Stiffer Right Rear/Progressive Spring

[Cranky]

What does adding a stiffer right rear spring do to the car? Im guessing it holds the rear up more, less rollover and loosens the car up? Does it also affect the left front through the middle and off the corner possiby contributing to carrying the left front wheel more? How about a progressive spring, say like a 250/450? I know people have the dual this and that. I cant afford that stuff. Im looking to do some testing but wanting to hear what will happen just by adding more RR Spring. Thanks in advance.

[MasterSbilt_Racer]

What does adding a stiffer right rear spring do to the car? Im guessing it holds the rear up more, less rollover and loosens the car up? Does it also affect the left front through the middle and off the corner possiby contributing to carrying the left front wheel more? How about a progressive spring, say like a 250/450? I know people have the dual this and that. I cant afford that stuff. Im looking to do some testing but wanting to hear what will happen just by adding more RR Spring. Thanks in advance.

It will plant the rr more on entry and how ever far you go off throttle. Will loosen car on exit on throttle.

Stiffer spring will reduce LF carrying on exit, yes. Most people just install spring rubbers to make a progressive spring. A true progressive spring is not a great idea as the point where the rate picks up is fixed and cannot be changed.

[TheJet-09]

Every so often I get in a mood and try a 250, 275, and even a 300 on the RR. And every time I just go right back to the 225. Best I can describe is it feels like the car "stands up" on the RR. I'm guessing my driving style (outdated) prefers the feel of the car getting over on the RR (but not to the point of lifting the LF).

[Jking24]

Most of the time now days when guys go up on rr rate it's because they want to get the car lower at ride height but still maintain a particular compressed load at say 1.5-2"of compression and they've exceeded the usable range of spring rubbers. For instance my particular setup is 2 rubbers. At 3 rubbers my the 225 is basically exactly like a 250 in my usable range with the exception of the 225 still has a little more stored energy ( less gap when rr is in droop). So that is my switching point from one to the other. I will add that in my opinion every thing mentioned above has its biggest effect @ late entry and across the center in most scenarios

[billetbirdcage]

Say your ride pin to pin is 20"

Changing rates but keeping similar load at 18" will be different then changing rates and keeping ride load the same (20").

What effect you see is dependent on which load numbers your affecting, like your 22" or 20" or 18".

Keep in mind the RR is typically only below 20" for less then a second (many times much less then a second) and typically only on off gas entry.

[LRtireCHANGER]

Ten years ago, more or less, the go to right rear for a late model on a larger momentum type track was a rr that consisted of a 225 spring with two spring rubbers in it. The stacked/preloaded stuff that people run now lets you fine tune the initial rate AND the compressed rate independently, and the 225 with 2 rubbers could be tuned for compressed rate by using different combos of rubbers. The pre compressed rr, and a precompressed/stacked rr offer a much wider tuning range than the rubbers did.

[MasterSbilt_Racer]

Ten years ago, more or less, the go to right rear for a late model on a larger momentum type track was a rr that consisted of a 225 spring with two spring rubbers in it. The stacked/preloaded stuff that people run now lets you fine tune the initial rate AND the compressed rate independently, and the 225 with 2 rubbers could be tuned for compressed rate by using different combos of rubbers. The pre compressed rr, and a precompressed/stacked rr offer a much wider tuning range than the rubbers did.

That digital thinking, with odd dislocations and transitions in the analog load vs displacement curve creates its own challenges, where again, crutches and compromise is made

The question that would really move the needle is "why are these pieces necessary"?

[Cranky]

Whats the Scenario

So what's the Scenario for the 225 with the spring rubbers? Do you start the night off with the rubbers installed when the track is wet or tacky and as the track slicks off you pull rubbers out? I currently have a 225 in the right rear but wanted to do some testing when the car is finished in a couple weeks.

[MasterSbilt_Racer]

So what's the Scenario for the 225 with the spring rubbers? Do you start the night off with the rubbers installed when the track is wet or tacky and as the track slicks off you pull rubbers out? I currently have a 225 in the right rear but wanted to do some testing when the car is finished in a couple weeks.

It has to be tailored to what the car and driver will be doing. Often, rubber is added on slick