progressive rate vs. constant rate springs

[ragtop69gs]

I am starting to think about replacing my fork springs, I have read almost every thread on the VR forums pertaining to fork springs and have not seen any discussion comparing the two different spring types and why I would choose one over the other.

 

What are the handling characteristic's of the 2 ? Does riding style matter or is it just the weight of the bike, rider and gear ? I'm about 170# with 30" inseam if it matters. When I do the springs I'm also going to move the forks up 3/4-1" in the triple tree.

 

Ever since I bought this bike it has never felt sure-footed in the twisties, it's always felt like the front end wants to slide out. Changing pressures in the forks, tires & rear shock have made little difference in handling. I installed a new shock today, springs are next.

[bongobobny]

OK the main difference with progressive style springs vs constant rate springs is the more you compress variable rate (progressive) springs the change in resistance is non linear so they act stiffer and stiffer as they compress. The main advantage of this is to prevent bottoming out with stronger forces such as hard braking, hitting a pothole, etc. A constant rate spring will have the same increase in stiffness for 1 inch compression, 2 in compression, etc.whereas a progressive rate will have1 unit of change in stiffness for the first inch, perhaps twice as much change for the 2nd inch, etc.

 

That being said, I believe the stock RSV is a progressive type, but I havn't taken mine apart yet. Youm can tell a progressive style spring by the spacing between coils. The spacing will not be linear but rather some coils will be closer thanothers. Constant rate springs have the same spacing between coils. I'm still in the dark as to which springs to put into the trike but I want overall increase in stiffness to help minimize front end oscillations. The Sonics are constant rate but supposedly are stiffer than stock.

There seems to be a debate whether or not Progressive makes a better than stock spring for the RSV...

[ragtop69gs]

I just looked at the Race Tech constant rate with emulators, $384 which includes all new bushings and seals.

[MiCarl]

It's been awhile since I was into an RSV but it might come stock with a dual rate spring.

 

A dual rate spring looks like two springs put together end to end. One end will have close coil spacing and the other will be widely spaced. It also functions like two springs - soft for part of its travel then abruptly becomes firm for the remainder. The rationale for a dual rate spring is it gives a soft ride until you hit large bumps or brake hard and then stiffens up to control front end dive.

 

A progressive spring has the coil spacing vary continuously across its length. One end will have close spacing and the other wide like a dual rate spring, but there is not a sudden transition. In this type of spring, the stiffness PROGRESSIVELY increases from soft to firm rather than the sudden transition of the dual rate. The progressive spring takes the rationale for the dual rate spring to the next level, instead of the abrupt change it stiffens up gradually giving better control.

Edited February 25, 2013 by MiCarl

[Seaking]

What are the handling characteristic's of the 2 ? Does riding style matter or is it just the weight of the bike, rider and gear ? I'm about 170# with 30" inseam if it matters. When I do the springs I'm also going to move the forks up 3/4-1" in the triple tree.

 

I had installed progressive springs in my RSV a few years ago. Apart from the ability to eat bumps and pot holes better, the biggest difference I had noticed was a lot less nose dive when being aggressive on the front brake. Instead of the front of the bike pitching down which causes the rear of the bike's weight to shift forward and up, reducing traction with the road (rear tire skid), the bike now feels like it hunkers down evenly and more sure footed, thereby reducing braking distance. Though the rear wheel can still skid if too much rear brake is applied, it's less apt to do so with progressive springs in the front.

 

I also find it more sure footed in sweeping curves on uneven roads.. With the progressive springs, leveling links and Works rear shock, I find my bike a lot more nimble than when it was stock, allowing me to toss the bike around a lot better and with more confidence. The handling is so much better..

 

But that's me, your YMMV...

[ragtop69gs]

If anyone has had both types installed on their RSV, I'd like your opinion on the pros and cons of each one.

[Freebird]

I have the Sonics and really like them. Had Progressives on a first gen but not on the RSV.