Lowering the rear (IRS)

[vujade]

What do you have to do to lower the rear 2.5" to 3" on an IRS???

I know how you reset the spring plates, but how many splines to get the desired lowering as stated above?

thanks
joe

[kdanie]

I can't tell you how many splines for a specific change in inches but as I understand it, if you move 1 spline each way you will get 1 degree of change. There is a different number of splines on each end of the torsion bar. 1 spline on the inside is a different change than 1 spline on the outside.

This was little help when I lowered my IRS because every time I pulled out the torsion bar to turn it, it popped out of the inner splines instead of sliding out smoothly and I lost track of where I was trying to put it back. I got out my Handy-dandy angle finder and did some trial and error until both sides were the same and put the tires back on and tried it out until I got the height I was after. Not very scientific but it didn't take that long.
ken

[Supa Ninja]

Hey Joe,
Try rotating the torsion one inner spline that should put you where you want to be. Ken is right you will most likely have to do it more then once to get it right. The first time I lowered the rear of my Supa I went two inner splines and the result was the turbo hideaway muffler was on the ground. Good luck.

Nick

[vujade]

thanks guys....
I am probably going to wait to do this when I get my adjustable spring plates.

[TitoRay]

To avoid losing track of where you are at, you can mark where the spring plates are originally. I have read that using a protractor to measure the adjustments will make it a little easier also.

[Shadowbug]

I only dropped mine one inner spline, and I scrape my muffler on any big bump or speedbump.

but then again my muffler is hanging fairly low.

[Tim]

If I don't remember wrong from somewhere I read in the web, the outside has 44 splines and the inside has 40 splines. Changing one outer spline will raise or lower 60mm while one inner spline will move 66mm. You can change the inner and outer in opposite directions to get your desired ride height.

Tim

[vujade]

thanks for all your help guys....

I am probably gonna order my adjustable spring plates & also lower it 1 spline too.