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New Bike: Throw some springs in it and call it good?

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I'm weighing the pro's and con's of getting my suspension redone on my '08 RM-Z450. It is stock as of right now except for the RG3 link.

I had my last bike, '06 YZ450F, all set up for an intermediate cross country. I wasn't too happy with it. It felt way too soft in the fast stuff and slowed me down in the whoops.

I do about 50/50 woods and MX. I don't want to ruin the handling on my new bike by making the suspension mushy. Could I get away with swapping the springs out for my weight and leave the valving stock?

Thanks!

By the way, I weight 210 w/o gear and run an IMS 2.6 gal tank, handguards, damper, and wear a .75 liter camel back when I race.

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Stock Stack on RM-Z 450 08 (Europe!!!!)

fork Base

23x0,25

24x0,15 2x

25x0,15 2x

26x0,15 2x

27x0,15

28x0,15

29x0,10 4x

20x0,10

30x0,10 6x

reb

16x0,30 2x

12x0,20

13x0,15

14x0,15

15x0,15

16x0,10

17x0,10

18x0,10

19x0,10

10x0,15

20x0,10 2x

mid valve

11x0,20 2x

10x0,20 2x

8,5x0,20

7,9x1,78 (Spacer)

spring

20x0,10 6x

Shock RMZ450/08 Europe Stock valving!

Comp

30x0,40 3x

20x0,25 (Base)

24x0,25

28x0,25

30x0,25

32x0,25

34x0,25

36x0,25

38x0,25

40x0,25

42x0,25

44x0,25

25x0,15

36x0,15

44x0,25 4x

Reb

24x0,30

26x0,30

28x0,30

30x0,30

32x0,30

34x0,30

36x0,30

38x0,30

40x0,30

26x0,10

40x0,20 2x

there are the stacks, they are similar to the 250 but not the same, i dont really know how they would work from looking at the stacks, the shock looks reasonable and the forks better than the 250f but still not a great stack.

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sorry i have gone over your head, these are the shim stacks for your bike, they determine how the bike will feel when you ride it, often people come on here asking how to change the shim stacks around to make the bike feel better, the dogger wrote a huge write up on how to change shims including pictures.I guess what you would prefer to know is ....can the rmz be improved with valving, the answer is yes.

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I don't think he's talking about revalving at all. He was just wondering if changing out the springs will make a big enough difference for him on a stock valving setup.

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most susp companies add 15lb for gear then you have the extra fuel and camel back and dampner etc so say another 5lb at least so now your at 230lb and i would say at that weight the stock springs are gonna be to soft. i would def think you would benifit from stiffer springs. that would be for the MX part in my op. the woods you would prob be able to get away with the stock springs bc you would want it to be on the soft side in the woods right?? i guess you may have to give to get and decide which one you want to give on. maybe ride it and see how it feels with stock and go from there

me personally i ride some trails/woods also and i prefer to give in the woods and have my bike 100% for the MX part and i deal with the stiffness in the woods. that was on my past bikes, i have an ohlins set up now and it is so adjustable i can tune it for trail days as well

I'm weighing the pro's and con's of getting my suspension redone on my '08 RM-Z450. It is stock as of right now except for the RG3 link.

I had my last bike, '06 YZ450F, all set up for an intermediate cross country. I wasn't too happy with it. It felt way too soft in the fast stuff and slowed me down in the whoops.

I do about 50/50 woods and MX. I don't want to ruin the handling on my new bike by making the suspension mushy. Could I get away with swapping the springs out for my weight and leave the valving stock?

Thanks!

By the way, I weight 210 w/o gear and run an IMS 2.6 gal tank, handguards, damper, and wear a .75 liter camel back when I race.

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ok, but on the rear rebound its marginal at best, if you go stiffer it will need more rebound damping via a revalve.

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Hmmmmm.... here are the recommended spring rates according to Race Tech's spring calculator. It takes into account for oversized tank and asks for rider weight w/o gear.

2008 Suzuki RM-Z450

1. Type of Riding:

Motocross

Gas tank Size:

Oversize Gas Tank

3. Rider Weight (without gear): 210 lbs

FRONT FORK SPRINGS

Recommended Fork Spring Rate: 0.497 kg/mm (use closest available)

Stock Fork Spring Rate: .470 kg/mm (stock)

Available FRSP 4349 Series Springs are:

Part Number

Description

Price Select to Buy

FRSP 434938 RT FRK SPR 42.7x493mm .38kg $109.99

FRSP 434940 RT FRK SPR 42.7x493mm .40kg $109.99

FRSP 434942 RT FRK SPR 42.7x493mm .42kg $109.99

FRSP 434944 RT FRK SPR 42.7x493mm .44kg $109.99

FRSP 434946 RT FRK SPR 42.7x493mm .46kg $109.99

FRSP 434949 RT FRK SPR 42.7x493mm .49kg $109.99

FRSP 434952 RT FRK SPR 42.7x493mm .52kg $109.99

REAR SHOCK SPRING

Recommended Rear Shock Spring Rate: 5.90 kg/mm (use closest available)

Stock Shock Spring Rate: 5.5 kg/mm (stock)

Available SRSP 6727 Series Springs are:

Part Number

Description

Price Select to Buy

SRSP 672740 RT SHK SPR 66.9x64x267mm 4.0kg $109.99

SRSP 672742 RT SHK SPR 66.9x64x267mm 4.2kg $109.99

SRSP 672744 RT SHK SPR 66.9x64x267mm 4.4kg $109.99

SRSP 672746 RT SHK SPR 66.9x64x267mm 4.6kg $109.99

SRSP 672748 RT SHK SPR 66.9x64x267mm 4.8kg $109.99

SRSP 672750 RT SHK SPR 66.9x64x267mm 5.0kg $109.99

SRSP 672752 RT SHK SPR 66.9x64x267mm 5.2kg $109.99

SRSP 672754 RT SHK SPR 66.9x64x267mm 5.4kg $109.99

SRSP 672757 RT SHK SPR 66.9x64x267mm 5.7kg $109.99

SRSP 672760 RT SHK SPR 66.9x64x267mm 6.0kg $109.99

So it looks like I'm .027 KG/MM off from stock on the fork springs and .4 KG/MM off on the shock spring.

Considering that I race mainly fast-paced cross country, tight woods, and some motocross, what would be some good options?

I'm definitely thinking a 6.0kg spring, but I'm not sure if I want to go with stiffer front springs because I don't want the front forks to be too harsh.

Need feedback from the suspension experts.:)

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I'm a little heavier than you, but I make up for it by being slow.... My first change was .49 fork springs.. it balanced things out nicely. the increase in spring rate can in fact make a suspension feel SOFTER.. by keeping the bike propped up and out of the harsh range of either the linkage rising rate(rear) or the dramatic rise in air chamber pressure (front forks). in addition, especially for the rear, a proper spring requires less initial preload. this can drastically improve the "feel" of the suspension by allowing the spring to react to smaller impacts.. there is nothing more frustrating IMO than a suspension that is both harsh and mushy at the same time

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Well there's is a lot of options to go with NorCal, here's another.

I think the changing of the springs will make the difference you are looking for if you get the right rated springs....revalve later if you think you need too.

I would change the forks to the .49kg, that is a good match, and will keep you from bottoming hard on the MX stuff. The shock I would NOT go with the 6.0kg because it will be to stiff and you will not be able to set the proper sag. Look for a 5.8kg progressive or two stage spring....they're out there.

You will have to add rebound on both the forks and the shock, but it will work good.

good luck

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I'm a little heavier than you, but I make up for it by being slow.... My first change was .49 fork springs.. it balanced things out nicely. the increase in spring rate can in fact make a suspension feel SOFTER.. by keeping the bike propped up and out of the harsh range of either the linkage rising rate(rear) or the dramatic rise in air chamber pressure (front forks). in addition, especially for the rear, a proper spring requires less initial preload. this can drastically improve the "feel" of the suspension by allowing the spring to react to smaller impacts.. there is nothing more frustrating IMO than a suspension that is both harsh and mushy at the same time

Cool....what did you do to the rear?

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Well there's is a lot of options to go with NorCal, here's another.

I think the changing of the springs will make the difference you are looking for if you get the right rated springs....revalve later if you think you need too.

I would change the forks to the .49kg, that is a good match, and will keep you from bottoming hard on the MX stuff. The shock I would NOT go with the 6.0kg because it will be to stiff and you will not be able to set the proper sag. Look for a 5.8kg progressive or two stage spring....they're out there.

You will have to add rebound on both the forks and the shock, but it will work good.

good luck

Thanks for the info.

Where might I begin my search for the progressive shock spring?

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Cool....what did you do to the rear?

I'm still stock in the back... after my race sag adjustments and static sag measurements came out alright I decided to try to run the original spring and I found my only real complaint was a bit of unbalance.. (soft in front).... once the .49 fork springs were installed I liked the balance... oh and as an aside... I went to great lengths to find out the true rear shock spring rate.. turn out its 5.6k.. not 5.5 as listed by racetech... not a huge deal, but may be important to some.. oh and I range from 210 to 230 depending on the season. When I'm heavier and slower in the winter, I tend to like the same springs as when I'm lighter and faster in august... wierd, but works for me

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I'm still stock in the back... after my race sag adjustments and static sag measurements came out alright I decided to try to run the original spring

You can't really achieve optimal race sag and static sag unless your spring rate

is correct for your weight, right? It is pretty much one or the other??? Please

correct me if I'm wrong.

I'm wondering this because I had to crank my spring down tight in order to set

my race sag. I'll bet my static sag is all F-ed up and there is no way to fix it w/o

ruining the race sag. Right?:):banghead:

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here is an interesting article trying to explain it

http://www.tootechracing.com/Static%20Sag%20Suspension%20Tip.htm

but yes, the underlying theory is:if your spring rate is too soft, you'll have to crank the preload so far to get your race sag right that your static sag will be too little... and the opposite ... when your spring is too stiff for you, you'll end up backing off the adjuster so far, your static sag will be too much..

Ideally, after your race sag (with rider)is properly set at 100mm.(4in).. your unladen(static) sag will still be reasonable.. (.75 - 1.5in)

everything can be modified for personal preference, of course.

The suspension settings I like (high and tight) make my friends NUTS!!!

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I dont like the idea of running a really stiff shock spring. Your sag numbers will be off, and the bike will not squat thus giving crappy hook up. Also you're rebound will have to be nearly maxed out, which will screw with other things.

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I dont like the idea of running a really stiff shock spring. Your sag numbers will be off, and the bike will not squat thus giving crappy hook up. Also you're rebound will have to be nearly maxed out, which will screw with other things.

What numbers? If your spring is stiff because you are heavier than the average

rider then your race sag will be right on the money...but your static sag will be

off. Who cares about looks?

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MX Tech sales true progressive springs, not sure of the spring manufacture, but you can't go wrong the MX Tech.

It will be the best money you ever spent on your bike.

The ride will be so much easier.

good luck

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