I purchased a used Intrepid chassis for my first karting/LO206 season. The chassis came with 7.75 inch rear wheels and 7.1 inch rear tires. My local LO206 series (Houston, TX) uses Evinco Blue tires as standard, which are available in both 6.0 and 7.1 inch rear widths. I’d like to run the 7.1 inch rears in order to use the wheels I already have, but the Blue 7.1 inch tires are nearly impossible to find. That brings up the following questions:
- Does either rear tire size pose an advantage over the other for LO206 racing?
- Can a 6.0 tire fit on a 7.75 wheel, and if so, is it okay and/or advisable to run that setup?
- Will I even notice a difference between any of the aforementioned setups?
Thanks in advance for any help!
Whats most important is getting the the tire in the temperature range where it produces the most grip. A narrower tire at a good temp will be faster than a wider tire that you cant get enough heat into. It depends on your weight and driving style which one will be quicker.
Evinco Blues only come in 6 inch rears but you can often stretch a 6 inch tire to a 7 inch rear. This changes how the sidewall flexes, but I can’t quite explain the pros and cons of that.
Extremely interested to hear people’s thoughts on this.
I agree with comment above about it being critical to get tire within temp range. On a cadet for Evinco blue there are a few pressure windows that this work well.
The Blues actually do come in 7.1 inch rears (he said, like a know-it-all). I called Evinco to confirm it about a week ago, but they said they’re only just becoming available. The MG Red is an identical tire with different branding and it’s readily available in 7.1, but my ruleset stipulates Blues. Don’t wanna show up to race and be declared illegal.
The consensus seems to be that stretching the sidewall reduces the amount the tire can “roll over” under cornering loads, thereby decreasing grip. I’ve also heard the exact opposite—that the stretched, stiffer sidewall aids grip. I’m so new that I probably couldn’t feel the difference, but I like to have the mental boost of thinking my setup is “optimized”. ¯_(ツ)_/¯
Spot on. Thanks for the tips! Our senior LO206 class runs at 375 pounds minimum, and I’m light enough to be around there.
I’m going to get a pair of 6.5 inch rear wheels and run the 6.0 rear tires. They’re so much more readily available and it seems to be the de facto width for the class. Maybe once I have a more defined style and a better understanding of the kart, I’ll throw 7.1s on the back and see what happens. I doubt I’ll try to stretch the 6.0 on the 7.75 wheel unless the frontrunners swear it’s the magic formula.
@dpaddison We haven’t run the Evinco Blues but if they are the same as the MG Reds, the durometer is going to be in the mid 50’s out of the wrapper. Similar to the tire we run, Vega Red.
With a 6" rear tire we are running a 7.25 to 7.5 rear wheel. Many thoughts on wider being more “free” due to taking sidewall flex out. The way I like to think about it is consistency. With the sidewall being stiffer the tire will not have the ability to roll under and release and unload as often. Thus giving the kart stability through the turn. This stability gives the driver/tuner the ability to tune to a more constant input.
You will also have the heat as mention before. Typically a narrower wheel will generate heat faster due to the crown of the tire. On a hard club tire (duro 62+) we will run a 6.5 on a 6" tire to generate that heat. With a softer tire, you generally do not want to generate heat as fast. It will cause the tire to fall off late in a run.
All this is just my thoughts and what I have found to work. Every chassis is going to be a touch different and every driver is going to want a little different set up. Any of the info in the thread is good. With this being year 1. Mount up what you’ve got and go have fun, ask questions, learn a ton. Most importantly, HAVE FUN!
Don pretty much said what I was going to type. I stretch a 6.0 tire to fit the standard euro 210mm wheel that a normal 7.10 goes on.
Seems like the wider wheel frees up the rear end of my kart. Which is probably what you will want with the Intrepid.
Just speaking from my experience our club last year allowed us to run either the 7.1 or 6.0 on our YLC’s. The beginning of the year I ran the 7.1 and it worked great until the heat of summer kicked in and the track rubbered up. I was dealing with the chassis binding a lot and losing speed from the rear gripping too much. I bought a new set of tires halfway through the year and bought 6.0’s. The change was amazing the kart freed up and I wasn’t losing speed like I was before from the rear. Personally I think 7.1’s might be too big for the 206.