Topic: 750 K8 Tire size combos

[lucky]

The stock tire size for the Honda CB750 was 3.25 ( INCHES)

Then tire sizing numbers changed.

3.25 inches = 82.54 mm. ( if they made one)
3.93 inches = 100    mm.  100(mm)/90-19

So the 100/90-19 tire is only about 1/32 inch wider
on each side than the 3.25 stock tire. Only .340 thousandths larger on each side.
Look at that on your vernier calipers.

I am not the only one using this Avon Road Rider tire for the front.
The tires are made much better than they were 33 years ago.

[brewsky]

If you look closer at the measurements of the front rim and front tire in the pics you will see that the front tire (dunlop 404 - 100/90) is 1.1" wider than the outside width of the rim.

The Avon tire chart says the 100/90 Roadrunner is 10mm wider (109mm) than the 100/90 Dunlop (99mm).

I know many people are running the Avons and liking them, that's why I was seriously considering them for my replacements. And when I called Avon for recommended size confirmation I got the 100/90 and 130/90 recommendation just like their chart says........until I questioned their minimum rim width listing of 2.15 for the front.

That's when he said no way would they recommend a 100/90 on a 1.85 rim, and questioned whether I had the stock size rim on my bike.

I know it CAN be done, and I know many ARE doing it (including ME), but that doesn't mean it is the best choice.

Would you mind to call Avon, tell them you have 1.85 stamped on your front rim, and then ask them what size front they recommend for your bike?

Also, how about measuring the width of your front tire and see if it isn't wider than 100mm?

[lucky]

OK..I measured my new AVON and it is 3.93 almost exactly.
3.93 thousandths is 100mm.

It does not look extreme at all.
I am not going to Daytona to race.

I certainly would not go down to a 90 width thats for sure.
That is what I had on my chopper. Way too skinny.

I am sorry that you had to go through all of this. I had to go through it all too.
But when I mounted my front tire on the rim I felt much better because it fit right.
It did not look weird.

[lucky]

Honda sold the CB750 with a 3.25 inch wide tire on the 1.85 rim from the factory.
Would AVON recommend that?

[brewsky]

Honda sold the CB750 with a 3.25 inch wide tire on the 1.85 rim from the factory.
Would AVON recommend that?

Actually, they do (as a minimum) for the 69-76......but the issued front size for the K7 & K8 is 3.50-19, not 3.25.

And 3.50 x 25.4 = 88.9mm.......which is still narrower than a 90mm

The real question is why does Avon recommend the 100/90 in their fitment chart, and then tell you not to use it on the factory issued rim size .....and then confirm that warning on the phone?

[lucky]

I understand Brewsky. Very frustrating.