Weight Vs Handling

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Hey all! Another quick question here.

Currently I weigh in at 125-130 (I know, Im a small guy!)

My Kart (Intrepid Cruiser V, Demagnetized chassis, Rotax 125 SR) is weighing in 185-195.

I have yet to add weights and will be racing in the Sr class. This being said I am currently running Consistent 55.00-55.60 At Musselman Honda Track here in Tucson. I am also Runnin Mojo Red's and it is only my third session on the track. That being said, I know I have plenty to lose, but I feel I have been doing extremely well!

Anyways... I have been told that I might actually get aster after adding weights.

Currently I do not know how the kart is balancing out, as I have yet to weigh it on scales. For all I know the front end could be light etc...

This being said, I have been told these karts are designed around a weight range, and being too light could cause it to not flex properly, or bind up then unloading causing it to jump which is almost impossible to get rid of.

SO, Can I lose time by adding weight to become legal?

I am stoked with my times tonight, being only my third time in the kart for over 7 years, and that my class is running 54-55's with white and yellow tires not reds! Razz

Any input and constructive criticism is greatly appreciated! Please try to be nice though!

TJ Koyen · Joined: 03 Oct 2004 Posts: 1416

It's very rare to actually go faster with more weight. The only way would be if your kart was horribly out of balance and adding the weight stabilized the handling, but even then, more mass = slower.

I weigh 120 and am running Leopard, so I feel ya on the weight. What tends to happen when you throw that much dead weight in the form of lead on the kart, is you're unable to manipulate your weight in the corner like a taller, bigger driver could. Sometimes that can hurt you on the handling front if you're looking to improve a certain handling characteristic on the kart but you simply can't because the weight cannot be moved around a lot.

People always tell me "you have an advantage being small, you can put the weight where you want", but in reality, I have to put the weight where it fits and that's not always the best place for it in terms of handling.
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T.J. Koyen
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Dan Haynes · Posted: Sat Sep 22, 2012 9:05 am Post subject:

We are in a similar situation. My son weighs about 145 and to get to 365 we have about 30lbs of lead and struggle to find places to put it. I agree with TJ. While you might be able to optimize handling with being able to put the weight where you want, you might gain .2 to .3. But the extra 40lbs or so of lead will slow the kart about .5. So the end result is a slower lap. These numbers are just guesses used as an example. But either way, you will slow down some.
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Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

TJ Koyen · Joined: 03 Oct 2004 Posts: 1416

Mark Peters · Posted: Sat Sep 22, 2012 4:23 pm Post subject:

Like TJ, I need to add 70+ lbs of lead to make TaG Masters weight and I can tell you it has a significant impact on the karts handling and how much tuning leeway you have to make things work. I've considered going the PRD route, lighter and quicker, but no one seems to have much experience with making the PRD competitive.

My latest thought was to fill every non-chassis functional tube with lead or shot ie, sidepod bars, front bars for the nose, plug the sidepod bars with lead etc in hopes of getting some of the 70lbs off my seat.

If anyone has creative suggestions for adding lead anywhere other than the seat I'm all ears.
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Mark Peters
#54 Badger TaG Master Series

Dan Haynes · Posted: Sat Sep 22, 2012 4:50 pm Post subject:

TJ, we used to have about 70lbs. on it when we moved up from each class. In jr. can I think he weighed about 80lbs. When ho moved to TaG I think he was about 130. My back is glad he gained a little....and we DO have a kartlift! Laughing

_________________
Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

Oscar Aguilera · Joined: 18 Jul 2001 Posts: 1614

what i have read is correct imo...so where to put the lead....when i was youger and skinny...i had to add lead.

start with high on the back of the seat...then all the way down the back to the bottom. left side of the seat...under each leg...center below your croch...right side of seat down low there is usually room..

you can put some on the front but ideally you want to simulate a larger driver getting in the kart and the front end would only be legs...so you dont need that much weight up front.

and yes you are shooting for the 48...52% up to 45...55% front to back.

0 left to right

10 pound diving bricks work the best...imo then some 5 pounders.

use the large flat washers so the seat will hold up...saftey wire the weights and most tracks make you paint them white so they can be seen if they were to fall off during a race or session on the track.

there are pluses and minuses to most everything.

just my opinion

TJ Koyen · Joined: 03 Oct 2004 Posts: 1416

Oscar Aguilera · Joined: 18 Jul 2001 Posts: 1614

yea ive seen and heard those numbers before....i usually see a seat way laid back when i hear those numbers...

honestly i havent scaled a kart in years....i dont have lead to put anywhere and i put the seat where it goes and that is usually enough that i might have one tire a pound more than another?? but i havent experienced that either other than tracks that have many more lefts than rights or vice versa.

im usually same pressure all the way around....maybe hubs are different for me on one side compared to another?

on banked tracks i do alot more.

im 5'7" 165# an average euro size...even though im a mexican....so i dont have much trouble with the kart. i fit and with the seat in the right spot it is good for my legs and arms.

unless i bent the kart i dont find a reason to scale it for my height and weight.

but when you do add lead and scale the kart most are surprised by how much they need on the right side of the kart.

Dan Haynes · Posted: Mon Sep 24, 2012 5:08 am Post subject:

To elaborate...we have about 30lbs. on our Arrow X1 with a Leopard.

-we have about 3lbs. in front of the fuel tank on the floor
-we have the battery mounted on the front steering support (not part of the 30lbs but that's where it is
-we have a 4 or 5lb'er under each leg on the bottom of the seat
-we have about a 3lb'er on the left side of the seat in front of the radiator
-and about 15lbs on the back of the seat. It's mounted up high but we will lower it as grip levels come up

We have about 42.5% front weight like this. We will move the floorpan weight as needed for handling but if it is on the seat we are just under 42%.

We also usually run with about 1/2 tank of fuel.
_________________
Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

patrick slattery · Posted: Tue Sep 25, 2012 7:56 am Post subject:

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Thanks guys!

But do you all really think it will gain time? I mean Karts are specifically designed to flex properly at a weight range from 365-405 usually...

This being said, almost 50-60 pounds shy (I would think) could actually cause it to not properly flex? I have known a few fellas in my situation which said to have lost between .5-1.0 seconds by goign to the proper weight.

Anyways, while we are on weight, where is the best place to buy weights online?

Benn Herr · Joined: 18 Jul 2001 Posts: 1580

TJ Koyen · Joined: 03 Oct 2004 Posts: 1416

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Will do!

I definitely understand the power to weight for sure! The only part I was questionative about was a REALLY rough section of our track where I visually bounce around more than everyone else. same line, same speed, Other than that my kart handles GREAT! This is the only section where they gain on me. It could possibly be that I am running Reds and they are running whites.

So, I guess I just need to buy some Whites (or at least yellows) and add weights to my Kart, see where I am at.