metric rear control arm angle

[hot]

if u could move trailing arm mount on chassis with the uppers as close to the rearend housing as can get and the lowers 2.5 away from housing. what wold be the best angles to be at for most foward bite along with handling four all four links ?

[istock11m]

0 on both.

[Racer96m]

The best angle for Side Bite will be the uppers lowest to the housing and parallel to the ground and the lowers also parallel to the ground. This will give you the lowest rear roll center for a stock metric 4 link. Any angle in the arms is going to effect the RC one way or another, height or left to rt. Angle in the Lowers is going to add roll steer into the mix. The best angle for Fwd Bite? I dont think there is one good answer for that. What did my car have for angle? LR lower was 7deg, RR Lower was flat and the uppers had 17deg. Will this work for you? Hummmm, Lots of things go into making that work, but everyone who saw that car run would say it came off the corner like few others could.

Dave

[racingford]

The best angle for Side Bite will be the uppers lowest to the housing and parallel to the ground and the lowers also parallel to the ground. This will give you the lowest rear roll center for a stock metric 4 link. Any angle in the arms is going to effect the RC one way or another, height or left to rt. Angle in the Lowers is going to add roll steer into the mix. The best angle for Fwd Bite? I dont think there is one good answer for that. What did my car have for angle? LR lower was 7deg, RR Lower was flat and the uppers had 17deg. Will this work for you? Hummmm, Lots of things go into making that work, but everyone who saw that car run would say it came off the corner like few others could.

Dave

Dave, how can you be rumming 7 degrees in left lower when ump rules states must be mounted up close in stock location?

[turner]

The rule states stock location. I have 4 ford rearends on the farm, and all the lower mounting holes are diff from one to another.I guess Ump wants you to run the bars at the same angle, or the same distance from the tube. I have yet to see Ump check any cars at the track.They may at some tracks, but not at the tracks in Illinois.Pretty much run what ya want as far as control arm angles

[Racer96m]

Dave, how can you be rumming 7 degrees in left lower when ump rules states must be mounted up close in stock location?

The rules state,
I.) The lower rear trailing arms must remain in their stock OEM length, format and length, from the original OEM application and measurement system (English or Metric) and must remain specific to their particular chassis/frame and must be the same length on each side. The lower rear trailing arms must be mounted in the stock location. Additional holes in the frame and/or rear end will not be permitted.

My arms were stock, stock length, and in the stock location. We all know that when you put a 9" in the car, the mounts on the rearend wont be stock any more. So what do they mean by Stock Location? I was teched more than most, they were always checking the frame mounts. My frame mounts were stock, unaltered, and on the rearend they were looking for additional adjusting holes. My car had no additional holes. The rules never put a hard height measurement on the mounts, so they have nothing to tech it to. So it all comes down to the interpretation of "Stock location" If they were that worried about it, they would give you a measurement from the bottom or top of the axle tube, then you could tech it.

Dave

[turner]

The rules state,
I.) The lower rear trailing arms must remain in their stock OEM length, format and length, from the original OEM application and measurement system (English or Metric) and must remain specific to their particular chassis/frame and must be the same length on each side. The lower rear trailing arms must be mounted in the stock location. Additional holes in the frame and/or rear end will not be permitted.

My arms were stock, stock length, and in the stock location. We all know that when you put a 9" in the car, the mounts on the rearend wont be stock any more. So what do they mean by Stock Location? I was teched more than most, they were always checking the frame mounts. My frame mounts were stock, unaltered, and on the rearend they were looking for additional adjusting holes. My car had no additional holes. The rules never put a hard height measurement on the mounts, so they have nothing to tech it to. So it all comes down to the interpretation of "Stock location" If they were that worried about it, they would give you a measurement from the bottom or top of the axle tube, then you could tech it.

Dave
Very true Dave. Way to many different ford rears to say what a stock location is. One thing that our track did do is say that we had to have both lowers the same distance from the tube.Ump never said a word though.

[Ricky76]

I've wondered this myself ? What's the best way to get forward bite by changing the rear control arms ? I have my rr upper high that my lr upper and both my lowers are the same. They are both mounted 4 inches from the bottom of the rear end tube. (or 4 inches from the tube to the center of the bolts) I'm going to raise both lowers close to the rear end tube and try it that way this year during play day and see how it works for me. Not sure what to try for the uppers ?

[Krooser]

You guys that have this figured could help us dummies with a few photos....

[Racer96m]

I played around with my mounts for years, before I found what worked for my car. Some things to remember. If you lower or raise a lower arm mount position hole. You just dont drill a hole above or below where it was. The Arm scribes an arc as it moves, so account for the arc movement when you locate your hole. Otherwise your wheelbase will move. And speaking from some experience, those upper mounts better be very stout, and braced well. I ripped one right out of the top of the housing. The welds didnt brake, the housing did around the mount. What ever you do, just make sure the rearend isnt in a binde. Remove the shocks and springs and move the rear all around checking for a binde. If you have it free, it should flop around without much effort.

Dave

[MM90]

Google pics of IMCA stock cars. We can run adjustable control arm mounts. Dropping the LL control arm on the rear end, or more angle makes the car very tight and helps when the track slicks off. It makes the rearend rear steer to the left.

[istock11m]

Google pics of IMCA stock cars. We can run adjustable control arm mounts. Dropping the LL control arm on the rear end, or more angle makes the car very tight and helps when the track slicks off. It makes the rearend rear steer to the left.

Lowering the left puts more rear steer in the car. Pulls the left rear forward, steering the rear right. It will add more bite to the lr but it can loosen the car do to rear steer.

[hot]

Lowering the left puts more rear steer in the car. Pulls the left rear forward, steering the rear right. It will add more bite to the lr but it can loosen the car do to rear steer.

thnks for the info im more lost now than i was to many differt ways to do it

[Ricky76]

thnks for the info im more lost now than i was to many differt ways to do it

That's what I was thinking ? I agree with you !!!

[ToddSmith16]

If you buy the right brackets when you move the trailing arms your wheelbase should not change! If you are able to move your trailing arms without getting pissed while your doing it....you have the right brackets! If you have to jack, pull, pry, shed blood to move the trailing arms...the brackets are junk and you are moving the wheelbase! You are not helping the car and more than likely binding the rearend up all the while changing the wheelbase.

[ToddSmith16]

...those be the one's! I expect 10% Jeff....LOL!

[istock11m]

When your car rolls over it changes. The more angle in the lr the more it pulls forward.

[9car]

when you guys are talking about angle in the control arms , ( lowers for this example) you mean that the mounts on the housing are lower than the ones on the chassis, is this correct?

[istock11m]

Yes...........

[9car]

thanks, it makes more since now