Scale help

[Richard Gordon]

just put our new kart on scales.  Off a bit from where it needs to be.  Is for Lo206 class that uses a hard Duro tire.  Numbers that I’m shooting for are:

49% left side

50% cross

and 57% rear

numbers we have with driver and 1.5 gal of fuel are:

48% left

46% cross

59.5% rear

the RF spindle was dropped on spacer from neutral.  Tire pressure is equal all around.  Seat positioning is maxed out.  Where should I try mounting weight to get the percentages I want?  Will have to add around 35 lbs go get to class weight.  I don’t have adjustable bearing cages, guessing weight placement will be the best tool?

[Randy McKee]

Hey Richard,

A couple of questions and tossing out some ideas for things to try…

1.  You mentioned it’s a new chassis so why is the right spindle dropped one spacer?  Was this to compensate for the cross weight or something else?

2. What do you mean by seat positioning is maxed out?  All the way back or butted-up against something? (I’m guessing this is a tall driver and you don’t want to move seat forward.)

I’m not familiar with the setup on an Lo206 chassis, but the numbers you are shooting for are pretty standard for most karts.  It might require mounting weight at the front of the kart to achieve those % (based on where you are now).  Try scaling again, and rest the weights on the front center of the seat and your legs (just over the front seat tabs).  This should give you an idea if it’s possible to get enough weight forward without actually mounting the weights.  My guess is you’ll either have to mount a weight up near the steering shaft (not recommended) or move the seat forward a bit.

 

As for the cross weight:  That can be caused by minor movements in the steering when scaling as well as one tire slightly larger than other side.  Did you make sure steering geometry is set correctly (toe, camber, caster) and then scale several times to make sure you get consistent readings.  Also measure your tires to make sure they aren’t the cause of the cross-weight.

The right spindle thing is kinda weird, but you can easily fix a tweaked chassis (if that’s the reason for it), but jacking it up on one side and jumping on the other (lightly).  It’s done all the time, but don’t worry about that until you let us know why the spindle was dropped.

 

[Richard Gordon]

Thanks for the reply. Yes, had cross weight issues. Had to tweek the frame by bouncing on the RF. Is where I want it now so I can get the left and front where I want with added weight. Since it was new, didn’t think it would be out of square. Did double check the front end settings and the tires were all good. Made sure the scales were totally level too. Should be good once I get the lead I ordered. Hope to get to the track next week to test it out.

[Randy McKee]

Sounds like you’ve done everything correct so far.  I would consider putting the spindle back to matching the other side and tweak the chassis again to get matching side to side in front.  That will at least give you a consistent starting point with ride height in front.

When your weights arrive, try getting your %’s after resting some weights in various locations.  You might get really close with that much poundage.

BTW: I’ve had a couple of chassis that like 59% rear, but those were shifters (different requirements for rear grip).

[Richard Gordon]

Actually did move the spindle back to neutral and then got the numbers for cross. Will see how the rear percentage does. Seems like the LO206 needs more front. Most run around 53-55% rear. The chassis I have likes more rear. Got a good idea of where the weight needs to be bolted, but will play around with it on the scales and see what happens.

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