Heavier springs, are they worth it ?


20 replies to this topic
  • crf450319

Posted June 11, 2010 - 07:39 AM

#1

Thought I'd see if any of you guys have put heavier springs in your 450's and if you noticed any substantial improvement in hadling, or an improvement in general suspension feel ? I don't have any complaints with the suspension on my '09 but I wonder if new springs would make it any better ?

I'm 215 lbs without gear, Race Tech's spring calculator suggests 5.0 kg/mm fork springs whereas the stockers are 4.7 kg/mm. On the rear they suggest a 5.6, and the stock spring rate is 5.5 kg/mm. DSP offers both fork springs and the steel shock spring for $150 + shipping.

Is it worth it to go with a 5.6 kg shock spring when the stock rate is 5.5 ? The forks are a no brainer, but I don't know if a different rear spring would add anything as far as handling goes. I was also planning on replacing the stock pressure springs with DSP's 2.3 kg, for $39 why not ?

Thanks...

  • grayracer513

Posted June 11, 2010 - 07:49 AM

#2

Getting the spring rates right is the single most important thing you can do to your suspension. Without that, the balance between compression and rebound is all wrong, and in many cases, can't even be corrected by revalving.

The springs are what supports the weight AND what absorbs most of the impact energy. The dampers just control the motion. Definitely worth it, yes.

  • crf450319

Posted June 11, 2010 - 07:52 AM

#3

With the rear shock spring rate being so close to the suggested rate (5.5 stock, 5.6 sugg.), would it be worth the swap ?

  • Jim813

Posted June 11, 2010 - 07:53 AM

#4

Thought I'd see if any of you guys have put heavier springs in your 450's and if you noticed any substantial improvement in hadling, or an improvement in general suspension feel ? I don't have any complaints with the suspension on my '09 but I wonder if new springs would make it any better ?

I'm 215 lbs without gear, Race Tech's spring calculator suggests 5.0 kg/mm fork springs whereas the stockers are 4.7 kg/mm. On the rear they suggest a 5.6, and the stock spring rate is 5.5 kg/mm. DSP offers both fork springs and the steel shock spring for $150 + shipping.

Is it worth it to go with a 5.6 kg shock spring when the stock rate is 5.5 ? The forks are a no brainer, but I don't know if a different rear spring would add anything as far as handling goes. I was also planning on replacing the stock pressure springs with DSP's 2.3 kg, for $39 why not ?

Thanks...



I'm not an expert by any means, but I think you will need at stiffer rear spring. I believe I have a 5.7 kg ( I weigh 205 lb without gear) and it is on the verge of being too soft.

  • ridleyredraider

Posted June 11, 2010 - 07:55 AM

#5

Fronts, yes. Rear, probably not. The sag should be attainable with the 5.5. With springs for your weight, it will hold the bike and you up in the correct part of the stroke, making full use of your suspension. The way you're riding now, it's sitting too low in the stroke, and the front end could probably feel more plush.

  • MrBlahh

Posted June 11, 2010 - 08:05 AM

#6

you should already know if your rear is good enough, if you have set your preload up properly

it's either able to make it, or it's not

  • crf450319

Posted June 11, 2010 - 08:07 AM

#7

I just got off the phone with Fodi (sp?) from DSP and he suggested a 5.9kg rear shock spring, he said that 5.6 would be way too soft. I'm going to order them today, on another note he said that with the KYB forks they were leaving the stock pressure springs in and didn't suggest changing them out.

So, for you heavier guys that put new springs in have you noticed a difference in handling or general suspension action/feel ?

Thanks again :thumbsup:

  • Just_a_trail_rider

Posted June 11, 2010 - 08:12 AM

#8

I just got off the phone with Fodi (sp?) from DSP and he suggested a 5.9kg rear shock spring, he said that 5.6 would be way too soft. I'm going to order them today, on another note he said that with the KYB forks they were leaving the stock pressure springs in and didn't suggest changing them out.

So, for you heavier guys that put new springs in have you noticed a difference in handling or general suspension action/feel ?

Thanks again :thumbsup:

Springs alone don't always do the job. i am about 210 without gear and I always start out changing the springs. But that isn't quite enough and I end up with a revalve.

You need a suspension guy. Call Dave at Smart Performance Inc. to get his suggestions.

  • crf450319

Posted June 11, 2010 - 08:17 AM

#9

you should already know if your rear is good enough, if you have set your preload up properly

it's either able to make it, or it's not


The stock rear shock is too soft for me, my static sag is well below the recommended 20/25mm. Race Tech had suggested a 5.6 kg shock spring. My question wasn't wether or not the stock spring was sufficient, it was intended to point out the difference in spring rates - stock to sugg. and if there would be any noticeable difference with a change in such a small increment.

After talking to the guys at DSP, they've answered my question.

  • MrBlahh

Posted June 11, 2010 - 08:21 AM

#10

The stock rear shock is too soft for me, my static sag is well below the recommended 20/25mm. Race Tech had suggested a 5.6 kg shock spring. My question wasn't wether or not the stock spring was sufficient, it was intended to point out the difference in spring rates - stock to sugg. and if there would be any noticeable difference with a change in such a small increment.

After talking to the guys at DSP, they've answered my question.


the spring really does not affect damping like that, unless you go to a progressive spring or are way off, if your bottoming out your still gonna need a revalve

the difference in handling will be because the bike is sitting at the right preload and high enough in the shock travel so all of the suspension and geometry works right, if your rear was way off it's gonna definitely change how the bike turns

it's really noticeable on the forks, if your riding too far into the travel small bumps will be harsh

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  • schrode

Posted June 11, 2010 - 08:29 AM

#11

as a big boy with resprung/revalved suspension i can answer your question. yes, the difference is immediately recognizeable and a huge improvement. i thought my bike handled pretty good in stock form and was pretty happy with it, even with the preload cranked to hell to get the sag right. then i saw some photos of myself landing off some small jumps and how stink-bugged my suspension was. i thought, hey maybe it should be standing up to little stuff a little better. well, with suspension redone it almost felt harsh immediately but once i dialed it in and road it for a day i found a whole new gear on my normal trails. truly amazing what a proper setup will do for you.

  • crf450319

Posted June 11, 2010 - 08:29 AM

#12

it's really noticeable on the forks


I understand how the suspension travelling too far down in the stroke will negatively affect performance & handling. What I was looking for, and what you've offered in your last post was what I was after.

"it's really noticeable on the forks"

Someone who's made the change & noticed a positive improvement.

  • MrBlahh

Posted June 11, 2010 - 08:33 AM

#13

The stock rear shock is too soft for me, my static sag is well below the recommended 20/25mm. Race Tech had suggested a 5.6 kg shock spring. My question wasn't wether or not the stock spring was sufficient, it was intended to point out the difference in spring rates - stock to sugg. and if there would be any noticeable difference with a change in such a small increment.

After talking to the guys at DSP, they've answered my question.


I understand how the suspension travelling too far down in the stroke will negatively affect performance & handling. What I was looking for, and what you've offered in your last post was what I was after.

"it's really noticeable on the forks"

Someone who's made the change & noticed a positive improvement.



yeah you'll notice it, on ktm's the rear is critical too, not as much on linkage bikes

  • grayracer513

Posted June 11, 2010 - 09:11 AM

#14

I've resprung 4 YZF's for heavier friends of mine, ranging in weight from 220 to 270 without gear, and all of them said they were surprised at the difference it made.

Just getting the sag right in the rear is not going to solve a problem of too light a spring. If you crank down a too light spring, you'll end up with no static sag, and the rear will misbehave in light chop. You'll also end up with a spring that is either very near to, or actually does coil bind at full compression, and may break because of it. Compensating for an inadequate spring rate by increasing compression damping leads to a damping curve that's wrong either initially for the light bumps, or at deeper stroke, for the bigger ones. Very unsatisfactory.

Personally, I fall into the same category as Maurice does. I get a tremendous amount of value from having had the suspension redone. But a lot of 170-185 pound riders are quite happy with the stock suspension. With the right spring rates, the stock suspension will work the same for you as it does for them, and that might be enough for you. If it's not, you can easily go from there and get it reworked. But with the wrong rates, there's no hope of having it work like it should.

Changing them is an easy enough job for most anyone to do, and if you don't think you're up to the fork springs, you can have a shop do them on carry-in forks pretty cheaply.

  • crf450319

Posted June 11, 2010 - 09:41 AM

#15

I just ordered the springs, after talking to their service guy I went with the 0.50 fork springs and the 5.9 kg shock spring. I'll start with the springs and decide later on if I want to re-valve, as the bike is now with everything stock it still feels surprisingly good.

Keep in mind that I replaced the fork oil (both chambers) and shock fluid when the bike had 10 hours on it, my normal service intervals are every 20 hours but I wanted to get the contaminants/oem fluid out sooner.

I do all of my own suspension servicing (forks and shock), the only part I haven't played with are the shim stacks - something I wouldn't mess with unless I had something to change with proven results and a step by step guide. I just finished servicing a buddy's '01 CR 250R front and back and I'm supposed to be doing an '07 RMZ 450 this weekend. Putting the springs in won't be a problem.

I should have them installed by next Friday.

Thanks for the help guys

  • grayracer513

Posted June 11, 2010 - 10:17 AM

#16

I do all of my own suspension servicing (forks and shock), the only part I haven't played with are the shim stacks - something I wouldn't mess with unless I had something to change with proven results and a step by step guide.

Dave Johnson at SMART offers exactly that for his suspension mods on the YZF's. I did my own, and now two others. The results are great, the savings are big, you learn a lot, and it's surprisingly easy. A little tedious and detail oriented, but not really hard.

  • MrBlahh

Posted June 11, 2010 - 10:19 AM

#17

Dave Johnson at SMART offers exactly that for his suspension mods on the YZF's. I did my own, and now two others. The results are great, the savings are big, you learn a lot, and it's surprisingly easy. A little tedious and detail oriented, but not really hard.


who is this?

I would like to do my own too, but I do not know if there's a database of shim stacks and applications they are used for, for all the different bikes out there that a consumer/user can get to

  • crf450319

Posted June 11, 2010 - 10:35 AM

#18

who is this?

I would like to do my own too, but I do not know if there's a database of shim stacks and applications they are used for, for all the different bikes out there that a consumer/user can get to


Dave @ Smart Performance Inc.
http://www.smartperformanceinc.com/

  • Wiz636

Posted June 11, 2010 - 11:20 AM

#19

I have modified my forks using DaveJ's (Smart Performance) parts and recommendations and they are sweet. I'm not comfortable opening up the shock so I sent that to DaveJ for him to do and the difference is incredible.

Also, over the last couple years I have put on about twenty pounds (must be married life) and now weigh 206 without gear and just recently got heavier springs (front and rear) based on DaveJ's recommendation and all I can say is WOW! The front is so much more supple now because the forks are not already compressed past the initial part of the stroke and the rear tracks way better through whoops, off jumps, out of corners, etc.

  • makindue

Posted June 26, 2010 - 10:07 PM

#20

Thought I'd see if any of you guys have put heavier springs in your 450's and if you noticed any substantial improvement in hadling, or an improvement in general suspension feel ? I don't have any complaints with the suspension on my '09 but I wonder if new springs would make it any better ?

I'm 215 lbs without gear, Race Tech's spring calculator suggests 5.0 kg/mm fork springs whereas the stockers are 4.7 kg/mm. On the rear they suggest a 5.6, and the stock spring rate is 5.5 kg/mm. DSP offers both fork springs and the steel shock spring for $150 + shipping.

Is it worth it to go with a 5.6 kg shock spring when the stock rate is 5.5 ? The forks are a no brainer, but I don't know if a different rear spring would add anything as far as handling goes. I was also planning on replacing the stock pressure springs with DSP's 2.3 kg, for $39 why not ?

Thanks...


I use 5.6 kg shock spring . For me it is worth it. :)





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