Any Suspension Gurus That Can Help?

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10/13/2021 7:46 AM

Have contacted a few of the large suspension companies and have gotten some different numbers and wondering if anyone on here can help. Looking to retain stock valving and replace springs first.

2019 RMZ250
Novice Vet Rider
200lbs
All motocross riding

Any tips or input on what springs I need?
TIA!

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10/13/2021 8:28 AM

Measure sag, and see what your numbers are. Static sag after race (105-108mm) will let you know if you need a new shock spring. Should be in 35-45mm range, but 30mm at least and 50mm at most. At novice with stock, fork should work.

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Livin' the dream, two wheels at a time!

10/13/2021 8:38 AM

m21racing wrote:

Measure sag, and see what your numbers are. Static sag after race (105-108mm) will let you know if you need a new shock ...more

Thanks. According to Race Tech calculator they want me two rates softer in front, stock rear. But is this based on their valving not stock?

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10/13/2021 8:41 AM

I would see how the chassis is balanced with stock. Use fork tube height as well. When you check sag, see that front/rear move together. Start there before you buy springs.

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Livin' the dream, two wheels at a time!

10/13/2021 8:48 AM

m21racing wrote:

I would see how the chassis is balanced with stock. Use fork tube height as well. When you check sag, see that front/rear move ...more

Will do! The front seems very stiff, like rip hands off the bars on landings stiff. If things still feel odd can I do a spring rate or 2 down in the front even if it isn't what certain companies are saying should work? Or am I going to throw off the whole balance of the bike?

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10/13/2021 9:09 AM

You can do that. Try 10c and 14r in front with forks on lower line, raised in trees to start. Check with other companies that do a lot of showa stuff like pc and fc.

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Livin' the dream, two wheels at a time!

10/13/2021 9:18 AM

m21racing wrote:

You can do that. Try 10c and 14r in front with forks on lower line, raised in trees to start. Check with other companies that ...more

These come with KYB AOS forks stock. I checked with Enzo and they recommended stock springs in front and one rate stiffer in rear. Just felt stiff already and couldn't hardly believe I should go stiffer still.

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10/13/2021 9:32 AM

m21racing wrote:

You can do that. Try 10c and 14r in front with forks on lower line, raised in trees to start. Check with other companies that ...more

jamiechapman418 wrote:

These come with KYB AOS forks stock. I checked with Enzo and they recommended stock springs in front and one rate stiffer in ...more

Try lowering your oil height in your forks. At 200 I wouldn’t think you would need to go softer. I’m 175 and went up a spring rate in my forks and it’s plusher than stock now. I did have mine revolved though.

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10/13/2021 10:25 AM
Edited Date/Time: 10/13/2021 10:26 AM

^agreed on the oil height. I weigh 145 and Enzo nailed my spring rates. Also recommended taking some oil out of forks and I can say that helped. With stock valving and stock oil volume my bike would have felt like the James Stewart setup. With stock springs it would have been full on sx setup grin

-20 or -30ml of oil in the forks would be a worthwhile test.

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10/13/2021 10:45 AM

seth505 wrote:

^agreed on the oil height. I weigh 145 and Enzo nailed my spring rates. Also recommended taking some oil out of forks and I ...more

At 145 I'm sure you went much lighter on fork spring rate. What did you end up with for shock spring?

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10/13/2021 10:59 AM

seth505 wrote:

^agreed on the oil height. I weigh 145 and Enzo nailed my spring rates. Also recommended taking some oil out of forks and I ...more

jamiechapman418 wrote:

At 145 I'm sure you went much lighter on fork spring rate. What did you end up with for shock spring?

Yup, .46 fork springs and 4.7 shock spring. If I go too far on sag then I get bad rubbing on rear fender so I'm sure I could have gotten away with next heavier rear spring but it would have been really hard to get over 100mm sag if I did.

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10/13/2021 11:13 AM

seth505 wrote:

^agreed on the oil height. I weigh 145 and Enzo nailed my spring rates. Also recommended taking some oil out of forks and I ...more

jamiechapman418 wrote:

At 145 I'm sure you went much lighter on fork spring rate. What did you end up with for shock spring?

seth505 wrote:

Yup, .46 fork springs and 4.7 shock spring. If I go too far on sag then I get bad rubbing on rear fender so I'm sure I could ...more

Happen to know how many cc's are in each fork leg?

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10/13/2021 11:17 AM

jamiechapman418 wrote:

At 145 I'm sure you went much lighter on fork spring rate. What did you end up with for shock spring?

seth505 wrote:

Yup, .46 fork springs and 4.7 shock spring. If I go too far on sag then I get bad rubbing on rear fender so I'm sure I could ...more

jamiechapman418 wrote:

Happen to know how many cc's are in each fork leg?

I'm currently running 340ml rather than the stock 360ml. I'm a few clicks out on Compression and one click out extra on rebound (C13 out R14 out rather than stock, C11 out R13 out)

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10/13/2021 11:55 AM

An interesting thing to note about forks feeling too stiff: often times, you are really describing "too harsh." How?
If your spring rate is too soft, your weight will settle the suspension so it is riding lower in the travel, right where the stiffness ramps up in the midrange damping. On small bumps, the wheels won't be moving very much, making the forks feel stiff. Also, you may be tempted to run your clickers in a softer setting, which will allow you to blow right through the travel on hard landings.

With stiffer springs, you would be higher in the travel and have more of the initial plushness to deal with on small bumps, plus the extra travel needed to handle big hits. This may be why Enzo suggested you stay stock up front and go stiffer in the rear. At your weight, I think that makes sense, because 250Fs are often set up for 150-lb. riders. I would probably not go with softer springs up front unless Suzuki was waaaaaaaaaaaaaaaaaaay off with their spring rates. (Historically, they are too soft, if so.)

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Braaapin' aint easy.

10/13/2021 12:08 PM

Falcon wrote:

An interesting thing to note about forks feeling too stiff: often times, you are really describing "too harsh." How?
If your ...more

I believe that was the major complaint with these bikes that they were way oversprung for the average 250f kid. For me, that's fine. Just ya feels harsh. I did put on gear over lunch break with my buddy and double checked race sag. I'm at 105mm. Static sag is at 35mm. That would lead me to think rear is probably ok correct? I guess I will have to try taking 30ml out of each leg and see what happens.

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10/13/2021 12:56 PM

So am I accurate on that the Race Tech spring rate calculator is based on using their valving and not stock valving?

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10/13/2021 1:29 PM

Yes, your rear spring seems about right at 35mm static and 105mm dynamic sag.

Your spring rate in the forks should be independent of the valving, but of course in the real world we know nothing is completely independent. If I were you, I'd try the oil level adjustments and see what you get. Try the lower level, but also go higher and see what that does. Remember that oil level will only affect the last 1/3rd or so of your travel with any kind of measurable difference. You are increasing or decreasing the size of the "air spring" in your fork with an oil level change, and the spring rate ramps up exponentially with air. Less oil/more air = less severe ramp up, more linear. More oil/less air = more dramatic ramp up and more progressive.

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Braaapin' aint easy.

10/13/2021 2:21 PM

Correct me if I’m wrong. I think they recommend 4-8mm of preload on the spring instead of going off free sag. I run my sag at 108 on my RMZ 450 and there isn’t much preload on the spring.

My suspension guy went quite a bit stiffer on both ends, when I got it back and sat on it I thought it was going to be to stiff.

It’s much plusher now, but it also has way better bottoming resistance. It rides higher in the stroke like Falcon was saying.

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10/13/2021 4:19 PM

At 200lbs, I can't imagine needing softer springs.

Can you get the manual and see what it comes with? Like others have said, spring rate and valving should be somewhat independent. The springs setup the chassis in the correct ride height height geometry.... of course, you can go up or down slightly on spring to tune, but I can't imaging good valving making up for bad spring rates and vice versa.

It's well worth reading that race tech suspension Bible..... springs effect position of travel and valving effects rate of travel.

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10/13/2021 4:22 PM

Sandusky26 wrote:

Correct me if I’m wrong. I think they recommend 4-8mm of preload on the spring instead of going off free sag. I run my sag at ...more

The preload thing was more a ktm thing with their funky linkage.

Free and rider sag should still work for rhe rmz I would think

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10/13/2021 4:36 PM

Bruce372 wrote:

At 200lbs, I can't imagine needing softer springs.

Can you get the manual and see what it comes with? Like others have said, ...more

For some reason I do not see listed in the service manual the stock spring rates. I do believe though the front is .5kg and rear is 5.6kg

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10/13/2021 4:59 PM

Sandusky26 wrote:

Correct me if I’m wrong. I think they recommend 4-8mm of preload on the spring instead of going off free sag. I run my sag at ...more

Thats a good range of preload, but the factory springs tend to have a soft initial rate due to coils not touching. So the range is a bit higher like 6 to 10mm of preload, with good staic numbers. To me, static is something to pay attention to with stock more than when springs are changed drastically in either direction.

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Livin' the dream, two wheels at a time!

10/13/2021 6:07 PM

Race Techs spring rate calculator is too soft. They would have me at .88kg on there calculator and I’m running a .92kg in my ktm 350 with there spring conversion. Different bike I know but I think it applies across the board.

I even had a RT dealer valve it for me and he said their calculator is too soft. He also said the gold valves were a waste of money, most stock pistons are pretty good these days. Pretty cool cause he saved me a bunch of loot.

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10/13/2021 7:20 PM

jamiechapman418 wrote:

For some reason I do not see listed in the service manual the stock spring rates. I do believe though the front is .5kg and ...more

Yes, those are correct stock rates.

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10/14/2021 3:09 AM

Bruce372 wrote:

At 200lbs, I can't imagine needing softer springs.

Can you get the manual and see what it comes with? Like others have said, ...more

jamiechapman418 wrote:

For some reason I do not see listed in the service manual the stock spring rates. I do believe though the front is .5kg and ...more

seth505 wrote:

Yes, those are correct stock rates.

Damn, that’s the same stock spring rates as my 450.

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10/27/2021 1:03 PM

Little update if anyone can provide more insight. I drained fluid and went to 340ml of fluid with stock 5.0 spring rate on forks. On big stuff if I nail the downside landing decent it feels pretty good. Firm, but not the worst. On little chop its pretty harsh, braking bumps especially. Feels like the fork isn't moving at all. Also, on flat landings like after a ski jump or if I OJ something I feel like (and did happen once) it's going to blow my hands off the bars. Same on some steeper jump faces. Particularly when right out of a corner when I am hard on the throttle.

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10/27/2021 1:45 PM

How many hours since the last service? Fluid and bushings fresh? Forks aligned properly?

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10/27/2021 1:58 PM

walent215 wrote:

How many hours since the last service? Fluid and bushings fresh? Forks aligned properly?

12 hrs. Forks are aligned properly.

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10/27/2021 2:17 PM

walent215 wrote:

How many hours since the last service? Fluid and bushings fresh? Forks aligned properly?

jamiechapman418 wrote:

12 hrs. Forks are aligned properly.

Are you sure that the fork is better with the lower fluid volume?

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10/27/2021 2:36 PM

walent215 wrote:

How many hours since the last service? Fluid and bushings fresh? Forks aligned properly?

jamiechapman418 wrote:

12 hrs. Forks are aligned properly.

try some .48s and 5.4 ...you say you want to keep stock valving so aside from clicker changes/sag/ oil weight and volume adjustments, thats your next step. if they are too soft you can always put one of your stock springs back in and essentially achieve .49 rate between the two...

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