quicker lap times with less grippy tire

[michael smith]

i want to know if there is anyone out there who has gone quicker by putting on a less grippy tire.

there are two schools of thought on this
1. you can never have too much grip
2. you can have too much grip and have to get rid of some.

i know one can tune a chassis to provide less grip but what im more curious about is if anyone has specifically mounted less grippy/harder tires and it made the kart quicker.

low hp classes especially.

thanks.

[Gary Lawson]

I’ve had vega whites on a yamaha and went faster with a harder tire. Both sets were new. No doubt you can have too much grip

[michael smith]

thanks for the feedback.
do you have a theory on why it was faster with the less grippy tire?

thanks

[Gary Lawson]

Not really. Kart was just stuck to the track and lost a lot more rpm in the corners. The soft tires had so much grip I could go full throttle through most corners while with the harder tires I could lift and it would still exit faster.

[TJ Koyen]

On track with long straights, you might even find a super soft tire gives you so much more rolling resistance on the straights that you go slower.

Definitely have noticed this when switching between MGs and Bridgestones, even in TaG.

Driver/Coach/Wrench : Innovative Performance/Exprit
Owner : Oktane Visual - www.oktanevisual.com
www.facebook.com/oktanevisual
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[michael smith]

Great information guys. Thanks.

Is there a way to tell when it might be time to try a harder tire?

I guess going around turns full throttle is one way. any others?

[TJ Koyen]

Hard for most of us 2-cycle sprint racers to say. Most organizations spec a tire so you don’t have the option to try different compounds.

Testing different compounds would be the only way to tell for sure.

When you’ve exhausted all possible tuning combinations to free the kart up properly on a tire and you still are struggling to get it free, then a harder tire might benefit you.

I would think there would be SOME setup that would free the kart up to make the tires work properly, unless we are talking really low hp stuff. I feel like even in Yamaha you could get the kart rolling nice through the corners on a super soft tire. My note about straight line speed being compromised by the extra rolling resistance of the tire still stands though.

Driver/Coach/Wrench : Innovative Performance/Exprit
Owner : Oktane Visual - www.oktanevisual.com
www.facebook.com/oktanevisual
www.instagram.com/oktanevisual

[michael smith]

Thanks tj . I AM taking really low hp stuff.

I did an interesting test today. I took out timing from a clone to take out some power and see what the data looked like. It was very interesting.

Eg. Corner entry speed is 30 mph. So ,brake to 30 mph, turn, and then get on the gas. It was interesting to notice that, even with foot flat on the gas pedal, as long as the steering wheel was turned it would not accelerate . It just kept the same speed through the corner even with the throttle all the way open.

It was definitely an eye opener.

[Cory-Milne]

my experience is that you need drive the kart differently with newer/grippyer tires. More grip= more potential rolling speed. also kart setup plays an important roll in this situation. you may have to much grip in the kart when you add grippyer tires try pulling castor out of the kart, harder axle, shorter axle, higher airpressure,  or more positive camber if none of those help try the right foot.

[michael smith]

Thanks cory. Great info.

Another related question i have for all is can the ackerman setting have an effect on the freeness of a kart.

Ie, going to the inner holes provides more toe out on cornering. I know that excessive toe out or toe in on the straight leads to loss of speed. Can the same thing be happening in the corners?

[Gary Lawson]

Simple answer is yes but that will be very hard for you to feel. You will likely feel if you have too much Ackerman if the kart turns in very quickly or is darty on entry.

[michael smith]

thanks gary.
thats something i just need to test and see.

[TJ Koyen]

Ackermann is more of a driver preference thing in my experience. It gives a different front end feeling. A driver with quick hands might not like it since it makes the kart really reactive and darty as Gary said.

Driver/Coach/Wrench : Innovative Performance/Exprit
Owner : Oktane Visual - www.oktanevisual.com
www.facebook.com/oktanevisual
www.instagram.com/oktanevisual

[mark sawatsky]

I own a kart track and it also serves as a mini laboratory for my crazy experiments. In general, you deal with understeer by braking later and getting on the gas later and with oversteer by braking earlier and getting on the gas earlier. Because of this, we have seen karts with worn out rear tires get great lap times because drivers can get on the gas really early and accelerate all the way around turns. Once we put new rear tires on, balance shifted to neutral or understeery and lap times suffered even though overall grip went up. I’m no expert but I would try to increase grip on the front before I would try a less grippy tire on the back.

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