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Balance Undersprung Suspension?

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My brother in law weighs about 210lbs, and rides an 08 CRF450. All stock, so the spring rates are definately to low, but he doesnt have the cash at the moment to buy new springs. What are the thoughts on trying on trying to make the most of the suspension with the stock springs? After giving it some thought, I would think that you can "balance" the bike even without new springs by adjusting race sag accordingly. Typically you would want to set the race sag at 100mm, but seeing how undersprung we would are in this case, we would need way to much preload on the shock spring to get it to 100mm, and would definately throw our forks out of balance. I have a theory that by adjusting race sag on the shock accordingly, you can at least balance the bike, the balance may be lower in the stroke on both the forks and shock, but at least they are in balance. So in our case, I believe that by going with 110-120mm of race sag, we should be able to at least get the bike balanced, and should offer the best possible ride without changing springs. Obviously changing springs would be the best, but what do you guys think about finding the balance point when thats not an option?

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At 120mm sag you are getting too far into the linkage curve ratio and are sacraficing supple response. You are better off running correct sag, and running the forks as high up as possible. You may even run the top edge of the fork cap flush with the top triple.

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At 120mm sag you are getting too far into the linkage curve ratio and are sacraficing supple response. You are better off running correct sag, and running the forks as high up as possible. You may even run the top edge of the fork cap flush with the top triple.

Thats the thing, I dont think your going to get supple response no matter what. If you add enough preload to the shock to get a 100mm of sag, you wont have any free sag and will pogo in the small stuff. With an extra 20mm of race sag over the desired 100, you talking about the rear end sitting about 3/4 of an inch lower. Its true that the bike will ride in a stiffer part of the stroke, but wouldnt that be better than putting more weight on the forks. By running more race sag, your taking some pressure off the forks, and that should provide a more subtle feel through the bars. If you run the 100mm, its going to magnify the soft forks.

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I see what you are saying, that's why I suggest running the forks as high as possible, will take some load off forks, and maybe help balance without running too much sag? Only way to know is to try both ways and wing it, see what feels better!

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I see what you are saying, that's why I suggest running the forks as high as possible, will take some load off forks, and maybe help balance without running too much sag? Only way to know is to try both ways and wing it, see what feels better!

I see what your trying to do, I just have a feeling that the excessive preload on the shock is going to cause it to pogo and will not be able to maintain traction in the chop. Testing is the only way to know for sure. I just wanted to see what you guys thought. Theres going to be a serious compromise no matter what until we get the correct springs, but we can try and make the best of what we have until then.

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the way if you dont want change the spring is a little more preload on front and rear.

run 110 rear and 6mm preload on front.

thats help a little but the bike dont work correctly.

only the best compromise

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whats his sag numbers out of interest? here is what my spring chart says, this is not for sx type riding, more natural mx tracks

95-105 Kg STD fork 57.5 / 60 rear

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