30mm Chassis vs. 405+lb

We are planning to move to TAG Heavy on an OTK 30mm chassis. Is that “enough”chassis for 405lb class-weight?

That’s pretty heavy for the all 30. Right now the national Masters class at USPKS is 385, and that’s about the limit for the 30mm frame before it starts to become difficult to work with. I know the top Masters guys setups pretty well and once the track gets quite grippy they are having to work pretty hard to get the kart to stay stable.

At that weight I would recommend the 32mm. That was the OTK standard for 390-400 lbs Masters several years ago. At those weights I recall a Masters driver telling me the 30mm kart “felt like the inside rear wheel was going to hit me in the head every time I turned the wheel”, and they much preferred the 32.

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USPKS is 400. SKUSA just went down to 385.

OTK’s work just fine in this class at 400

Ah, I thought USPKS was 385 as well.

Regardless, yes OTKs do work well in the class (or any class), but specifically I would recommend the all 32mm OTK for anything over 385-390.

Do you mean the OTK 30mm or 32mm?

I think we all ran 30mm OTK at 405# in Rotax Masters in 2011-2015 with an exception of a one or two. Getting it to roll efficiently on exit didn’t usually happen. I drove the same kart at 365#, what a difference on exit roll.

I’m on a 30mm chassis north of 400lbs (kart and driver) without issue. That chassis will take it, that is non issue. Being competitive at that weight, that’s another conversation.

I don’t know which OTK the 15+ guys in the class run. It would be interesting to know. @tjkoyen I assume it is the 32mm.

I run a KR which is a soft 30/32. In 2009, I ran an all 30 Firstkart FX8 that was pure magic at 405, but I am short so normally have 45+ lbs of lead on the seat and the rear wheel never hits me in the head.

This past weekend the kart was too flat on exit out of the tightest slowest hairpin but I had a chassis problem Friday and Saturday that only started to get sorted on Sunday. Still needed more caster though.

Here I am St Pete at 390 with lots of rubber. All the karts looked like this.


Kopp is on a 30, but as I said he feels he’s at the limit of it. Clearly still works but he has to work at it and he knows what he’s doing.

Like I said, the OTK 32 has always been the standard for Masters. I can’t speak for other brands.

The demands of 206 racing compared to TaG are far different, with the softer tire compound, higher speeds and power, and in general a different style of racing.

Great point, I stand corrected. My experience is ONLY 206. Thanks for the education as always. :+1:

He is a big, no lead kinda guy, but he clearly knows what he is doing.

Thanks for all the input, fellas.

This is purely tyre/grip dependant.
Im at 385 and the kart is in its element with low grip tyres/tracks on a 30mm.

Once its gripped up its hard to keep the balance.
We are a fair distance away from “standard otk” setup.

If your racing x30 or tag open i would consider the 32.

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