ProFlex suspension do-it-yourself upgrades
Robert Berta
Thought some would like to have some feed back from my modifications to the
suspension on my ProFlex Animal (856 with Magura Hydraulic brakes).
Much of this information and the tech tips were found in various internet
searches and by my own trial and error.
Like most ProFlex users I always found the suspension to be very good but the
front fork in front seemed to be lacking in a few areas. My stock setup was
with the ODS (Oil Damped Suspension) shocks and the elastomers in appropriate
weights for my weight. The front suspension tended to have a lot of stiction
and over damping, the promised travel was compromised by the limited
"squeezeability" of the elastomers to perhaps 1.7" at the best....not the
promised 2.5".
The elastomers were designed for the earlier non ODS shocks and along with the
ODS damping gave too much damping. Some have had good luck by drilling out
center hole in the upper existing yellow elastomers to 9mm (just the
softer/smaller spring) and changing the oil to a lighter weight see below for
the method. The stock shock oil is 30 weight which is much to thick. Various
people recommended 10 weight oil for my 140 lbs. A much heavier person say of
up to 200lbs would go with 15 weight...but 30 weight appears to be more than
anyone could use for the front shock.
Rather than drill out the elastomers I opted for a set of Speed Springs in the
middle weight range which are appropriate for 130lbs to 170 lbs. I found the
factory recommendation to be spot on. I installed the springs prior to
changing the fork oil out to see if any difference. To say it was an
improvement was an understatement! Especially in the small bump and complete
lack of stiction. I thought though that the damping was still too much by a
large measure. One noticeable change was that the cam installed by ProFlex on
the upper link would provide very obvious differences in performance depending
on whether it was in the "sensitive mode" or the "anti-pogo" mode....much more
obvious than the stock setup. By the way racers tend to prefer the anti-pogo
mode with the dead stock setup because it maximizes the available travel. It
does greatly reduce the slow bump response but the big and hard hits are
great...especially since that position also lets the lower axle move in a more
"J" path away from the bump instead of perpendicular to it.
The next step required a lot more skill than the very simple spring change
out. Changing the oil in the shock requires the disassembly of the shock which
is simple with a couple of tricks...and nearly impossible without them.
To change the oil you first remove the stock elastomers, spring perches, etc.
Next place the shock upside down in a padded vice with an allen wrench
inserted through the upper mounting hole to keep it from rotating in the vice
(allen wrench jams against the vice jaws). You will see a silver colored metal
cap with two round holes in it. You will need a pin spanner that will fit in
it to unscrew it. You should be able to get one of these from a bike shop. I
used a VAR tool that I had laying around. Due to the close proximity of the
center shaft of the shock I had to file the inner jaws of the wrench down to
allow the pins to go into the holes and still clear the shaft.
Unscrew the cap (normal thread direction) keeping the shock shaft upside down
in the vice. You will see the top of the seal cap now under that cap. Put the
cap back on about half way, place the spring perch on top in its normal
position. I used a car spark plug socket on top of the shaft as a spacer
although you could probably make up a similar hard spacer by stacking two or
three socket wrench sockets), place the other spring perch on the stack you
now have a lastly the stock nut. Now use the standard compression adjusting
knob on the shock to put pressure on the stack thereby lifting the seal out of
the shock. You may want to go a little ways and than remove the make shift
assembly to check on your progress after a little while.
When I got the first metal seal block up I remove it and than continued in the
same manner to pull out the rest of the seal and shaft. You will now see the
oil in the shock body. Dump it out and refill it with 10 weight fork oil that
does NOT have seal swell. You want to fill the shock to 44mm from the top of
the shock edge....check the original fluid before you dump it to see about the
level you need. I made up a "depth" gauge before hand to measure the 44mm.
Now place the seal back in the shock, place the metal plug on top and push it
in....you will find it won't go in very easily or very far. Take another
smaller socket wrench socket and place on top of this seal, push the center
rod down to expose the top of the center shock shaft and lightly strike it
with a mallet or hammer. It should be just about even with the top of the body
of the shock. When you replace the shock cap cup and tighten it the seal will
be pushed all the way in and held tightly. Reassemble the shock using the new
Speed Springs...or the stock elastomers. BeVERY sure to adjust the center of
the two mounting points on the shock to 188mm as per the instruction manual.
Reassemble the spring in the fork and go for a ride.
Frankly I find the fork to be more stiction free and better acting than any of
the various other types of forks I have used. The combination also seems to
provide a very much greater travel than the stock setup not only in actual
travel but in feel. The variable rate spring of the Speed Springs allows for
great slow speed compliance but "steps" up as the demands are increased for
medium and hard hits. It also seems that you can't feel when it bottom out it
is so linear. No longer do I have that "wall" that you would come up against
with the elastomer. I would rate the shock/fork to now be a superb cross
country fork. Frankly the performance with these modifications provide a
performance equal to the very expensive Noleen shocks (now owned by ProFlex
and being supplied on the higher end bikes) since the shock design is
identical. I prefer the do-it-yourself version even if the price was the same
since the Speed Spring springs are in my opinion a much higher quality spring.
They are made by Eichback which is well known as the ultimate springs for car
racing (formula 1 and Indy cars for example). They are also triple rate
springs.
Setting up the springs as to sag should start with the factory recommendations
and go from there. As to the two fork modes...anti pogo vs. compliant....try
them both. I tend to lean toward the compliant mode now whereas I prefered the
other mode with the stock setup. But I should say that I am not a "jumping
fool". My rides tend to be more of a technical nature and long over constant
rough ground that will wear on you after many miles if not soaked up.
Are there any negatives? Only two....the cost of the conversion (Speed Springs
= $150) and the slight increase in weight....less than 1/2 lb front and rear
combined. The improvement in the suspension is worth the weight penalty and
you can get the weight back down by swapping out a couple of parts
elsewhere...titanium bottom bracket and lighter rear hub like a XTR, etc.
I have Speed Springs on the rear also but at this point haven't had a chance
to experiment with oil weight...although it appears that the existing weight
seems to work pretty well. They work very well also but the biggest
improvement was in the front end.
Of course all these changes and recommendations are without factory support or
recommendation nor can I be responsible for damage you inflict on your stuff
by your actions. And of course the factory warrantee is voided on the
shocks....but hey...try it you will love it. Finally....let me know your
impressions once you complete the modifications.
Bob Berta
jim frost
rk...@pge.com (Robert Berta) writes:
>Thought some would like to have some feed back from my modifications to the
>suspension on my ProFlex Animal (856 with Magura Hydraulic brakes).
>Much of this information and the tech tips were found in various internet
>searches and by my own trial and error.
Your instructions and experiences exactly match my own with the same
modification. You probably ran into it while you were doing internet
searches, but I have a tuning tips document at:
http://world.std.com/~jimf/biking/vector.html
>Rather than drill out the elastomers I opted for a set of Speed Springs in the
>middle weight range which are appropriate for 130lbs to 170 lbs. I found the
>factory recommendation to be spot on.
I tried both. The springs are considerably superior to drilling out
the elastomer, but if you can't afford the springs it's a damned good
intermediate solution. I did it primarily because it took so long for
the springs to show up for my weight; I ordered them in June but
Mountain Speed didn't start shipping the Pro2 (which is what you are
using on the front) until August.
>One noticeable change was that the cam installed by ProFlex on
>the upper link would provide very obvious differences in performance depending
>on whether it was in the "sensitive mode" or the "anti-pogo" mode....much more
>obvious than the stock setup.
Interesting; I didn't experiment with the cam at all, preferring to
keep it sensitive even with the stock elastomers. In sensitive mode
with drilled-out elastomers I saw good (but not great) small bump
performance.
A friend of mine prefers anti-pogo even with a spring, but he's into
big-hit stuff like trials and downhill.
>You will need a pin spanner that will fit in
>it to unscrew it. You should be able to get one of these from a bike shop. I
>used a VAR tool that I had laying around. Due to the close proximity of the
>center shaft of the shock I had to file the inner jaws of the wrench down to
>allow the pins to go into the holes and still clear the shaft.
Most bike shops should have pin spanners; I picked one up for $6 or
so. It's not a really great fit -- the pin holes are larger than the
pins on the spanner, and the spanner flexes a lot while you're
torquing it -- but it gets the job done.
>I used a car spark plug socket on top of the shaft as a spacer
>although you could probably make up a similar hard spacer by stacking two or
>three socket wrench sockets), place the other spring perch on the stack you
>now have a lastly the stock nut. Now use the standard compression adjusting
>knob on the shock to put pressure on the stack thereby lifting the seal out of
>the shock.
The use of the spark plug socket is a *great* idea. I didn't think of
that and ended up using the spring to accomplish the task. It worked,
but wasn't as easy as it would have been with a spacer that didn't
compress. I'll add that tip to my document.
>You will now see the
>oil in the shock body. Dump it out and refill it with 10 weight fork oil that
>does NOT have seal swell.
I used Finish Line oil, $10 for enough oil to refill the thing about a
hundred times.
>Frankly I find the fork to be more stiction free and better acting than any of
>the various other types of forks I have used.
I don't completely agree. A SpeedSpring-equipped Judy beats it in
small bump response (presumably because there's pivot stiction on the
Vector), but just barely. It totally wipes out every
elastomer-equipped shock I've ever tried, though.
Interestingly I've found that I'm more sensitive to pivot lubrication
now than I ever was before; I start noticing when the fork isn't
soaking up the tiniest bumps completely. You get used to plush really
fast :-).
>I would rate the shock/fork to now be a superb cross
>country fork.
So would I. It is a night-and-day change from the stock
configuration.
>Frankly the performance with these modifications provide a
>performance equal to the very expensive Noleen shocks (now owned by ProFlex
>and being supplied on the higher end bikes) since the shock design is
>identical. I prefer the do-it-yourself version even if the price was the same
>since the Speed Spring springs are in my opinion a much higher quality spring.
I'm not sure I'd completely agree with this; if I were buying a new
fork I'd get it with the Noleen to start. There's no real cost
difference, the Noleen is warranteed, and both have excellent
performance. It's also a hell of a lot less effort.
But I completely agree that there's not a lot of sense in upgrading an
existing Vector to the NR1 -- the performance of the SpeedPro solution
is spectacular at less than half the cost.
>Are there any negatives? Only two....the cost of the conversion (Speed Springs
>= $150) and the slight increase in weight....less than 1/2 lb front and rear
>combined.
If you only convert the fork it's $90. Weight difference is between 4
and 6 ounces, bulking the fork up to about 3.75lbs (real weight, not
marketing weight).
>I have Speed Springs on the rear also but at this point haven't had a chance
>to experiment with oil weight...although it appears that the existing weight
>seems to work pretty well.
Drop the oil weight there too. The rear will benefit a lot from the
increased travel you'll be getting. I do recommend going a bit
heavier in the rear -- something like 15wt.
jim frost
ji...@world.std.com
--
http://world.std.com/~jimf