Different uses/experiences with spring rubbers

[Basecircle]

Searching back through the archives, there sure is a lot of conflicting info over the years when it comes to when and where to use spring rubbers. Like everything else, what works now is the exact opposite of what worked a few years ago, and in a few years we might be right back to where we started. That said, what have you all been doing with spring rubbers in different locations and in anticipation of what changes in handling/track conditions? RF, RR, 5th coil, anywhere else? Always fun to compare notes before experimenting, and no fun to chase what you think is a new idea only to find out everyone else already tried it and threw it away.

[MasterSbilt_Racer]

Searching back through the archives, there sure is a lot of conflicting info over the years when it comes to when and where to use spring rubbers. Like everything else, what works now is the exact opposite of what worked a few years ago, and in a few years we might be right back to where we started. That said, what have you all been doing with spring rubbers in different locations and in anticipation of what changes in handling/track conditions? RF, RR, 5th coil, anywhere else? Always fun to compare notes before experimenting, and no fun to chase what you think is a new idea only to find out everyone else already tried it and threw it away.

The 4 link was tried and thrown away by the early 90s. Just because it was thrown away doesn't mean it can't work.

These days, a lot of people like to have some rubbers in both right side springs. Then you add or subtract depending on what the car needs. One guy may need to remove rubbers from RF later in night.

[Basecircle]

Thinking about dropping rf spring 25-50lb and adding rubbers to keep it comparable to what we’ve been running, but able to soften it up as the track slows down. Any input on RR? I haven’t played much with spring changes or rubbers there. How sensitive is it? Of course in general, I know everyone’s situation and setup may react a little differently. I just enjoy reading about things and it’s not something anyone puts in a setup book.

[MasterSbilt_Racer]

I have seen people have success adding to the RR to tighten the car. I find it to be a very noticeable change and often too much.

[Kromulous]

I have bought a lot them lately. I am interested in the durometer rating of them, and how that will impact the feel.

[goodolboy01]

What about the rebound rate of them? I figure that's part of the equation. Less rebound force to have to control with the shock?

[mickley.28]

I have seen people have success adding to the RR to tighten the car. I find it to be a very noticeable change and often too much.Adding rubbers to right rear will tighten entry but loosen exit.

[MasterSbilt_Racer]

Adding rubbers to right rear will tighten entry but loosen exit.

Not always. :)

[Basecircle]

What is considered “normal” compared to a “big swing” as far as adding/subtracting rubbers at the track in different locations? Example: if I drop 25lb in spring rate, how many rubbers would it take to compensate and stay about the same? How sensitive is it to remove each? I’ve seen guys cram 3 or more in a spring. Are they removing them all as a minor adjustment, or just 1 usually enough to be pretty noticeable?

[billetbirdcage]

It depends on several things:

1. number of active coils your spring type has
2. Durometer of the Rubber you're using
3. How tight the rubber fits

If you have a high travel spring with very few coils, say 6, then compare to some old afco spring that has 12 coils: That same rubber (granted since the coil gap is different sizes, the rubber that fit each spring isn't going to be the same rate, but lets ignore that for easy of discussion) is going to effect the one with the less amount of coils way more then the 12 coil one.

Basically if you deactivate one coil of the 6 coil spring your gonna make is somewhere close to 16% stiffer (again not accurate since it doesn't make the coil not move at all on that coil) and the 12 coil one would be closer to 8% stiffer.

Then throw on different hardness's of rubbers and how tight they fit and you're gonna get a ton of variances between different people and their product/combo choices.

[TheJet-09]

I was wondering how consistent they are, and not necessarily from a rate standpoint. I've only seen one person using them up by me (on the RF), and they'd keep "squeezing out" from between the coils. I'm sure others are using them, but he's the only one I've seen.

Maybe the shock/spring cover helps keep them in?

[billetbirdcage]

I was wondering how consistent they are, and not necessarily from a rate standpoint. I've only seen one person using them up by me (on the RF), and they'd keep "squeezing out" from between the coils. I'm sure others are using them, but he's the only one I've seen.

Maybe the shock/spring cover helps keep them in?

I've never had one come out, ever. Even during testing I don't run covers generally just to save time and never had an issue. I may have none to as many as 10 total on a car at a time.

I'm sure it likely depends on if you got the right rubber for your style of spring.

[billetbirdcage]

As far as consistency:

If you put the rubbers back to back with no coil gap between them, you may see a bunch of variance if you smash it 10 times in a row. The edge of the rubbers that wrap around the spring can touch each other during compression and sometimes slide off the side and lower rate or don't and raise rate. So every time you smash it (worse with the more rubbers you have) you will get different numbers. Keeping them spaced out will help to eliminate this.

It's been 5 or 6 years so I'd have to look at some old notes but on a RF with 6 to 7 rubbers in it, I could easily get several hundred pounds variance at max travel. Reason I avoid doing that.

[collateralDamage]

you can stuff a 12" 225 mx spring on a RR full of spring rubbers and not affect handling one bit in the range the spring actually operates. You can also put a single rubber in the RR and affect handling drastically.

You need to know the operating range of the spring before you really know what it will or won't do for wheel load. If you are using a spring rubber, you have to anticipate some level of progression in rate otherwise you may want to chose a different spring. Then again, it depends on the operating range of the spring and the type/dimension rubber you are using....

[Kromulous]

I would think with all these high tech spring smashers everyone is going wild to get would help get a picture of what your looking at when you install a spring rubber in various places and amounts.

Speaking of pictures, i had a friend of mine make me an excel spreadsheet that layouts out the points in a graph, so you can see it more in a graphical sense. Its helps to see the progression visually. Next thing i want to work on is a program that will record the sweep like a shock dyno, and not have to stop the machine to record it. How nice would that be? Start at max spring height, press it down to ride height, and its all recorded in a nice visual output. I just need to talk to some computer dudes LOL.

There was a video on FB by Booze Brothers Performance that showed a RR with a bunch of rubbers in it, very interesting to watch.

[mickley.28]

[QUOTE=MasterSbilt_Racer;2177110]Not always. :)[/QUOTECan you please explain when adding rr spring rubbers wouldn’t loosen middle-off??? It should load the right rear harder and or quicker which unloads the left rear which would loose exit correct?

[MasterSbilt_Racer]

If the car is still translating laterally across the surface as you exit the corner, a front with good grip can overcome the RR to change the direction of the car. If the RR is pinned harder, the front tires cant do as much.

The car is almost never going "straight". At tracks with decent arcs to the "straight" it really isn't.

There is also the scenario where the rear is not at optimal grip because the LR is overloaded. Any increase of RR load would tighten a car suffering that problem.

[mickley.28]

If the car is still translating laterally across the surface as you exit the corner, a front with good grip can overcome the RR to change the direction of the car. If the RR is pinned harder, the front tires cant do as much. The car is almost never going "straight". At tracks with decent arcs to the "straight" it really isn't.There is also the scenario where the rear is not at optimal grip because the LR is overloaded. Any increase of RR load would tighten a car suffering that problem.Won’t A car that has a left rear that’s overloaded on exit be extremely tight??? More load on left rear means it will be doing more work and providing more forward thrust than the right rear. All else being equal If left rear has more weight/thrust than right rear car will push the nose to the right when on the gas.

[Punisher88]

I would think with all these high tech spring smashers everyone is going wild to get would help get a picture of what your looking at when you install a spring rubber in various places and amounts. Speaking of pictures, i had a friend of mine make me an excel spreadsheet that layouts out the points in a graph, so you can see it more in a graphical sense. Its helps to see the progression visually. Next thing i want to work on is a program that will record the sweep like a shock dyno, and not have to stop the machine to record it. How nice would that be? Start at max spring height, press it down to ride height, and its all recorded in a nice visual output. I just need to talk to some computer dudes LOL.There was a video on FB by Booze Brothers Performance that showed a RR with a bunch of rubbers in it, very interesting to watch.If you search in your app store penske has am app called spring machine or spring smasher, I can't remember off the top of my head but it puts in in a graph for you after you enter the info. I just screen shot it and save it to my notebook on my phone. And it will email it to you in a spreadsheet form.

[MasterSbilt_Racer]

A decent driver is going to compensate and keep that LR heavy car going in a circle. He isn't going to just plow the nose every lap. That means breaking traction. And breaking traction is easier to do when one wheel does the heavy lifting.

[billetbirdcage]

I would think with all these high tech spring smashers everyone is going wild to get would help get a picture of what your looking at when you install a spring rubber in various places and amounts.

Speaking of pictures, i had a friend of mine make me an excel spreadsheet that layouts out the points in a graph, so you can see it more in a graphical sense. Its helps to see the progression visually. Next thing i want to work on is a program that will record the sweep like a shock dyno, and not have to stop the machine to record it. How nice would that be? Start at max spring height, press it down to ride height, and its all recorded in a nice visual output. I just need to talk to some computer dudes LOL.

There was a video on FB by Booze Brothers Performance that showed a RR with a bunch of rubbers in it, very interesting to watch.

The new accuforce smashers do that.

https://www.youtube.com/watch?v=ml-V3qSCT3c&feature=youtu.be

[billetbirdcage]

mickley.28

There is lots of times stiffening the RR with tighten the car on exit, but it's extremely situational. I've done it a bunch of times in private tests where the driver had it in his head it would loosen the car (so driver had a preconceived notion what it was gonna do) and after I did it came in scratching his head, lol.

Honestly it takes experience to know when it will and when it won't and I can't say I can do that all the time.

There are several things that will give you the opposite reaction at times, another example of this is J-bar. The most common answer to raising the J-bar on the frame is it will tighten the car, but there are situations where I raise it to loosen the car especially thru the middle. I've had people pitted next to us watch me do that to someones car when about everyone is fighting a tight condition on a real heavy track and ask me: "Wasn't you guys tight too? so why are you raising the J-bar". I just answer "Yes, we was tight". They always give me a strange look and think I'm nuts, but are really confused when we win the heat race.

Some of these things I can't find a decent theory to explain it that I can't poke holes in or seems rock solid correct, but they happen and it just takes experience and a ton of testing to really get a feel for when these things happen. Only making changes at races and no testing where you get back to back examples, you're probably not going to get a good data base to sort out when this happens.

[Kromulous]

That Accuforce smasher is nice, maybe i can buy one when my ship comes in.

Until then, that APP looks nice too, or my ole spreadsheet.

[fastford]

mickley.28

There is lots of times stiffening the RR with tighten the car on exit, but it's extremely situational. I've done it a bunch of times in private tests where the driver had it in his head it would loosen the car (so driver had a preconceived notion what it was gonna do) and after I did it came in scratching his head, lol.

Honestly it takes experience to know when it will and when it won't and I can't say I can do that all the time.

There are several things that will give you the opposite reaction at times, another example of this is J-bar. The most common answer to raising the J-bar on the frame is it will tighten the car, but there are situations where I raise it to loosen the car especially thru the middle. I've had people pitted next to us watch me do that to someones car when about everyone is fighting a tight condition on a real heavy track and ask me: "Wasn't you guys tight too? so why are you raising the J-bar". I just answer "Yes, we was tight". They always give me a strange look and think I'm nuts, but are really confused when we win the heat race.

Some of these things I can't find a decent theory to explain it that I can't poke holes in or seems rock solid correct, but they happen and it just takes experience and a ton of testing to really get a feel for when these things happen. Only making changes at races and no testing where you get back to back examples, you're probably not going to get a good data base to sort out when this happens.

In theory , putting a spring rubber or a stiffer spring in rt rear will loosen car from middle off , and most of the time it will , but you guys are right , sometimes , according to driving styles and other variables , it will give a tightening effect , here is another example of going against the norm , back 15 years or so ago , we were at a track that lost all grip , the more bite you gave the car , the worse it got from middle off , after qualifying , i said what the heck , and we put reverse wedge in it , about a 100 lbs when we got home and put it on the scales , and drove around every body and won the race , this is what i like about dirt , the norm does not always win races........

[CCHIEF]

In theory , putting a spring rubber or a stiffer spring in rt rear will loosen car from middle off , and most of the time it will , but you guys are right , sometimes , according to driving styles and other variables , it will give a tightening effect , here is another example of going against the norm , back 15 years or so ago , we were at a track that lost all grip , the more bite you gave the car , the worse it got from middle off , after qualifying , i said what the heck , and we put reverse wedge in it , about a 100 lbs when we got home and put it on the scales , and drove around every body and won the race , this is what i like about dirt , the norm does not always win races........ I concur, this works very well on big sweeping corner tracks, when they go dead slick and slow down, there is corner speed to be (re)found by putting static load on the rr instead of relying on transfer. Spring rubbers are convenient, but often inconsistent. Nice to have for "adjustments" in 100 lappers. For a regular Saturday night shoot out, your far better off without. My 2 sense. YMMV