Which American Racers size?

[FreakShee]

Hi gents 

The bike made 85hp/62tq and +4 swingarm  My weight 171lbs. 
 

I Roll racing on asphalt!
No dig race no dragstrip! 

I tried AR 18x10x10 not sure what compound but no traction at all!

 

I’m thinking to go 21.5x10x10 SD23 or should I go with smaller such as 20, 20.5 or 21? 

Thanks in advance 

[trickedcarbine]

What clutch set up? What gearing? How high is the rear sitting?

[Stupify85]

I ran rd23 20.5's(65) and 22's(69) before.  Seemed to hook fine for me, but mine was stock and bracket racing on a prepped track. Rd10 is softer yet, but may not last. I just put on a new set of M/T ET Jr.'s 19/10/10. We'll see how they do in about a month.