Home Forums General Karting Discussion Rim Width

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    • #22270
      Joshua Guiher
      Participant

      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.

      Where should I start?

    • #22271
      David McDowell
      Participant

      Josh,

       

      You are looking at rim width not circumference. Most rear wheels ran today are 5″ circumference.

    • #22272
      Joshua Guiher
      Participant

      Yes, but as you stretch the width from 210 to 218, does that now change the circumference (roll out), at least a small amount?

    • #22283
      Joshua Guiher
      Participant

      Yamaha Senior (Piston Port) following WKA rules

    • #22287
      Gary Lawson
      Participant

      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.

    • #22289
      Joshua Guiher
      Participant

      Thank you all for the responses, I understand now.

    • #22277
      Walt Gifford
      Participant

      You want wheels that are 1″ wider than your tires. Don’t worry about the roll out, RPM is controlled by changing the rear sprocket.

      Gif

      FAA certified jet engine and aircraft technician,
      Nicholson Speedway class champion 2001,
      Yamaha KT100 Service Center,
      41 years karting experience

    • #22278
      James McMahon
      Participant

      Welcome to karting.

      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.

      What class are you running?

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