Rear Track Effect

Michael Suda · Posted: Tue Oct 09, 2001 5:43 am Post subject: Rear Track Effect

I have gone through the excellent article on this site provided by Century Performance Products "Basic Chassis Setup". It's description on the effect of narrowing the rear track seems opposite from what I understand and what others have told me. My understanding is that narrowing the rear track increases rear end grip.

I am racing 2-stroke Yam Senior Sporstman, sprint (road courses).

Also there is a good article on the following website which supports my understanding at http://www.pkpkarting.com/yfcatalog.htm Look at the last tab "Info/Now What"

Which is correct?

Thanks,

Mike

Rick Blood · Posted: Tue Oct 09, 2001 7:07 am Post subject: Rear Track Effect

What most articles will tell you is a basic setup. Both directions will loosen or tighten the rear. For example, If you start full wide the kart should be loose. As you narrow up, it should start sticking. Keep going narrower and it should start getting loose again.
Many things affect the loose / tight condition and the rules don't apply the same way for every person.
There are 384 basic setup combinations on a kart not including the amount of the change (1/2", 1/4", etc.). Testing what works for your driving style takes time but the chassis is where the biggest gains are made.
I trust Chuck and Dustin at Century and I would start with their advice.

Mark Dismore Jr · Advertiser Joined: 21 Jul 2001 Posts: 1096

quote:
Originally posted by Mike Suda:
I have gone through the excellent article on this site provided by Century Performance Products "Basic Chassis Setup". It's description on the effect of narrowing the rear track seems opposite from what I understand and what others have told me. My understanding is that narrowing the rear track increases rear end grip.

I am racing 2-stroke Yam Senior Sporstman, sprint (road courses).

Also there is a good article on the following website which supports my understanding at http://www.pkpkarting.com/yfcatalog.htm Look at the last tab "Info/Now What"

Which is correct?

Thanks,

Mike

Widening the rear makes the kart more stable, especially under braking. Narrowing the rear gives you more grip on exit and under power. However there is a happy medium on width. Test, Test, Test!

Mark

Tim Lewis · Posted: Tue Oct 09, 2001 7:48 am Post subject: Rear Track Effect

Mike,

I'll give you my read on this, it certainly isn't gospel, so don't treat it as so.

I used to have a very hard to tune kart that was always LOOSE. So much so that people in my club would come over and say things like "You're scary to watch drive" and "You should do something about that".

Anyhow, from reading the books, websites, etc. I thought that narrowing the rear would help it out. Besides making the kart bicycle (not a good feeling) around some corners, narrowing the rear would make this kart 'side-hop' even more in the rear and get even looser. By widening out the rear (the max I could get on this beauty was 49 1/2") I would reduce the rear 'hopping' and reduce the oversteer.

On my present kart where hopping is not a real big issue widening the rear increases oversteer.

My guess is that the rear width effect is going to be highly dependent on what kind of 'loose' you are dealing with.

1 more thing. If you have to go over a bunch of choppy pavement, a wide rear track lets the axle flex more and really improves the ride.

Hope this helps a little,

Tim Lewis

Ashton Westenburg · Posted: Wed Oct 10, 2001 9:55 pm Post subject: Rear Track Effect

Saw the article too..Contrary to my experience as well. Though the following posts make some good sense, as a rule narrowing track applies greater pressure on same tire patch yielding better grip. In my very neophyte opinion and experience.

Keith Archambeau · Posted: Thu Oct 11, 2001 10:32 pm Post subject: Rear Track Effect

Hi everyone! This is just my 2 cents. This has been our experience. When we first started karting, we were chasing the rear width thing also. From much help here's what we found works best for us.
Rear width at maximum rules allow. Ajust traction with , Axel, hubs, bearing tention, struts, weight & or seat placement, ride height, tire pressure, wheel types, rear bumper, bars (whew!)
Then ajust front bite, in much the same way except fiddle with width.
The guy that told us this only said keep rear at max, then mess with the front.
Basic but helpfull.
There is a track out here that we do narrow the rear though. This track has very, very slow tight corners, it's really just a drag race from corner to corner track. Even at this place we are only talking about 1/4-3/8"
narrower. Hope this helps.
RACE!

Ashton Westenburg · Posted: Fri Oct 12, 2001 9:58 pm Post subject: Rear Track Effect

Hey Kieth:

What are the direct benefits of running the widest track allowed?

Eric a new karter

Tim Lewis · Posted: Sun Oct 14, 2001 6:52 am Post subject: Rear Track Effect

It's easier to block once your in the lead!!!!!!!!!!!!

Art Lee · Joined: 24 Jul 2001 Posts: 25

The way it has been explained to me is most chassis are designed to work with the rear track at a certain distance (usually max allowed). When I've talked to my chassis designer he told me to always start with the rear track at max (55") and adjust with hubs and axles. Maybe give the Kart shop/dealer of your chassis a call and see what they recommend. and Like Tim said helps you to block

Arthur Lee
L & L Racing Equipment

Keith Archambeau · Posted: Mon Oct 15, 2001 8:18 am Post subject: Rear Track Effect

Eric, I asked the same question myself a few years back. The answer I got was. Wider is faster!
RACE!

Gary Kozuma2 · Joined: 03 Aug 2001 Posts: 446

Keith,

How does that bearing tension thing work?

Keith Archambeau · Posted: Tue Oct 16, 2001 8:40 am Post subject: Rear Track Effect

Gary,
Most rear bearing cassets are split, with a pinch bolt. The cassets & bearings are spherical. Ajusting is to lossen the top 2 hanger bolts, leaving the bottom one tight so not to lose your ride height. Then you can tighten or losen the pinch bolt. Then retighten the hanger bolts. A tight pinch bolt will act like a slightly stiffer axel & visa versa. Not much though! Also have your third bearing pinch bolt loose with no set screws in the collar, kind of floating. This keeps this part out of the equasion. Also the bearing has a collar. Collars facing outward will make axel stiffer & visa versa.
RACE!