Which Fork Spring Rate? - Ducati.ms

BlueST2 · Feb 18th, 2006, 5:39 pm

I am looking to do some suspension improvements for my '01 ST2 before or during the current riding season. I have already decided to go with an Ohlins rear shock which then brings my attention to the stock front forks.

From what I've read here, Race Tech Gold Valves and springs will deliver the most bang for the buck compared to much more expensive options such as a Traxxion Dynamics cartridge kit at $1099.95 right?

So here the dilemma; I have gone to the Race Tech site and entered my weight (without gear as indicated) of 205lbs (in street clothes) and come up with a spring rate of 0.965kg/mm for street riding. The available spring rates are 0.95kg/mm and 1.0kg/mm. Hmmmm? Stock spring rates are shown to be 0.840 kg/mm for a ST2.

Question; do I go with the 0.95 (closest rate rounded down) or the 1.0. If the application was for racing then the rate would be 1.030 for a 205lb rider. I don't want to much softness but not to firm either. Goldy locks likes a rate that's just right! Any suggestion on which you would choose?

Now a little background on some additional riding weight; I always ride with the sidebags on and I have a rear topcase which is on 75% of the time. I ride solely on the street and primarily solo/one up. I hope to do more two up riding with the misses in the future which will entail fully loaded sidebags and tank bag. I weigh in at 220lbs with gear The misses in roughly 135lbs (she'll kill me if she find out I posted that!) without gear.

I'm leaning toward the 1.0kg/mm rate but don't want the bike to be toooo stiff. Help please! Thank you.

PS...I'm open to other alternatives to the Race Tech Gold Valves and springs to improve my stock front suspension. I figure if I'm going to invests in a Ohlins shock for the rear then the front forks can get equal attention.

Thomas

NCRick · Feb 18th, 2006, 6:30 pm

Thomas, Do yourself a favor and go for a revalve while your in those forks. I have been doing a fair amount of forks on the ST Ducatis of late and the Race tech (or if you want to go nuts), the Penske conversion is almost a must do up-grade. With regard to the springs, it has a lot to do with how you want the bike to feel and what you have done to the rear suspension. We like to strive for a closely matched balance between the front and rear. Also, do you ride two up or loaded often? For me, I would go with the .95 set as I prefer a little more compliant ride and I would use that bike for long day trips. Even with gear most of the additional load would be at the back of the bike and I would be tooling down the road with that on anyhow. If we were doing the forks, we would modify the valving dependant on the spring selection. If you really like track days and/or want the bike to flick around a lot go to the 1.0s In track bikes or street bikes we are really dialing in, we will sometimes put a .95 in one tube and the 1.0 in the other to get "right there". Plan on spending a fair amount of time getting your sag set correctly. You may have to take the spacers out to recut them one time after testing the sag. I recommend using a 25mm spring preload on the 1.0 and something closer to 30MM on the .95 springs if you go with those. We just got a new piece of equipment that allows testing the sag with the forks off the bike.

If you let me know what spring you are using on the Ohlins I can make further recomendations. We would set up the rear spring based on what you were looking for as well.

It is well worth the effort to get these things "just right".

BlueST2 · Feb 18th, 2006, 7:30 pm

Rick, how does the Penske conversion for forks differ compare to the Race Tech Gold Valve kit with of course new springs? My suspension knowledge is sadly lacking!

I know that in 2001 Ducati took some of the adjustment out of the stock ST2 forks ie. mine do not have the adjustment screw on the caps (I think it's the rebound adjustment???). Is it at all possible to have fully adjustable forks like the earlier models or the ST4s by reworking my stock '01 forks?

To answer your question...I ride primarily one-up without much gear in the sidebags. no track riding, just the occasional spirited riding on the twisty bits! I hope to do more two-up riding in the future which is why I was curious if the 0.95kg/mm springs would be too soft. However, I do like a nice comfortable ride but I don't want lots of front end dive if I have to brake quickly. Looking for that balance between sporty performance and comfy touring (it is a ST after all).

It makes sense that most of the weight will be in the rear of the bike which is why I'm looking to balance out the suspension for the future installation of an Ohlins rear shock which will be resprung for my 205lb body (220lbs with gear). Thanks for your input, you have been a great help in the past as well!

NCRick · Feb 18th, 2006, 8:12 pm

With the right parts, it is possible to mod the fork to be full adjustable. I don't think that is that big a deal if you set up the valving correctly. The Penske conversion uses a more involved compression damping system and also replaces the rebound side of things with a new valving set-up. The Penske can only be installed by an approved shop (like us). The Gold Valve is a great do it yourself project for the folks who like to play with that stuff. I think the Gold Valve is a good compromise for your bike. It will really transform the forks!

I recommend you go with the .95 springs from what we have discussed. I would have to talk to you a little more to recommend the valve stack but I would think a C-35 would be a good choice.

**st2lemans** · Feb 19th, 2006, 5:10 am

I'm 195 and have Ohlins 0.90 springs in my ST2, and I like them a lot *have RaceTech valves too).

I'd go for the 0.95 in your case.

Tom

dharhay · Feb 19th, 2006, 7:07 am

Thomas I just installed springs and the Gold Valve in my ST4s forks. So I know the questions you are asking us and yourself.

Is there any way that you can ask a riding buddy or a person who is known to work on Ducatis on the side in your area?

For my application, I chose the lower of the nearby choices, or the .90 springs. That did not get me much of a change, but I was not looking for a huge difference either. I sort of wanted the Gold Valves and bought the springs since I was in there and would always wonder.

Dave Harhay

NCRick · Feb 19th, 2006, 8:13 am

Dave, the Gold Valves will be a nice improvement to those ST4s forks. Have you put many miles on the new set up "testing"? The biggest problem I see in GV installation is cut o-rings due to burs on those damn stake point that have to be drilled. If the O ring is cut, the damping is short circuited. The ST4S fork is a bit different than the ST2 and the biggest change is the stock spring which on the ST4s is already a straight wound spring. (This thread made me think that I must remember to measure the one I have in the shop before returning them to the customer). I guess that the stock ST4S spring is around a .80 Kg/mm

The ST2 has a dual rate thing that gives the bike a lot more of a dead spot in the forks making them feel more vague and wooden.

BlueST2 · Feb 19th, 2006, 8:21 am

Thanks Tom and Dave. It sound like the 1.0kg/mm springs would be too harsh for my street only application and the 0.95 rate appears to be the way to go. I appreciate the input as I know I don't want to rework my forks and later go "Damn, I should have gone with the springs rated XXX" (sound dirty...yes)!

I'm still open for any further input from others as what they have done to increase the feel and performance of their forks. I'd rather spend the money only once! The Penske and Traxxion alternatives sound pretty interesting but I believe I'd have to ship my forks out to have these items installed elsewhere and that runs into heavy shipping costs (to and from) for and already pricey adjustment, hence the Gold Tech alternative for my street bike. If anyone here has had excellent results and feels it's worth the $$$$ for the Traxxion or Penske rework please speak up. Thanks as always!

Thomas

mcd · Feb 19th, 2006, 9:24 am

Thomas,

From an ex-New Englander to a current one... I just wanted to put in a plug for Rick. I just upgraded some ST4s forks and, as you can probably tell by the level of effort he put into responding to your questions, he was both extremely helpful and responsive. Whatever path you choose it might be worth your while to give he and his shop some consideration. Like me, I'm sure you'll be glad you did in the end.

Matt

p.s. the author of this note is in no manner, shape or form affiliated with NCRICK but... damn if he's not a good guy.

BlueST2 · Feb 19th, 2006, 10:51 am

Quote:

Originally Posted by mcd

Thomas,

From an ex-New Englander to a current one... I just wanted to put in a plug for Rick. I just upgraded some ST4s forks and, as you can probably tell by the level of effort he put into responding to your questions, he was both extremely helpful and responsive. Whatever path you choose it might be worth your while to give he and his shop some consideration. Like me, I'm sure you'll be glad you did in the end.

Matt

p.s. the author of this note is in no manner, shape or form affiliated with NCRICK but... damn if he's not a good guy.

I'm already ahead of you Matt, I've recently PM Rick and told him thanks for the info and that the business would most likely flow his way after I finish paying off some prior purchases of Duc goodies. I believe you take care of those who take care of you and Rick has been a great asset when it comes to my ST!

Best to all,

Thomas