I wanted to post up for future searches:

Rider: 230lbs. in street clothes

Forks:
Sag Target: Fork travel 10.2 inches = 259mm; 259 x .25 = 64.75mm
Racetech .46 fork springs
Measured Static Sag = 45mm
Measured Race Rag = 67mm

(Notes: RT recommends 4mm preload on the forks and oil to 90mm from top of lower tube. I did NOT use any spacer/preload, and used Torco RFF 5 at 90mm)



Rear Shock
Sag Target: Rear Travel 9.1 inches = 231mm; 231 x .33 = 76.23mm
DSP 6.2 rear shock spring
Measured Static Sag = 40mm (before adding 13mm preload) <-- this wasn't my final number... was most likely close to zero after adding the preload.
Measured Race Sag = 82mm

(Notes: Rear spring preload was adjusted to measure approximately 120mm from the center of the top mounting bolt to the top of the spring. Stock according to the manual is 107mm)

I took a simple measurement, standing in the attack position I bounced a couple times and let it settle. That's close enough for me, although I've read of methods that involve averaging. YMMV

Racetech's calculator recommends .50 fork springs and 7.4 rear spring. So far, I'm happy with the .46 and 6.2, although I would probably also be fine with .48 and 6.4. Personally, for 2017 I plan on dropping at least 20lbs, which should put me spot on.

Now to start saving up for Gold Valves.....

 

Racetech's recommendation on the shock spring baffles me. For the KLX300, you'll get a 6.2 recommendation from them.

 

Roger that, I've done a few singletrack miles this weekend and am very happy with the 6.2 Can't imagine how harsh 7.4 would be...lol

On a similar note, now I have to figure out what pressure to run my new tires (K760 rear, Scorpion XCMS front) Like riding on marbles at 15psi, better at 12psi. ...I see rimlocks in my future...lol

 

Abrams,

A lot of factors go into those calculators, including a pretty subjective assessment of what class rider you are. I think you have to figure what you think is best and give it a try.

Your post caught my attention because I also run .46 and 6.2, though I weigh 175 and carry about 25 lbs of gear and fuel (on the bike, not on me) when heading out for a long ride into the backcountry or forest service roads. I like it a lot and look to GVs as the next suspension upgrade.
I could not measure front sag by myself but was able to dial in what I understand to be the ideal rear sag, 25-35mm static and 33% of travel for rider sag, which calculated out to an even 1" static and 3" rider sag.

I am interested to know how the GV installation goes for you. Looking at videos on the web, I think I can handle the fork installation, the but the rear shock looks pretty intimidating.
Keep us posted!
TC

 

Tim,
I plugged in "old fat beginner trail rider" to get RT's rec's... and believe at my weight, a more aggressive rider my want another step up or two from my choices. I added a fair amount of preload to the rear (but in spec according to the manual) and a 6.4 might have been a better choice.

It will be awhile before I can get the gold valves. I have no real off-road gear and my riding boots are about worn out (old model Oxtar Infinity) so valving is low on the priority list.

I'll post up when that day comes...

Happy New Year!

 

Be aware that true off road setup on many dirt bikes can be somewhat soft. The most challenging spots on a given trail ride consist of those slow, rocky, herky-jerky conditions where the suspension has to be extremely responsive. In fact many/most off road competition bikes have suspensions that make an MX track way less than optimal.

I think we all know that suspension setup is always a compromise unless one rides in only one type of terrain that has only one type of feature. That almost never happens in the real world. I'm 195, have a 3.7gal tank, and carry a huge back pack and tail bag with some decent weight in case I'm stranded with a mechanical and have to spend the night. I run a 6.0 spring that is just about perfect for reasonably aggressive off roading. I tried a RT 6.4 spring, but it was way too heavy, even with me an all my gear. I run .44 springs in the fork.

I think there's a school of thought for newer riders to real off road riding that the suspension needs to be relatively stiff. That's usually not the case at all. A bike should bottom occasionally or you're not getting all your travel and probably dealing with some harshness in the midstroke. Yes, it's all a balancing act, but if your bike doesn't bottom a little bit on the rougher trail sections, you may be sprung too stiffly.

 

Update:

I decided I was a little light on springs. I've gotten faster over the last 6 months and was bottoming more than I liked. I went conservative with my original spring choice because I couldn't find verifiable info for the 09+ at the time. I have since found another source to compare to racetech's req's and bought slightly heavier springs for my 230-pound self (plus gear).

I think the .46 + 6.2 combo would be perfect up to 200-210 pounds. As best I can tell, the increased weight of the 09+ KLX250s calls for an extra .2kg step on the shock spring vs. the '06-'07 models. Note: I was not unhappy with that combo even at my fighting weight; combined with Gold Valves they gave a nice plush ride... great for casual trail riding.

For replacements, I chose to shoot for a 225lb rider, which gave me .48 fork springs and a 6.6 shock spring.

The fork springs are plenty stiff, even at 230lbs + gear. I don't think I would like .50's like Racetech recommends. My first impression is that the .48's are perfect.

I went with a 6.6 shock spring, and it also feels just about right... static sag indicates it is still just a little light for my current weight (about 10mm) but it is close enough. (That's with race sag set to 85mm)

While I was in the forks, I dropped the Gold Valves down one step on the HS compression. I'm currently running 18 clicks out.. so next time I'm in the forks I may take a shim out of LS compression as well.

 

Difference between 06 07 and later models is the link (117 compared to 119mm) and travel (less travel needs more spring to have have the same force at the end of travel).

Stiffer springs do not give a stiffer ride unless you have gone too far. It's a myth generated by the inexperienced. The opposite is usually the effect and simple math will show it to you.
Find the rate per inch, add the preload value and that is spring force about 1/3 travel. Add one more inch of rate to the first number and that is spring force at about 2/3 travel,,, and so on.

Advantage of stiffer springs in off road use is the fact they require less preload to support you and the bike. This helps when off throttle on stuff like downhill logs,rocks and roots. IE if you have 150 lbs of preload on a stiff spring compared to 250 on a soft spring, that is 100 lbs less force trying to whack the seat into your butt as the rear is unloaded.
The 100 lbs less preload from a stiffer spring carries on through the travel as the spring rate builds during compression and eventually ends up higher in rate at the end but is not stiffer all the way through. We only have about 3" of total spring travel anyway.
Win win in comfort and control if dampened correctly.

My 07 and me (230ish) like .47 in the front and 7.2 on the rear. Front is preloaded 6mm and rear is preloaded just 8mm to get the correct sags. Plush and supportive.
If I have my low speed compression adjuster set loose I can bump the shock bump stop on a log at walking pace. Definitely not oversprung.

If you make a couple of spring spacers for your shock (only have to do it once) you will open up a huge, cheap rear spring source for our bikes.
There seems to be tons of used KTM springs at every suspension shop lol. They are the correct length and just a bit different in ID's. Come in many different rates in our range too.
So other than color lol, perfect for those looking for perfect.

 

Ahhh... then perhaps Racetech's rec of 7.4 rear is not too crazy...lol

 

I looked into Race Tech's rear springs. They recommend an 8.4 for me, but the biggest spring they have isn't even close to that.