Tomac Bikes, who just released their first 29″er, the Flint hard tail, for 2010, now are announcing that they are adding a full suspension bike with big wheels for 2011. Dubbed the “Diplomat”, the bike is aimed at trail riders with a 120mm travel rear and designed for 120mm travel front forks. Tomac Bikes’ Joel Smith gave us the low down on this bike which will follow after the image.
The Diplomat 29 delivers 120mm of travel in a compact, nimble handling package. It features a tapered head tube for additional stiffness, direct mount derailleur for crisp shifting. and plenty of tire clearance to accommodate those high volume tires.
Joel explained to us that it isn’t easy designing a full suspension bike around 29″er wheels that works well, but added, “But overcoming those constraints is also what makes the Diplomat such a nice riding bike. For example, just to make the chain stays as short as possible, we designed a removable seat stay arch and attached the front derailleur directly to the chain stay yoke. This allows us to keep the chain stays at 17.5 inches, one of the keys to making the bike nimble handling.”
One of the other pitfalls to designing a full suspension 29″er is lateral and torsional flex, something that Tomac Bikes was also concerned with in developing the Diplomat. They used the tapered 1 1/8th”-1.5″ tapered head tube size and will spec 15QR forks from Fox on the complete bike offerings to combat flex in the front. However; they didn’t forget about the rest of the frame either. Joel explains, “Because the swing arm typically sees the majority of lateral (side to side) flex, the Diplomat uses a fully triangulated rear swing arm to increase stiffness. Stiffness in the swing arm translates both into better rider control, but it also allows the suspension to be more active in rough terrain. When the rear end is suffering from lateral flex during suspension movement, it binds the shock and will limit suspension movement. The front triangle has also been designed with stiffness in mind. The top and down tube are specially shaped to maximize lateral stiffness, and are triple butted to ensure minimal weight.”
Tomac Bikes is employing a Fox RP 23 Fox shock with a “XY” secondary air canister which Joel says will result in a flatter suspension curve especially from the mid-stroke to the end of the travel. Joel also explained that climbing prowess was also a main goal of this design so it could get up and down rough, rocky tracks with minimal impact on the rider while giving the rider more control. Tomac used the proprietary IAS suspension system on the Diplomat which Joel explained to us as follows:
IAS is a simple yet effective system that improves overall suspension action without sacrificing pedaling efficiency or rear end stiffness. With IAS, a CNC machined link between the rocker pivot and seat stay end, carried by high end full-compliment bearings, allows the rear shock to initiate more quickly and the suspension to be more responsive. IAS suspension makes quick work out of bumps, especially repetitive hits (think braking bumps) where quick suspension action means less transmitted to the rider.
Besides the upper links, the Diplomat uses a main pivot that is slightly forward and above the bottom bracket. This position was picked especially to give optimum pedaling efficiency without sacrificing small bump compliance. Joel explains; “The Diplomat’s main pivot is located so that it maximizes pedaling efficiency, but not in a place that would create excessive pedal feedback or minimize the bike’s ability to absorb bumps. We used a Fox RP23 shock with XY secondary air canister because it’s more linear from middle stroke and has low initial stiction (because you are running lower initial pressures). The Diplomat has a relatively flat shock rate, which maximized the character of the air shock. It allows the bike to pedal well, get full travel and still feel bottomless throughout the travel.”
Here are some features and information on the Diplomat sent to us by Tomac Bikes:
* 6.8 pound/3100g frame weight with Fox RP23 shock
* 6069 aluminum with custom butted top, down and seat tubes
* Fits Shimano direct mount front derailleur’s
* Full seat post extension
* Up to 2.5 tire clearance
* 71 degree head angle, 73 seat angle, 13.1 BB height, 17.5 inch chainstays
* Available in medium, large and extra large
Full availability end of September, MSRP $1399.00 USD for the frame only. There will be a complete model with two spec levels as well: MSRP $4299.00 USD (XT/XTR) – $2999.00 USD (SLX/XT).
Thanks to Tomac Bikes and Joel Smith for answering our questions and supplying the image and information in this post.