Q for Tom A types / engineers

[Old Proflexer]

i'm picking up an air shock (to play) with 2" of travel for the back end of my 4500.  it's designed for a bike that gets 5" of travel with the 2" stroke - i should presume thats a 2.5 to 1 ratio (not sure on the rising or falling ratio thing).

if my pivot design is about 2.7 to one or thereabouts, should i presume that the shock will be softer than the bike it was intended for and by about how much?  (.2 diff / 2.5 orginal would be about 8% diff)

will my frame design make this shock feel mushier or firmer at the end stroke?  should i presume that i'll need to put in about 10% extra air poundage to keep the shock somewhat functional.  i'm thinking my high pivot design will counter balance any negative effects of 'bob' if that be the case.

new shock is 8.25" eye to eye.

any input would be appreciated - i'm not a math wiz and as you all know by know, engineer by the seat of my pants.

OP

[Carbon_Angus]

but i'd start by playing with it "the seat of your pants" way.

calculations ARE a great way to understand what and why but ride it and tell us what you think (remember i'm a j~path believer!) i respect a sage opinion

and.............

what type of air shock that's my curiosity!  [smiley=laughing.gif]

[Scott]

OP-sounds as though the gram counting has only just begun....careful, there's no way back once bitten by the easy spin of a light, yet solid ride with no "stupid light" parts on board.

[Old Proflexer]

fox talas r off a trek liquid 20

i saw the rl and it looked like the lock lever would interefer with my swingarm but have plenty of room with just an r knob.

with an 8.25" eye to eye should fit with minor mods.  the shaft has 2.9" exposed to the eyelet center and with a 2" thro - shouldn't bottom out against the plates on my carbon - even if so, i figure i could shave/file that small lip on the main shock body as the diff is in the 100ths to fit cleanly.

i happened into a local cyclewerkz and was caught "mic'in the bike shocks!"  
(managers a friend of mine but he wasn't in so they escorted me out as being a spy type person)

so i was wondering about air pressures, leverage ratios (again) ride characteristics etc. - gonna try it in place of the 5th for a bit then restructure my guest ride carbon that's most all xtr - gonna stay with the crosslink that has the disc mount, go with the yellow race disc wheels that have been hanging since i moved to the 959's and look around for some avid cable disc brakes.

pic of shock:



OP

(i may soon start parting with my box of nr-4's and rear smart shocks but i do have a special project in mind for one of the shocks and some rainy day i'll get to it.)