Topic: Max Rim and Tire size?

[MCRider]

Hello:
I'm building my version of a Japanese Custom based on a CB750K2. I'm stuck on the rear wheel. I 've downsized the front to an 18" and want to take the rear to a 17". Does anyone know the widest rear rim that will squeeze in comfortably?

For example, I have a rolling frame (CB750F) with an Akront 3.00x18 and a 130/80-18 tire. That just barely clears the rr disk stay arm.

I thought I could use a 3.00x17, but no one seems to have it. Buchanan's has a 2.75 or a 3.5, but the 3.0s have been discontinued. The 2.75 is just a tad narrow to please me, but I'd hate to buy a 3.5 and then eat it. But a 3.5 would be kewl.

What are all these high powered Cafes running?
Thanks!
Ron

[hymodyne]

what you run on the rear may be determined by the rear brake stay. I've got a 120 on my bike and it just barely clears the brake stay. It also wears much faster in the center of the tire than it would if I were running a narrower tire...

many threads about tire size and selection here. check through what has already been discussed and you might (most likely) find your answer.

hym

[MCRider]

what you run on the rear may be determined by the rear brake stay. I've got a 120 on my bike and it just barely clears the brake stay. It also wears much faster in the center of the tire than it would if I were running a narrower tire...

many threads about tire size and selection here. check through what has already been discussed and you might (most likely) find your answer.

hym

Thanks for the prompt reply. After seeing my CB750F (lack of) clearance, and reading your post I looked again at my setup and agree the rear brake stay appears to be a potential problem. Luckily I have a good welder on board and he can reposition that.

The wider rim, even a 2.75, would correct the profile of the 120 or 130 to make the wear more acceptable. I think the stock rim is a narrow 2.15.

I have been searching for "rim" and "tire" threads and will continue to do so. Nothing definitive yet.

More comments?
Ron

[FunJimmy]

I have a 3x18 alloy rim with a 130 tire on my 550 cafe and everyting is great.
If I were you I'd consider relocating the brake arm.

[MCRider]

I have a 3x18 alloy rim with a 130 tire on my 550 cafe and everyting is great.
If I were you I'd consider relocating the brake arm.

Thanks, was pretty sure the 3.00 would work, but held out for info on 3.5. EastCoastWheels.com told me they have sold 3.5 for CB750 with no negative feedback. Said if I bought it (Excel) and it didn't work they would exchange it for DID 3.00, so I bought the 3.5 with SS spokes. I'll lace it myself. Used to do it 30 years ago, so I'll have another whirl. Bought a truing/balancing stand off ebay for $130.

I'm expecting to move the brake stay.
Ron