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lɐʇuǝɯᴉɹǝdx&#4
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Discussion Starter · #1 ·
So, now that I've got the SECApoclypse in a test jig, I've figured out the wheel rates... and I realize I have no idea what they "should" be. My impression is they are somewhat arbitrary, but typically higher rates are used for tighter handling or heavier wheels (to keep harmonic rate high), and maybe to combat dive / squat.

What are typical wheel (not spring) rates, front and rear, for street bikes? When progressive rates are used, how strongly progressive are they?
 

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Maybe just jam an old shock in there and play with leverage a bit..





Jon
 

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lɐʇuǝɯᴉɹǝdx&#4
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Discussion Starter · #4 ·
Maybe just jam an old shock in there and play with leverage a bit..
It's already built; there's a shock in there, and I was measuring the wheel rate. The shock I used came off a bike of the same weight, but my funny mounting position gave it a bit less travel and a whole lot more progression. On a big bump, it will act like a hard tail.

I was waiting to see if anyone posted on this, but since no one has what are wheel rates?
About 70 lbs/in in front, and 135-270 (progressive) lbs/in in back. My impression (from mc chassis builder email list) is the back is a bit stiff and MUCH to progressive, and the front is much to soft. The front is not hard to fix (springs are fairly easy to get, and changing leverage to give less travel & higher rate may not be to hard) but the back may be difficult / expensive to fix (would likely take a whole new shock, ideally one that has a longer stroke, allowing for a new upper mount location).

I'll probably just leave it as is until I can ride it and find out just how awful it is.
 

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lɐʇuǝɯᴉɹǝdx&#4
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Discussion Starter · #6 ·
https://en.wikipedia.org/wiki/Suspension_(vehicle)#Wheel_rate

I measured wheel rate directly by pulling up on the wheel with a scale. Its more relevant than spring rate because if I say my rear end has a 800 lbs/in spring and ask if that's a good or bad thing, that's meaningless to anybody else; the wheel rate produced by the shock setup is what matters to the ride quality. And even then, the "correct" wheel rate depends a lot on what the unsprung mass and wheel loading is, because for decent handling you need to get the natural frequency of wheel motion to work out in the right range.
 
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