Great suspension setup how-to link

[jaimev34]

Gonna hijack a thread I started for a little bit.

Back in December, I sent my forks to Racetech to have springs, valves, and oil installed. They installed .90 kg/mm springs, which is what the calculator suggested. When I got the forks back from RT, I installed them and measured the sag. Back then, I used a much lower sag number (~32mm) and payed no attention to the free sag. Well, I checked my rider and free sag today, as well as my suspension travel. With the preload backed out all the way and with a half tank of gas, I was able to get a maximum of ~35mm rider sag. My free sag was somewhere around 23-25 mm. After riding around all day with a zip tie attached to my right fork, I know that I've got about 1 inch left of travel. Well, my rider sag and susp. travel are ok, but my free sag is too high as a result of not using any preload to achieve a decent rider sag number. I weigh about 185-190 lbs with gear on, which is heavier than I was when I sent the forks to RT.

What do you guys think of my numbers??

I think you may have a tad stiff spring. The same rules/numbers for Free Sag and Rider Sag don't apply to forks that apply to the rear (shock).

Per Keith Code & Andy Ibbott: Front Static (Free) Sag for a road bike: 30-40 mm

Front Rider Sag for a road bike: 35-50 mm

The fact that you're not using all of your front fork travel also reinforces my thoughts. You shouldn't be bottoming out at any time, but under hard braking into a corner or an emergency stop, you should use up just about every mm of travel available in your forks.

One of my critiques of many suspension shops (including RaceTech) is that they are so racing oriented that they don't always adjust properly for the street rider.

Hate to say it but it's just a fact of getting suspension dialed in - you may have to purchase/swap for another set of springs and do some experimenting. It is next to impossible to get the suspension spot on with the first try. I would suggest trying to borrow some 0.85 springs so you can swap them out and compare them to the 0.90's.

That doesn't seem to leave very much dynamic sag? Ohlins recommends (front) 15-30mm static & 35-50mm dynamic.

Travel can be affected by fluid height also, how much did RT put in? Cutting out 10-15mm of the preload spacer should get you right about in the right range, I'd do it in 5mm increments though and test after each cut. Your numbers seem ok, it's just your preload adjuster is at the end of the range. I would doubt you need new springs, too many things to check and dial in first.

my 24 mm free sag and 36 mm rider sag seem to fit within those ranges.

[SilverVee]

I also think that maybe .85kg would be closer unless you plan on approaching the 200# mark (lots of donuts). I'm using .95kg's for my 220# with just small amount of preload. When I built my forks I made sure my package length (spring + spacer) was the same as stock. My forks are purrrrfect.

Looks like your setup is close to what I'm looking for. Did you use the R/T valve(s) as well? What oil/weight?

[jasonsmith]

I also think that maybe .85kg would be closer unless you plan on approaching the 200# mark (lots of donuts). I'm using .95kg's for my 220# with just small amount of preload. When I built my forks I made sure my package length (spring + spacer) was the same as stock. My forks are purrrrfect.

Looks like your setup is close to what I'm looking for. Did you use the R/T valve(s) as well? What oil/weight?

Yep used the G2-R Compression and the High Frequency Rebound valves. 5WT non RT oil.

[JamieDaugherty]

I have no issue with your method if it gives accurate results JD, and if your 15mm preload method actually provides the correct spring rate for a specific bike/rider combo than I guarantee that that set-up Will Have Free/Static sag in the range of the manufactures recommendations and all manufactures seem to want Free sag in their set-ups.

Free/Static recommendations vary depending on intended use just like Rider sag does.

Point 1: Just about every tuner & all manufactures recommend Free sag and you say it's meaningless?

Point 2: You recently posted up spring rate recommendations for our VFR's based on your New rate calculator formula and in one range it actually is very similar or identical to what others here like Pete, Jason & myself have found using the Free/Static method and that is the one 220 lb rider range.

The remainder of your suggested rates especially on the lower rider weight range seem radically HIGH! :beer:

Please reprint those suggested numbers here again so that I don't misquote, but I seem to remember that it suggests a spring rate for a 120 lb riders several hundred lbs heavier than the stock VFR set-up. I think your (example A) was from that chart in a previous post.

My concern here is that before you and I discussed rear spring rate issues in PM's just last year you were using a calculator and suggesting spring rates to our members that were extremely LOW. Now you have reworked that same formula because you said you found an error in it(at the time you said it was the same calculator that many shops were using). You've recently reworked the numbers in it and now suggest spring rates that are extremely High IMO, except in the highest range of rider weights.

My point all along is that for Years our members have been getting erroneous rear spring rates suggested to them and have even bought new shocks from manufactures that installed the wrong springs on them and w/o and control or check method there was no way for most of our members to know what they had. Like I've mentioned before there are 190 lb members here who have had suspension Pro's suggest spring rates to them from as low as 800 lbs to as high as 1200 lbs, who's right, who's wrong or is a 400 lb range close enough. Unlike any other method, using the manufactured suggested Free(static)& Rider sag numbers method at least gives you 2 control points. Saying 35mm Rider sag is all you need is an Uncheckable reference, now if you added a second check like say your 15mm of preload equal 35mm Rider sag as you suggest then that also works, if it's true throughout the rider range! :fing02:

Hell if I remember correctly Elka just slapped 850 lb springs on most of their shipped shocks because I guess they basically used the stock spring rate or used the same error-ed calculator you once used. :beer:

So for most of use who don't have or can't find shops, tuners or manufactures who can provide accurate Rear spring rate suggestions for our VFR's then using the Static/Free Sag numbers are our Only control along with Rider sag numbers.

I am no expert and I don't need to be right, I am just trying to find and suggest a control method that any VFRD member can use to calculate if in fact they have the correct spring rate, instead of just being told a number that for the most part have been proven wrong from everything I can tell so far.

The entire idea is to benefit our DIY members and the more checks you have the more accurate the results.

BR

I would agree with much of what you are saying here. I've spoken with Traxxion a couple of years back and they stated they install a 1300lb/in on all VFR800 applications. The information on their website right now suggests they are still doing this. Other calculators give really low rates, far lower than I would now suggest. At one time I had skewed my numbers in that direction because I assumed there was something I was missing. After gathering some more data concerning the leverage ratio on the VFR, and with your help as well, I realized that much higher rate springs were needed. Much of suspension tuning is trial and error and I continuously gather data and compare it to my database of setups. Every year that goes by I feel that I can better help fokls with suspension configurations. Hopefully I never stop learning!

Here's another thought to throw out there - I feel that the VFR's are a special case. In fact, they are probably the most challenging applications for me. Some riders ride agressive and even spend some time on the track. Others do more long trips carrying luggage, bags, passengers, etc. quite often. That's why I try to get as much info about the rider, their wants, needs, desires, and anything else in order to make the best judgement call. Looking at my setup data I can see that for other models the spring rate and valving setup is very consistent for a given rider weight. For the VFR's it's more scattered because of the additional variables involved. It goes back to a saying that I like "If it was easy, everyone would do it."

[Guest]

Yep used the G2-R Compression and the High Frequency Rebound valves. 5WT non RT oil.

G2-R valves make all the difference in the world. I don't know why RaceTech continues to sell the old valves. There's what - only $10 difference in the two but a world of difference in performance.

[Guest]

I've spoken with Traxxion a couple of years back and they stated they install a 1300lb/in on all VFR800 applications.

Max installed a 1400# spring on my VFR shock and only a 1000# spring on my ST1300 shock. I have wasted so much money with Traxxion having to go out and purchase the correct springs for my Penske's. I guess I'm a little bitter about them, but they screwed me on all three Penske's I bought from them.

I've got where I just deal directly with Shane Sweigert at the Penske factory in Reading, PA. Very, very sharp guy and treats you right.

[RustyA]

I've spoken with Traxxion a couple of years back and they stated they install a 1300lb/in on all VFR800 applications.

Max installed a 1400# spring on my VFR shock and only a 1000# spring on my ST1300 shock. I have wasted so much money with Traxxion having to go out and purchase the correct springs for my Penske's. I guess I'm a little bitter about them, but they screwed me on all three Penske's I bought from them.

I've got where I just deal directly with Shane Sweigert at the Penske factory in Reading, PA. Very, very sharp guy and treats you right.

I see you had the pleasure of dealing with Max too. :warranty: :mad:

[Baileyrock]

I feel that the VFR's are a special case. In fact, they are probably the most challenging applications for me.

I agree and the basis of my point only involves calculators for VFR rear spring rates that have been flawed for a decade IMO. Not finding reliable sources of info for that long a period is very frustrating and why many of use have had to learn it ourselves. :comp13:

[Guest]

I see you had the pleasure of dealing with Max too. :comp13: :ph34r:

Oh yeah. The real pisser is Traxxion Dynamics is only about half an hour from my house. But to get good service, I have to ship my shock all the way from Georgia to Pennsylvania.

I can't praise the guys at Penske enough. Why go through a suspension shop that has to order all of their shocks and hardware from Penske when you can deal with Penske direct? That have a pdf form that you can fill out telling them exactly the service you want or the shock you need built. Very slick operation.

Oh, and they return phone calls in a prompt, professional manner, and speak English.

[JamieDaugherty]

Why go through a suspension shop that has to order all of their shocks and hardware from Penske when you can deal with Penske direct?

Very true.... as long as you have a Penske!