There don't seem to be any off-the-shelf springs and shocks for my bike here stateside. Cogent Dynamics offered to make me custom springs (for a very reasonable price) but I was wondering if progressive springs would be good idea. I wrote the company but I haven't received a response yet. Does the progressive spring mean that I don't have to worry about the spring rate like I do with static springs?

Thanks.



http://hyperprousa.com/catalog.php?c...type=COMBI-KIT

 

interesting concept. Investing in the suspension is my next move for the KLX but Id like to hear from someone that has experience with this type of spring before I order some.

 

Here's where suspension tuning can get hinky. Doesn't the KLX...dirt model...have a rising rate rear suspension design? In other words, it gets harder to compress the suspension as the wheel goes through its travel...especially toward the end of travel. I'm asking because I don't think I've seen this addressed specifically. It feels to me like it is rising...or at least linear. It's hard for me to tell now with my Race Tech valving, and it sucked so badly before that I couldn't tell. Linear rate means the compression characteristics of the design are pretty much equal from begining to end. Falling rate means that it gets easier to compress the suspension as it goes through its travel...especially as it nears end of travel. Those are the 3 main recognized designs...generally. This is an engineered design issue, not the spring weight issue.

That said, progressive wound springs can be a benfit to a given bike depending on the aformentioned suspension design, or the rider's style, the terrain ridden, personal preference, or all of the above. They can be a horrible mismatch also. Generally a progressive wound spring is not a good match to a rising rate suspension design...too much force required for compliant compression. Generally they are a better match to a linear or falling suspension design. You notice I say "generally". It's hard to make blanket statements about suspension in many cases, but it's something to consider if you'll use progressive wound springs.

Also, if you're talking about an SM application vs. a dirt bike, you're probably looking at either small or big differences in suspension requirements depending on the rider.

 

Thats what Im afraid of when it comes to these type of springs. The concept sounds great but in real world riding it may be disastrous.

 

its linear. trust me, it feels good on trails, but on almost any jump you can tell its linear (ie HARD bottoming out, no bottoming resistance at all). does anyone make a progressive spring for us, that would be killer for me.

 

I've got some .36/.46 progressive rate fork springs I tried, one ride. They work great on the street, very compliant to the small bumps but weren't heavy enough for me offroad so I took them out. Wonder if the link shown uses the same spring? I'd sell them if you find out it's the same spring. Right now I'm using a .49 in one leg and .44 in the other (.465) but I have an 06 S. Your SF might use a shorter spring.

The shock spring in the posted link doesn't look progressive to me? I have a spring for my XR that was advertised progressive iand it wasn't in the truest sense. Of course ALL springs are progressive as they get stiffer as they are compressed.

 

I think the rear spring rate is constant along its compression travel. However, it looks to me the linkage makes it a progressive rate suspension. There is more spring travel (or compression) for the last few inches of wheel travel than the same few inches at the beginning.

Applies only to the rear, the front does not benefit from a linkage with progressive ratio of wheel displacement to spring compression.

Does it make sense?

 

did you measure this?

back when ktm's used linkage they gave us rising, linear, falling rate rockers to tune with. The quickest link accelerated the shock so fast that they would sometime break shock shafts on big landings, ouch.

some other useless trivia, Kawasaki was one of the 1st with linkage susp. na dirt bike KDX 175 if I remember right. The japanese engineers worked so hard to make the linkage ratio act like a twin shock bike that the susp totally bombed from what it could have been. Knowing Kawasaki and it's giant use of the parts bin, this link is probably on our klx, LOL

 

we where talking about the spring not the rear suspension as a whole. yes, the system as a whole is progressive.

 

Yes punk, we were talking about the spring(s), but in my post I was talking about how a shock spring can match or not match the design "rate" of the rear suspension...rising, linear, falling. This has nothing to do with the spring. The OP seemed to be talking about fork and shock springs. Of course the fork has no linkage or pivot, so that rate issue isn't a factor. I think Ray Cour is using the term "progressive" interchangably with my term "rising rate". I seem to remember reading that the KLX rear has a rising rate, but I can't find any reference to which style it is now.

Rim, I had one of those '79 KDX175's with the first Uni-Trak. I think they used it for at least 2-3 years. It was a whole different design than the dog bone linkage on our KLX's. It had linkage arms on top of the swingarm with big heim joints. Interesting design. Actually it worked very well on the KDX...remember this was 1979. I even won the 2-day Odessa, TX state circuit enduro in the 200B class that year on that bike. Compared to many other bikes out there, it was a fairly awesome bike.