Bicycle Suspension - Virtual Pivot Point


The VPP (or Virtual Pivot Point) is a linkage designed bike frame that is built to activate the suspension differently depending on what inputs the suspension has received. The "Virtual Pivot" system used in bikes by Santa Cruz and Intense use a specific type of Virtual Pivot design that was originally developed and patented by Outland Bicycles in the late 1990s. The patents cover a specific linkage configuration and rear wheel travel path that is designed to aid the pedalling performance of a rear suspension bike without negatively affecting the overall bump absorption capabilities of the suspension. Yeti Cycles has created a unique rail system to eliminate pedal jacking (aka "bob"). Giant's Maestro is yet another design that works well, and is considered by many to be an attempt to replicate aspects of the dw-link design. Patents have drawn definite lines among the manufacturers.
The VPP family of suspension systems fall into the four bar linkage category. They have short links instead of the longer links on a conventional four bar (chainstay and rocker).
The VPP (Virtual Pivot Point) system used by Santa Cruz and Intense, also claims to have reduced the problem of pedal bob. Soon after the VPP was introduced, the creation of the Progressive Suspension 5th Element rear shock (based on Currnut's platform damper) near the beginning of the Millennium allowed riders to adjust almost any frame, regardless of design, to be pedaled without the pedal bob that plagued earlier designs. Other companies have followed Progressive's lead (mainly Manitou with its SPV system based on the 5th Element and Fox's ProPedal which uses a shim stack rather than an air pressurized valve) and new designs in suspension design have come out. These 'intelligent' shocks always have to compromise between their resistance to bob and performance with smaller bumps. VPP designs typically use shocks that include some sort of platform damping.
However, the four bar linkage may cause pedal bobbing, lockout, and brake jack. With the rise of more complicated shocks and a larger market share for full suspension bikes, mountain bike suspension tuners have now arrived. It is now possible to have shocks tuned to each individual rider's desires.


Source: http://en.wikipedia.org/wiki/Bicycle_suspension#VPP

Gowes Soka Indah


Mission accomplished!!!
Itulah kira-kira yang kami rasakan saat finish di areal parkir Soka Indah.


Perjalanan dengan bersepeda yang semula berupa wacana akhirnya menjadi kenyataan dan terlaksana pada hari Sabtu 21 November 2009, 8 biker start dari Renon jam 6 pagi, 1 lagi biker start dari Canggu, 1 lagi start dari Munggu jam 7.30, total 10 biker melaju mengikuti rute yang sudah disurvey oleh duet surveyor (Ermil "Eric Xtrada" & Kenik "Pangeran Hussar") menggunakan sepeda motor beberapa hari sebelumnya.



Namun dikarenakan sesuatu dan lain hal, 5 biker berhenti di pantai Kedungu, sedangkan 5 biker lain melanjutkan perjalanan menuju garis finish di Soka Indah, mereka adalah Ermil "Eric Xtrada", Kenik "Pangeran Hussar", Andi "Shrek", Ferry "uCoX", Oket.



Rute lengkapnya bisa dilihat di http://gpsed.com/track/3915656525327543381, thanks to Ermil "Eric Xtrada".


Singkat cerita, sesampainya di Soka Indah, yang memang benar-benar indah, kami beristirahat sejenak, lalu mencari warung untuk makan siang sambil menunggu mobil pickup yang akan mengangkut 4 biker beserta sepedanya untuk kembali ke rumah masing-masing.


Lho... kok cuma 4 yang pulang naik pickup???

Crank Length


Subject:      Re: Crank Length Suggestions
From:         Roger Marquis (marquis@roble.com)
Date:         1997/03/12
Newsgroups:   rec.bicycles.racing

In rec.bicycles.racing Tony Pinto (tony@cttc.org) wrote:
>I was planning to purchase new cranks in a slightly longer length (175) but
>read a section in "Serious Cycling" that said someone of my height 5'10"
>should be using 170's. I have other books that do not seem to agree with
>this recommendation but now I am wondering what the effects will be of an
>increase.

At 5'10 you're borderline for 172.5 cranks, assuming a normal leg
length.  The best all-around crank length could be either 170s or
172.5s depending on your inseam.

Watch out for long cranks, they cause a very sharp bend in the knee
at top dead center right where you begin to apply power.  Too short
cranks don't pose a risk to the knee joint but they also won't be
efficient unless you spend a lot of time at high cadence.

The general rule of thumb is:

  * below 5'10 use 170mm cranks on for general (road) racing and
    training,

  * 5'10 to 6'1 use 172.5mm cranks,

  * 6'1 plus use 175mm cranks,

And modify for specialized events:

  * subtract 2.5mm for track racing (or more on short steep tracks
    or short events),

  * subtract 2.5 to 5mm if you have frequent knee problems,

  * add 2.5mm for time trials and hilly races, (and MTB races),

  * add 5mm for pure hillclimbs.

Roger Marquis
(www.roble.net/marquis)

Source: http://www.roble.net/marquis//crank.length

JH B2W in Hong Kong






Please welcome our new JH B2W Hong Kong member, Jeff Mok, he's in Hong Kong and looking forward to biking together with us here on his next visit...