Topic: f2/f3 cb750 front wheels.

[DAVE H]

Hi can anybody help,i have a cb750 f2, and a cb750 f3, i want to put the front comstar wheel of the f2 onto the f3 as it in better condition, looks nearly new, when checking the sizes i noticed the f2 has a 2.15 rim, and the f3 has a 1.85 rim,could it be the wider rim is off a cbx or cb 900,and will putting the slightly wider rim affect the handling.the wider rim has not got the black plastic pieces fitted to the spokes.
thanks
Dave.

[scondon]

I would think the 2.15 is a better choice for the 100/90/19 tires. The stock F2 rim(1.85) is so narrow that the tire profile is somewhat distorted. Just for giggles I went with the tire manufacturers recommended 90/90/19 on my 2.15 front rim and the bike corners pretty nice.

  Take a closer look at your front rim and you might notice a difference in the spokes when compared to your rear. I'm guessing it's from a '79 by your description.

[78 k550]

My F2 has a 1.85 and a 100/90/19 Have not ridden it yet but look's like the tire will do fine. Same size as on my 78 550.

Paul

[scondon]

   Yeah, I've always ridden a 100/90/19 on my F3 with no problems. After reading all the posts on tires I decided to check into what the tire manufacturers recommended for rim size fitment. I couldn't find a single manufacturer that recommended the 100/90/19 for anything narrower than 2.5 rims. Now they do squeeze on to the 1.85 rim, but I think the profile gets a bit distorted. Not that it really matters, I just wanted to see for myself if there was anything to it.

   In comparing the 100/90/19 on my 1.85 Comstar next to the recommended 90/90/19 on my 2.15 Lester, the Comstar really squeezes the 100/90/19 at the waist while the tire on the Lester fits real nice and takes the turns muuuuuch better. 90/90/19 is a pretty narrow tire and I don't know many people who would trust it to hold the road, so I'm not recommending that people switch.

  BTW, I could not find a single tire manufacturer selling tires to fit a CB750 that had a suggested rim fitment below 2.15. Typically they state a recommended range(2.5-3.0) and then a minimum and maximum width that they state their tires can be used on. 2.15 is the minimum for 100/90/19 tires according to Dunlop,Pirelli, and Avon.

  We've got people here squeezing 130/90/18 tires onto 2.15 rims who report no ill effects.Just wanted to say that if I had a choice between a 1.85 and 2.15 rim, I would choose the 2.15 rim to fit a 100/90/19 to.