K2 / Proflex Riders Group
General => Tech Forum => Topic started by: Oz-SUB on February 20, 2003, 09:02:17 pm
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OP
I've seen pics of your luuurrrvveely 4500 with a Vanilla and a 5th Element. Which one is current?
Also, what i2i and stroke do (did) you run with these, and how do you rate them?
Oz-SUB
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Op, what's the weight of the 5th? I had my fingers on the send button for a brand new 5th for $250 in Alban,y N.Y. but read of 800 + grams for them so hesitated and it was gone...
Thanks,
Scott
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well, shock eye to eye is 8.50", 2.50" stroke and took some minor mods to get it to fit - namely the lower spring clip required the swingarm mounting plate to be filed on to accomodate. if they came off a bullit - they should fit a k2
extremely adjustable for the 5th although a bit on the heavy side. that is of minor concern considering the great ride.
sorry, i don't have my weights and measures on the 5th but is probably available somewhere at the progressive site.
i paid $210 with spring for mine but had to play with the bushings to fit the 4500 - i might be interested in picking up another but may look to a vanilla rc which i don't have - also considering going to one of the springless models and give one a try on one of my other 4500's - maybe an astro or such
OP
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OP
Does this mean you have 3 or 4 4500's?
My local LBS has an overhauled Vanilla RC 8.75" i2i with 2.5" stroke, I've worked out this gives 6" travel in my OZ. I've spoken to the UK Fox distributor, and they want £189 for a new Ti spring to go with it! How much could one of you guys get a Ti spring in the US of A?
My LBS also have an unused Vanilla RC 8.75" i2i with 2.0" stroke, this will give 5" travel.
Oz-SUB
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humbly - just 3 -
i was gonna pick up a 4th for my wife - one of these preowned mediums you see for sale around, but she balked at the idea as she loves her rebuilt and repainted '57 and won't let me change a thing on it 'cept the brake pads and to fix an occasional flat.
(what a woman)
OP
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Actually, the 2.5" stroke will give you closer to 7" of travel. The 2.0 should give you approx. 5.4" (Really basic rule of thumb is 2.7 x the stroke length to get total travel).
As for the i2i length, 8.75" will mess with your frame geometry. A few people who have tried 8.5" have said they don't like it as much, although I can't see 1/4" being that noticeable either way. Nobody seems to complain when the i2i is slightly shorter though. 7.875" seems to be popular (that's the length of my Stratos and it works perfectly).
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Actually, the 2.5" stroke will give you closer to 7" of travel. The 2.0 should give you approx. 5.4" (Really basic rule of thumb is 2.7 x the stroke length to get total travel).
As for the i2i length, 8.75" will mess with your frame geometry. A few people who have tried 8.5" have said they don't like it as much, although I can't see 1/4" being that noticeable either way. Nobody seems to complain when the i2i is slightly shorter though. 7.875" seems to be popular (that's the length of my Stratos and it works perfectly).
Does the Stratos and Risse "retrofit" measure out to exactly 8.25" i2i? Or is it simply a close retrofit with the same 7.875" as my Fox RC?
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Matno
I don't completely agree with you here. For instance when I measured the ratio I got 2.63 (not 2.7). Also, I don't think the ratio is a straight line because the angle of the shortening shock 121 is changing. I'll check this next time I remove the shock.
Also, from measurements I made two days ago, going from 208mm to 8.5", only raises the travel by 15mm, and going to 8.75" raises it by another 15mm. 30mm in total, which after the increase at the front end, going from a XLink to a 4" travel fork or a 5" travel Psylo, is small by comparison.
These measurements can be checked by taking off the back wheel and shock, tuning the bike upside down, and placing a length of planed wood by the wheel drop out rsting on the floor, to mark against. Then you can measure the shock i2i against changes in travel.
Oz-SUB
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personal preferences -
i've noticed that going to a 8.5" shock with a bit extra sag, (induced only by my excess personal girth) and moving to a psylo at the same time, gives an abundance of varying geometries for a variety of riding situations. putting the psylo to 4 or 5" balances the bike.
i'd have to say with a +/- 80 mm front fork, a 7.875" rear shock would balance the bike quite well and would be about right for xc.
not sure if one could set a 8.75" shock with enough sag and still have it work well - the spring might be a tad soft but with a great deal of adjustability on the shock, might work just fine. one could make an adapter plate on the swingarm (that we've discussed previously) to allot for the longer shock or maybe reposition the uppper mounting holes pending shock head shape and room to mount it properly.
i should imagine we all get somewhat used to our rides regardless and figure that that's the way a bike should feel. it's not till we try something different or have a variety to chose from that one could see a desired difference.
OP
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I was going by a long fancy post from TC last year that had a much more detailed description of the EVO frame's travel. He gave the 2.7 figure as a general reference number to easily get in the ballpark. Obviously, the travel is not linear though so, that number would be more accurate in some parts of the travel than others. However, even with the 2.63 ratio you suggest, it's still closer to 7" than it is to 6" (but only barely!) ;D
I agree with OP that the way your bike feels depends mainly on what you're used to. When I switched from a 3" fork to a 4" fork on my 5000, it felt way better (I didn't like what I was used to at the time!) Switching to a 7.875 rear shock only affected the way my suspension felt to me. Not the geometry, but then, it's really not that much difference. Of course, I think of myself as a trailrider more than an XC rider. To me, XC means something I could ride on my hardtail. I know there are guys who can ride anything and then some on a HT, but the trails I like most were mostly unrideable (and not very fun at all) to me before I got the EVO...
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Oz-SUB and Matno,
Just use the handy-dandy EVO swingarm calculator!
http://idriders.com/proflex/files/swingarm_travel.xls
The leverage ratio is nonlinear. But, it's NOT nonlinear enough to really matter. It starts out at just over 2.7:1 and ends up just shy of 2.7:1.
So....for an EVO type frame, the magic 2.7 number is a good one to use. I discovered this when OP mentioned it after I had already gone through the goemetry and spreadsheet building to figure it out. The nice thing about the spreadsheet though is that you can modify the inputs to use on any other single pivot frame.
Enjoy [smiley=nod.gif]