Suspension Set up and Balancing

[COWBOY]

I'm planning on having my suspension reworked next month and have been reading a number of threads on here regarding spring replacements for the front and back.  Frankly I thought I had it sorted but now I'm not so sure so I'd appreciate some help/advice.

The Bike   --   2005 S2R with the rear raised .75"

The Rider --    175 in street clothes roughly 185 geared up.

The Forks --   2003  ST4 with stock springs etc.

The Shock --   2005 S4R  with stock spring

Last summer I had the oil replaced and had a local Ohlins certified tech help me with set up (sag, balance, rebound and compression settings).  The process was rather involved (serviced first then the settings work began ---  adjust, tech rides it, adjust, I ride it, adjust I ride it again, then moved on to next setting, rinse repeat).  After having it done the bike was better than new.  The difference was noticeable immediately.

We ended up with the following from my notes.

     Front full extension 126mm

     current sag settings:     front 34mm   rear 26mm

Do these settings look correct?  I know the springs are all stiff for my weight which is why I've been planning to change them all soon.  Around town the roads here in Charlotte are fairly flat but I do get out to the mountains to enjoy the twisties  5-6 times per year  (Smokey mountains, Deals Gap, Blue Ridge Parkway).

Any advice on what parameters I should be shooting for?  I'd love to be able to remove the forks and ship them off to ducvet or jason but that's not in the cards (the bike is my second family car).

Thanks.

[stopintime]

I'm not going to be able to help much, but I'm wondering if the sag numbers are backwards? I've seen numbers around 30-40 rear and less up front.

Let's wait for the experts

[ducpainter]

I'd be looking for some more sag in the back.

[COWBOY]

I thought they were backwards to.  I just rechecked my notes and they are correct and I had written this was due to the ride height adjustment and the difference in springs (1.0 in forks if memory serves and shock is for a 160-170 rider).

I can confirm that the bike is balanced meaning the front and bike move up and down together at the same time.

From your two posts am I correct in inferring that once the bike is correctly sprung for my weight using paired spring weights front and back that my settings should be a tad lower with the front moving less?

At this point I just want to make sure I get it right once I buy the new springs (leaning to .85 or .9 for the front and a hyper spring for a 185 pound geared rider).

[♣ McKraut ♣]

i'm interested to hear what others have to say about this as well...i had my sag measured on saturday (i'm about the same weight) on my S4R (stock suspension) and i had 40mm rear and a whopping 47mm front.  looks like i need to crank up the preload on the front forks a good bit.

[Speeddog]

I'd say a 600 lb/in spring for the rear, and some .85 springs for the front, both straight-rate.

And yeah, more sag on the rear.
If you install the spring with about 1/2" of preload on it, it should be close.

OEM S4R spring is progressive, so it's difficult to accurately measure the rate.

OEM ST4 front springs were purportedly .84 on earlier models.
According to the parts catalogue, '03 ST4 had same springs as '02 S4, those are .87.
*Assuming* the forks still have the stock springs, I don't see a lot of improvement switching to .85.
Those ST4 forks have the same valving as the S4, which are quite harsh on compression.
Re-valving would be a noticeable improvement.

[COWBOY]

Thanks Speedog.  That helps a lot. 

What are your thoughts on going to .90 on the front?  I've been debating this using the Race Tech calculator for a while now (aggressive street riding v. touring setting). 

It's been a year but I think my tech mentioned this as well last year -- if memory serves I think he said the softer front as compared to the rear PLUS the increased ride height meant we need to increase sag up front and really move the rebound and compression settings up to balance the bike F to R and stiffen the ride.  Does that sound right?   Unfortunately it's been a year and I didn't bring a notebook last year (doh!).

I prefer a stiffer ride to a soft one but I don't get to the track and even on the Dragon soaking up the bumps associated with street riding is paramount.

Would a stiffer front help balance the sag numbers given the increased ride height of the rear?


EDIT:    Regarding revalving.    What kits would you recommend and can I use those marked for the S4 or do I need to find a kit specific for the ST4?   I've searched Race Tech, Traxxion and Matris and it's slim pickins for the ST4.    I chose the ST4 forks over others because they were adjustable, bolt on AND longer (i use clip ons over the triple as a result).  My main concern has been that since the forks MAY be different lengths that the springs may be as well which may or may not mean the valving is different or other things. Thanks.

[Ivan]

Thanks Speedog.  That helps a lot. 

What are your thoughts on going to .90 on the front?  I've been debating this using the Race Tech calculator for a while now (aggressive street riding v. touring setting). 

\

FWIW, you and I are about the same weight, and my ride height is set similar to yours....

I have  0.9 Racetech fork springs in my S2R1K and it is too much, the front sag is about 25 mm with the preload adjustment set for minimum.  The Racetech folks told me that the internal preload spacer is as small as they can make it, without risking top-out problems.  I will eventually change them to 0.85.  I ride aggressively, but there are quite a few miles on the slab between home and the canyons, so my goal is to get the fork sag to 30 mm with the preload adjusters close to the center of the range. 

My Penske shock has a 625# spring with 5/8-inch preload, and it is just right (sag is about 35mm).  The rear of the bike is notably more plush than the front (in a good way, smooth and well controlled), but since the front is too stiff there is a bit of an imbalance. 

I'm really happy with the Penske shock, but so far I'm not so impressed with the way that Racetech setup my fork.

[Speeddog]

I weigh 165 ungeared, my S4 is a bit heavier than your S2R, and the OEM S4 springs (.87) are a bit on the stiff side, IMO.
So, no, I wouldn't recommend going for the .90's.

Not sure what to make of what your tech mentioned.
I'm not doubting what he said, but it doesn't make sense to me. YMMV.

Raising the rear ride height mostly just reduces your head angle and trail, and makes the bike more maneuverable.
It will transfer a *tiny* bit more weight to the front, but IMO you'd be hard pressed to measure it.
It does also change your rear swingarm geometry, so it'll have less squat under power.

I'd say get your rear sag number closer to what you have now on the front, *with* a proper rear spring.

AFAIK, the RaceTech valves will be the same as S4 units for your forks, as the Ducati parts catalogue says the damper cartridges are the same.
Kinda explains why the S4 forks are harsh...

FYI, if you're going to change the front springs, the RaceTech springs aren't *exactly* a drop-in.
I've got custom spacers I use to make them fit properly, and modify the springs slightly.
Same for their rear springs, but all they require are spacers.

------------snip-------------
The Racetech folks told me that the internal preload spacer is as small as they can make it, without risking top-out problems. 
------------snip-------------

Do you know which spring part # they put in?

[COWBOY]

I weigh 165 ungeared, my S4 is a bit heavier than your S2R, and the OEM S4 springs (.87) are a bit on the stiff side, IMO.
So, no, I wouldn't recommend going for the .90's.

done.  .85 it is.  thanks.

Not sure what to make of what your tech mentioned.
I'm not doubting what he said, but it doesn't make sense to me. YMMV.

It's probable I'm butchering what he explained to me due either to a bad memory or being a suspension newb and not understanding what he told me or both. 

Whatever he did transformed the bike in every aspect.  Less dive on braking, less squat on accel, better absorbtion of bumps both straight up and midcorner and a general feeling of being on rails through corners.

He DID make it a point to tell me that the springs F and R were wrong for me and the bike and strongly suggested getting them swapped.  I just didn't have the SO approved funds to really explore it further.

I'd say get your rear sag number closer to what you have now on the front, *with* a proper rear spring.

AFAIK, the RaceTech valves will be the same as S4 units for your forks, as the Ducati parts catalogue says the damper cartridges are the same.
Kinda explains why the S4 forks are harsh...

FYI, if you're going to change the front springs, the RaceTech springs aren't *exactly* a drop-in.
I've got custom spacers I use to make them fit properly, and modify the springs slightly.
Same for their rear springs, but all they require are spacers.

Does the front # seem right then?  I was under the impression that the front should be around 30mm along with the rear?  Would a 35mm front and rear sag be ideal then?

Does the same hold true for the Traxxion fork spring kits?   Since they're in Georgia and as such within 3-4 hours drive I was considering going that route if for no other reason than being able to reach out and touch them should something not be right.

I've heard great things about Race Tech and am certainly willing to change my mind on this.  So advice and experience would be helpful.

Thanks again Speeddog!

Cheers

[Speeddog]

Unless there's some particular issue in working with him further ( like he's now 1000 miles away, etc.), it sounds like your previous suspension guy made your bike a lot better.
Give him a shot at telling you what you need.
One advantage of dealing with someone local is that they likely ride the same roads you do, and will have a good idea of what you need to best cope with those roads.

Initially, I'd go for 35mm on both ends, but you could try 30.
I'd consider that range well within personal preference.

I've got no FHE with Traxxion products.
I've heard good things about 'em.

RaceTech is located very close to me, and I know what parts they have.
Big convenience factor.

done.  .85 it is.  thanks.

It's probable I'm butchering what he explained to me due either to a bad memory or being a suspension newb and not understanding what he told me or both. 

Whatever he did transformed the bike in every aspect.  Less dive on braking, less squat on accel, better absorbtion of bumps both straight up and midcorner and a general feeling of being on rails through corners.

He DID make it a point to tell me that the springs F and R were wrong for me and the bike and strongly suggested getting them swapped.  I just didn't have the SO approved funds to really explore it further.

Does the front # seem right then?  I was under the impression that the front should be around 30mm along with the rear?  Would a 35mm front and rear sag be ideal then?

Does the same hold true for the Traxxion fork spring kits?   Since they're in Georgia and as such within 3-4 hours drive I was considering going that route if for no other reason than being able to reach out and touch them should something not be right.

I've heard great things about Race Tech and am certainly willing to change my mind on this.  So advice and experience would be helpful.

Thanks again Speeddog!

Cheers

[Ivan]

Do you know which spring part # they put in?

Spring: FRSP S3827090
Valves: FMGV S2040S (compression) and FRGV S02S (rebound)

Preload was originally set for 15mm.  They reduced the preload to 10mm to get closer to the sag that I thought was reasonable.

[Speeddog]

I think if you drop in a set of .85's, you'll be pretty close.

Spring: FRSP S3827090
Valves: FMGV S2040S (compression) and FRGV S02S (rebound)

Preload was originally set for 15mm.  They reduced the preload to 10mm to get closer to the sag that I thought was reasonable.

[COWBOY]

the guy is gone - moved.

I'll use your recommendations as a baseline and work from there.

thanks again speeddog.

[COWBOY]

Speeddog

I read some lit on hyperpro springs (fork and shock) and am now considering them as well.   

You mentioned on another thread that you have experience with them.  Care to share your thoughts on them as compared to the Race Tech or Eibach? 

On their US site the S2R/S4R aren't listed.  Which bike is closest in weight etc to the S2R?   If you're a dealer it may be a way to repay some of your great advice so shoot me a PM with prices if so.