I’ve bought a set of rebel racing adjustable perches to go over my rear bilstein dampers.

Unfortunately, for the duel rate springs I have (tender and main spring), the isolator collar (between the two springs) ID at 54mm is just too small to go over the OD of the threaded tube, meaning I have to go up in spring size to 60mm ID I think

Question: what ID springs do people use with this Rebel Racing set up and do you find the springs rub on the threaded tube ?

See below

Thanks, Chris

I use 2.25” ID springs that came with the coil over kit from Rebel. No issues with rubbing on the threaded collar

57mm=2.25
54mm=2.125

I can not give you my specks but this is what I have on the rear of 41. Helper springs as well

Bob BClick to view attachment

Flip it over...put the helper spring on top above the threaded tube...

Or try this if the hat slides done the spring will stay seated.. Less friction on the threads ,, will thump if jumped.

that's a good call. I had thought about that, but was thinking that on a big bump, the damper could go up and hit the insulator plate/collar. This is it mocked up. I guess it will also depend on where the adjustable perch starts.

thanks Bob. Do you have an insolator plate between your main and helper spring ?

I am about to install the Rebel Racing Coilovers with 150lb Eibach springs. No helper springs though - can somebody explain the benefit of the helper springs?? Am I missing a trick here?

Thanks

Simon

Found this Simon:

When you jack your car up without the helper springs, the mainspring has to re-index and the car's rear springs will either "click" back in or "thump" if you are driving.

Ask me how I know.

The post above explains it pretty much but like a lot of things, it isn’t a case of just putting anything on your car. It also controls frequency as you go over a bump as the suspension unloads.

I had to get a spring pro to calculate a duel spring equivalent to my 150lbs progressive, fixed perch, set up. He recommended a 300lbs helper/tender spring (this is an eibach spring which has a 1.75” travel (so the free length is around 3.25” ish) with a 160lbs 9” main spring. But this is on a car with a 3.2 and 915 box so will be heavier. Most people have stiffer springs, but for fast road use I think it’s overkill.

The problem with a duel spring set up using the rebel racing system comes when you have to fit the duel perch/isolater plate between the springs when you fit a 2.25” ID spring. The diameter of the perch plate is slightly too small to fit over the threaded tube. I’m ordering a 60mm tender spring + duel perch plate, and hopefully that will be ok to fit over the threaded tube. My main spring is a 2.25” ID but actually measures 60mm so I think I’m going to be ok. Something to bear in mind if you’ve already got a 2.25” ID main spring. I’ll report back, but as I see it, there is a flaw in their design as the tolerance is way too marginal - the movable perch collar should be a larger diameter...

PS I also learnt there are different metal compounds for these springs. I was told you need silicone chrome springs, which don’t sag - Eibach are made this way.

I ordered Rebel Racings 2 1/4 kit and they shipped me a 2.5" kit. I ended up ordering the helper springs and helper spring spacer from Summit.
Click to view attachment
Click to view attachment

PMB put them in. I am sure that they are right on.

Bob B

PMB

FWIW I've been running my /6 track car with no helper springs...just zip tied the hat to the top of the spring and it just slides up and down. Over 8000 miles on the track in past five years, no problem.

Another pic...