Topic: Another wide tire thread..

[Johnny340]

I have searched and not found the answer:

Has anyone actually run a 160mm rear tire (on a wide 17" rim) on a '75 CB750F?  I realize that the disc brake stay will have to be relocated or switched to a 550 style flat bar that can be bent.  I'm more concerned about swingarm clearance and chain to tire clearance.  Will offset sprockets be enough for the chain to clear the tire on a '75 F model?

I would like to be able to run Bridgestone Battlax S21 tires and the smallest size is 160/60x17.

[calj737]

Check with Devin @CognitoMoto. I believe his 750 runs a 160 and he can tell you want sprockets and swing arm he used for fitment.

[Johnny340]

Check with Devin @CognitoMoto. I believe his 750 runs a 160 and he can tell you want sprockets and swing arm he used for fitment.

Will clarify with Devin, thanks!

[Jwexperience]

I think you'll need either a 550 tubular swingarm or 77/78 stamped swinger. Other wise it's a 150


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[Retro Rocket]

Believe it or not, this is a 17 X 4.5 rim with a 180 slick, {of a 1988 GSXR750 race bike and wider than a 160}, in a CB750 F1 frame and swingarm, it was a tight fit but it did fit, I never used this combination so I can't help with chain line but i would think a set of offset sprockets would definitely help...   Get out a tape measure and measure the inside width of the swingarm...

[Jwexperience]

Isn't the f1 swingarm and k6 swingarm the same? I had a 150 tire in my k6 and I had about 1/16" on either side of the tire. 180 would not fit mine.


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[Retro Rocket]

Isn't the f1 swingarm and k6 swingarm the same? I had a 150 tire in my k6 and I had about 1/16" on either side of the tire. 180 would not fit mine.


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I wasn't suggesting to use a 180, I just said the slick fit inside the swingarm, just, a 160 should be not as wide. I don't have the 2 swingarms to compare but I doubt there's much difference, if any.. I haven't looked at the stock arm lately but from memory, there's a seam on the inside that could easily be ground down and welded up flush, if someone really had to use the stock arm, all my arms are aluminum now and have more clearance  ...

[Johnny340]

I wasn't suggesting to use a 180, I just said the slick fit inside the swingarm, just, a 160 should be not as wide. I don't have the 2 swingarms to compare but I doubt there's much difference, if any.. I haven't looked at the stock arm lately but from memory, there's a seam on the inside that could easily be ground down and welded up flush, if someone really had to use the stock arm, all my arms are aluminum now and have more clearance  ...

That 180 slick looks huge!  Cool, but all I want to fit is a 160.
There is seam of weld on the inside of the swingarm that I was thinking could be ground for more clearance.  It measures as enough room already but who knows how with the tire will actually be.  What kind of aluminum swingarm do you use? 
I'm thinking the chain clearance will be the hard part.

[calj737]

He's got one of those super cool CalFab swing arms made by MotoGP Werks in SoCal. He's just showing off, the boastful prick! 

[Retro Rocket]

He's got one of those super cool CalFab swing arms made by MotoGP Werks in SoCal. He's just showing off, the boastful prick! 

Yeah, I have a calfab 750 arm, a GS1100 alloy arm and a modified GSXR1100J alloy arm, that should make Cal happy...

[calj737]

 

[Johnny340]

Isn't the f1 swingarm and k6 swingarm the same?

I was wondering this too.  I thought the F1 was longer??
Also, I assume the sprocket carriers (cush drive) are interchangeable from 75/76 to 77/78 models, but what about from disc to drum hubs...Did the K models also get sprocket carriers with more tire clearance too?

[Retro Rocket]

Isn't the f1 swingarm and k6 swingarm the same?

I was wondering this too.  I thought the F1 was longer??
Also, I assume the sprocket carriers (cush drive) are interchangeable from 75/76 to 77/78 models, but what about from disc to drum hubs...Did the K models also get sprocket carriers with more tire clearance too?

Sprocket carriers from 77/78 are 10mm wider, as is the gearbox output shaft on those models..