The Transition TR450 Prototype Downhill bike
The TR450 is currently in prototype stages for testing. We are expecting production models to be available late 2009 in time for the 2010 season.
The TR450 is Transition’s new dedicated downhill racing machine. Heavily researched and selected with direct input from pro rider Lars Sternberg, this is an aggressive geo built for speed and stability. With a careful ratio between chainstay length and head angle, the frame has a neutral feel in corners with good rider weight balance between the front and rear wheels. The TR450 gets 8.25” of travel from a 9.5” x 3” shock placed low in the front triangle. The linkage was tuned to provide a gradual change from beginning to ending leverage rate. The suspension ramps up very evenly through the travel to give the bike a supple top stroke and good bottom out control without excessive sag or mid stroke wallow. This result is a consistent progressive suspension feel that is predictable and yields a high amount of tunability.
There are large cartridge bearings at all pivot locations, with an absolute monster of a bearing used at the main pivot for durability and frame stiffness. All bearings are pressed directly against post welding machined bearing seats inside the linkages, eliminating misalignment that can occur when bearings placed at outer edges are “pinched” together. The overall suspension design was selected to keep the shock low in the frame, while still protecting the rear shock from tire roost. The pivot points have been laid out to triangulate loads and keep the rear end stiff, which helps keep the bearings turning smoothly, and your wheels tracking straight.
Custom tube shapes were developed and the downtube has a tooled reinforcement rather than a traditional weld on gusset. This thicker section reinforces the underside of the downtube/headtube junction without the stress riser created at the edge of a weld on gusset. The front triangle features double welding, which creates a thick but smooth weld and yeilds a significant increase in strength for high stress areas. The TR450 has a tapered headtube with an integrated Cane Creek size top bearing and standard 1.5” bottom intended to run a zero stack cup. The shape of the headtube better matches the toptube and downtube size and shape, and leaves plenty of clearance for fork crowns. The short headtube length gives riders lots of room for handlebar height adjustment and an aggressive low stance.
Mud shedding was a key concern in the design of the frame. Excessive pockets were avoided and many parts, like the dropouts and rear triangle yokes, are hollowed from the inside and smooth on the outside so mud won’t collect in hard to reach places. The smooth aesthetic carries over into the lines of the frame. When viewed from the side, the linkage stays hidden from view right up to the sag point. This is a clean frame, any way you look at it. In the End, the TR450 was designed to be a bike that could be ridden hard and put away wet while being a dependable top level race bike you can trust race after race.
- 210mm (8.25″) Rear Wheel Travel
- Fox DHX RC4 Coil 9.5″ x 3″ stroke
- 6000 Series Heat Treated Aluminum
- Sizes: Small, Medium, Large
- Current Production Run Colors: TBD
- Decals: TBD
- Frame Weight: 9.5 lbs (without rear shock)
- Complete Bike Weight Range: 38-40 lbs (Depending on Rear Shock and Fork current test prototype bike is 39 lbs.)
- Tapered headtube 1 1/8″ to 1.5″
- Compatible with up to 8″ dual crown forks
- 12 x 150mm thru axle Dropouts Standard
- 83mm bottom bracket spacing
- Accepts up to 8″ Rear Disc Brake Rotors
- Easily fits up to 2.8″ rear tire
- 1 year defect warranty, Lifetime crash replacement
- Shock Specs: 9.5″ eye-to-eye x 3″ stroke, Rear Pin 22.2mm x 8mm, Forward Pin 22.2mm x 8mm
- Bottom Bracket: Euro 83mm shell
- Headset: 1.5″ Lower (deep cup compatible) / 1-1/8″ Cane Creek Integrated Compatible (drop in bearing)
- Seatpost: 31.6mm
- Seat Clamp: 34.9mm
- Rear Dropout Spacing: 150mm x 12mm
- Disc Brake Mount: International Standard
- ISCG 05 Mounting Tabs
Great article and more photos at NSMB.com
Check out our sponsor Black Rock Bicycles for Transition Bikes. They do an awesome job setting up your new Transition!