Change of philosophy of suspension design?

[Akagi]

I was just thinking...

back in the late 90s, The smart shocks controlled dampening that allowed full movement during small bumps and resisted movement during bigger bumps that supposedly gave the feeling of the suspension having more travel than in actuality.

But now a days, platform shocks, designed to eliminate bobbing from pedaling forces, in effect also hinders small bump performance, while still remaining plush over bigger hits.

So back in the day, Proflex were worrying more about small bump performance and terrain tracking/ traction; which leads to efficiency.
Now a days, they are worrying about pedaling efficiency and not interfering with the shocks function through pedaling.

Do you guys think one philosophy is "more right" than the other?  Or have the shocks adapted to changing aggressiveness of trails? Or something else?  Lets compare XC bikes, since the amount of travel hasn't increased all that much.

[jazclrint]

Ahhh, almost.

I don't feel the Smart shock was supposed to make the bike feel like it had more travel, I think it was just suppose to work better, and it did at the time.  There are 2 types of dampening.  The first is compression, which controls how fast the shock compresses.  The second is rebound, which control how fast the spring pushes the shock back out.  The Smart shock had electronically controlled variable compression.  This meant on a smaller bump it would give you less compression dampening so your rear wheel would stay in greater contact with the ground, and hence greater control.  But as the bumps got bigger it adjusted and stiffened the compression dampening up so you wouldn't use up all of the stroke of the shock and bottom out, and be able to maintain control.  By the time the Smart shock came out Proflex/K2 had the bike sorted out well enough that if you had a smooth pedaling style, you didn't bob anyway.

Now, the issue became that pro racers wouldn't ride the FS bikes even though they were as light (at one point) because they said they weren't stiff enough and they lost power to suspension bob.  It seems to me that motorcycle racers and XC racers have the same issue.  They feel a harder/harsher feeling suspension is fast, but it's not.  Chassis dynos on AMA level race motorcycle proved that.  Also, I read one company (specialized I think) put it too the test.  They built one of their hardtails racers and one of their FS XC racing bikes to the same weight for one rider and set him (her?) out on a course.  The rider said the FS bike didn't climb as well but descended better as the hard tail, but that they were quite certain the hardtail was faster.  Turns out they were wrong.  They did the course in the same exact time on both bikes.  The difference?  They had a heart rate monitor on the rider and they used less energy riding the FS bike. 

Now, remember how I said there were 2 different types of dampening?  Within each of those types is low speed and high speed.  Say you hit a root, or rock.  It's small right?  But it's a sharp, quick bump.  That's high speed, as the shock compresses quickly.  But right after that is a dip in the trail.  The shock has to react to that, but it moves slowly when doing so.  That is low speed dampening.  These platform technologies are a form of low speed compression dampening, because the shock sees low speed pedal induced bob just like it sees that dip in the trail.  By giving you firm low speed dampening, it gives you a firmer more efficient feel, while still being able to maintain normal bump absorption rates as well.  It's also a fix for crappy suspension design, but that's just my opinion.

So, it's not a different philosophy, it's just technology has come so far.  If the smart shock came out today, it would probably be very similar, but have something like a pro pedal to give it a firmer feel when mashing the pedals.

Your bike was the second to last revision of that frame.  On the next model the pivot point was moved a bit to give it less "dig-in", but better bump compliance in the middle and big rings.  If you look at "modern" bike Like Cannondale's Rush, and Santa Cruz's Superlight, you will see a VERY familiar pivot point.  FS bikes have always had more of a DH or All mountain feel to them.  It's not been until the last 5 years maybe have I seen a real effort by the big manufactures to make a racing XC FS bike.  I'm sure there are exceptions, and maybe my dates are off a bit, but . . .  Proflex was just a different bike to begin with.  It was started by an out of work Aerospace engineer who lived in Connecticut, and who wanted a FS bike that would help him ride the trails in his area better.  Proflex's philosophy has always been different, so you are not comparing eras, as much as one company to the rest of the industry.

I hope that was helpful, and as always, my 2 cents.
Rich

[DugB]

What I find interesting is the gradual movement back to single pivot bikes. For a few years it seemed that manufacturers thought that more pivots, combined with the right shock, would prevent pedal bob. Now, though, they seem to be putting more of the onus on the shock to prevent bob, and making pivot designs simpler (except when it comes to virtual pivot point designs, where the emphasis there seems to be to obtain more travel by making the wheel travel up and down AS WELL AS being hinged into the seat tube.

In general it seems that our rear frames, combined with the right shock, could possibly perform as well as more recent designs like the Titus MotoLite...all the more reason why we need an off-the-shelf lower eyelet adapter from RDS for standard double-eyelet rear shocks. I made one from steel this past weekend but f'd up by misaligning the through-hole.

Callum, you listening? ;-)

- Doug :-)

[orange]

Wow - this is a really good conversation - keep it up

[jazclrint]

From what the guys at the LBS that sells Santa Cruz, when VPP came out they lost their minds.  Being a bit more of a DH/Freeride crowd, and they said the purpose of it was to create a different travel path that helped maintain forward momentum.  Basically, more efficient.  It's not as big a deal in XC where much more time can be made up on the climb (ala Santa Cruz Super light).  But in DH racing, it was huge, or so I was was told.

It also seems single pivot designs aren't the only thing making a bit of a comeback:

http://www.german-a.de/german-a/kilo.html#

http://weightweenies.starbike.com/forum/viewtopic.php?f=1&t=69595&p=619180#p619180