I am new to karting this year and need to get a couple sets of wheels. I have a Birel S3, so Freeline and Douglas seem to be my best options.
A new set of Douglas wheels is about the same price as used Freeline it seems.
For Freeline, they only seem to come in 130 / 210 for a set, while I have seen the Douglas come in 212, 214, 216 & 218 for the rears.
How do you know which size you want? I understand that a 212 would have less contact area, making the rear slide faster, but it would also have a bigger circumference so you would need less revolutions on the rear axle to get down the straight.
As mentioned contact patch is unaltered and circumference differences are cancelled out by gear changes. The difference is the change in sidewall stiffness. Wider wheels stiffen the sidewall and decrease grip. On a spec tire like ylc you want the 210 or 212. No bigger.
Keep in mind, assuming tire pressure remains the same, tire/wheel width actually has no affect on contact patch size, only shape. If you significantly change the circumference then that’s different, but otherwise, the adage that a wider wheel = bigger contact patch is incorrect.