Rear Spring Upgrade
 

I'm having trouble with the rear suspension bottoming on moderate terrain. I've set the sag and increased compression settings. Looking for feedback on what rear spring to use. Been searching the forums but have found little info.
2009 KLX. I read that the bike is setup for a 150lb rider. I'm 185lbs. When I plug in my info into the Racetech calculator it comes back as the stock spring of 5.6kg/mm and recommends a 6.9 kg/mm.
Looking through other threads the highest spring rate I see mentioned is a 6.2 kg/mm.
Doing the simple math. The increase from 150 lb to 185 lb rider is 23%. The proposed Racetech increase (5.6 to 6.9) is 23%. So seems their recommendation seems right.
Appreciate any feedback and real world experience.

I just ordered a rear spring for mine and that was the same rate they gave me. Im bottoming out way to much and i don't like to increase preload. The front that they recommended was night and day difference so im guessing the back will be too.

Thanks for the response. Guess I'll give it a try.
As I always look for the best deal. It appears that the spring is a 2.5 diameter x 10" length spring. The 6.9kg/mm converts to a 386 lb/in spring. I can get a 375 lb (or 400 lb) spring from Summit Racing for $38. Link.

I ended up using a 7.5 from Procycle.
It was listed for a DR650. Fit fine.
I got the 6.4 from Race Tech and it was too soft for me,
220 Lbs.

im 180, so ill give the 6.4 a shot and see how that works out

I didn't think there was much difference in the spring requirements/dynamics between the '06/'07 and later models. I used a 6.0 Eibach spring on my '06, and it was perfect for my 190 pound weight with the addition of a heavy backpack and tailrack bag I use on my big rides...along with a 3.7 gal. Acerbis tank. I also tried a 6.2 or 6.3 Racetech spring, but it was too harsh. I'm a decent rider who pushes my KLX off road, and to me these 6.4, 6.9 area springs sound like 3/4 ton pickup springs. Maybe I'm missing something here on the ratings being listed, but I think a 180 pound guy isn't going to be happy with a 6.4 spring. I can't see you needing more than a 6.0.

Now...it's been awhile since I modded mine...also with Race Tech Goldvalves front and rear...so maybe I forgot or missed that '09 and later models require dramatically different spring rates. What say y'all? Anyone remember?

i have the preload increase beyond where it should be and the compression almost maxed out and i am bottoming out way to easy

Maybe you've lost the hydraulic fluid in your shock. Do you notice a difference when you change the compression damping adjustment?

Ride on
Brewster

I was wondering about that too. If his '09 KLX shock has never been serviced, who knows what's in there. Brewster, can you recall the normal spring rate upgrades that most of us used for real humans in the 180-210 range?...well...at least American humans.:D I was also curious as to whether the '09 and later models used dramatically different spring rates...I didn't think so from memory. The 6.0 Eibach for a KLX300 worked miracles for my '06.

It was "suppose" to be services last November, after i increased the preload it helped in the bottoming but decreased the ride quality