Jump to content

How to Calculate Spring Rate? Calculator I can trust?

Recommended Posts

Hey guys,

I'm looking to order new fork springs and a shock spring for my 2017 KTM 250 XC-W.  Question is this... where in the world do I determine the correct spring rate?  I'm not on either extreme end of speed, ability.  I'm not fast, I'm not slow.  I'm not fat, I'm not skinny.  I'm 5' 11" and 185lbs (without gear)

Where can I go to calculate the correct spring rates that I need to order?  I'm pretty sure that I'm beyond the stock spring rates ;)  Went to WP Suspension's site, without luck...

Or if there is a 185lb rider (without gear) out there on my bikes suspension, let me know what you have!

Thanks guys!

Share this post


Link to post
Share on other sites

Factory WP springs are white for both ktm and husky for that year. If you get an aftermarket spring and are concerned about color, you need to ask the manufacturer to be sure.

As I said before, most people use race tech to get their spring rate. They have a calculator. You could always call a reputable tuner and ask them what spring rate you need for your weight if you don't want to use the calculator (Factory Connection, Race Tech, Stilwell, Kreft, ect). 

Don't forget to factor in the weight of your water pack and tools, if you carry those on the trail. If you are running a larger tank than stock, that is a factor as well.

Edited by CSAR FE

Share this post


Link to post
Share on other sites

Don't u believe my previous 2 answers on this? lol. I weight what u weight, I got the exact same bike as u, and got the heavier springs like you'll gonna need! 

Share this post


Link to post
Share on other sites
Don't u believe my previous 2 answers on this? lol. I weight what u weight, I got the exact same bike as u, and got the heavier springs like you'll gonna need! 


I didn't know you told me? Or forgot ;). I'll have to go back and look it up. So you're sprung for about 200lbs with gear?

Share this post


Link to post
Share on other sites

Yep. It's in your manual and I emailed slavens also. It's the 4.4 front and 63/66/69 rear, and yes I got the orange spring?

  • Like 1

Share this post


Link to post
Share on other sites
13 hours ago, Southernend said:

Yep. It's in your manual and I emailed slavens also. It's the 4.4 front and 63/66/69 rear, and yes I got the orange spring?

What weight is the rear spring in N/mm...? I'm confused on the 63/66/69 designation. According to the manual it should be a 48 N/mm spring on the rear for that weight. That is the one I ordered from Jeff for me. For reference I am 190 with gear.

 

springs.jpg

Share this post


Link to post
Share on other sites

Stock is 60/63/66. Next stiffer shock is 63/66/69. Good for 187 to 200 lbs all geared up. 

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, KennyMc said:

That's the progressive spring numbering :thumbsup:

Oh that is right..!! I forgot the KTM version of my bike is PDS and uses the progressive spring. Thanks! 

  • Like 2

Share this post


Link to post
Share on other sites

Hey guys, quick question.  When my new shock spring and fork springs arrive, do I need a special tool for the Xplor forks to swap out the springs?  I see Motion Pro has a wrench of some sort.. is it necessary?

Share this post


Link to post
Share on other sites

Yea I bought the wrench from slavens with the springs. Rear spring needs no wrench. Lot of u tube videos on it. 10 minute job for rear. 1/2 hr for front because u gotta unhook handlebar to access top of forks. Super easy for both 

Share this post


Link to post
Share on other sites
Yea I bought the wrench from slavens with the springs. Rear spring needs no wrench. Lot of u tube videos on it. 10 minute job for rear. 1/2 hr for front because u gotta unhook handlebar to access top of forks. Super easy for both 


Is it the motion pro one? For the fork springs?

Share this post


Link to post
Share on other sites
50 mm blue wrench for $16.20 is the one I got 


Thanks for all the help! Being Canadian sure does suck right now when I have to add 30% to everything I buy in the US (which is the only option for this stuff). Slavens is where I'm going to order everything from. Just waiting to hear back RE shipping costs

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×