Shock length and spring rate versus ride height

[yorkie_chris]

Originally Posted by mjc

I cant directly answer your questions on geometry as i havent got round to doing my own shock yet. but if you measure the length and angle of linkages between back tyre and seat and make a sketch it should be possible to figure out the ratio, and also the force of rider weight transmitted through the spring, which would then give you an approximation for the static displacement for a given weight and spring rate. this could also be used to find effective spring rate of a shock not designed for the sv. in fact i was planning to do all this myself when i get round to sorting my suspension, and i would be very interested in your results if you go through with it.

if you havent found it already, the racetech spring calculator is a good resource http://old.racetech.com/evalving/menu/searchstreet.asp

i believe pretty much all shock swaps require a battery box chop, kawasaki more than most because they use a piggyback resevoir

I wouldn't advise figuring out the ratio like this, if you are interested measure it based on whel displacement vs shock travel. (you will need to take spring off shock to do this)
Guy on SVrider figured it out mathematically from bad measurements and argued for hours that the leverages made it a progressive link DESPITE shock length being directly proportional to wheel travel
(search for posts by napkin on there if you want read up)

I think that's a complicated way of doing things, linkage is about 1.8:1, stock spring rate is too low. Get target sag numbers in mind and try select a spring based on that then you will chase your tail for ages.

If you're about 11 stone then you'll want a 600# spring or similar.

All the good shocks have a reservoir somewhere, you could rebuild something with a remote res I suppose.
Problem is spring rate is still a bit low, kawa for instance is about 550 IIRC and it's way too short. Bike feels so much better under power with a shock thats 350mm+ long.

[CSpronken]

Originally Posted by yorkie_chris

I wouldn't advise figuring out the ratio like this, if you are interested measure it based on whel displacement vs shock travel. (you will need to take spring off shock to do this)
Guy on SVrider figured it out mathematically from bad measurements and argued for hours that the leverages made it a progressive link DESPITE shock length being directly proportional to wheel travel
(search for posts by napkin on there if you want read up)

I think that's a complicated way of doing things, linkage is about 1.8:1, stock spring rate is too low. Get target sag numbers in mind and try select a spring based on that then you will chase your tail for ages.

If you're about 11 stone then you'll want a 600# spring or similar.

All the good shocks have a reservoir somewhere, you could rebuild something with a remote res I suppose.
Problem is spring rate is still a bit low, kawa for instance is about 550 IIRC and it's way too short. Bike feels so much better under power with a shock thats 350mm+ long.

Actually after further research I figured that the 03/04 ZX6RR shock with it's 340mm and 543lb/in, might be the best for my weight and driving, quite rare though.