5.4 vs 5.6 shock spring for 175lb rider on 2 stroke RR

[Goatse]

I'm about to (finally) order new springs for my 250RR, and I'm indecisive on the shock spring. My real world results (sag numbers) show that I 'should' just need the next rate up (5.4), but other guys' real world experience shows they're happier with the 5.6 spring. 

 

I'm currently about 180lbs, and will be 175lbs by the time race season fires back up. Geared up (about 205 lbs) I can get 100mm race sag which results in 28mm static. So it's at about the ceiling of what 'should' be OK. So I would think that bumping up to the next rate should net me some good numbers. But I see that many guys in that range have been going with the 5.6 rear spring, and are liking it. I ride mostly rocky terrain, and do hit the Endurocross track on a regular basis.

 

For the forks I'm already set on ordering a single 46, as I'm going to throw it in the left leg for a total rate of 44 (mixed with the stock 42). Then if it's still a bit soft, I'll order a 44 for a small bump to a 45 total rate. If the shock spring was available in a 5.5, I would have just ran with that. 

 

 

So has anybody in a similar situation went with one or the other? 

Edited March 5, 2018 by Goatse

[wwguy]

For me your current sag numbers are perfect.  (I.e. race sag at 1/3 of wheel travel and static sag near 25mm.)  For me any static sag more than 35mm or so indicates a too-stiff spring, and it looks like you might be in that territory with a 5.6 kg spring... especially if you're losing weight.

The spring's job is to hold the bike up at the correct attitude under the weight of the rider, his gear, and anything he's strapped or bolted to the bike.  Based on your sag numbers yours looks to be about right.  Springs are load sensitive, but not speed sensitive. Valves are speed sensitive, but not load sensitive. So if you want to change the way the suspension feels under you while riding I'd look at valving changes first.

Just my two cents from the cheap seats.

[MartyMOOSE]

1 hour ago, wwguy said:

For me your current sag numbers are perfect.  (I.e. race sag at 1/3 of wheel travel and static sag near 25mm.)  For me any static sag more than 35mm or so indicates a too-stiff spring, and it looks like you might be in that territory with a 5.6 kg spring... especially if you're losing weight.

The spring's job is to hold the bike up at the correct attitude under the weight of the rider, his gear, and anything he's strapped or bolted to the bike.  Based on your sag numbers yours looks to be about right.  Springs are load sensitive, but not speed sensitive. Valves are speed sensitive, but not load sensitive. So if you want to change the way the suspension feels under you while riding I'd look at valving changes first.

Just my two cents from the cheap seats.

The thing is if you use the 1/3 rule he will be out! The beta doesn't have 300mm of rear wheel travel. Try 96-97 loaded and it will be closer to the 1/3  rule. 

MM

 

[motoxgiant]

You could be happy with the 5.4 or the 5.6 ... because as a general rule spring manufacturers try to hold a 5% tolerance, and as such one spring marked 5.4 may in fact be stiffer than one marked 5.6. That said, I'd try to get a verified 5.4, particularly if you're stable or losing weight yourself.

I agree whole-heartedly with Marty that you want to shoot for 96-97 loaded and run a good front tire.

[wwguy]

1 hour ago, MartyMOOSE said:

The thing is if you use the 1/3 rule he will be out! The beta doesn't have 300mm of rear wheel travel. Try 96-97 loaded and it will be closer to the 1/3  rule. 

Sorry about the error.  (Xtrainer rider here.)

[Goatse]

The thing is if you use the 1/3 rule he will be out! The beta doesn't have 300mm of rear wheel travel. Try 96-97 loaded and it will be closer to the 1/3  rule. 



MM



 

You could be happy with the 5.4 or the 5.6 ... because as a general rule spring manufacturers try to hold a 5% tolerance, and as such one spring marked 5.4 may in fact be stiffer than one marked 5.6. That said, I'd try to get a verified 5.4, particularly if you're stable or losing weight yourself.
I agree whole-heartedly with Marty that you want to shoot for 96-97 loaded and run a good front tire.

I was actually aiming for 95mm race sag, but my lock nuts ran out of thread on the shock.

[NW_drZ]

185lbs no gear. 4.6 / 5.6 gave me good sag numbers. Running a fatty up front. The springs alone made a big difference from the stockers for me.

[hawaiidirtrider]

Im 225 in street clothes and running a 6.0 behind.  Around up to 270lb on the high side of spring rate. It’s good. Id go on the higher spring rate. It’s a couple of spring rates up from your weight. I think sag is 100 or so., 

The only way is to try to see the difference. I tried a couple spring rates. The stiffer was best so I have a .50 in front and a .60 behind. Its plush enough and stable with plain old stock valving. 

[tsouth556]

What spring brand you use also makes a huge difference. The beta springs use a open ended coil spring so the rate is not consistent like a closed coil spring. Here is what the last spring I measured came in at. It was labeled as a 5.4kg from beta

 

10-30mm compression 5.0

30-50mm compression 5.1

50-70mm compression 5.2

70-90mm compression 5.3

90-110mm compression 5.4

 

The problem here is that the shock shaft only has 133mm of travel and typically 8-10mm of preload on the spring. This means that the bike won’t see the 5.4 rate until the last 1/3 of the travel. I always suggest using a “hi performance” spring that way the rate is consistent through the entire travel.

 

Being that your numbers are close with the open coil spring I would suggest going to a 5.4kg hi-performance spring over going up in rate on a open coil spring.

 

 

 

 

 

[hawaiidirtrider]

42 minutes ago, tsouth556 said:

What spring brand you use also makes a huge difference. The beta springs use a open ended coil spring so the rate is not consistent like a closed coil spring. Here is what the last spring I measured came in at. It was labeled as a 5.4kg from beta

 

10-30mm compression 5.0

30-50mm compression 5.1

50-70mm compression 5.2

70-90mm compression 5.3

90-110mm compression 5.4

 

The problem here is that the shock shaft only has 133mm of travel and typically 8-10mm of preload on the spring. This means that the bike won’t see the 5.4 rate until the last 1/3 of the travel. I always suggest using a “hi performance” spring that way the rate is consistent through the entire travel.

 

Being that your numbers are close with the open coil spring I would suggest going to a 5.4kg hi-performance spring over going up in rate on a open coil spring.

 

 

 

 

 

So what “ high performance “ spring did you use on your Beta?

[tsouth556]

So what “ high performance “ spring did you use on your Beta?

Racetech is what we use on all the betas

[hawaiidirtrider]

3 minutes ago, tsouth556 said:

Racetech is what we use on all the betas

I used racetech on a couple of my Betas. I thought they were standard open coil.

[tsouth556]

I used racetech on a couple of my Betas. I thought they were standard open coil.

No racetech uses closed coil springs. There springs will measure the same rate all the way to coil bind.

[hawaiidirtrider]

4 minutes ago, tsouth556 said:

 

No racetech uses closed coil springs. There springs will measure the same rate all the way to coil bind.

 

And you feel the difference???

[tsouth556]

And you feel the difference???

Against a spring that starts as a 5.0 and ends as a 5.4..... absolutely

[hawaiidirtrider]

57 minutes ago, tsouth556 said:

 

Against a spring that starts as a 5.0 and ends as a 5.4..... absolutely

 

 

Well good thing I have racetech springs. I didn’t think there was a difference.. 

 

[typeone]

Goatse, your weight and terrain sound exact to my situation... currently i'm at ~182lbs will be 175 (or a bit less) by season kickoff...

i've tried every rear spring from 4.8 > 5.4, each one got better, I'm now on a 5.6 rear with 30mm static, 96mm race towards front of the bike, 98mm towards rear. up front i went from .42 > .44 + MXT inserts. i'm expecting the bike to handle our rocky terrain very well. if the forks feel a little too over sprung, i will swap a .42 in one leg.

EDIT: on the 5.5, i almost tried a titanium 5.5, think it was a KYB spring, but read they are a little bit wider. didn't want to chance rubbing the air boot. dealt with that on my Husky WR. was always checking for wear.

Edited March 6, 2018 by typeone
added detail

[GP]

I'm 182 lbs now and run the 5.6.  I could easily run the 5.8 and may try one.  Too soft rear is the kiss of death (and the ground) on this bike with the stock shock length.  Also beware that fatty front tire raises the front quite a bit as well, another reason don't like those.  If you measure an M59, you will find its within a couple mm of a fatty in width, but much lower in profile, why it works so well.

[GP]

17 minutes ago, typeone said:

Goatse, your weight and terrain sound exact to my situation... currently i'm at ~182lbs will be 175 (or a bit less) by season kickoff...

i've tried every rear spring from 4.8 > 5.4, each one got better, I'm now on a 5.6 rear with 30mm static, 96mm race towards front of the bike, 98mm towards rear. up front i went from .42 > .44 + MXT inserts. i'm expecting the bike to handle our rocky terrain very well. if the forks feel a little too over sprung, i will swap a .42 in one leg.

EDIT: on the 5.5, i almost tried a titanium 5.5, think it was a KYB spring, but read they are a little bit wider. didn't want to chance rubbing the air boot. dealt with that on my Husky WR. was always checking for wear.

That sounds a bit soft up front.  I'm 4.6 in KYB closed chambers with a 2k ICS spring and its perfect balance. 

[typeone]

Just now, GP said:

That sounds a bit soft up front.  I'm 4.6 in KYB closed chambers with a 2k ICS spring and its perfect balance. 

hmm, good input, thanks. i've been discussing with Warren at EnduroSpec, gave him all my specs and we went with .44 to start. only one way to find out, i'll give it a go pretty soon. another ~foot snow coming tomorrow, ugh.