Rental kart bouncing


As I’m trying to get faster at my local track with rentals, I find that the kart sometimes suddenly starts to bounce rather violently in one specific corner. After doing some research on my own, I found out that it might be the rear inside wheel that’s being lifted up and dropping back down too fast.

This is definitely slowing me down, and also throws me around in the seat which is not very pleasant. I’m not sure if my theory about the inner rear wheel lifting and dropping is correct, but more importantly I don’t know how to prevent/fix this behaviour (am I entering the corner too fast? am I steering too much?).

I found a video of this thing happening at the same track in the same corner,

Depending on the kart, the bouncing can be worse or better and sometimes also happens in the fast, full-throttle corners (the bouncing is less severe in these corners). Again, I’m not quite sure how to prevent this and how to react when it does happen.

Though a rental kart is going to be much less affected by traditional hopping since it’s heavier and running harder tires, your theory is correct. Typically hopping is caused by the inside rear unloading and loading quickly, in oscillation.

You can try a couple things to fix it with driving. Less severe steering inputs will help keep the kart more stable and reduce the likelihood that you overload the tires and cause it to hop. You can also try using your body to control where the weight transfer is going. If you really lean outward into the corner and press your body into the outside of the seat, you can try and put more weight on the outside tire and keep the inside tire from dropping down in the corner.

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Thank you! I’ll try this next time. Would adjusting the seating position also help with this? I imagine putting the seat a tad more towards the rear might help settle the inside rear?

Yeah if seat position is adjustable, absolutely. I would move it back a bit at a time and see what that does.

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I found this useful.

Slightly unrelated question however (apologies) given the harder compound of rubber used on a rental, is it possible to heat these up? Or is trying to do so (physically) just going to attract more bemused looks from the staff?

Basically, are these compounds workable in the short space of time you are in a rental session?


Yes. The hard compounds get grippy like regular tires after a warm up period. In our case, 2-3 laps. You will see folks swerving in the out laps to try to heat tire.

I don’t know that I’ve ever overheated a rental tire. Once the grip comes in it stays the same throughout the race. Dont feel drop-off.

Nice track and nice quality rentals. I do a fair bit of rental racing. The rental karts can get a nasty hop that appears to be weight related. It seems that if you ask too much of the kart in terms of how much you load up the kart laterally, there’s a breaking point. The kart then violently hops mid turn. Can be severe (I hurt myself, once).

So, for the corner in question, I rounded the entry and made the braking less late. Hop goes away.

Thanks for that.

I was a little conscious that staff would be looking on thinking “what an idiot, who does he think he is warming them up” or words to that effect :joy:

I’d get it if you then proceeded to be terrible but I’d like to think that isn’t the case.

The variables on rentals give me anxiety as I’m competitive to the point that If given the choice, I’ll look for the one with the least fuel in and will literally diet before going :joy:

The hopping was initially what I was looking and somewhat comforting to know others have had similar issues so that advice is great, thank you.

To be fair, tire warming can be a WTF moment and has led to many a pre-race tangle.

The idea is to go left right left rhythmically, working the tire. It’s not a fast scrub. It’s more of a rub-rub-rub, feeling the tires schlorp against the surface of track.

Also, heat brakes. Very important if discs involved. Not sure if some rentals use non-disc. This is simple. Brake a bunch to heat. Dont do big braking or you’ll get rear ended by the guy warming up his tires behind you!

Your experience with kart parity is hopefully better than mine at NJMP. In our case there’s a 5s gap from fastest to slowest kart. One needs to develop an alternate strategy than “win” if you get a slow one. Victory can be had by driving the heck out of a slow kart and doing better than expected.

To be honest, the funnest races are when you get a bunch of people whose karts are appropriate to their skill level. IE the less good drivers get the screamers and the experienced guys get the slower karts, for example.

Geneally, karts are done by lottery. It’s like a box of chocolates where occasionally you get the one filled with poop.

This may be a local issue. My pal who worked at a rental place said that his facility in France had parity and they would change out karts every 2 years.

Re: Diet. Right there with ya. I went from 215 to 165 to become faster. We didn’t weight adjust and the lads are light!

I can totally relate. Like Dom mentioned, adjusting your seat forward or back and using your body to lean in or out through the corners will help with rear inside lift and duration. Sometimes its just a question of how much steering input you apply or how quickly you apply it. Because each kart may be different, it takes time to learn their idiosyncrasies and apply the best strategy to overcome them. If it is not too busy, you may be able to request the same kart for a few sessions in a row. There may be some similarities between them as far as best seat location. Some may have a twist in the chassis that will inhibit their turning in one direction over another. So it pays to try several of them to sort out what works best for each. This will pay off in dividends if your track does League Racing and randomizes kart choice.