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Stiffer springs = plusher ride?

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Can anyone explain why my buddy’s bike’s suspension feels better to me than my bike’s does, when his bike is sprung and valved for his body weight (around 220) and I only weigh 160? We both had our bikes sprung and valved by the same reputable suspension company, according to our weight. His bike is an ’09 KX450, mine is an ’07 RMZ450. I realize they are different bikes with different suspension (KYB vs Showa), different frame geometry, and probably different steering head angles and wheelbases, but it still seems like if his bike is sprung for his weight at 220, with .49 front springs and (if I remember right) a 5.5 shock spring, shouldn’t it feel extremely stiff to me? It doesn’t, it feels very plush, smooth and controlled. I loved it. His bike is the reason I spent the money to get my bike’s suspension resprung and revalved, hoping it would feel as good as his, but it doesn’t. While it was an improvement over stock, it is nowhere near as plush and controlled over the braking bumps going into corners, the acceleration chop coming out of corners, and even in the whoops. I would call mine harsh compared to his. My springs are .44 in the front and 5.1 on the shock. It doesn’t make sense to me, why his feels smooth and composed over the rough stuff, and mine feels very busy and transmitting much more impact to my arms through the bars. I have adjusted the clickers all over the place, made sure the sag was correct, adjusted fork tube height, but nothing smoothed it out much. Again, I know they are different bikes, but its still springs holding the bikes up, and oil going past shims and valving, I would think if one can feel so good, the other should at least get close. And yes, my bike does feel better than when it was stock, so I don’t consider it money wasted, but it’s not near as plush and good as my buddy’s and I feel like it should be at least close. His bike even feels better launching and landing from jumps, very smooth and confidence inspiring compared to mine. If anybody can give me some ideas as to why his stiffer sprung bike feels plusher and smoother than my bike, I would love to hear it. I feel like that info is telling me something (stiffer = plusher?) but I’m not knowledgeable enough about suspension to figure it out. I’m even considering those expensive flexx bars or even sub tank/air cells, but I really don’t want to go down that path if I can help it. But now that I know how good a suspension can feel (and improve my riding), it’s bothering me not getting it on my bike. Thanks in advance for any insight, response, or help.

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Unfortunately, it's not likely the suspension setup. It's the bike.

The frame has a lot to do with how the suspension feels. Flex characteristics are engineered into the frame...and the Suzuki 450 has a ridgid feel. If you love the feel of you buddies Kawi, you may want to get a Kawi rather than chase the suspension on your Suzuki. I wish I could make every bike feel like a YZ125.

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the 07 had a vary confused shim setup , it maybe possible to improve it further with different valving ( not knowing what the tuner has done so far) also the springs look a little soft I would look at 0.45 or 0.46 what are your sag front and rear ? 450 need stiff springs to control fork dive and acceleration squat

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Can anyone explain why my buddy’s bike’s suspension feels better to me than my bike’s does, when his bike is sprung and valved for his body weight (around 220) and I only weigh 160? We both had our bikes sprung and valved by the same reputable suspension company, according to our weight. His bike is an ’09 KX450, mine is an ’07 RMZ450. I realize they are different bikes with different suspension (KYB vs Showa), different frame geometry, and probably different steering head angles and wheelbases, but it still seems like if his bike is sprung for his weight at 220, with .49 front springs and (if I remember right) a 5.5 shock spring, shouldn’t it feel extremely stiff to me? It doesn’t, it feels very plush, smooth and controlled. I loved it. His bike is the reason I spent the money to get my bike’s suspension resprung and revalved, hoping it would feel as good as his, but it doesn’t. While it was an improvement over stock, it is nowhere near as plush and controlled over the braking bumps going into corners, the acceleration chop coming out of corners, and even in the whoops. I would call mine harsh compared to his. My springs are .44 in the front and 5.1 on the shock. It doesn’t make sense to me, why his feels smooth and composed over the rough stuff, and mine feels very busy and transmitting much more impact to my arms through the bars. I have adjusted the clickers all over the place, made sure the sag was correct, adjusted fork tube height, but nothing smoothed it out much. Again, I know they are different bikes, but its still springs holding the bikes up, and oil going past shims and valving, I would think if one can feel so good, the other should at least get close. And yes, my bike does feel better than when it was stock, so I don’t consider it money wasted, but it’s not near as plush and good as my buddy’s and I feel like it should be at least close. His bike even feels better launching and landing from jumps, very smooth and confidence inspiring compared to mine. If anybody can give me some ideas as to why his stiffer sprung bike feels plusher and smoother than my bike, I would love to hear it. I feel like that info is telling me something (stiffer = plusher?) but I’m not knowledgeable enough about suspension to figure it out. I’m even considering those expensive flexx bars or even sub tank/air cells, but I really don’t want to go down that path if I can help it. But now that I know how good a suspension can feel (and improve my riding), it’s bothering me not getting it on my bike. Thanks in advance for any insight, response, or help.

ive heard this from others before and it seems to ring true in our experience as well.

my friend is 165 with an 01 cr250, stock springs. sag set. im 245 with an 00 cr250 0.49 in front and 6.0kg spring in back, so other than springs the bikes are almost identical less the slight suspension settings honda did from 00 to 01. my buddy jumped on my bike and he said that my bike with the heavy springs soaks up the chop MUCH better than his bike. no clicker changes made his bike feel plush. neither has been revalved yet, just spring changes and clicker settings.

Edited by mynewcr250

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..... nowhere near as plush and controlled over the braking bumps going into corners, the acceleration chop coming out of corners, and even in the whoops. I would call mine harsh compared to his. ..... mine feels very busy and transmitting much more impact to my arms through the bars. I have adjusted the clickers all over the place, made sure the sag was correct, adjusted fork tube height, but nothing smoothed it out much. .....but it’s not near as plush and good as my buddy’s and I feel like it should be at least close. .....

What make and weight of fluid are you using in the front fork?

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the springs in the rmz are too light. in my opinion. you could try .47's/5.3 without knowing the valving.

i serviced a bike for a rider that had rg3 do his stuff. 05 cr250. he was 160. they had the smart valve in the forks with 1.6 pressure springs, and .49 main. the shock was a 5.3

it looked like too much spring at first. the forks had 405cc of fluid. but, he liked it.

old desert tuners have utilized the heavy spring/light valving approach forever.

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Thanks everyone for all the responses. The fork oil is 5wt maxima. There is a 385 written on the fork tube sticker, I'm not sure if that means there is 385cc of oil in the tube? The suspension tuner set my sag while I sat on the bike, he told me it was 100mm race sag and 30mm static, but I haven't checked it myself. I'm not sure what the fork sag is, I've never checked that before. I still have my original springs, they are .47 for the forks and 5.5 for the shock. I'm half tempted to put them back in with the new valving just to see what happens. Heck, maybe I should go back to the tuner and tell him to set it up for a 220lb rider. In my admittedly limited knowledge of suspension workings, I'm wondering if the soft springs don't hold the bike high enough up in the stroke, or let it blast through the stroke too fast and get into the harder spring compression/valving to fast, even on smaller chop like braking bumps. I thought about lowering the oil height or even lighter weight oil, but I've read the light weight oils will make the clickers much less useful. Thanks again for all the help.

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it's because it's riding farther up in the stroke, all you gotta do is throw in some stiffer springs, cheap and very easy to test

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Thanks everyone for all the responses. The fork oil is 5wt maxima. There is a 385 written on the fork tube sticker, I'm not sure if that means there is 385cc of oil in the tube? The suspension tuner set my sag while I sat on the bike, he told me it was 100mm race sag and 30mm static, but I haven't checked it myself. I'm not sure what the fork sag is, I've never checked that before. I still have my original springs, they are .47 for the forks and 5.5 for the shock. I'm half tempted to put them back in with the new valving just to see what happens. Heck, maybe I should go back to the tuner and tell him to set it up for a 220lb rider. In my admittedly limited knowledge of suspension workings, I'm wondering if the soft springs don't hold the bike high enough up in the stroke, or let it blast through the stroke too fast and get into the harder spring compression/valving to fast, even on smaller chop like braking bumps. I thought about lowering the oil height or even lighter weight oil, but I've read the light weight oils will make the clickers much less useful. Thanks again for all the help.

The poster appears to have just about perfect sag numbers. I thought this was the starting point "HolyGrail" and then work on the valving. If heavier springs are used will not the static sag be thrown off? Is this not important anymore starting with today? Is there an assumption being made that the tuner measured wrong? I thought assumptions were very, very bad. I am even more confused.

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I know when i ride my friends 2011 KTM 450SXF , it feels like a Cadillac compared to my 02 R (re-valved) , mine is decent now since i started messing with the re-valve (thanks to the Dogger), but its nothing like my friends bike when i ride it , its closer , but his just floats over everything with me on it , my friend weighs 260+without gear , the springs are 0.54 fork and 6.2 shock , i weigh 204 +/- ,*usually +* without gear , my bike has 0.49 fork - 5.5*stock* shock **about where it should be for my weight**, and is better than it was with stock 0.47 springs , i have considered going this route as well and go to 0.50 / 5.7 and see if i like it better , i am up in the air about this , it could just be his bike is very soft valving (it has been re-valved for his speed style **mid to upper -B rider**) and stiff springs , i really dont know how to explain it except , i can ride his bike more comfortably than mine , it should buck me off with the springs it has , and i hate getting off it , its so plush

Edited by 450XJimDirt

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depending on what the pressure springs are, the stiffer mains will help this condition. if the forks have more than 375cc of fluid, and they're still harsh compared to a ktm, you should go up in spring, and use less fluid. too much fluid and a lighter spring will cause a harsh condition. this is just me, but unless you're jumping; mx, you don't need as much fluid as some suggest.

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yhgeorge, trust me, I am confused as well. There is no assumption that the tuner did anything "wrong". I didn't check what the sag was when I rode my buddy's bike, but I'm sure if I had, the numbers would have been all wrong according to conventional wisdom. All I can tell you is the suspension felt great when I rode it. I just can't figure out why it felt so good.

450xjim, I feel the same way when I ride my buddy's bike, I hate to give it back. I am more comfortable on his and feel like I ride better, and it's all from the suspension. I could ride his longer without getting tired and without arm pump. According to conventional suspension wisdom, his bike should be all wrong for my weight and beat me up, but instead it feels great. I sort of feel bummed out getting back on my bike after riding his.

gd170, I am jumping, I ride mx exclusively. But it is the sharp square edged braking bumps, chop and whoops that are giving me the most trouble. My forks have 385cc in them.

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i would put back in the 47's in the forks, with 375cc of oil, and see how that does.

you should get good sag numbers with a 5.3 shock spring at 160lbs.

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Found this quote in a DaveJ post. I thought it was relevant to this thread...and very interesting.

"the best cushion (firm but plush) comes from running the compression damping right on the edge of being too much. Tricky stuff. This is often why making a fork stiffer, (if done in the right way) provides for a smoother ride. And yes, sometimes when you make them softer, the rider is more harsh or rough."

I'm not sure what my tuner did with the valving in my bike, to go along with the softer springs he put in, but I'm curious how the new valving would feel with the original, stiffer springs.

Edited by rbreak
added info.

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Make sure you guys are having your springs tested too. Just cause it says .47 on the box or on the spec sheet, doesn't mean that's what they really are. Any reputable suspension shop will have/use a tester like an Intercomp spring tester.

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Make sure you guys are having your springs tested too. Just cause it says .47 on the box or on the spec sheet, doesn't mean that's what they really are. Any reputable suspension shop will have/use a tester like an Intercomp spring tester.

This is probably the most relevant post in this whole thread if you asked me. Somebody else on here went through three rear springs before he got one that was actually what it was marked on the box.

The the OP, Id say put stiffer springs in there too. Leave everything else the same so you can compare apples to apples.

And I think worrying about where the static sag falls in is over rated on the heavy end. In other words, more than the recommended static isn't as big a deal as not enough (in my experience)

And with the stiffer spring in the rear dont assume you have to run more rebound damping. Especially if your static sag is deeper than what some suggest.

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Found this quote in a DaveJ post. I thought it was relevant to this thread...and very interesting.

"the best cushion (firm but plush) comes from running the compression damping right on the edge of being too much. Tricky stuff. This is often why making a fork stiffer, (if done in the right way) provides for a smoother ride. And yes, sometimes when you make them softer, the rider is more harsh or rough."

I'm not sure what my tuner did with the valving in my bike, to go along with the softer springs he put in, but I'm curious how the new valving would feel with the original, stiffer springs.

He would have removed shims from comp and rebound as lighter springs don't need as much comp and rebound as heavy springs

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This thread has really brought out some good stuff. Thanks to all the smart guys for putting your explanations in understandable form. Its really appreciated. :bonk:

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