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Author Topic:   Ackerman
iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted August 28, 2005 04:42 PM  
Has anybody ever experimented with it on dirt or is it even possible with a stock type front end geometry

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted September 01, 2005 07:22 PM  
Do anybody know about this? I think that It really would help

Normal Sullivan
Dirt Full Roller

Total posts: 39
posted September 01, 2005 09:46 PM  
I know something about it. But are you talking about increasing or decreasing ackerman angles? Why? To improve cornering? tire temperatures? Reduce rolling resistance? My experience has been that the LESS ackerman effect designed into your steering the better. If there's any benefit to be had regarding slip angles on the front tires it would probably be from running very small amounts of positive ackerman, allowing the L/F to do a bit more work. The challenge to obtaining real world results from ackerman changes alone, seems due to things like wheel offsets, etc which effect the track width, and of course the steering angle required to turn a given corner. My 2cents. What are your thoughts?

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted September 02, 2005 10:44 PM  
Well I was doing some reading and it sayed to run 3 degrees difference3 between the lf and rf in other words if the rf moved 10 degress then the left front should move 12 or 13 degrees


This new car the we built is just a bit loose in the center of the corner. I think that we can correct this by adding caster OR doing this with ackerman but have no idea what to do with ackerman to help it

So my question is IS can you even adjust ackerman in a stock type suspension or does it take aftermarket products to achive what we are trying to get here?????

merf23
Dirt Roller

Total posts: 23
posted September 03, 2005 04:43 AM  
TO adjust ackerman, you need to move the steering assembly closer to the axle centerline (longer or relcoated idler arm/pitman arm, steering box) or bend the steering arms (outward for more, inward for less)

Both of these things are limited by clearance if you want more ackerman (control arm, and rotor). The steering arm adjustment will channge your bump steer.

Eljojo
Dirt Forum Champ
Total posts: 968
posted September 03, 2005 07:09 PM  
After giving it some thought, I think you could drill out the existing hole in the left spindle arm and install an offset bushing. Then ream it to a tie rod end taper. Just guessing I'd think you wouldn't have to move the tie rod pick up point out more than a quarter inch. I question how much this will increase your lap times tho, unless you are racing on a very smooth very flat racetrack. Just my 2 cents.

JohnG
Dirt Maniac

Total posts: 137
posted September 04, 2005 09:42 AM  
its used on pavement spindles. they have a elongated slot with bushings to adjust.

your lf will allready turn more than your rf with toe out

I think your wasting your time even thinking about it on dirt expecially small tires

bending the arm is the only legal way to do it on a hobby stock

when you have ackerman present it also negatively effects when you counter steer which we do a lot on dirt, I know I steer right way more than left ever.

36 Race Team
Dirt Full Roller

Total posts: 45
posted September 04, 2005 10:30 AM  
I believe that 1 degree is equal to 1/2 inch of toe for an 85 inch tire 3 degrees sounds like way too much.

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted September 04, 2005 09:48 PM  
If you ever have the chance to watch our cars on dry slick tracks we dont go sideways like a lot of people its straight.
So not a lot of coutnersteering this was just a thought.

O on a side note this new car is the weirdiest thing we have a 13 inch spring in the lr and a 11 inch in the rr to make the ride heights go where we want them.

anybody else do this or have ever done this

racin78p
Dirt Freak

Total posts: 333
posted September 05, 2005 07:38 AM  
Rear springs different heights? No, we just use spacers, about a 1" split right to left to get the right ride height and scaling numbers.

The ackerman and bump steer thing. We went to the big Impala spindles and tall upper and lower ball joints this year on my GM metric. My front end set up guy did a bunch of messuring and he said that the bump steer is perfect and ackerman is just about right. I believe a 2 degree split? Don't have my set up book with me so I think that is correct.

Anyway, all I know is the car corners/steers better than anything I have ever drove. It is nice to be able to drive a car in the corners and know exactly what it is going to do going in and coming out! Curious thing is it doesn't seem to matter if the track is tacky or dry slick. It does great on both.

Race on.

------------------
racin78p
if it ain't fun, then don't run

36 Race Team
Dirt Full Roller

Total posts: 45
posted September 05, 2005 03:03 PM  
what are the ride heights with the rears like that sounds like you'd have alot of crossweight depending on the rates

racin78p
Dirt Freak

Total posts: 333
posted September 06, 2005 08:13 AM  
My ride heights are not what I originally was shooting for, but they are:
LF 6 1/4"
RF 6 1/2"
LR 6 3/4"
RR 7 1/2"
The big thing is the scaling numbers and how you get them, and what it does on the track. I used to love a tight car, but a good friend and local mod racer convinced me to let him set it up the way he wanted to, and if I didn't like it, then he would put it back the way it was. He did a lot of changes and "freed the car up". I will say one thing about his set up. I'll never go back to the way it was.

Race on.

------------------
racin78p
if it ain't fun, then don't run

mike9
Dirt Full Roller

Total posts: 72
posted September 07, 2005 06:38 AM  
i checked the ackerman on a metric front and stock they have a 3 degree gain in other words you turn the steering to the left and the right tire is at 10 degrees the left is at 13 degrees

monk
Dirt Newbie

Total posts: 3
posted September 27, 2005 06:08 AM  
3 degree gain is what I have observed..Loose in the center,is probably the result of a problem getting in...
Take the turn apart to 3 segments,getting in,apex,exit..
Simple remedies,reduce stagger,add crossweight,reduce caster or a simple shock change,all other factors being considered.

    

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