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-   -   Best brand of springs? (https://www.rctech.net/forum/electric-road/1037949-best-brand-springs.html)

LzREngineering 02-27-2019 11:38 AM

Best brand of springs?
 
Looking at getting some short (20mm) TC springs, which brand is the most accurate and well matched?

Fastfreddy74 02-27-2019 11:43 AM

SMJ springs are very well matched, I'm using em since a while and I'm pretty happy

https://smj-rc.com/products/springs/smj1200

johnzhou2476 02-28-2019 08:51 AM

+1 on the SMJ springs

RBLove 02-28-2019 03:12 PM

Xray, Axon, and SMJ are all great options.

1spunspur 02-28-2019 04:48 PM

Can anybody tell me what's up with the spring ratings on some of these things? Some are rated at 30lbs. and 40lbs. And others rated in the single digits. (I'm referring to A.E.) My understanding was that springs were rated at lbs. of pressure to compress the spring 1".

LzREngineering 02-28-2019 11:31 PM


Originally Posted by 1spunspur (Post 15404915)
Can anybody tell me what's up with the spring ratings on some of these things? Some are rated at 30lbs. and 40lbs. And others rated in the single digits. (I'm referring to A.E.) My understanding was that springs were rated at lbs. of pressure to compress the spring 1".

C= means how many newtons to compress the spring by 1mm.
This tool comes in handy .: Spring Rate Conversion Calculator :. | NorWest Suspension LLC


glennhl 03-01-2019 11:51 AM

I like the SMJ springs, but I also like the Associated springs, I've found them to be very consistent.

LzREngineering 03-03-2019 02:47 PM

https://cimg1.ibsrv.net/gimg/www.rct...212d1162a7.jpg
Just got some xray springs, initial measurements suggest they're not 100% perfectly matched. Also the 'linear' springs are still fairly progressive.

LzREngineering 03-04-2019 01:03 PM

More detailed measurement of the xray springs... there's an obvious mismatch between the springs in each pair :( also the progressive springs are softer over the whole useful range, they may get up to C=2.8 at the very end of travel but that's never practically going to happen.
https://cimg4.ibsrv.net/gimg/www.rct...9af5795f1d.jpg

DavidNERODease 03-04-2019 02:09 PM

What level of accuracy is reasonable to expect? The the worst case scenario in this graph looks to be about a 96% match?

LzREngineering 03-04-2019 02:35 PM


Originally Posted by DavidNERODease (Post 15407458)
What level of accuracy is reasonable to expect? The the worst case scenario in this graph looks to be about a 96% match?

I don't really know. Obviously the number of turns/spring length and thickness of wire can be easily controlled to a high degree in the manufacturing process, but that doesn't always translate to exactly the same 'springiness'.

Closest to 100% perfect match left/right would be ideal, especially when you think of the lengths we go to to de-tweak our cars, it makes sense to have perfect springs.
Does anyone have a set of SMJ springs they'd be willing to measure?

Bry195 03-04-2019 08:46 PM

I think that if you find springs that have a similar slope and are within .1 to .2 you can make up for the difference in collar preload fairly easy. Looking above it looks like .5mm of preload will bring the slopes together.

you can also condition the springs by working them for awhile. They stop changing as you condition them fairly quickly. There are some weak bonds that break fairly quickly.

LzREngineering 03-05-2019 12:39 AM


Originally Posted by Bry195 (Post 15407712)
I think that if you find springs that have a similar slope and are within .1 to .2 you can make up for the difference in collar preload fairly easy. Looking above it looks like .5mm of preload will bring the slopes together.


My worry about correcting using the preload collars is that on full droop, one spring may be loose whilst the other is still slightly compressed. Could this lead to some strange handling at max roll?


Originally Posted by Bry195 (Post 15407712)
you can also condition the springs by working them for awhile. They stop changing as you condition them fairly quickly. There are some weak bonds that break fairly quickly.

Any tips for softening or stiffening springs slightly?


Bry195 03-05-2019 08:03 PM


Originally Posted by LzREngineering (Post 15407784)
My worry about correcting using the preload collars is that on full droop, one spring may be loose whilst the other is still slightly compressed. Could this lead to some strange handling at max roll?


Any tips for softening or stiffening springs slightly?

the metal fatigues. Some of the internal bonds are weak and break softening the spring over time. Use your thumb to compress the heavy ones over and over again but the amount of weak bonds is randomn so you will just have try it and dont over do it. Start by repeating 5mm compressions then 10 then 15...

You will never get your springs perfect and probably wont notice a difference in them being a little off but you can shim a spring or bend a portion to increase length. Conditioning doesnt just have to be about compressing. You can stretch them to get length and compress them to get comparable yield. If you condition a long spring with repeated compressions you can condition a short spring to be longer. The stretching and compression will break the bonds in both directions so if the measurement is 2lbsfor 10 mm and you have one that is short you can drop the resistance by stretching and compressing. The bonds break in both direction they dont grow back in a stretch.

you will find that the bonds break in a very narrow window. For example 5mm stretch or compression may not break very many or any bonds but 6 will break allot.

think of a bolt being screwed into a and aluminum joint. It might take 180 degrees to damage the threads from over tightening. Now think of a bolt screwed into a cast iron joint. Torque rises very quickly and you can damage the threads in 90 degrees. Its the same bonds being broken in a spring. The harder the metal the smaller the window is before the metal loses elasticity and bonds break.


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