I'm looking at upgrading the spring on my stock shock. I would rather replace the whole thing, but don't have the cash right now to buy an ohilns or a penske. I went to the race tech site and they didn't have anything listed for the 97 M750, I called and there was nothing in their database for a stock shock size. The I went to Traxxion and placed an order there, I got a call and they didn't know what the stock spring size was. They asked me to take the shock off and send it in, i would rather avoid having to do that. I did some searching and found an old thread that someone with a 96 M900 replaced his spring and he used a;
SRSP S5818116 RT SHK SPR 58.2x178mm 11.6kg
Would this be the same size for a 97 M750?
I'm interested in reading any responses you get.
Been needing to do the same thing for a while now.
I'll try to measure up an early Monster shock tomorrow, but I'm pretty sure that spring size will work.
That's a metric description of a 2.25" ID x 7.0" long spring, 650 lb/in.
That's a *very* stiff spring, moreso for an early Monster.
Quote from: Speeddog on February 25, 2011, 09:15:33 PM
I'll try to measure up an early Monster shock tomorrow, but I'm pretty sure that spring size will work.
That's a metric description of a 2.25" ID x 7.0" long spring, 650 lb/in.
That's a *very* stiff spring, moreso for an early Monster.
That would be awesome if you can measure one!
The description came from the race tech site, I believe. I'm looking for a spring for a heavier rider, I'm about 220 and I don't think the stock one is made for someone my size.
I'm pretty sure the spring for an early Monster is longer than 7 inches.
The weight should be close....maybe one rate too stiff.
I'm 180 ish and I run a 10.0
There's only a 1/4 of an inch in it. That's if the stock yellow spring from my 95 M900 is typical.
My Eibach spring is shorter but the preload thread runs way down.
Yeah, I'm about 190 and running a 550/10kg ish spring. I think you're right about it being close to one step above. With gear on, dinner and a beer he should be right.
The spring off of the '95 M900 shock is 7 5/16" long.
Looks like a 7" spring would work to me.
You can't put a whole lot of preload on, but should be sufficient.
If that 220 is without gear, I'd say fit a 10.7kg/mm or 600 lb/in spring.
Run the preload collars down until the spring is ~6.5" when the shock is on the bench.
That should get you in the ballpark on sag, but check and adjust as necessary.
Quote from: Speeddog on February 26, 2011, 02:33:51 PM
The spring off of the '95 M900 shock is 7 5/16" long.
Looks like a 7" spring would work to me.
You can't put a whole lot of preload on, but should be sufficient.
If that 220 is without gear, I'd say fit a 10.7kg/mm or 600 lb/in spring.
Run the preload collars down until the spring is ~6.5" when the shock is on the bench.
That should get you in the ballpark on sag, but check and adjust as necessary.
That much pre-load?
Quote from: ducpainter on February 26, 2011, 03:11:58 PM
That much pre-load?
SWAG.... precious few 1st gen Monsters come in for suspension upgrades.
How much do you have on yours?
Quote from: Speeddog on February 26, 2011, 04:12:46 PM
SWAG.... precious few 1st gen Monsters come in for suspension upgrades.
How much do you have on yours?
The optimum preload as I was taught by the vet is 15 mm. My Ohlins has exactly 15mm of preload with a 10.0. That is why I think an 11.0 or 11.5 will work for the OP.
A spring that is preloaded more than that will react harsher initially and then over compress. Believe it or not a stiff spring with very little preload will feel softer than a soft spring that has a ton of preload wound in.
Try it.
May be the difference between 1st gen and 2nd gen Monsters.
I've got the OEM spring for my 1999 M750. I put a spring kit that was supposed to fit an earlier M900 and no issues.
I can measure my OEM spring if you need me to ~
JM
Quote from: Speeddog on February 27, 2011, 12:37:54 PM
May be the difference between 1st gen and 2nd gen Monsters.
Pretty sure the 15mm is universal.
The spring rates for the different gen monsters are different due to linkage ratios.