsets. Check the part no's are correct for that year of bike.

Thanks for reply Sam but he's now got shot of it and bought one of those fast red Suzuki things that kill your back after about 50 miles...... each to their own I suppose