stretching springs?

[Hardline]

I've been running mini-T rear springs but want to try the softer rate fronts which are a little shorter. Too short as it turns out.

I can put a spacer under the spring cup, but that will limit the stroke more than I'd like. I don't have a very good method for spacing down the top of the spring.

Has anyone ever tried just pulling hard enough on a spring to change it's length? I'm pretty sure it's doable, but don't know what kind of problems might pop up. Like having trouble getting two to match.

Don't need opinions -- I got plenty of those. Just wondering if anyone has actually tried it.

 

[Charlie-III]

I've done it for other uses (not crawlers), one of the issues is that you then change the spring rate (I believe it makes it higher/stiffer) so you may want to try a different spring rate to start so you end up with what you want after stretching.

How much the rate changes is partly how far you stretch it which is a % length change from "stock" NOT an actual measurement.

 

[shelljeep]

Stretching the spring will definitely make it's rate more firm.

 

[craddock35]

I have done it but only stretch part of it so that only that section of it changes or at least that is the way it seems to do. I usually do just one end just depends on what I am doing it for. I have done just the middle and it does fine just takes more pressure the last 1/4" of travel it seems like with it in the middle but if I do it on the end it isn't really noticeable or at least to me it isn't.

 

[hoghead5150]

you might want to check the spring rates between the front and rears on the mini-t springs. there really isn't much difference at all. i think the silver rears are like .89, and the pink fronts are like .86. not gonna gain much. another option would be to look at the losi MRC springs. not sure on the rates, but they are close to the mini-t rear spring size. just a thought.

 

[Hardline]

you might want to check the spring rates between the front and rears on the mini-t springs. there really isn't much difference at all. i think the silver rears are like .89, and the pink fronts are like .86. not gonna gain much. another option would be to look at the losi MRC springs. not sure on the rates, but they are close to the mini-t rear spring size. just a thought.

You're right about the mini-T silvers...thanks for reminding me. I'm not aware of any MRC RTR springs anywhere near that soft. Please post a part number if I'm wrong. The mini-T springs get kind of pricey if you only need one rate and have to throw 2/3 of the pack away.

But in any event, running small springs on the Big Bore always seems to have the problem of lack of preload adjustment as found in threaded body shocks. So being able to resize a spring would add some capability there.

BTW, the other comment of stretching a spring changing it's rate is wrong. You haven't changed the wire diameter, spring diameter or number of free coils -- Those three things determine the rate. But of course you do probably change the preload which will stiffen the suspension independent of rate.

 

[shelljeep]

Its not wrong. You are changing the slope of the coil and that does affect the rate.
Grab a Losi gold and set up a jig to compress it 1" on top of your scale. Take a reading then stretch your spring and modify the jig to compress it 1" at the new length. You will see a difference.

 

[Charlie-III]

its not wrong. You are changing the slope of the coil and that does affect the rate.
Grab a losi gold and set up a jig to compress it 1" on top of your scale. Take a reading then stretch your spring and modify the jig to compress it 1" at the new length. You will see a difference.

+1.