Would I benefit from a 5.2 shock spring?

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makeshoes
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Would I benefit from a 5.2 shock spring?

Post by makeshoes »

I'm a "C" class enduro rider, weighing 225 in street clothes. I prefer to have two wheel on the ground at all times and only ride in the woods,2nd + 3rd gear (no MX). My race sag is 4" and this results in 13/16" of static sag. From most info here, I should be using the 5.2 but if my sag settings are close.....??

Also, I am doing the 2 shim removal in my stock forks. By doing this, can I run the next stiffer fork springs without much notice to them being stiffer? My only real complaint is that it seems very soft front and rear. To bad you cant rent springs to see if you like them before you buy them! Thanks.

Current setup '02 KDX 200 .42 FRP fork springs 5.0 stock shock spring
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Post by Mr. Wibbens »

Racetech makes triple rate springs. I believe they are .42-.44-.46

I don't know if you can use them in an H but I've got them in my E
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Post by gregp »

IIRC, the stock frok spring are .35 (kg/mm?). I have fork springs from a 1998 XR400 in my '04 KDX. I think they are .39's. I weigh in at a little over 210 and the forks feel fine to me for woods riding where I spend most of my time. I also have 2 shims removed. I actually like my forks to dive a lot for turning in the trees.
I also have the rear shock spring off of the same XR, but I believe that it is *much* stiffer (something like a 9.0?) than the stock KDX spring. I was going to install it just to see if it even fit, but I never got around to it.
IMO - If you are a 225lb C rider, you would be better off spending the money on a V-Force cage, a pipe, RB carb and head mods, or Race Tech Gold Valves for the forks.
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sthutch
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Post by sthutch »

I am similar in weight, 220ish, ride mostly single-track here in Michigan, 2nd and third also, and love two wheels on the ground. I am 46 and have only been riding for 2 seasons after a 30 year absence. I replaced the stock fork springs with .44s. I think they are a bit to harsh, but the improvement in handling was amazing! I am going to do the shim stack mod to see how that helps. A riding buddy, he is also similar in weight, put .42s in his KDX and loved'em.

I am also putting in a 5.2 spring today (as soon as my garage heats up). After I get the suspension zeroed in I will begin to tackle the various engine mods.

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OLHILLBILLY
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Post by OLHILLBILLY »

I'm a little lighter than you (205-210) and am using a 5.2 spring. I've set the sag a little on the high side (3 1/4" instead of the 3 1/2"+ recommended) to keep it more level with the KX forks.
Have never really worried about the static sag reading, but the stock spring was pretty mushy IMO. Had the pre-load collar ran down a little past what the manual said was maximum adjustment to barely maintain a 3 1/2" sag. The collar is a full inch up from previous with the 5.2 spring, to maintain the 3 1/4" sag. Big difference.
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makeshoes
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Post by makeshoes »

Thanks for everyones replies!

sthutch - I would be interested to hear how the two shim removal feels on your .44's. Also, would like to know how the 5.2 shock spring feels. Are you using the full metal preload spacer from the factory in your forks?
P.S. I'm in my late 40's also.

olhillbilly - I'm thinking running less sag in the rear with the stock forks might really overload them. My preload collar (or top of shock spring) is at 4.75" from the top shock bolt centerline (as per the manual should be between 4.05 and 5.0") to yield my 4" sag.

I don't know if anything is really wrong with my suspension, I just don't know if it could be better!
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Post by OLHILLBILLY »

>|<>QBB<
makeshoes wrote:olhillbilly - I'm thinking running less sag in the rear with the stock forks might really overload them. My preload collar (or top of shock spring) is at 4.75" from the top shock bolt centerline (as per the manual should be between 4.05 and 5.0") to yield my 4" sag.
I don't know if anything is really wrong with my suspension, I just don't know if it could be better!
I'm using KX125 forks, which are roughly.75" longer than the stock KDX forks (plus less sag too I figure). I have the KX fork tubes up 1/2" in the triples (far as I can go without hitting the bar), so the 1/4" less sag in the rear I'm figuring will pretty close to even everything out.

If you want to make a night and day improvement to your KDX suspension, do the KX fork swap. After 3 rides, the difference in mine still amazes me.
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Post by rbates9 »

>|<>QBB<
OLHILLBILLY wrote:>|<>QBB<
makeshoes wrote:olhillbilly - I'm thinking running less sag in the rear with the stock forks might really overload them. My preload collar (or top of shock spring) is at 4.75" from the top shock bolt centerline (as per the manual should be between 4.05 and 5.0") to yield my 4" sag.
I don't know if anything is really wrong with my suspension, I just don't know if it could be better!
I'm using KX125 forks, which are roughly.75" longer than the stock KDX forks (plus less sag too I figure). I have the KX fork tubes up 1/2" in the triples (far as I can go without hitting the bar), so the 1/4" less sag in the rear I'm figuring will pretty close to even everything out.

If you want to make a night and day improvement to your KDX suspension, do the KX fork swap. After 3 rides, the difference in mine still amazes me.
I also noticed the KX forks being a little bit longer. I could get mine up 3/4" and before I did any thing I took measurements and when I was done the top of the steering stem is about 1/8" higher than stock. After I sit on it I don't think it could even be noticed. But after I got mine swaped over I have not been able to ride between snow and my screws not coming in.
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Post by sthutch »

I replaced the rear spring with a 5.2 and completed the Shim stack mod. The mod went just like everyone says, straight forward. Hopefully I will ride this weekend. Just gotta screw in 396 more tapcons.

I used the factory metal preload spacer. The springs that I installed measured the same as the factory ones I took out, so I didn't change them.

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makeshoes
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Post by makeshoes »

Here's some info I have recently found out on my bike about using the whole factory metal spacer with aftermarket fork springs. While the length of both the OEM and aftermarket spings are the same length (470mm) unsprung, the aftermarket has more coils (37 1/2) than stock (33) and is also .010 thicker material (.182) than stock (.172).

So what does this mean mathmatically?
The OEM spring fully compressed .172 x 33 = 5.676"
The aftermarket spring fully compressed .182 x 37 1/2 = 6.825"

That's approx 1 1/8" difference in the compressed length. There is not room in the stock forks for this extra 1 1/8" of material if you were to completely bottom out your forks while riding.

In my case, I need to cut at least 5/8" off the 90mm stock factory spacer to insure my fork tubes bottom first before the internals do. I guess I should have just been running the 10mm preload I read about on here instead of just blindly throwing in the full stock spacer.
Last edited by makeshoes on 09:44 pm Jan 02 2011, edited 1 time in total.
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Post by Mr. Wibbens »

well duh
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