Giant Training - Part 2

Posted by PeterD Fri, 07 Dec 2007 18:48:00 GMT

A piece of good advice I once heard was that you should avoid debating about religion and politics, as people hold strong feelings on these that they rarely will change. I think that Mountain Bike Suspension design could be a third area to add to the list.

That being said, here is the second part of Berry’s report from the Giant Training he and John went to a few weeks back. This will be on various suspension designs…

The most interesting part of the talk was given by Andrew Justaitis (sp?), which contained a lot of basic and useful info on all the various kinds of rear suspension designs, how they work and their characteristics, both good & bad. He called it a Suspension Rating Report Card, giving ratings for Activity, Efficiency and Independence; how well the rear suspension works separately from the rear brake, whether they influence each other or not. Below is his Report Card, which I found very informative. He went to great lengths to be fair and neutral and didn’t bad mouth any other brand or design type.

The report card is based on the basic design. Technology can be used to mask or minimize deficiencies of their rear suspension design. The “Brain” shock that Specialized uses is one; it controls the pedal bob inherent in classic 4 bars. Other manufacturers use shock valving or add ons of some kind to improve on the suspension design.

1) Single Pivot Example: Heckler, Bullitt and many others (Super Light shown in picture). Easy to make, light, durable, but reliant on shock technology to be even remotely efficient or independent. Activity = B Efficiency = D bad bio-pacing Independence = F lots of brake jack, where braking locks up the rear suspension, making the bike feel like a hard tail under braking (not to be confused with feeling like a hard tail when climbing, which is good).

2) Modified 4 Bar Where the rear pivot is above the axle; Kona and Turner (shown in picture) are examples. Activity = A Efficiency = C Noticeable pedal feedback Independence = D lots of brake jack

3) 4 Bar/Horst Link Specialized owns the patent. Activity = A Efficiency = C- Again, pedal feedback Independence = A-

4) R1i Trek’s new design, patented, currently on their Fuel EX; the rear axle is the pivot. Activity = B- Efficiency = B+ Independence = C+

5) VPP Santa Cruz holds this patent; Intense pays royalties. Generically a dual link design, with an “S” shaped wheel path. The wheel starts going backwards, then goes forward, then ends up going rearward again. The linkages have a counter-clockwise rotational path. Activity = B Efficiency = B- Independence = A

6) DW Link Licensed to several companies; Ibis, Titus, Pivot and Iron Horse are some. Activity = B Efficiency = B- Independence = B

7) Maestro (shown in picture) Generically a dual link, but with clockwise rotational movement. Progressive and bottomless. Activity = A Efficiency = A Independence = A

Of course (given the source) you’d expect this report card to favor Giant, but he went into a lot of detail on the good and bad of each type.