Cadet kart tire widths

[mike willey]

Hi I’m looking for good front and rear wheel width measurements for my son’s cadet kart. It’s a 90’s invader that we overhauled with a softer wider 42″ long rear axle. It’s currently 49″ outside to outside on the rear wheels and 41 in the front. Any info would be great

[Gary Lawson]

39 front and 46 rear is a good place to start based on what newer karts run.

[mike willey]

A friend was tellin me 52 in the rear, what happens when you go too wide?

[FREDDY SANDOVAL]

Mike, you’re kid is doing a lot better

Kids are very funny and if you share too much info with them it gets even funnier.

Make a few adjustments, just to test, but don’t tell him anything, just let him drive it, and see how he does. I was checking out the videos from this Saturday night race, and he looked really good, nice and smooth, and very consistent.

If you really wanna try 52″ at the rear, he may lose lift at the inside rear tire, at the pit turn, but considering how light he is it may work to his advantage. Try it first, and if you don’t like it you can always go back all the way or closer to 49″

Is he complaining of a handling  issue right now?

T

[mike willey]

Thanks Freddy, no complaints just trying to make sure the kart is where it needs to be and not holding him back any. Yeah when I do change things I don’t tell him and he always says it’s fine. So hard to tell sometimes if my changes are affecting anything.

[Gary Lawson]

Is this actually a cadet kart? What size axle does it have and what wheelbase? Also what size tires and wheels are you using? Doesn’t sound like you’re on 130mm wheels on rear with 450 tires and a 30mm axle like what is spec on most cadet karts

[mike willey]

Gary, yes it’s a late 90’s INVADER cadet kart that we rebuilt with proper ackerman steering and put in a softer wider 1-1/4″ rear axle. We run the small tires front and back 10×4.5×5? Anyway these chassis are very stiff so getting them loosened up is a challenge. Lol

[Gary Lawson]

I think you will find that going any wider than 47 1/2″ in the rear unless you have an abnormally tall/big driver will cause the kart to sit too flat. Don’t be afraid to use a sawzall to the frame in appropriate spots to soften the kart. A popular area is the inside motor rail if it is tied in and also if it has “k”struts. You can always get a clamp and reconnect it if you don’t like the change

[mike willey]

Okay got the kart pulled into 46″ in the rear and 39″ in the front. Worked great he dropped a full sec on his lap time. It seems the kart is pushing out of the turn some now and he’s having to input a lot more steering. What do you think? It needs more front grip? Widen out the front track? Lower front spindles?

[Gary Lawson]

Put the front at 40. If you still need more then add some caster.

[Gary Lawson]

If those changes don’t help lap times much then try moving the seat forward 15mm

[mike willey]

Thanks!

[marc-andre hubert]

not sure where you race but Rok cup USA has decided to make the max rear width 44.25″ ?? why not sure.

[mike willey]

We race in Bakersfield CA at the Bakersfield Kart Raceway. It’s local club racing no sanctioned racing but maybe soon, just having fun right now. Haven’t got to try the set up yet. Caster is maxed, maybe it’s just more seat time. I’ll update

[mike willey]

Okay, went out today and the kart looked great! Moved the font width out to 39.5″ took the toe out in a hair and lowered the rear tires 1psi and he was cookin around the track. I guess it’s all about seat time now.

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