Moving the RF out?

[missile07]

Talked to several people/chassis builders about moving the right front out on a chevelle clip car. Got several different reactions on it and something I failed to ask was....

Is there a difference in buying an extended right front lower or changing the offset by different wheels/spacer to stick it out further? Are there other ways? Or are they running shorter rearends?

See a ton of UMP cars & late models with the right front out a lot further than normal and I understand the reasoning behind this is for the car to scotch up earlier and turn better.

Would love some feedback from HeavyDuty

[jsf74]

Pretty sure it has everything to do with upper and lower ball joint locations and control arm lengths rather than just tire locations.

[HEAVY DUTY]

There are a lot of things to consider when moving the RF out. There is a difference between moving it with a wheel spacer or with an a arm. If you move the tire out with a wheel spacer, you increase the scrub radius of the tire. The tire rotates around the kingpin axis, and the farther it moves out from there, the more the tire moves frontwards and rearwards when you steer it. It also is harder to steer and has more feedback thru the steering wheel when you hit a bump. Some tire scrub is good for driver feel, but too much is a bad thing. Moving the tire out with the a frame ( if legal) would be better. It would help with shock clearance, which is a problem on most chevelle cars. It will create more camber gain ( if you don't lengthen the upper, but just space it out an inch) because of the upper a frame to lower a frame length ratio has gotten less. It will change the spring rate motion ratio. If the inch is added out side the spring, you will need to stiffen the spring to keep your wheel rate the same. If it is added inside the spring, you will need to soften the spring. The bump steer will need rechecked, because the camber curve will be different, and the tie rod will be longer. Now the big question is will it make the car faster? Maybe. It may cause you to start chasing the setup again. It should tighten the car all the way around the racetrack, because you have created more tire misalignment in the right side tires. It will increase the leftside weight percentage, if you don't move the right rear out too.

[missile07]

Thanks Heavy Duty...you hit most everything I was looking for. While off throttle wouldn't it loosen handling due to increased leftside weight?

[jbh25]

So missile what all did the tell u about it

[HEAVY DUTY]

Thanks Heavy Duty...you hit most everything I was looking for. While off throttle wouldn't it loosen handling due to increased leftside weight?

Just adding left side percentage would loosen off throttle, but more right side tire misalignment would tighten, probably more than the left side % change

[stock car driver]

How tempermental do you think these cars are to that right side alignment?


I ask because I been running my rr 1 inch narrower AND my car is notoriously tight all the time? I will buy new beadlocks if needed but was trying to use the 4 inch back space with a 1 inch spacer since I had 15 of them from my stock car.

[LFMotorsports]

I wouldn't say the typical car is temperamental to offsets but a good car will respond to offset changes. We will change the RR from a 3" offset to a 4" offset to tighten the car up OR if the track has a larger radius corners. 1/2" spacer can also be noticed if used in the right location.

[jsf74]

Same here scd. On my old car the difference bewteen a 3 off and 4 off was huge. There's so much traction these cars need freed up.

[missile07]

Very different opinion on two different builders....one builder who is fairly big in UMP stuff said that he believes that sticking the right front out with the illegal a-arms loosen entry but the effects when the track slickens off are too much and hurt the overall balance. Basically he thinks each time its a crutch.

Another builder said they have tried it two different ways...either by having the illegal a-arms or by changing frame mounts and have yet to see any real gains.

We run outlaw IMCA and run a 3 off in the heats and 4 off in the feature. Haven't seen much of a gain from going one step further from a 3" to a 2 ".

Good posts on this so far.

[mod11h]

would it make a big difference if u had a car with the stub turn on it too. Looking at a Hugh's I see guys running a 1 inch spacer on the right front

[missile07]

Also....a question was brought up instead of turning the right front more by moving the mounts could you pull back the left front? Would this mess up front end geometry?

[powerslide]

They dont pull the left front back because they are likely already at the 108 measurement and if they shorten the LS anymore they will be illegal. When tracks do tech they always measure the LS

[MasterSbilt_Racer]

On no car, mod or late, have I experienced moving the rf out in relation to the rr result in a looser entry race car.

[missile07]

Powerslide....we have no rules on our measurement.

To me it makes sense that turning the left front/pulling it back would serve the same purpose as turning/moving the right front forward to make a car turn a little better.

mastersbilt....the chassis builder I spoke with a IMIS said he personally really liked moving the right front out an inch on larger/banked tracks because he felt that the car scotched better on the right front and turned easier in the muddy/tacky conditions. He then said that it would hurt him if the track slicked off so he would make other adjustments to compensate. He also mentioned lower his rear percentage when sticking the right front out further.

Whether it works or not I haven't tried it but he took home many trophies last year & it certainly got me thinking.