Virtual Pivot System

[Borriz]

I read on a review of suspension designs the one guy comments that bunny hoping with a virtual pivot system, like you find on Santa Cruz, is very difficult if not impossible.

 

Can anyone please confirm or elaborate on this? Especially if you have a bike that uses VPP or similar designs!

 

Ciao

[fatcyclist]

Own a Santa-Cruz Blur, can bunny-hop it

[Tumbleweed]

own a giant and have been known to get over things.

[Bos]

mm.. If I may...

I also got a BLur. LT. and Though I cannot bunnyhop it over park bench like I can my jump bike, I can definately get it about knee high.

 

Heres why they might say so. Sthe VPP/magic link/ DW link all try and achieve somehing along the lines of a variable shock rate, In otherwords not a shockrate which just gets harder to compress the deeper it goes into Its travel. What VPP does (and I cant say for the others) Is that It has a S curve on a graph. In other words in the beginning of the stroke/travel it"ramps- up"/ gets harder up to a point and then becomes more "linear"/easyer to compressthrough the mid stroke and then "ramps" at the end again to eliminate bottomouts.

 

Why all this.? This Is to get the rider to sit In the travel in otherwards halfway through the stroke, rather than on top of it. this way when you go over a hole your wheel has some travel to extend and smoothen the hole, following the trail= more traction and smoother ride.

When you do hit a bump the suspention gives way easyer through the midstroke absorbing more of the bump before it translates into a upwards hit which you -the rider feel. And then the last bit is obvious, ramping up to not damage shock or be notable to the rider.

Off the SANTACRUSE SITE..

Go look at "joes corner" under shock rates and axil paths...you can learn lots there.

VPP Shock Rates:
Shock rate plays a huge part in any suspension frame design. Shock rate refers to how much the shock compresses for a given amount of rear wheel travel. A "falling rate" design is harder to compress at the beginning of the travel than at the end of the travel. A "rising rate" design is the opposite, easier to compress at the beginning than at the end. By experimenting with hundreds of different pivot placements and linkage designs, our engineers tune the shock rates on VPP bikes to both rise and fall at different points throughout the suspension travel, tailoring the attitude of the bike for different conditions and uses and maximizing the benefits of the VPP linkage and axle path.

[Hog_]

No offence, but you weight WAY more than your bike. A bunnyhop is just you moving and taking your bike with you. I don't see how a full-susser will make that impossible. More difficult, yes, but not THAT bad.

 

See here: http://www.youtube.com/watch?v=mpYpT5Esl9w

 

 

 

[Bos]

Oh I forgot to give the actual point of why you "cant bunnyhop" these bikes.

 

This S curve in the suspention would perhaps "give way" a bit more than traditional evenly sprung bikes when you compress to lift for your bunnyhop, and In doing so you wil break newtons law of action=reaction as some of the force is absorbed by the damping in the shock. If your rear shock was a naked undampened spring it would shoot you up with the same force as you put in.

 

Of course that is exactly what bikes try to eliminate, as when this senario is turned upside down, and the force you put in to bunnyhop Is seen as a bump in the trail, you would have been sent flying..

 

AM I somehow getting it across?

[Bos]

With a FS you just have to stretch out the motion. In other words Pull up and back like youre going to put your front wheel on top of a knee high step and halfway through the motion you rotate your body forward which will bring the rear up.

 

mmm its easy in my mind but to explain.. hehe. You'll figure it practice! she slower you can make that movement  the better for FS and the higher youll be able to go. quick sudder Jerks will be absorbed by your suspention.

[Ghostface]

you have to do what some kids call a "pigeon hop" where you lift the front wheel real high and then pull the rear up with your legs. Dont just try pull the whole bike up in one motion.

[Borriz]

Thanks. Everything makes sense. Suppose proof is in the pudding - need to get my bum on a LT and decide for myself. Just wish there were a few around!!!

[Ghostface]

Try Mike's Bikes.