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Author Topic:   Need help understanding wheel offsets
Steph
Dirt Full Roller

Total posts: 60
posted May 29, 2001 09:21 PM UIN: 6762482
A question from my hubby, the driver:

quote:
I need help understanding how wheel offset affects car handling. Most explanations that I have read refer to moving one wheel in or out. I am more concerned with moving both wheels in or out. For example, how does a car handle with 4-inch offsets on the front of the car as opposed to 2-inch offsets? Our car builder recommends 4 inch offsets on the front, but other car builders and setup books have suggested making the front end as wide as the rules allow. So, how does increasing the offsets on the front of the car change its handling characteristics on wet, tacky, dry-slick, and black tracks? As a driver, I need to know how it affects the handling. What are the advantages and disadvantages? I need to understand how the same changes affect the rear as well.

Here's what I think... the narrower front end is going to let the car roll over better... but that doesn't really tell him how it is going to feel on the track (loose, tight, unstable, whatever). He says that you can use springs for rolling it over, so why wouldn't you want a wider "stable" front end?

Help here would be appreciated guys. Thanks!

[This message has been edited by Steph (edited May 29, 2001).]

dirtracr
Dirt Full Roller

Total posts: 34
posted May 29, 2001 09:38 PM
from my experience, right or wrong, wider in the front should make the car tighter, wider in the rear, looser..we run a three inch offset on lf, two inch on rf, two on lr and a four on rr...heavy track move lr in and kick out rr or move in rf and kickout lf to loosen car up, do the opposite for dry slick..although, again right or wrong, we usually dont mess with the front...i will sometimes play with the lr..trying to get the right tire size and amount of stagger with a certain offset for a certain track condition can be tedious sometimes with the hoosiers we run..so i tend to keep the offsets the same and adjust elsewhere for the track conditions..right or wrong....

[This message has been edited by dirtracr (edited May 29, 2001).]

[This message has been edited by dirtracr (edited May 29, 2001).]

Racer4
Dirt Forum Racer

Total posts: 93
posted May 30, 2001 01:09 AM
ok, first off never confuse wider with wheel offset with longer lower control arms, longer control arms are the better, but not allway's detrimental to a dirt car, the wider front on a fast track, long arching corners will usually handle better through the turns - not necessarily a heavy track, but not as good as longer control arms. If you experiment with wheel offsets on the scales you will see various differences on perentages, if you understand what your scales are telling you with your car then you can use them as a further handling tool while at the track to go with other suspension changes for various track conditions, "right or wrong", just my thoughts. I had a car once where we went to 8" on the left and 10" on the right with varous offsets, we went from a lost cause to an excellent handling car with wheel offsets and a single spring-ride height change. Wheel offsets can definetly help you if you know exactly there effects on your particular car. Never, remember never go by what soenso said his car did with a certain offset, you have to use your cars exact wieght's to your advantage. Excuse the long reply

LITTLEMAN
Dirt Forum Racer

Total posts: 82
posted May 31, 2001 06:58 PM
MOVING THE WHEELS OR WHEEL ON THE LEFT SIDE OF THE CAR IN WILL INCREASE THE WEIGHT THEY CARRY,MOVING THE LEFT SIDE WHEELS OUT WILL DECRASE THE AMOUNT OF WEIGHT THEY CARRY.MOVING THE LEFT REAR TIRE IN WIIL TIGHTEN EXIT.THE RIGHT SIDE TIRES ARE THE SAME WAY MOVING THEM IN WILL INCREASE THE WEIGHT THEY CARRY.MOVING THE RIGHT REAR IN WILL TIGHTEN ENTRY,SO A NARROWER REAR TRACK WILL TIGHTEN A RACE CAR IF EVERYTHING ELSE STAYS THE SAME.HOPE THIS HELPS,LITTLEMAN

brownstone
Dirt Full Roller

Total posts: 45
posted June 01, 2001 11:31 AM
With the kind of racing budget your team has, yall should be able to buy every offset and ultra light wheel that you need just keep changing them till you get it right...lol

All the kidding aside the old IMCA how to race book written by Steve Smith does a good job explaining how to measure and use wheel offsets on your car.

The way we starting learning was by changing wheels on the car while we were scalling it and look at the differences in percentage and then making notes of those changes before you go to the track so we know what wheels to put where when we got to the track if needed to make a change.
Good luck

awkwardjeff
Dirt Freak

Total posts: 218
posted June 01, 2001 02:55 PM
Steph, All the people here are right....as WHEEL-OFF sets go.........the thing everyone is missing is the track of the car.....this is very important.......if you move the right rear outside the right front this will make the car real loose........
Your chassis builder must have a great car, and a good reputation.......that's why you went to him to purchase the NEW car......If he tells you to run a 4 off on the front I would think the width of the front was changed by using different lower A-frames....My only point is the track of the car is as important as wheel off-sets.....
MOST people move the left rear in toward the center of the car to tighten the car up for the dry slick.......try spacing it out once, you maybe surprised it will tighten the car up being spaced out.......this is because as the rear of the car slids it will need to slide farther to get to the same point as if it had a 4 off wheel on the left rear.....
This wouldn't work to tighten the car up for a driver that runs the car real straight to start with.......but for a guy that slips and slids his why the 2 off will tighten the car to his feel.......It will help him feel the car get loose before it's too late and spins out............
TRACK OF THE CAR AND DRIVER FEEL ARE MORE IMPORTANT THAN WHEEL OFF-SETS.........
I have seen cars win with the rear tires moved to the left and I have seen cars win with tires moved to the right.....ALL ON THE SAME TRACK.........it just depends on the driver......
If what you're trying now isn't working the way you think it should try doing things backward to see if they help.......I'm not kidding.......And nobody lied either....it's just your driver needed a little something different, that's all.
Jeff

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