Jump to content
Sign in to follow this  

Rear spring too heavy?

Recommended Posts

I think it's my anal-retentive side that makes me such a natural when it comes to over-dissecting a simple thing such as rear sag. However, I've got a dilemma and a few questions. :banghead:

I checked my rear race sag last night with a full tank of gas for the first time, in street clothes, standing (for consistency) on the pegs. It came out to 105mm - perfect. Then, I checked the free sag it was around 42-43mm. Now, at almost 220lbs in street clothes (just weighed myself), it's hard to believe that the stock rear spring may be too stiff, but that's what the numbers are telling me. Is that possible?

So here are my questions:

Do you guys check your rear sag with the tank full, 1/2 empty or don't care? It would seem like it should be full for consistency's sake; then, if it's muddy, you could say that the burnoff of gas (9lbs per gallon) would be (over-)compensated for by the weight of the mud.

I know that there has been some discussion as to spring accuracy, but where could I get my shock spring tested to find out what the rate really is? I've called two local shops and neither has a spring rate tester. I don't feel like shipping off the spring to have it tested and not being able to ride in this great fall weather. Also, I'm afraid to order another spring (lighter?) since I don't know what I'm dealing with now.

Do you guys set sag rates compensating for mud or gas expenditure?

What do you all think? Am I missing something here? Just making a mountain out of a molehill? As always, your help is greatly appreciated. - Bri

Share this post


Link to post
Share on other sites

wow that is a lot of thinking my head would hurt. I never check it. Have it set then forget

Share this post


Link to post
Share on other sites

Id bet youve got a loose shock bearing thats dropping a tad and giving you a funky free sag number. It wouldnt take a bunch either because of the mechanical advantage the swing arm has over the shock & linkage. Id be super surprised if at 220 the stock spring is too stiff.

Share this post


Link to post
Share on other sites

I measure my sag with a full tank of gas, all riding gear on, this includes camel pack with any tools. This give a true running sag measurements, I figure as the fuel is being consumed, mud is being added to the bike, I'm sure you need a 5.7/5.8kg spring.

Share this post


Link to post
Share on other sites
I checked my rear race sag last night with a full tank of gas for the first time, in street clothes, standing (for consistency) on the pegs. It came out to 105mm - perfect. Then, I checked the free sag it was around 42-43mm. - Bri

You're not alone. The sag when my '05 CRF250X was brand new was 2.0" inches.

https://thumpertalk.com/forum/showthread.php?t=296410

Share this post


Link to post
Share on other sites

I am about 185 lbs. without gear, and with the stock 5.5 kg spring, I was way out of the acceptable free sag range. Now, with a 5.3kg spring, and full riding gear, I am right on target as far as free sag/ race sag comparison go. The bike is much more plush in the rear and corners better. I would think you would be about right with the stock spring, though, at your weight.

Share this post


Link to post
Share on other sites

I am 220lbs. and check sag with street clothes and a full tank of gas with a 100mm setting. I went to a 5.7 spring and had the shock revalved. The static sag is one inch. Nice and plush.

Share this post


Link to post
Share on other sites

I've been told I was completely wrong when I stated this before but I'll state it again.

My Pro-Action suspension guy said the stock springs on my 450 are made for a guy that weighs approximately 215#s and were way to stiff for my 183# ass. I was reluctant. I told him that Motocross Action always says these 450s need a stiffer fork spring. He politely stated that they are idiots and that they are attempting to compensate for very poor valving.

So I handed my suspension too him and he put softer springs in it and revalved it. He saw me ride and said he was setting it up for a "Novice racer." Basically I jump all the big jumps and stuff but I'm not terribly fast but not real slow either. I also OFTEN overjump or come up short.

Well, he was 1,000,000% right. The bike is soooo much better now. The suspension is much plusher yet even when I screw up it just sucks it all up. Plus my severe arm pump problems are completely gone w/ the new suspension.

So yah, your rear spring is too heavy.

Share this post


Link to post
Share on other sites

I disagree with all of the above. The CRF/Showa setup should have much more free sag then the typical 3/4 to 1 inch. I am a reasonably fast 195 lb B rider and have gone up to a 5.7 rear spring and find it more plush than the stock spring. I expressed the same concern to Factory Connection before the did my first 05 450 and they said ignore the free sag measurement. I just had my other 450 done by RRP here in NJ and he is on the same page. The stock fork springs are way too soft too.

Share this post


Link to post
Share on other sites
I disagree with all of the above. The CRF/Showa setup should have much more free sag then the typical 3/4 to 1 inch.

I wonder what the reason behind the, " much more free sag " is all about?You'll have to admit, it's not a common thing - sag being too far away from 1"

After adjusting mine from 2" (that was stock) sag to about 1 1/8", which put my race sag at about 3.8" (170 lbs with gear), I find no handling issues at all.

In fact, I'm very pleased with it.

Share this post


Link to post
Share on other sites
I measure my sag with a full tank of gas, all riding gear on, this includes camel pack with any tools. This give a true running sag measurements, I figure as the fuel is being consumed, mud is being added to the bike, I'm sure you need a 5.7/5.8kg spring.

That's the way to do it, all right - set your sag AS YOU WOULD RIDE.

Share this post


Link to post
Share on other sites
You're not alone. The sag when my '05 CRF250X was brand new was 2.0" inches.

https://thumpertalk.com/forum/showthread.php?t=296410

I discovered the problem...

The CRF250X manual says the rear shock spring should measure 10.2".

I never looked to see what the manual said about the stock spring length when I noticed the sag was 2". Like I said before, this was when the bike was brand new.

I adjusted the sag right at 1" before I even rode it. This had me pre-load the shock spring at least 1/2".

I just measured the rear spring as per the Manuals instructions, and it's right at 10".

Conclusion; Obviously my shock spring was never adjusted correctly at either the factory or dealer prep. I'm not sure where that process goes down, probably the factory.

Share this post


Link to post
Share on other sites
I wonder what the reason behind the, " much more free sag " is all about?You'll have to admit, it's not a common thing - sag being too far away from 1"

Well here is the deal.

If you set your sag at about 4" and your free sag is less than 1" you have a too soft rear spring. You had to tighten it up so much to get your sag correct that your free sag diminishes to less than 1".

If on the other hand you set your sag at about 4" and your free sag is more than 1" you have too stiff of a spring. You had to loosen it up so much to get your sag correct that your free sag becomes excessive.

So (I feel) that you guys that have 2" of free sag while having 4" of sag have WAY TO STIFF of rear springs. And to be honest, this should not really be up for discussion w/ any competent suspension tuner. They should know this.

Share this post


Link to post
Share on other sites
I think it's my anal-retentive side that makes me such a natural when it comes to over-dissecting a simple thing such as rear sag. However, I've got a dilemma and a few questions. :banghead:

I checked my rear race sag last night with a full tank of gas for the first time, in street clothes, standing (for consistency) on the pegs. It came out to 105mm - perfect. Then, I checked the free sag it was around 42-43mm. Now, at almost 220lbs in street clothes (just weighed myself), it's hard to believe that the stock rear spring may be too stiff, but that's what the numbers are telling me. Is that possible?

So here are my questions:

Do you guys check your rear sag with the tank full, 1/2 empty or don't care? It would seem like it should be full for consistency's sake; then, if it's muddy, you could say that the burnoff of gas (9lbs per gallon) would be (over-)compensated for by the weight of the mud.

I know that there has been some discussion as to spring accuracy, but where could I get my shock spring tested to find out what the rate really is? I've called two local shops and neither has a spring rate tester. I don't feel like shipping off the spring to have it tested and not being able to ride in this great fall weather. Also, I'm afraid to order another spring (lighter?) since I don't know what I'm dealing with now.

Do you guys set sag rates compensating for mud or gas expenditure?

What do you all think? Am I missing something here? Just making a mountain out of a molehill? As always, your help is greatly appreciated. - Bri

Your not alone as I also have a tendency of overexamining things, sometimes to a point where all the variables make reality Gray. :busted::busted::crazy::crazy:🤣🤣🤣🤣🤣:busted:

I too came to the same issue with my sag. My X is sprung for a much heaver rider than myself, I reduced the rate to a 5.0 and set my sag to 100 mm. My free sag was way off the recommended tolerance. I think it was like 2.4" [+/-] I was calling everyone who would listen and I really couldn't get an answer that satisfied my curiosity. I did get answers though. :banghead:

My deduction is this; Free sag is just a general reference and really dosenot effect the way the bike preforms as compared to the race sag. Race sag is an actual result of your weight on your bike with your spring and it's adjustment. In otherwords don't worry about free sag set your race sag and ride it, don't even measure your free sag at all. :busted:

On my bike for me to get both within "tolerance" my spring would be so soft that it would nearly bottom under my own weight. I can't give you an analytical rational :busted: but that's what I learned and my bike handels and rides very well, as far as the rear suspension is concerned.

Share this post


Link to post
Share on other sites
Your not alone as I also have a tendency of overexamining things, sometimes to a point where all the variables make reality Gray. :banghead::busted::busted::busted::crazy::crazy:🤣🤣🤣🤣

I too came to the same issue with my sag. My X is sprung for a much heaver rider than myself, I reduced the rate to a 5.0 and set my sag to 100 mm. My free sag was way off the recommended tolerance. I think it was like 2.4" [+/-] I was calling everyone who would listen and I really couldn't get an answer that satisfied my curiosity. I did get answers though. :banghead:

My deduction is this; Free sag is just a general reference and really dosenot effect the way the bike preforms as compared to the race sag. Race sag is an actual result of your weight on your bike with your spring and it's adjustment. In otherwords don't worry about free sag set your race sag and ride it, don't even measure your free sag at all. :busted:

On my bike for me to get both within "tolerance" my spring would be so soft that it would nearly bottom under my own weight. I can't give you an analytical rational :busted: but that's what I learned and my bike handels and rides very well, as far as the rear suspension is concerned.

Naw man, no offense, but that's just wrong. 2 1/2" free sag is WAY out of the ballpark by any measure.

You're giving up a full 1 1/2" of your suspensions travel while also changing the entire handling characteristics of your bike.

The effects of a setup as you discribed should be- Your bike is stable as hell on straights but doesn't turn worth a flip. And probably get a lot of front end push in turns.

Share this post


Link to post
Share on other sites

Wow, I thought that my post was dead! I went back and forth with ShawnMC about this for a few days after my original post. It's cool to read such great input.

Here's what else I've found out:

I called Factory Connection and explained the problem. Steve told me (I think that was his name) that the CRF's handle better with between 104 and 108mm's of sag. Strange, eh? Weirder yet, I should only be looking for a free sag of between 35-45 mm (not the manual's 10-25mm. So at 104/42, I'm good to go.

Steve also explained that the springs effective rate is not always consistent. Essentially (and, no I don't understand it) the springs are lighter in the initial phases of compression, and then firm up as the compress more - a progressive rate spring for lack of a better term. (ie, Kawi fork springs in the 98,99 era...).

However, he also said that at my weight I should not be getting those readings. Long story short, the springs are perfect for me but far heavier than a typical stock spring. I guess I'm lucky I like hot wings and beer. :banghead:

It would seem to me that the progressive nature of the spring would really throw off the readings between static (or free) sag, and race sag. But what the hell do I know?

As an added note, I do have the .49's in the front, so that would, in theory, put more weight on the rear as well.

So, that's where I'm at. Fat, old, and I just saved $100 on a new shock spring!

Share this post


Link to post
Share on other sites
Naw man, no offense, but that's just wrong. 2 1/2" free sag is WAY out of the ballpark by any measure.

You're giving up a full 1 1/2" of your suspensions travel while also changing the entire handling characteristics of your bike.

The effects of a setup as you discribed should be- Your bike is stable as hell on straights but doesn't turn worth a flip. And probably get a lot of front end push in turns.

What you say makes sense. But dose my having more than 35mm of free sag reduce my travel? I wasn't aware that that was a side effect. :banghead:

When I purchased the spring from Factory Connection they first sold me a 5.1 and than when I told them of my readings they exchanged the spring to a 5.0. Honestly there was a negligible difference, maybe 5mm on my free sag.

FC responce was that its OK on this bike to see that much sag and I really only needed to concentrate on the rider sag. So I believed what they told me.🤣

Based upon what you said, I am lead to believe that FC is wrong and I always wondered as their tech article on free / race sag said 25-35 mm of free sag. Just to confirm thiswhat you said about how I preserve to bike to Handel is true, it dose track very well and front end is poor. 🤣

Conversely I had recently gone ridden with a seasoned and fast rider who rode a KTM 300 2 strk., he was really impressed with the way my bike felt. :banghead:

Share this post


Link to post
Share on other sites
Wow, I thought that my post was dead! I went back and forth with ShawnMC about this for a few days after my original post. It's cool to read such great input.

Here's what else I've found out:

I called Factory Connection and explained the problem. Steve told me (I think that was his name) that the CRF's handle better with between 104 and 108mm's of sag. Strange, eh? Weirder yet, I should only be looking for a free sag of between 35-45 mm (not the manual's 10-25mm. So at 104/42, I'm good to go.

Steve also explained that the springs effective rate is not always consistent. Essentially (and, no I don't understand it) the springs are lighter in the initial phases of compression, and then firm up as the compress more - a progressive rate spring for lack of a better term. (ie, Kawi fork springs in the 98,99 era...).

However, he also said that at my weight I should not be getting those readings. Long story short, the springs are perfect for me but far heavier than a typical stock spring. I guess I'm lucky I like hot wings and beer. :banghead:

It would seem to me that the progressive nature of the spring would really throw off the readings between static (or free) sag, and race sag. But what the hell do I know?

As an added note, I do have the .49's in the front, so that would, in theory, put more weight on the rear as well.

So, that's where I'm at. Fat, old, and I just saved $100 on a new shock spring!

So how do you feel about how your bike handles with those readings? Dose the front push more than before?

Share this post


Link to post
Share on other sites
What you say makes sense. But dose my having more than 35mm of free sag reduce my travel? I wasn't aware that that was a side effect. :banghead:

When I purchased the spring from Factory Connection they first sold me a 5.1 and than when I told them of my readings they exchanged the spring to a 5.0. Honestly there was a negligible difference, maybe 5mm on my free sag.

FC responce was that its OK on this bike to see that much sag and I really only needed to concentrate on the rider sag. So I believed what they told me.🤣

Based upon what you said, I am lead to believe that FC is wrong and I always wondered as their tech article on free / race sag said 25-35 mm of free sag. Just to confirm thiswhat you said about how I preserve to bike to Handel is true, it dose track very well and front end is poor. 🤣

Conversely I had recently gone ridden with a seasoned and fast rider who rode a KTM 300 2 strk., he was really impressed with the way my bike felt. :banghead:

If I may ask, how much do you weight? I'm thinking that the 5.0 spring should be great for most your average riders.

Also, with your bike on a stand, what's the length of your shock spring? Your manual should show you how to measure it. But of course, it's basically from bottom adjusting nut to top bottom spanner.

My manual (CRF250X) says the optional 5.0 spring should measure 9.7 inches.

I got a good measurement with some help. It was kinda hard trying to measure it by myself and get a good reading. Your manual should differ some, but not a whole lot.

Remember, ADDING pre-load (shorten) to the shock spring will decrease the free-sag distance and decrease the race-sag also. But because of the leverage ratio, the distance will effect the free-sag more than the race sag.

Example: On my bike, I cranked about 1/2" more pre-load on my spring. This changed the free-sag 1" and the race sag less than, but very close to 1/2".

I'm very close to 1" sag 4" race sag and my CRF250X handles very, very well.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...