New XR1 rocket right fronts

[racinrocket1]

So I've been told by a kid that a has new XR1 that all the new cars are running a 275 lbs spring with 3 - 4 spring rubbers in it. Now my question is are they stacking the bottom of the spring with the rubber so that on entry your still on the 275 to help the ccr turn in and then once it gets on the spring rubbers its like a stacker deal where the spring gets stiffer ? That's the only conclusion i can come up and also wonder what durometer of spring rubbers they are running ? Im currently running a stacker but just looking for another option if the track gets a little choppy

[RacerX10]

So I've been told by a kid that a has new XR1 that all the new cars are running a 275 lbs spring with 3 - 4 spring rubbers in it. Now my question is are they stacking the bottom of the spring with the rubber so that on entry your still on the 275 to help the ccr turn in and then once it gets on the spring rubbers its like a stacker deal where the spring gets stiffer ? That's the only conclusion i can come up and also wonder what durometer of spring rubbers they are running ? Im currently running a stacker but just looking for another option if the track gets a little choppy

It doesn't really matter where the spring rubber is. You're essentially removing a coil and increasing the spring rate. Somebody like Matt49 will disagree ( :) ) because that isn't 100% accurate, but for our purposes on dirt ... it doesn't matter IMHO.

They are probably doing what I said I was thinking of doing in my other thread .. pulling spring rubbers out as the track slicks over.

[Kromulous]

I was told that a lot of touring guys like to run them that way because there is not as much spring back, or spring return in the rubbers. You can mash it, but it doesn't rebound as hard, also the rubbers control how much the car rolls onto that corner, so its more of a roll stop / bump stop type deal, i know its not the same but similar.

[Matt49]

If you put a spring rubber to a 275, it isn't a 275 anymore...at any point. As was stated, you're "removing" coils which stiffen the spring but the spring rubber compresses also so that coil isn't entirely removed from taking load. So it can create a progressive effect depending on the hardness and height of the spring rubber.

[Matt49]

Krom, I can definitely see what you're saying also. You compress a spring one inch and let go and it is coming back to free height RIGHT NOW. Compress a piece of rubber and it will usually be slow to "un-compress"

[billetbirdcage]

Krom, I can definitely see what you're saying also. You compress a spring one inch and let go and it is coming back to free height RIGHT NOW. Compress a piece of rubber and it will usually be slow to "un-compress"

Keep in mind if your putting the rubbers next to each other or if have many of them, you will find that the rate will be inconstant. This can be do to several things, but it's usually cause the rubbers top edges don't always like up with themselves and sometime will or won't push against each other. Meaning sometimes the edge jumps off the side of the other rubber, thus changes the rate.

Take a 200# spring and throw 4 or 5 of them in it and put it in a spring cruncher and test it thru 4" of travel like a RF with it's preload and you will likely get numbers that are different thru out it's travel. The amount of variance may surprise you, lol.

Just something to be aware of, some rubbers by the way they are designed are worst about it then others.