A Piece of History from Japan

A bunch of downhill, slalom, and trail bikes from the old days, including the F4, the Zulu DH, and the Zulu DSS.  These bikes were all hand-built in Anaheim, California.  Check them out here: http://kamazou.web.fc2.com/dss-3.htm

Stolen CHUMBA VF2 Complete

A customer e-mailed this to us, so if you see it come up anywhere suspicious, please give the owner a ring.  I'm sure he'd greatly appreciate it.

Bike4Passion & CHUMBA: A Partnership for the Ages

We are pleased to report that we have signed Bike4Passion as our exclusive distributor for the country of Italy.  Marco, the owner, is a passionate rider and enthusiast, who has previously been the sole distributor for brands such as Devinci.

He chose CHUMBA based on the technical prowess and personalized attention he receives.  He says, "CHUMBA has the makings of a strong following here in Italy, and we hope with the new HX1, new HX2, VF2, and new EVO G2, we will be able to provide the highest quality products here in Italy."

He's been building a number of aggressive VF2s sporting coil rear shocks and 6 inch forks up front.  Check out the bikes and his website and give him a call if you are in the area.

 Bike4Passion: http://www.bike4passion.altervista.org/

The Most Stunning Hardtail Yet: 2011 HX1 Frame

The Most Precise, High-Quality Welding in the Industry

The picture above is a randomly-selected frame out of our production batch.  All of our frames will offer the quality you see above. It’s no secret, CHUMBA offers the highest quality in manufacturing today.  Impeccably-laid dime-shaped weld beads, you won’t find messy or blurred welds on our bikes, many even ask if these welds are laid robotically.  However, the truth is that these welders are selected for decades of experience, and are the best welders in the industry.  If you have any doubts, grab any CHUMBA frame and put it up against another rig to see for yourself.

Quality, Design, and Innovation Ensured for Over 17 Years

We’ve designed, manufactured, and tested frames for over 17 years for national champions like Duncan Riffle and Lars Tribus; but we’ve  also paid a lot of attention on designing frames for the rest of us, weekend warriors.  We integrate the same attention and quality to detail on all of our frames as if you would be competing in a UCI World Cup.

A Legacy of Innovation and Performance: Features

Integrated Seat Mast for Increased Rear-end Rigidity

•   Tapered Zero-Stack 1 1/8” – 1/5” Headtube – accepts Cane Creek angleset

•  Double-butted, hydroformed tubeset

•  Same Race-proven Geometry of Original HX1

•  EBB for Single-speed or Geared Offering Flexibility for Build Options

•  New Graphics for 2011

•  Ultra-wide Seatstay and Chainstay Yokes for Exceptional Rear Tire Clearance

•  MSRP: $699.00

New Partnership with ELKA Suspension

Hello everyone,

We'd like to announce a new partnership with ELKA suspension.  We've worked very closely with them to custom-valve, and custom tune the rear suspension to the linear chassis of the VF2.  The results of pairing the linear active 4-bar with the linear coil shock, with the right amount of compression dampening and rebound have been stunning.

For those of you that haven't heard of ELKA, they are a leading suspension manufacturer for ATVs and other sports equipment.  They produce all of their products in-house and offer high-quality CNC machined parts for their products and technical custom prowess to all of their products and customers.  The results on the CHUMBA VF2 prove that this will be a well-suited partnership.

We begin testing with sponsored Yamaha ATV rider Dustin Nelson who has done extensive consulting work for Yamaha's R&D division.  He's proved instrumental in maximizing suspension performance for our bicycles as well.

We are providing a very limited run of ELKA Stage 5 shocks with the VF2, so if you are interested, give us a call (888-997-2666) or e-mail (info@chumbaracing.com) to discuss these exciting new developments!

For those that are interested, here's some words from ELKA with comments from our engineers on the work they've done on the VF2:

Elka Suspension’s approach to the mountain bike market is the same that made it successful in other markets such as ATV, Side-by-Side Vehicles and Motorcycles: we analyze the vehicle’s geometry (bike) and adapt our product to get the most out of it. Our customers thus benefit from the same advantages they would get from a personalized suspension tuning (i.e. Push) straight form the factory, without any additional charges. Below is a simplified explanation of the process our R&D staff will go through in order to develop a custom-tuned valving for any bike design, using the new Chumba VF2 and EVO G2 model as an example.

1.       During initial product development, our engineers have done data acquisition on many bikes with various suspension designs. This helped them understand what is happening at the wheels on any kind of terrain, independently from the bike design. The data logged was the bike’s speed and the position, velocity and acceleration of the wheel. This allows them to calculate the forces at the wheel that needs to be absorbed for all kinds of impacts.

2.       The designer / engineer / product manager of the bike manufacturer provides us the following information:

a.       Bike model name and year(s)

b.       Wheel travel

c.       Leverage ratio curve (graph showing the variation of the ratio throughout the wheel travel)

d.       Mounting hardware dimensions

e.       Additional information input about the intended use, suspension feeling goals, performance goals, etc.

3.       When that information is not available (or not enough), we get the actual bike in our R&D labs and measure it to get the data we need. We also further use the bike for testing with our development racers and riders.

4.       Our engineers will process that data using a special software (Bike Checker’s Linkage) to analyse the geometry, determine how the shock needs to work to optimize certain ride characteristics based on the leverage ratio and linkage design. Using the data logged on the trail combined with dynamometer testing, our engineers are able to replicate wheel movement on the dyno at the shock level and therefore create a dynamic calculation chart to generate data for shock tuning, independently from the bike’s geometry and suspension design.

5.       For example, Chumba's VF2 uses a relatively linear leverage rate curve from beginning to end; being slightly regressive during the beginning towards the latter half of its stroke, with a slight amount of progressiveness towards the end of the stroke for increased bottom-out resistance.  This gives a deep, supple feel during the beginning and middle of it's travel providing a bottomless feel, but also a slight ramp-up towards the end to preventing bottoming out when the maximum amount of travel is used.  Given this information, we've been able to dial in the appropriate amount of compression and rebound to compliment this feel.

      On the other hand, Chumba’s new EVO G2 model uses a similar shock size/stroke as the previous generation but has a slightly higher leverage ratio with a slightly more progressive curve from fully extended until the last quarter of the wheel travel where it becomes digressive. That means the bike will feel smoother initially, then will feel gradually stiffer and use less travel on mid-sized bumps to finally tend to be easier to bottom-out. It also has a mild anti-squat effect built-in to improve pedaling eficieny. To get the most out of this design, our shock needs to have less low-speed compression damping than the previous generation in order to keep and smooth initial feeling with just enough pedaling “platform”. The shock also needs to have a strong damping and high threshold point for the high-speed compression circuit to prevent harsh bottoming-out. This is how we can tune the shock to achieve the best ride possible from a suspension design.

6.       The engineers will produce some prototypes that are custom-valved and will test them on the dynamometer to generate data that will help validate if the valving provides what the bike needs at the wheel. Once these results are good, they will send the prototypes to the manufacturer for testing and approval.

7.       Once the manufacturer has approved our tuning, it is then offered to the general public in the aftermarket and sometimes as stock on the bike (OEM) or as an upgrade by the manufacturers.

8.       That’s what involved for each you see on our huge application list !

Featured Bicycle: 28lb. VF2 Trail Slayer - Carbon Components

Happy New Year Everyone!

We've been busy reorganizing and planning for a successful 2011!  Our loyal customer base produced some stunning bikes based off of our VF2 chassis and we thought we'd share some pictures with you all.

This custom build offers a CCDB with Titanium spring and DT Swiss front carbon fork.  The VF2 is a perfect frame for the most elite level builds and offers performance to match.

We offer custom builds and would love to discuss any build options or plans you might have.  Shoot us an e-mail at info@chumbaracing.com to discuss!