Mounting weights up front on frame? Options?

Through some creative motor mount/clutch/seat tetris I was able to get the weight distribution just about spot on.

43.7% front/56.3% rear and cross weights very close.

In order to achieve this I found the best effect and potentially a convenient spot where I show in this pic below.

I am looking for ideas how to mount the weight up there without welding on a tab? THe floorboard is too flimsy and not sure its even legal to mount lead to it.

Any examples of how people have mounted weight here?


Yeah I wouldn’t mount to the floorpan there, probably wouldn’t last long. And not sure I would want to mount the frame anywhere there either.

Can you put it on the frame where the steering shaft mounts? That’s a pretty typical place and won’t affect chassis flex.

You should probably be shooting for about 48% cross weight on a predominantly left hand track If you’re putting this much effort into scaling.

Scales?!?! 48%?!?!? You are a mad man!

I think this is where you are supposed to say put the seat in the factory location and dont touch it :wink:

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You’re 100% right on that for a Euro chassis. :grin: It’s hard to screw up the weights on those if you place the seat right and pile the lead on the seat.

I have never seen lead…


Confused Wile E Coyote GIF by Looney Tunes

I feel you there…

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Soooo…anyone have any suggestions for mounting up front?

If you must:

I reiterate that you should see if you can move some stuff around and mount it here on the steering column mount and still be close on your cross:

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Bolt it to the tab on the right of the photo where the front bumper mounts to. You’ll have to drill the hole out to M8 to be legal in most series. It’s further to the side from your CG so you may be able to get away with a smaller weight than that one.

Can you fill the hollow torsion bar with weight without affecting its function?

Short answer: No you cannot.

So what’s the long answer? Not allowed under rule sets generally or just a bad idea?

Filling it with anythign solid would effect its function (stiffness, flex, torsion, etc). Filling it with lead shot or something similar is against most (maybe all?) organizations safety regulations.


Just for my own curiosity and education, would it not be better to mount that weight in the center on the steering column bracket, like TJ said, to keep your front percentage, then jump on the chassis to tweak the cross back in line?

If you go the bracket or tab route, that seems like a pretty “active” part of the chassis to mess with how it could flex in any way, especially asymetrically. To kinda put this in perspective, how tight that bumper bolt is right above where you show your weight going can change how the kart handles. I’m not good enough yet to really feel those type of things, but I have been told it really matters by people that know way more than I.

You would use the inherent slop in the rear cassettes before you start jumping on the chassis.

You can normally grab a percent or more cross just by loosening the cassette bolts and letting the chassis settle or smacking the cassette downward lightly with a mallet.

Most people aren’t going to feel or notice .5-1% on cross and you can adjust around it if it’s slightly off by fine tuning elsewhere. OP would be better served just sticking it where TJ says and not putting as much emphasis on a perfect scale. At track setup adjustments are going to change it anyway.

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Yeah I wouldn’t be jumping on my chassis to try and bend it into submission to get my cross % correct. You can probably move a.weight somewhere else and get the cross to be right if you center mount the front weight.

But also I would like to note that I haven’t checked cross weight on a kart in probably over 5 years. Getting it within a couple % is probably going to be close enough that you won’t really notice the difference.

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Ahhh, good to know. Makes sense for the little tweaks.

When you want to get real precise with your cross, you will grind out the notches between your ride height holes to give you infinite adjustability on cross. TJ is definitely the expert here, but when it comes to low HP stuff, cross is one of my tuning tools. I start every single weekend on the scales to get my baseline perfect and then adjust over the course of the weekend. I use this on every chassis I own now: