Topic: Front/Rear Tire question

[macisaguy]

I'm replacing my front tire on my '78 CB550.  Front tire is old/dry rotted.  Back tire is in beautiful condition. 

I'm planning on a Metzeler 3.25-19 on the front.  HOWEVER, the back is a Pirelli 120/90-18

That's obviously a pretty big difference in tires.  Is that an issue? I read you don't want more than a 10mm diff.  I'd like to be able to save some $$ and not replace the back tire, because I don't have to.  Even if I put a 3.50 on the front (which I think is actually close to original stock size?), that's still a 30mm difference. 

Am I even understanding this correctly?

Anyone have thoughts?  I'm still new when it comes to workin' on my bike, and this is the first time I've worked with changing out tires.

Thanks!

[Bankerdanny]

That back tire is a bit large for a 550 (I ran a 110/90 on mine), but since it obviously fits the swingarm that's fine. 3.25 would have been the stock front size and 3.75 was stock in the back.

Big differences in front and rear width are very common these days, I don't see where it would be a problem.

That said, don't assume that just because it appears in good condition that the rear is worth keeping. What is the DOT date code on it?

[goldarrow]

All of my 550 and 750 bikes, I run 100/90/19 front and 110/90/18 rear.  No issues,...well all my rims are mags.