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boxxer - 888 spring weight comparison and equivalencies

vitox

Turbo Monkey
Sep 23, 2001
2,939
1
Santiago du Chili
just wanted to share this with you guys since i was calculating what sort of spring to put on some 888's

two soft 888 springs is 5,4kg/cm equivalent to 30lbs/in or two silver boxxer springs (or one white and one yellow)

one soft and one stock is 5,8kg/cm or 32,5lbs/in

two stock springs is 6,2kg/cm or 34,7lbs/in almost exactly one yellow and one silver spring

one stiff one stock 888 spring is 6,5kg/cm or 36,5lbs/in

two stiff 888 springs 6,8kg/cm or 38lbs in just under what stock boxxer is.
 

vitox

Turbo Monkey
Sep 23, 2001
2,939
1
Santiago du Chili
S.K.C. said:
Say... just out of curiosity - can you use 2005 Boxxer springs in an 05' 888RC???

i havent done it but i plan to as soon as i get the rc2x in, it was discussed earlier here and someone mentioned having seen that setup.

main problem is that the 888 spring is 300mm vs 390 for the boxxer spring, but theres lots of space on top of the original spring anchoring point and the guy that posted about the setup said just a pvc spacer was needed to keep it firmly in there.
 

S.K.C.

Turbo Monkey
Feb 28, 2005
4,104
24
Pa. / North Jersey
Spacers???

Don't you mean I should cut down the longer Boxxer springs to fit into the 888?

You said the 888 springs were 300, and the Boxxer springs were 390, right?

Are the 05 Boxxer and 05 888 springs the same inner/outer diameter???

Do you remember the link to the previous thread that addressed this?
 

vitox

Turbo Monkey
Sep 23, 2001
2,939
1
Santiago du Chili
nono what i mean is that since the boxxer spring is longer, you have to fix it to someplace else than the notch in the damper rod where it normally attaches to, its quite simple really and i have made the spacers already so im hoping the new rc2x isnt any different but thats another story.

the springs arent the same diameter, the boxxer ones are narrower but not narrow enough so that it could be a problem as they are a lot bigger inside than the damper rod, it all can sound complex but once you see the inside of the fork youll understand its no biggie to have the boxxer spring live inside the 888, the preload youll have to adjust by putting smaller or bigger spacers inside thats pretty much all there si to it.
 

Cave Dweller

Monkey
May 6, 2003
993
0
vitox said:
nope, the fork will remain at stock length so oil level will not need to be changed.
Nah.

I am not 100% sure what the inside deal is with the rc2x, but with the old 888 that spring retainer disc serves 2 functions.

1. To hold the spring in place and give it some pre-load
2. To reduce the inside volume of the stachion, meaning less oil = reduced weight.

If you remove that disc you will need to increase the oil level to maintain the same oil/air ratio to keep the same air spring effect. This means your weight is going to go up and you will not have any more preload adjustment.

If you keep the oil level the same without the disc your fork is going to become very linear and will loose its progressive feeling.

It would be easier to cut down the boxxer spring me thinks.
 

Bati

Monkey
May 8, 2003
354
0
Santiago - Chile
Cave Dweller said:
Nah.

I am not 100% sure what the inside deal is with the rc2x, but with the old 888 that spring retainer disc serves 2 functions.

1. To hold the spring in place and give it some pre-load
2. To reduce the inside volume of the stachion, meaning less oil = reduced weight.

If you remove that disc you will need to increase the oil level to maintain the same oil/air ratio to keep the same air spring effect. This means your weight is going to go up and you will not have any more preload adjustment.

If you keep the oil level the same without the disc your fork is going to become very linear and will loose its progressive feeling.

It would be easier to cut down the boxxer spring me thinks.
So... you'll have to consider the different spring volume. Remember that they have differents diameters... does it matters?... if your fork works well now, will work well too with a 3mm higher or lower oil level...