Author Topic: choosing the right shock springs (Read 8183 times)

dem3500 · « **on:** April 25, 2016, 09:49:36 AM »

winter before last i sent my shocks to a professional to have them setup for me cause i diddnt know squat about custom suspension and i diddnt have the time to learn it and do it myself. well all last race season (1015) i battled with suspension problems. my rear shock was back to the builder 4 or 4 times and the fronts once. i talked to a lot of the guys i race with about my problems and they all said that i hsould not have the problems. one of the guys i race with helped me revalve my rear shock. it made a little bit of a difference. i kept stopping during my first race of my season yesterday to adjust compression and rebound on my rear shock. it made it a lot better but its not where i think it needs to be. the fronts are a different story. i THINK there sprung too heavy and are too fast on the rebound. so.....at this point i think i have a ok grasp on how the internal valving works and i know what to change to make things slower or faster but what i cant figure out is how do i figure out the correct springs? maul tech has a spring calculator to find out the rate of an unknown spring. i figured id use it to find out the rate of my rear spring so at least i knew where i stand but how do i know what spring i actually need. do i figure that out from figuring race sag? before or after i set ride height? basically im going to just learn all this stuff and do it myself. i cant afford to keep sending my shocks back and fourth a bunch of times lol

rablack21 · « **Reply #1 on:** April 25, 2016, 10:25:25 AM »

First things first, sir. We need some info from you to help ya out. (Generally the spring rate is stamped on one of the flats of the spring, very top or very bottom of spring)
Fill in the following:
Your race weight:
Type of racing:
Front a-arm specs (stock, +2, +1? long travel or standard?):
Brand of front shocks:
What adjustments:
Front shock length:
Type of swingarm:
Rear shock brand:
Rear shock length:
Type of adjustments:
Ride height that you are running:
Front tire size:
Rear tire size:

What problems are you having? What is it doing or not doing?
Have you ever measured your shock mounting eye to eye dimensions with the chassis frame height at 12 inches and 1.5 inches off the ground? If so, what were the dimensions?

dem3500 · « **Reply #2 on:** April 25, 2016, 11:31:47 AM »

i will look on my rear spring again but when i looked i diddnt see any. its old so i dont know any history on it. i did the maultech caculator and it came out to 227. i had a buddy punch in the numbers and i dont trust the numbers so im going to do it again myself lol. with the rear it was coming up and hitting me in the rear end when i would break on a down hill. like it was chattering bouncing. i made it better by slowing down the rebound. i also feel like im not using all of the travel in the rear. like its a little stiff for my weight. i have the compression all the way counter clockwise. its just not a plush ride like i see other peoples when they go flying by me as i get beat to hell from the rough terrain. once i improved the rear shock by adjusting the rebound a little i really started to notice my front shocks. they feel like a pogo stick. very very stiff. it does not dive when im in a corner. the choppy stuff will yank the bars out of my hands sometimes. if i have any chance at going through choppy stuff fast i have to try to carry the front end. its almost like the front is not compressing. the main springs on the front are new as of last year and i can get the numbers off them tonight.
i have never measured the shock mounting as you described. is this to determine that my shocks are the right length? when i measure them do i have to drop the rear end too to keep the frame parallel?

Your race weight: 155
Type of racing: XC
Front a-arm specs: +1 standard travel
Brand of front shocks:elka stage 3 (as i was told) remote reservoir compression adjustment only
What adjustments: compression adjustment only
Front shock length: will measure tonight
Type of swingarm: stock 88
Rear shock brand: elka stage 3
Rear shock length: 16'' iirc
Type of adjustments: compression and rebound
Ride height that you are running: 8.25 rear 8.5 front. im not able to get the rear end any lower without taking all the preload out of the rear spring. i had to bring the front up a little to get the front high enough.
Front tire size: 20" iirc
Rear tire size: 21" iirc

rablack21 · « **Reply #3 on:** April 25, 2016, 11:57:14 AM »

Yes, measuring the shock mounting is to make sure the shock lengths match the actual extended and compressed lengths of the actual chassis.

Ok, let's cut this into usable chucks. Let's start with the rear for now.
You said it was bouncing up and hitting you in the butt, you slowed the rebound, and it improved. You are on the right track.

1. Ride height seems about right. You shouldn't be putting any more preload on the spring than needed to either achieve ride height or keep the spring from bouncing freely. How many turns would you say you put on the preload adjuster ring in order to achieve the ride height (rough guess)?

2. You are not sure if you are using all of your travel. You said you checked your race sag, what were your measurements?

3. You said that you have your compression set to fully soft on rear shock, correct?

dem3500 · « **Reply #4 on:** April 25, 2016, 12:19:02 PM »

Ok when I set my preload I would say that I turned it just enough for the spring to not flop around. That's kind of why I think the spring might be a touch too stiff. The shock I pulled the spring from was a stock R revalved for a 180lb rider. So I was told so take that info with a grain of salt.
I have not checked race sag. I was just reading about sag and race sag. Still not 100% understand the concept but I'm going to keep reading. (Slow day at work lol). Looks like it's a correlation between the sag when I'm on it vs the sag with only the weight of the quad to determine if the spring is too soft or hard. Right?
Rear shock compression is full soft. I do not feel like it's bottoming out. I was thinking about putting a zip tie on the shaft and hit some whoops to see if it is or not.
And again, I don't know much about this stuff. Just a bigger picture concept so don't assume I know what I'm doing haha.

rablack21 · « **Reply #5 on:** April 25, 2016, 12:58:40 PM »

Race sag and ride height generally correlate very well together. These measurements will tell you whether the spring rate is correct for your weight or not.

Watch the following video. This will help a lot, including how to measure race sag.
[video=youtube;SFFGe8Sp3D0]https://www.youtube.com/watch?annotation_id=annotation_3333890895&feature=iv&src_vid=wFd_qeVrJ8I&v=SFFGe8Sp3D0[/video]

dem3500 · « **Reply #6 on:** April 25, 2016, 01:06:30 PM »

ok ill go through all that and report back. thanks for your help!

dem3500 · « **Reply #7 on:** May 01, 2016, 05:02:46 PM »

@rablack21
Ok my sag is 4.25" for the rear shock. thats measuring with the bike on a stand and the shock fully extended minus the measurement with me on the bike.

rablack21 · « **Reply #8 on:** May 02, 2016, 10:26:01 AM »

A couple quick questions:
1. You are running 1inch taller tires in the rear. Is that normal? I know for mx, it's usually the opposite.
2. Did you check your ride height with your normal air pressure in all 4 tires?

dem3500 · « **Reply #9 on:** May 02, 2016, 10:34:19 AM »

I run XC not MX. When I set my ride height I had 5 lbs of air in all 4 tires

rablack21 · « **Reply #10 on:** May 02, 2016, 10:41:57 AM »

I realize you run xc, but most of the setups I'm seeing usually run 21-22 inch tires in the front and 20 in tires in the rear for xc.

dem3500 · « **Reply #11 on:** May 02, 2016, 10:58:07 AM »

Ok your probably right and I brain farted haha. I'm sure the rears are 20 and the front are 21. I'll double check that.

dem3500 · « **Reply #12 on:** May 02, 2016, 11:31:30 AM »

Ok I confirmed. 20 rear 21 front

rablack21 · « **Reply #13 on:** May 02, 2016, 12:38:15 PM »

That sounds better. lol. Ok. So let's go through this.

Your sag is close, you are aiming for 4.5 inches.
Your should aim for a rear ride height of 8 inches. You are at 8.25 (with absolutely no preload)
Your tire pressure should be about 5-7psi, which it is.
Your rear spring is probably 1 size too stiff.
If I remember Andy correctly, 1 spring rate change (25lb increments) equate to about 1/2" ride height change.
This is entirely up to you which one you want to run. You would have no problem with reaching a ride height of 8" if you were to drop down 1 spring size. It wouldn't take much preload to get you there. So I would say that some of your rough ride is probably coming from having a spring that is a tad too stiff for you. You usually want the softest spring possible that will get you the ride height and race sag that you are aiming for.
So, I would say this is your first breakthrough to your suspension woes.

dem3500 · « **Reply #14 on:** May 02, 2016, 12:55:09 PM »

Quote from: rablack21;67187

That sounds better. lol. Ok. So let's go through this.

Your sag is close, you are aiming for 4.5 inches.
Your should aim for a rear ride height of 8 inches. You are at 8.25 (with absolutely no preload)
Your tire pressure should be about 5-7psi, which it is.
Your rear spring is probably 1 size too stiff.
If I remember Andy correctly, 1 spring rate change (25lb increments) equate to about 1/2" ride height change.
This is entirely up to you which one you want to run. You would have no problem with reaching a ride height of 8" if you were to drop down 1 spring size. It wouldn't take much preload to get you there. So I would say that some of your rough ride is probably coming from having a spring that is a tad too stiff for you. You usually want the softest spring possible that will get you the ride height and race sag that you are aiming for.
So, I would say this is your first breakthrough to your suspension woes.

AH HA! lol good! ok ill go find a lighter spring. so basically my thought process from the seat of my pants was right lol. too stiff. ok easy fix. more $ but easy. how can this process apply to diagnose my front shocks? considering that the springs my OLD shock builder installed on my rear shock was very heavy (idk if i mentioned but the spring i put on the rear is a lighter spring rate spring that i had laying around so the original was quite a ways away from correct) and my seat of the pants feel is the same for the front but worse now is it safe to assume that my front springs are way too stiff as well?