Rear springs
 

I'm working hard to upgrade the KLX suspension. Moto-Pro .44's are installed on the front and I just received my Racetech gold valves today. Weekend install.

I need a heavier spring for the rear and am hoping for first-hand experience.

I'm just under 200 pounds buck naked so about 215 riding weight. The moto-pro calculator recommends a 6.0 rear for my weight but I'm not sure that only one click higher on the spring rate is enough. Feel like I might benefit from the 6.2.

Anyone out there the same weight and have experience with the 6.0 and 6.2 springs?

Anyone bought the 6.0 and wished they had gone higher?

BTW, the KLX is a 2007 and I ride it mostly bad, rocky, ledgy, steep ATV trails in New England.

TIA

I went through a bunch of this just recently. I've had an Eibach 6.0 spring on my '06 for about 3 years. I'm about 190-195 nekkid, and I often have a massive backpack, rack bag, fender tool bag, and number plate bag. I was beginning to believe that my 6.0 wasn't sufficient for my riding because of several factors, most of which was a bit of over-assumption on my part and a lack of appreciation on how a little preload distance makes a very notable effect on ride height and sag. So without spending some time rechecking my preload and playing with such, I bought a new rear spring. Eibach makes a 6.3 and Race Tech a 6.4. There's nothing between those and the 6.0 from anyone. My sources didn't have the Eibach, so I got the RT.

So...I spend a whole day swapping springs and playing with setup like I should have done more seriously to begin with. I noticed I had no real preload on my 6.0 spring...hmmm. Long story short. You can have 20mm of preload on this shock and these springs. With only 13mm of preload I had a perfect...IMO and for me...95mm of static sag and 30mm of free sag. The bike performed excellently on my test rides. That sag fits that Bruce guy's recommendations about stored energy, and it complies with 90% of the other various sources I boned up on.

Anyway, take that for what it's worth. The 6.4 was too stiff for me on the mid-to-end-of-travel portion of stroke, and when the static sag was right, the free sag was too little. That indicates the formula for too heavy a spring. Your '07 is just like mine, but with the stock shock valving especially, the 6.0 spring should work for you. I think the Gold Valve shock damping on my shock is actually a little plusher/softer than stock but just a smoother ramp up to bottomout.

Will these same spring rates apply to the 2009+ bikes? I need a rear spring too... I'm around 170 but I have a big fat rack and tend to carry extra stuff with me. I have .48's in the front and love 'em. No gold valves though.

Rob

I've wondered about that on the '09. I'd bet it's going to be awfully close if not the same rates. Rob, how heavy are you? Just curious because of the .48 fork springs.

Tequila ?

I am 6-2, 210# without gear. I just installed a Race Tech 6.0 on my 2012. I adjusted the sag and noted that this spring is a touch too stiff. I backed off the preload 1/2 turn so its seems OK. Problem is if I follow my doctor's orders and lose 10 lbs I will be out of spec on this spring.

Pass the ice cream please!

Okay so it sounds like I need a 5.8 or something if available.

Rob

Isn't your stock spring a 5.8? At 170, the 5.8 may be fine. Check this link about rear spring stored energy. It's a meaningful issue that has real bearing on the final performance of the shock.

kb1

LOL!...no, wildcard...no tequila. Maybe late night reading comprehension.

I dunno. If it is, it's definitely too soft. I have the preload cranked way up, and if I catch even the slightest amount of air, it's enough to bottom the rear shock.

It's okay right now as long as I don't get too agressive... but I'd like to get it right so I can play more.

Rob

I've never done anything to a shock but install the correct spring, so take it with a ghrain of salt, but....

If you bottom the shock regularly at 170 pounds you may want to check the nitrogen charge in your shock.

Are you sure you aren't feeling the giant compression spike in the travel midrange that our stock valving causes?

Do you have so much preload that the bike bounces (and feels like it's bottoming) over every obstacle? See the link TNC provided for details.

That's the case with mine. At 200 pounds with the stock spring, I need so much preeload (to meet sag specs) that every little thing I hit feels like I've bottomed out. Couple that with slow valving and the shock feels rock hard.

On my KTM, and I'm sure it's the same with the KLX, you could check the nitrogen charge by removing the shock, removing the spring from the shock and then compressing the springless shock while on a scale. The weight shown by the scale should rise to a certain poundage (58 pounds on the KTM PDS shock) and then level off. If the poundage required to compress the shock was less than that figure, then your nitrogen charge was going south. The poundage is determined by the psi of the N-charge and the size of the orifice.

Any one know what the quick check figure is for the KLX? What psi is recommended?