Please check out our new VF2 Product Brochure! It goes over product features, design and production overviews. Print copies may be available as well. Let us know if you have any questions.
Click on the link below:
Click here for 2010 VF2 Product Brochure
Showing posts with label Frame Design. Show all posts
Showing posts with label Frame Design. Show all posts
Monday, May 3, 2010
Friday, February 5, 2010
Insight into Prototyping of the New EVO G2
Hello CHUMBA friends and family,
It's a rainy day here in Southern California, but the work hasn't stopped. Ted Tanouye, designer and founder of CHUMBA Racing is hard at work getting the new EVO dialed and ready for production. We were running the EVO as a 1*9 because we had to make some modifications before we could fit in a front derailleur. With the popularity of Hammerschmidt, we thought it was appropriate to weld on some ISCG tabs and give the drive train system a try on our new chassis during prototype phase.
Ted custom fabricated a ISCG tab for a clean fit on to the frame from a solid block of aluminum in our factory.
Metal art!
CHUMBA Frame designer and fabricator Ted at work!
A picture of the machine
As many of you know, this bike is designed with the following features:
- 68 degree head angle with 140mm fork; 67 degree head angle with 160mm fork
- 13.3" bottom bracket height with 140mm fork, 13.5" with 160mm fork
- 150mm of travel
- ISCG 05 mounts (Hammerschmidt compatible)
- Expected weight 6.3 lbs. without shock
* These numbers are based off of a prototype and current set-up; actual production numbers may vary slightly but they will also be released before ship date.
The bike MSRP will be set at $1,650.00 and we are hoping for a ship-date in July 2010. We will keep everyone updated - prototyping and production is never a completely smooth process, so thanks for your patience and understanding!
-CHUMBA
Thursday, January 21, 2010
Interview w/ Ted Tanouye - Headtube Sizes
Ted Tanouye is CHUMBA's head designer and founder. The son of a NASA engineer with mulitple ground-breaking designs under his belt that have competed successfully in national and international races, Ted is one of the sport's true legends.
Interviewer: The rage these days seems to be on tapered headtubes, do you think they will become an industry standard?
Ted: I can't say for certain what will happen in the future; however, building frames for over 20 years, I have seen ovalization of head tubes at the lower cup area on race frames, and we have seen manufacturers react to this. What they have done, including myself, is add headtube wall thickness and gussetting of the headtube junction areas. For instance, on the F5, we do use a 1.5" outer diameter, as well as wrap most of the headtube with a reinforcing gusset. The number of reported instances of stress risers and ovalization on recent DH frames is almost zero.
Interviewer: What about trailbikes? What is your experience with ovalization?
Ted: Aluminum will always have a fatigue life. And, depending on the type of usage these bikes expose themselves to, you could see massive amounts of force applied to the lower area of these bikes. 10 years ago, I woud never have imagined that trail bikes would be subjected to the type of abuse that they undergo today. Also, it's not only the ordinary usage, but flat-landings and slip-ups during jumps and drops could mean that the head tube is subjected to forces that are far magnified compared to ordinary trail-riding or if you were to have a smooth transition or landing. Taking all of this into consideration, manufacturers seem to be trying to deal with this problem by increasing the head tube size by using a larger bearing to dissipate stress, and increased surface area for mitering; however, it's tough to say how effectively these proposed solutions will work out in the long-run. However, we can say with some certainty that the lower head tube area will usually ovalize first over time wth repeated stress.
Interviewer: So what is the future of CHUMBA's headtubes?
Ted: Any time we propose a change in the frame, we deliberate over the change, and try to review as much data as possible to make sure that the change really affects performance and durability in the long run. We really try to resist the urge to jump on the band-wagon, as there is a lot of pressure from industry hype to adopt new standards. We will take a wait-and-see approach before committing to a change.
Interviewer: Thanks for the information, and hope to talk again soon.
[END]
Interviewer: The rage these days seems to be on tapered headtubes, do you think they will become an industry standard?
Ted: I can't say for certain what will happen in the future; however, building frames for over 20 years, I have seen ovalization of head tubes at the lower cup area on race frames, and we have seen manufacturers react to this. What they have done, including myself, is add headtube wall thickness and gussetting of the headtube junction areas. For instance, on the F5, we do use a 1.5" outer diameter, as well as wrap most of the headtube with a reinforcing gusset. The number of reported instances of stress risers and ovalization on recent DH frames is almost zero.
Interviewer: What about trailbikes? What is your experience with ovalization?
Ted: Aluminum will always have a fatigue life. And, depending on the type of usage these bikes expose themselves to, you could see massive amounts of force applied to the lower area of these bikes. 10 years ago, I woud never have imagined that trail bikes would be subjected to the type of abuse that they undergo today. Also, it's not only the ordinary usage, but flat-landings and slip-ups during jumps and drops could mean that the head tube is subjected to forces that are far magnified compared to ordinary trail-riding or if you were to have a smooth transition or landing. Taking all of this into consideration, manufacturers seem to be trying to deal with this problem by increasing the head tube size by using a larger bearing to dissipate stress, and increased surface area for mitering; however, it's tough to say how effectively these proposed solutions will work out in the long-run. However, we can say with some certainty that the lower head tube area will usually ovalize first over time wth repeated stress.
Interviewer: So what is the future of CHUMBA's headtubes?
Ted: Any time we propose a change in the frame, we deliberate over the change, and try to review as much data as possible to make sure that the change really affects performance and durability in the long run. We really try to resist the urge to jump on the band-wagon, as there is a lot of pressure from industry hype to adopt new standards. We will take a wait-and-see approach before committing to a change.
Interviewer: Thanks for the information, and hope to talk again soon.
[END]
Custom-made F5 frames from Spain
Our distributor in Spain, Gavarres bike, has made these custom frames based off of the F5 chassis, using new geometry, custom graphics, and a new top tube. These bikes are not yet available, as they are still in prototyping phase, but you can check out pictures here and e-mail us for more information.
Let us know what you think!
Monday, January 18, 2010
The Beauty is in Simplicity
In Malcolm Gladwell's best-selling book "Blink," he describes a phenomenon of rapid cognition - meaning the mind makes a split-second decision on a person, a product, or an idea - and has a gut feeling or intuition that is often times correct. When we set out to design the VF2 - this book heavily influenced our design philosophy - we wanted a bike that just "looked" and "felt" right without any excuses. We aimed for simplicity in design, we didn't want too many moving parts, forced pivot locations, or excessive tube bending and shaping - what we aimed to do is make a bike that "flowed" and had a natural elegance to it.
We emphasized our constantly linear suspension - one designed around a simplistic yet enduring engineering philosophy - don't over engineer the linkage - keep it predictable and constant. So, we naturally went with a 4 bar fully active linkage. Second, we wanted the bike's proportions - front and rear triangle to look natural to the eye - and we didn't want to warp parts of the bikes just to fit in pivot points and make the linkage work.
What we came up with, is what we believe to be one of the most beautiful frames on the market - you can see how the competition stacks up and judge for yourself.
Compare different designs - 2 different philosophies - complexity vs. simplicity:
We emphasized our constantly linear suspension - one designed around a simplistic yet enduring engineering philosophy - don't over engineer the linkage - keep it predictable and constant. So, we naturally went with a 4 bar fully active linkage. Second, we wanted the bike's proportions - front and rear triangle to look natural to the eye - and we didn't want to warp parts of the bikes just to fit in pivot points and make the linkage work.
What we came up with, is what we believe to be one of the most beautiful frames on the market - you can see how the competition stacks up and judge for yourself.
Compare different designs - 2 different philosophies - complexity vs. simplicity:
Coil or Air?
Some people swear by air shocks - others by coil. Sure, there are obvious benefits to air shocks, such as generally being lightweight, and less expensive than a coil with titanium spring. However, the way these shocks work with different suspension linkages also influence people's decisions. Since air shocks increase dampening exponentially as a shock compresses, frame designers often use a regressive leverage rate towards bottom-out to create the desired "linear" feel. This is why some frames like the Ibis HD, which uses the DW Link, instruct riders to only use air shocks with their frames. If a coil shock was used on this bike the suspension would end up feeling softer as you compress the linkage past the sag point towards full compression - essentially providing little bottom-out resistance.
On the other hand, many 4 bar frames have linear linkage feels, this gives the option to either run a coil shock or an air shock. A coil shock - which is inherently linear coupled with a linear linkage - will give a feeling of controlled and predictable travel. This is largely because the suspension would compress with an equivalent amount of force throughout its travel. Conversely, if you ran a progressive air shock on this type of linkage, you would get a progressive feeling suspension. So you have the option to run either coil or air with a linkage like the CHUMBA VF2 or XCL.
It's conceivable that some riders have used coil shocks on frames not designed to accept the linear rates of these dampers. It's important to always double check with manufacturers first before swapping out different shocks to make sure that the results of the damper change will coincide with the desired ride feel.
You can shoot any suspension set up or tuning questions to tech@chumbaracing.com. Just to be clear though, all of CHUMBA frames were designed to accept either coil or air shocks, and we encourage the use of coil shocks.
Happy trails.
On the other hand, many 4 bar frames have linear linkage feels, this gives the option to either run a coil shock or an air shock. A coil shock - which is inherently linear coupled with a linear linkage - will give a feeling of controlled and predictable travel. This is largely because the suspension would compress with an equivalent amount of force throughout its travel. Conversely, if you ran a progressive air shock on this type of linkage, you would get a progressive feeling suspension. So you have the option to run either coil or air with a linkage like the CHUMBA VF2 or XCL.
It's conceivable that some riders have used coil shocks on frames not designed to accept the linear rates of these dampers. It's important to always double check with manufacturers first before swapping out different shocks to make sure that the results of the damper change will coincide with the desired ride feel.
You can shoot any suspension set up or tuning questions to tech@chumbaracing.com. Just to be clear though, all of CHUMBA frames were designed to accept either coil or air shocks, and we encourage the use of coil shocks.
Happy trails.
Tuesday, January 5, 2010
CHUMBA Racing - Cane Creek Double Barrel Shock Tuning Program
This whole project started because customers asked if the VF2 was capable of being more than just an XC bike and if they could improve upon the RP23 that was fitted to the VF2. Awhile back, Ted Tanouye, head of R&D at CHUMBA, and I were riding the Fullerton Loop in California. After climbing a steep section of the trail, we stopped, and I asked, “How is that rear shock?” Ted said “the VF2 with a CCDB could outperform an EVO equipped with an air shock.” For Ted - a man who developed championship-winning race bikes out of his garage – to make such a claim, gave cause for serious attention to this rear shock and how it would interact with CHUMBA frames, specifically, our VF2 linkage system.
So I turned to one of the industry’s most knowledgeable shock gurus – Josh Coaplan, head of R&D at Cane Creek. Josh helped develop the Double Barrel alongside other engineers at Ohlin’s Racing, the premier shock manufacturer for off-road equipment, like ATVs, snowmobiles, etc.
I sent Josh a VF2 frame for analysis of axle path and leverage ratio to help us optimize the complex settings of the CCDB for the VF2. From my conversations with Josh and Malcolm at Cane Creek - we hoped that this shock properly tuned to the VF2’s linkage would provide the basis in which to help reduce pedal-induced bob while retaining the superior bump absorption and traction that the CCDB is famed for. Coupled with the VF2’s linear linkage (more on that later) the CCDB would offer unrivaled shock tune-ability and performance.
Upon receipt of the frame, Cane Creek proceeded to build their own hardware to make sure a proper fit of the Double Barrel in the shock mount locations of the VF2. After Cane Creek received the VF2, they proceeded to equip it with the proper hardware, and started to do a full analysis of the leverage ratio, axle path, and other relevant data all from real-world data acquisition.
The data Cane Creek acquired, matched all of the R&D testing that we had confirmed in our 3-d modeling, as well are our prototypes, and actual production models.
CHUMBA’s frames have the unique advantage of allowing the suspension to behave the same way at all points of travel, allowing for smooth technical climbing, pedaling through rock gardens with a fully active suspension, and descending with complete confidence and predictability, whether riding on the trail, or hitting bigger drops and jumps.
Given the linear nature of the VF2’s leverage ratio curve relative to other bikes in its class (although technically it is regressive and slightly progressive towards bottom out), the linkage will reflect a shock’s tuning very closely. This means, if you tune up the low speed compression, you will immediately feel this throughout the VF2 linkage’s travel without varying leverage rates from the linkage interfering with what you want the shock to do.
This means if you own a VF2, or are interested in one, you have the advantage to really custom tailor your Double Barrel to how you want it to perform at low speeds or high speeds, and the linkage will remain neutral to accept your change, making the combination of the VF2 and the Double Barrel one of the most customizable rides on the market.
I sent Josh a VF2 frame for analysis of axle path and leverage ratio to help us optimize the complex settings of the CCDB for the VF2. From my conversations with Josh and Malcolm at Cane Creek - we hoped that this shock properly tuned to the VF2’s linkage would provide the basis in which to help reduce pedal-induced bob while retaining the superior bump absorption and traction that the CCDB is famed for. Coupled with the VF2’s linear linkage (more on that later) the CCDB would offer unrivaled shock tune-ability and performance.
Upon receipt of the frame, Cane Creek proceeded to build their own hardware to make sure a proper fit of the Double Barrel in the shock mount locations of the VF2. After Cane Creek received the VF2, they proceeded to equip it with the proper hardware, and started to do a full analysis of the leverage ratio, axle path, and other relevant data all from real-world data acquisition.
CHUMBA and Cane Creek jointly analyzed shock settings and performance by testing the CCDB on the VF2 with professional riders, engineers, and test riders both at CHUMBA and Cane Creek. We then confirmed data between each other and found similar results. Here's a pic of Cane Creek's VF2:
Given the linear nature of the VF2’s leverage ratio curve relative to other bikes in its class (although technically it is regressive and slightly progressive towards bottom out), the linkage will reflect a shock’s tuning very closely. This means, if you tune up the low speed compression, you will immediately feel this throughout the VF2 linkage’s travel without varying leverage rates from the linkage interfering with what you want the shock to do.
This means if you own a VF2, or are interested in one, you have the advantage to really custom tailor your Double Barrel to how you want it to perform at low speeds or high speeds, and the linkage will remain neutral to accept your change, making the combination of the VF2 and the Double Barrel one of the most customizable rides on the market.
Headtube Debate: Frank from Crank Brothers weighs in
I stopped by Crank Brothers to ask questions about trends in headsets and other products that might affect the second gen EVO. Frank, the head of engineering at Crank Bros. said that he believes a tapered headtube (1 1/8" to 1 1/2") could be the best option because riders could use a standard steerer tube without running 2 sets of spacers (on a 1.5") - a potential weight-savings. He also pointed out that the forces from the wheel would likely be transferred directly to the lower headset area first - making a larger diameter headset area more durable in the long run. He explained that forces would be magnified at the lower headset area, and eventually partially dissipate making for less force loads traveling to the upper headset area.
I am beginning to embrace the idea that a tapered headtube with a reducer cup could be a great option - however, I am also still very fond of the 1 1/8" for it's simplicity - and long-term durability when used on CHUMBA frames. We've also had extremely good results with the 1 1/8" inner diameter and 1 1/2" outer diameter headtubes on our F5s. We still have some time to make the final decision - so we'll see!
Some serious standover -
UPDATE: The effective top tube reported is 21".
Monday, January 4, 2010
CHUMBA Tech Article - Leverage Rates
There have been many exciting developments with CHUMBA over the last few months. But, before I get into that, I would first like to thank all of our loyal supporters and riders, and let everyone know that CHUMBA is truly on its way to becoming one of the world’s most prestigious bicycle brands. CHUMBA is focused on quickly developing and tuning our suspension technology, along with offering aesthetic and performance options unmatched by any other high-end company. Here are a few of the things we’ve been doing:
1. Identifying Suspension Curves and Accompanying Shock Settings to Maximize Performance
To make things easy – just remember that a decreasing leverage ratio means compression resistance is increasing; and increasing leverage ratio means compression resistance is decreasing. Just remember the analogy of a lever – imagine that you are trying to compress the shock with a lever. The longer the lever is the easier it will be to compress the shock; so the more you increase your leverage ratio, the easier it becomes to compress a shock. As your leverage ratio decreases, it will become harder to compress the shock.
As you can see in the chart above published by Trek’s R&D team, the leverage ratios at a given area in shock travel vary tremendously for some manufacturers. As you can see on the DW-Link Mojo – the dramatically varying and increasing leverage ratio towards the end of stroke means less bottom out resistance from the linkage. Additionally, the Santa Cruz Blur probably has one of the largest varying suspension rates, going from as high as 2.7 all the way down to 1.65. Further, on the DW Link and VPP, the leverage rates increase and decrease all throughout the curve – making for varying feels throughout the travel.
As you can see with the VF2 – the leverage ratio is predictably constant – making the travel feel extremely consistent and predictable when compared with the competition. You can see the variance of the compression resistance is minimal, being slightly regressive with a small amount of bottom out progressiveness at the end. Yamaha MX and CHUMBA test rider Dustin Nelson put it well when he says “linear rates give you the most amount of controlled feel over travel” – as you don’t need to compensate suspension feel with a varying leverage rate to try and make up for pedaling input from
the suspension.
the suspension.
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