The International CBX Owners Association

Done some reading..the original tyre was a 130/90. I think a 30 profile difference could explain the higher revs..or what you guys think?

So you have a Prolink then? 130 is the tyre size whilst 90 refers to the sidewall profile. Can you post a pic of your bike for us to see?

There should be online resource to calculate the difference.
I rode my bike this morning and I'm getting about 4800@65mph.
There is a big difference and I think that cause is more than jut tires. I would check both gauges for accuracy,

Guys!!!! Motorcycle basics! The 60 aspect ratio on the 160 makes that tire about 18% smaller in diameter than the 130/90. That will produce over 1000 rpm at 6000 rpm

EMS wrote:Guys!!!! Motorcycle basics! The 60 aspect ratio on the 160 makes that tire about 18% smaller in diameter than the 130/90. That will produce over 1000 rpm at 6000 rpm

Well that was actually what I had in my mind but waited until someone more knowledgeable than myself spoke up...

Thought so..anybody know what sprocket sizes will get revs to where they should be?

You could go here and play with the numbers http://www.gearingcommander.com

mcferreira100 wrote:Its a Bridgestone Battlax 160/60 ZR18 M/C

Any chance you could post a pic of the wheel you have on your bike?
If you do start changing sprockets be careful when removing both of them watching for spacers/washers. With a different wheel and wider tire you MIGHT be requiring offset sprockets.

cbx1956 wrote:

EMS wrote:Guys!!!! Motorcycle basics! The 60 aspect ratio on the 160 makes that tire about 18% smaller in diameter than the 130/90. That will produce over 1000 rpm at 6000 rpm

Well that was actually what I had in my mind but waited until someone more knowledgeable than myself spoke up...

Well, sorta. It makes the sidewall smaller, but it's still on an 18" rim. If the tire had an aspect ratio of zero, it still wouldn't be 18% less circumference.

Does this pic help?

Rick Pope wrote:
Well, sorta. It makes the sidewall smaller, but it's still on an 18" rim. If the tire had an aspect ratio of zero, it still wouldn't be 18% less circumference.

You are absolutely, right, Rick. The 18% refers only to the sidewall. The total tire diameter difference is a tad less than 6%. The rpm effect at 6,000 is only 360 rpm.

EMS wrote:

Rick Pope wrote:
Well, sorta. It makes the sidewall smaller, but it's still on an 18" rim. If the tire had an aspect ratio of zero, it still wouldn't be 18% less circumference.

You are absolutely, right, Rick. The 18% refers only to the sidewall. The total tire diameter difference is a tad less than 6%. The rpm effect at 6,000 is only 360 rpm.

Thanks Mike, for doing the math. When I responded this morning, I was only half way through my first cup of coffee, so I wasn't going to attempt any calculations. A man's gotta know his limitations.