I have a minor right fork oil leak and am going to be getting it fixed soon, and i though while thats being done might as well upgrade the front springs since they are so soft stock..  I weigh about 150 and was wondering which type of spring would be best for me, progressive or a stiffer straight rate spring? They cost about the same.  I kind of like the idea of progressive but I really dont know much about the actual handling differences. Thanks

If majority of your riding is commuting (you do not do track days) then go for progressive. I have them and love them, they smoothed my riding experience a lot!
I have to mention that I never had straight rate installed in my bike, although I read here that they are somewhat stiff for everyday street riding.
I weigh about 155.
good luck

In order to keep the vote count even... ...

I say straight rate.  Why use the one size fits all progressives when you can use straight rate designed for your weight.  I have to mention that have I never had progressives installed in any of my bikes.

I chose Straight Rate based on some reviews/info I found (and made sense to me) that Progressives go through the soft settings incredibly fast - so you are effectively using the stiff part for only half (or less) of the compression distance.  This may be completely ridiculous (also, my weight is a bit more than yours ) but I put in Straight Rates and I've never looked back.  I recommend Sonic Springs - great product, good prices, fast shipping.

I outweigh you by quite a bit (haven't seen 199 in quite a few years on the scale) and was happy switching from stock to progressive - having had good results from progressive on other bikes in the past. As per usual for this thread, other than the stock straight rate incredibly soft springs, I have not had straight rate springs in it for comparison. But I can't imagine that you'll overload the progressives in any way, either. I was bottoming the stockers going over the railroad tracks - Progressives solved that problem.

As for folks that are supposedly tuning it to their specific weight - what happens when they carry cargo or a passenger? Or gain or lose weight, for that matter?

How often do you carry cargo or passengers Andy? if never is your answer is no, like it is for me, maybe think more about the harder straight springs.  If it is yes, then think more about the progressives.

simply put, if your riding weight will stay relitively the same, get springs with the same resistance throughout the travel, if your riding weight varries like DoDoi mentioned, get springs with varriying resistance

never have had a passenger, only been riding for like 1.5 months though..

prob will keep my riding weight the same usually.   The straight rate springs ive seen have been for higher weights usually, like 185 and below was their lowest one. the stock springs supposedly is good for a rider who weighs 55 lbs..  lol.

what would be the best straight rate springs for 150lb ppl?

Quote from: Andy13186 on December 04, 2009, 03:59:49 PM
what would be the best straight rate springs for 150lb ppl?

Go here...

http://www.racetech.com/#

Then move your mouse over search and click on spring rate search.  Then enter your info.  It'll tell you what rate you should use.

^thanks for the link.. taht one said .838 mm

looked into sonic springs and found this calc  http://www.sonicsprings.com/catalog/calculate_spring_rate.php#calculate

this one reccomends .75 for normal street .80 for aggressive street

ill prob go with .80

I've been looking at these too. My 2 cents.

At 170 lbs, I want a .75 kg/mm spring for street use by the calculator. Minimum rate from Sonic or Racetech is .80, which is probably fine.

Progressive Spring for this bike is .58/.80, which is a bit softer building up to the highest rate I'd want. Note that the highest spring rate is still the lowest straight rate available.

Stock is something like .45, so any of the above is an improvement.

I ran Progressive Springs on my last bike and liked them a lot. I'll probably buy them again this time if I upgrade.

Wheres the best place to get new fork seals?  I cant seem to find any for an 07..   will any of the forks seals fit on any year? not sure if theres any diff with the forks from year to year.  this is the cheapest ive found but it says 89-96

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250450795247&crlp=1_263602_263622&ff4=263602_263622&viewitem=&guid=c216815d11d0a0b5874514e5ffd88c3d&rvr_id=&ua=WVF%3F&itemid=250450795247

Here's our take on it, it's why we only make straight rate springs.

http://www.sonicsprings.com/catalog/straight_vs_prog_tech_article.php

Some other points.

If you're a lighter rider and don't ride very aggressively, then the real world difference between our springs and the progressives won't be that big. The heavier you are and the harder you ride the more extra benefit straight rate springs will be.
It doesn't matter if your load varies, the straight rate springs are still better.
Because the stock springs are so bad any aftermarket spring is going to be a big improvement. But just because it's a lot better doesn't mean that it's as good as it could be.
Straight rate springs aren't necessarily harsher/stiffer than progressive ones, you just need to pick the right rate for your weight, riding style and preferences. If you have any questions on what rate to get just shoot us an email.
Among the better straight rate manufacturers, there's no difference in quality of the spring itself. We all use the same alloy and the same processing steps. Pick your vendor based on the combination of support, service and price that you feel is best.

QuoteAmong the better straight rate manufacturers, there's no difference in quality of the spring itself. We all use the same alloy and the same processing steps. Pick your vendor based on the combination of support, service and price that you feel is best.

That's why I chose you guys + you had reasonable overseas postage costs.

I am very happy with my 0.85kg/mm springs and rate it the best upgrade I have ever done to my GS 

Quote from: RichDesmond on December 06, 2009, 04:26:13 PM
Because the stock springs are so bad any aftermarket spring is going to be a big improvement.

Why is that?

I used to work at tuning vehicles for a major automotive OEM. NVH  / ride and handing. I have a good handle on the tradeoffs for automotive; essentially as suspension stiffened for a given layout, the relative handling improved as ride and NVH degraded. The balance between these two desireable qualities is the "tuning" of the suspension, and a lot of time is spent on this.

There are local impacts to the phenomenon of "tuning":

If you're engineering cars in Detroit, with some of the worst roads in the country, your engineers point you toward softer suspensions in order to isolate the driver from potholes. GM, Ford, Chrysler

And if you're tuning cars in California for the US market, with great roads / no ice, your engineers point you toward firmer suspensions to take advantage of improved handing. Honda, Mazda

But motorcycles should already be tuned for good roads and no ice, right? I'm not riding my bike down a pothole-ridden section of 12 Mile; I'll take my car at that point or find another route, and at any rate I wouldn't expect my bike to "isolate" me from the ride. Why tune a bike suspension for isolation when it's probably not a desired attribute?

But it is a desired attribute - if you're just cruising along or going on a long trip.  I have been on some unbelievably poorly maintained highways (imagine bumps every 2 seconds for ~4-5 miles), that are still in major use.  If you have extremely stiff springs... you are in for a hell of a ride (and it was ).  If you are a motorcycling enthusiast who takes every corner as fast as you (safely?) can - and I count myself in this group - yeah you want as much info from the tires as possible.

Quote from: galahs on December 06, 2009, 06:05:34 PM

QuoteAmong the better straight rate manufacturers, there's no difference in quality of the spring itself. We all use the same alloy and the same processing steps. Pick your vendor based on the combination of support, service and price that you feel is best.

That's why I chose you guys + you had reasonable overseas postage costs.

I am very happy with my 0.85kg/mm springs and rate it the best upgrade I have ever done to my GS 

Thanks, always good to hear from a happy customer!

Quote from: noiseguy on December 06, 2009, 06:37:35 PM

Quote from: RichDesmond on December 06, 2009, 04:26:13 PM
Because the stock springs are so bad any aftermarket spring is going to be a big improvement.

Why is that?

I used to work at tuning vehicles for a major automotive OEM. NVH  / ride and handing. I have a good handle on the tradeoffs for automotive; essentially as suspension stiffened for a given layout, the relative handling improved as ride and NVH degraded. The balance between these two desireable qualities is the "tuning" of the suspension, and a lot of time is spent on this.

There are local impacts to the phenomenon of "tuning":

If you're engineering cars in Detroit, with some of the worst roads in the country, your engineers point you toward softer suspensions in order to isolate the driver from potholes. GM, Ford, Chrysler

And if you're tuning cars in California for the US market, with great roads / no ice, your engineers point you toward firmer suspensions to take advantage of improved handing. Honda, Mazda

But motorcycles should already be tuned for good roads and no ice, right? I'm not riding my bike down a pothole-ridden section of 12 Mile; I'll take my car at that point or find another route, and at any rate I wouldn't expect my bike to "isolate" me from the ride. Why tune a bike suspension for isolation when it's probably not a desired attribute?

I wish I knew why they choose some of the rates they do. 

Let me give you an example. Kawasaki puts very soft springs in the EX500, about 0.58kg/mm. Barely enough for the weight of the bike with no rider at all. On the Ninja 650R, which is the replacement for the 500 and weighs about the same, they put insanely stiff springs in. Progressively wound, starting at 1.2 and going up to 1.6kg/mm. Stiffer than we put in Gold Wings. Even for a guy who weighed 350lbs that's too much spring. There's absolutely no logic that supports either choice, but that's what they did. It's a mystery to me.

I knew the GS500f needed a spring upgrade when I discovered the front bottomed out on speed humps and under hard braking.


What is the stock GS500's spring rate? I remember reading it in the past but I have forgotten.

^someone said in this thread its around .45 kg/mm

i ordered the .80 sonic springs, ill let u guys know how i like them when i get them installed

according to the racetech spring calculator, the early models up to '90 had 0.45 and then they had .594 up through '02. for the '04 and after they do not have a rate listed. 

I recently bought the 0.80 Sonic Springs (didnt want to pay the extra at racetech, and I am sure the springs are comparable), due to diving on braking and bottoming out on just about everything. I weigh 160 pounds. After a bit of riding, I am wondering if maybe I should have gone slightly stiffer.  Get the right springs in there, then set your sag and your bike will be a hole new ride!

Passenger and or saddle bags primarily put more weight over your rear tire, so for riding, turning etc this will not overly impact your front suspension. This additionial weight will have some affect on the front during braking as that additional weight effectively moves forward, making the front dive more.  So maybe step up your front spring late slightly if you will carry passengers or lots of luggage often, but no so much that it causes your general riding to be too stiff. Of course your rear shock should be set accordinglly.

My understanding of progressive vs straight is that the travel in street bikes is so minimal that you really cannot get the wanted effect from progressive springs.  Also, who is to say which part of the progressive spring rate you will end up at once you set sag?  So use straight, and you get a progressive effect anyway near the end of travel as the air in your forks compresses and excerts more pressure. I am experimenting now with oil level in the forks, as more oil means less air and more of a ramp up in force as the forks near bottoming out.  anybody else done this?

Another option to help avoid bottoming out under sudden bumps is heavier oil, but this impacts the responsiveness of your forks. So far I have stuck with 10 weight, but I think lots of people go up to 15 weight.