Suspension Tuners Chime In

Related:
Create New Tag

5/11/2018 9:00 AM

Interested in theory behind tuning air forks for the "heavier" guy. I'm 250lbs+, 2017 KTM 350 SXF (WP AER), average vet class speed. I've had a few tuners tell me that air forks don't work for people over a certain weight given the characteristics of the Air Spring through the compression and rebound of the forks since you need a very high air pressure to balance with a properly sprung and valved shock. I've had one tuner who told me that he thinks the WP AER would work for my weight.

Standard theory - When you jump up spring rates necessary for the bigger guys tuners adjust compression and rebound damping to counteract the force of the spring.

My question - Is it possible to go stiffer and more progressive in the valve stacks so that the valving takes some of the load off the air spring and balances the bike with less air in the fork?

Not even sure if I'm on the right path here. Debating getting a spring conversion and I'm interested in information from people who know what they're talking about.

|

5/11/2018 9:12 AM

if a tuner tells you they cant tune that fork for 250lbs, you need to look for a new tuner.

|

5/11/2018 9:26 AM

Yes you can. We have a local guy here on air forks at 250lbs and fast as hell. I like to be over sprung most of the time so yes just pump up the air. I dont know WP forks but yes it can be done and easier with air.

|

5/11/2018 12:01 PM

They haven't exactly said they can't tune it...they've mentioned how the air spring reacts to bottoming which I've felt on my PSF1 equipped CRF450R. They've more or less said they don't feel confident that I would be happy with it, I want a plush fork that's really progressive with good bottoming resistance.

The one tuner said verbatim "I wouldn't convert that fork (WP AER), its light years ahead of the other air forks. Your best bet is to valve/spring the rear shock so that you can set the sag. Leave the forks stock, but increase the pressure so that the front end balances with the shock, and ride it. At most we would need to valve/spring the shock, then revalve the forks."



|

5/11/2018 12:10 PM

TJMX947 wrote:

They haven't exactly said they can't tune it...they've mentioned how the air spring reacts to bottoming which I've felt on my ...more

yes, because its an air spring, when you have to run at higher weights for a heavier rider, the fork can get very progressive as that higher pressure ramps up very quickly at the end of the stroke.

I would go with the guy that wants to setup your shock- air forks can be tricky to setup, but if you get a good shock setting, it holds the bike up properly and makes the fork do its job.

|

5/11/2018 1:16 PM

My dad is around the 240-250 mark on his 17 RMZ and Enzo has it dialed! Same with his 15 that he had. No issues

|

2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/11/2018 1:20 PM

Bruce372 wrote:

if a tuner tells you they cant tune that fork for 250lbs, you need to look for a new tuner.

x2

|

2020 YZ450F
2018 KTM 450SXF FE
2016 YZ250F 2008 CRF450R
2015 YZ250F 2008 CRF250R
2001 CR250R
2010 YZ250 2012 CRF150R
2009 YZ125 2010 KX109.5
SSR Motorsports Dealer YCF Motorcycles
TAGMX Suspension & Graphics! www.tagmxsuspension.com https://www.liquidskinzdesign.com/