Progressive rear springs?

[westladog]

I was at the Santa Clara track last thursday and had a chance to talk to Randy Blair, Vinvcent Blair's dad...

He recommended that I get the "progressive" rear springs for my 125 SX. Has anyone heard of this?

[flem]

the progressive springs work really well or KTM's as the don't have a linkage to to create a rising spring rate that the japanese bikes do. you need to have your suspension set up correctly to take advantage of the spring. Enduro engineering did the suspension on my bike and used a progressive rear and I love the suspension.

[Dwight_Rudder]

Enduro Engineering is now recommending straight rate springs.

Mike Lafferty has a 8.8kg on his. You don't need a progressive spring if you have the right weight spring to begin with. I don't care for progressives as the make your inital response too stiff. Quite the opposite from what you are looking for. I have been running straight rate springs on my bikes for 2 years and have probably one of the plushest and best suspensions out there.

Cher'o

DR

[Dwight_Rudder]

I was at the Santa Clara track last thursday and had a chance to talk to Randy Blair, Vinvcent Blair's dad...

He recommended that I get the "progressive" rear springs for my 125 SX. Has anyone heard of this?

Who is Vincent Blair ?

DR

[flem]

EE just did my suspension 2weeks ago and that is what they recommended for my EXC. I went stiffer from the stock 8.8 a 7.6-9.5 progressive in the rear and .44s in the front. I'm 207 with all my gear and enduro pack.

[StormTrooper]

I think it's funny that a few years back when KTMs came with the progressive springs, everyone had the shock revalved and put on a straight rate spring. Now they come with a straight rate spring and I'm hearing that folks get them revalved and put progressive rate springs on.

I thought that WP has impoved the shock to the point where good progression is built into the shock so a straight rate spring is in order. What gives? ?

[Dwight_Rudder]

EE is overstocked now with progressive springs.

IMHO,

Dwight

[Dwight_Rudder]

EE just did my suspension 2weeks ago and that is what they recommended for my EXC. I went stiffer from the stock 8.8 a 7.6-9.5 progressive in the rear and .44s in the front. I'm 207 with all my gear and enduro pack.

That is an overall softer spring than a 8.8 not stiffer . It will feel stiffer to start with because you are running so much preload to hold the bike up with your 207lbs. If you are running a 03 or 04 model your top out spring is totally collapsed. To verify, put on stand and step on wheel. It should go down another 10mm or so. If it doesn't your topout spring is collapsed. For your weight on a 03-04 model I would have recommended a straight 9.4 kg. Preload set at 115-120mm as a base. On a 05 I would have used a 9.0 or 9.2 kg spring. Set at 110mm.

Cher'o,

Dwight

[westladog]

Last place rider at the US Open ?

I was at the Santa Clara track last thursday and had a chance to talk to Randy Blair, Vinvcent Blair's dad...

He recommended that I get the "progressive" rear springs for my 125 SX. Has anyone heard of this?

Who is Vincent Blair ?

DR

[Dwight_Rudder]

Still probably a better MX rider than I am. BUT sorry , never heard of him.

Dwight

[jeb]

I think it's funny that a few years back when KTMs came with the progressive springs, everyone had the shock revalved and put on a straight rate spring.

I don't personally know anyone that went to straight rate on the 03 and older shocks. Everyone I know stuck with progressive springs. Maybe the straight rate was popular for MX or from some tuners and for sure for guys that were pretty heavy but I'd say the vast majority of folks stayed with progressive springs.

[Travis_D-37]

EE just did my suspension 2weeks ago and that is what they recommended for my EXC. I went stiffer from the stock 8.8 a 7.6-9.5 progressive in the rear and .44s in the front. I'm 207 with all my gear and enduro pack.

That is an overall softer spring than a 8.8 not stiffer . It will feel stiffer to start with because you are running so much preload to hold the bike up with your 207lbs. If you are running a 03 or 04 model your top out spring is totally collapsed. To verify, put on stand and step on wheel. It should go down another 10mm or so. If it doesn't your topout spring is collapsed. For your weight on a 03-04 model I would have recommended a straight 9.4 kg. Preload set at 115-120mm as a base. On a 05 I would have used a 9.0 or 9.2 kg spring. Set at 110mm.

Cher'o,

Dwight

EE has you set up with the right springs for the type of riding you are doing. The above quote from Dwight is where people make their mistake in using a pds spring. If you take just the numbers of the pds spring and average them the pds does look like it is softer overall.

However this is not how a pds spring works you have to take into account where the "crossover rate" or progression curve comes into play with regards to spring rate. The pds spring has a rate curve where it is a lower rate the first 25% of compression and crosses over at about 30 % compression then it gets a progressivly heavier rate during the last 70% of compression. If you take into acount the compression curve rate and average that you will end up with a slightly heavier spring than Dwight is recomending in a straight rate spring.

The reason a lot of tuners are still using a progressive spring is with a starting rate of 7.6 the bike will handle smaller bumps better and the action will feel plusher than a 9.0 straight rate spring. Simple physics tells you it will not take as much force to compress a 7.6 rate spring as much as it would a 9.0. And the oposite is true for bottoming: it will take more force to compress a 9.5 rate than it will a 9.0 rated spring. Like I said the cross over point is every thing in a progressive rate spring.

The lower rate of a pds spring is only in the first 25mm or so of compression after that the heavier rate takes over. I've found on the newer bikes that the "golden rule" 115-120mm rider sag is crap and the bike will handle like crap unless of course you run a softer front end like dwight does which will keep the bike more balanced.

[Dwight_Rudder]

I think it's funny that a few years back when KTMs came with the progressive springs, everyone had the shock revalved and put on a straight rate spring.

I don't personally know anyone that went to straight rate on the 03 and older shocks. Everyone I know stuck with progressive springs. Maybe the straight rate was popular for MX or from some tuners and for sure for guys that were pretty heavy but I'd say the vast majority of folks stayed with progressive springs.

Jeb, You know I used straight rate on my 03 525EXC and I weight about 175lbs. I know of quite a few that went to straight rate and prefered it. IF you never tried straight rate , don't knock it till you have. I have let several folks who were none believers at the Nat'ls try my bike and they couldn't believe how plush and controled the ride was.

Cher'o,

Dwight

[Dwight_Rudder]

Travis, A progressive spring with too much preload does not feel plusher. It feels stiffer even if it started at 7.6kg. You have to crank in too much to make it stand up right. NOW , if a progressive spring was much closer in rates , like only a .5kg difference then it would probably be a good thing.

Cher'o,

Dwight