Misschien hadden ze best nog even gewacht met een foto hier te plaatsen,deze foto vraagt wel om reactie's.saiko schreef:op andere foto's lijkt de band net niet te raken, mss is dit nog een prototype.
Ook staat op hun blog dat custom geometrie mogelijk is.
Best nog even afwachten met conclusies tot de fietsen effectief beschikbaar zijn.
nadien kreeg ik nog een mail dat een andere optie was geweest om de zitbuis een boog te geven zoals hierboven al aangehaald.That frame is a prototype. HipC, our Belgian distributor, will be sent the definitive frames in the first days of January.
One of the main goals in designing this frame, as you guessed, was to keep the geometry as close as possible to that of a racing 26" frame. In our view, 29" wheels are all advantages and almost no drawbacks when speaking of rigid bikes, and we think 26" will be gradually repalced by larger wheels except for small sizes and medium to long travel suspension bikes in which non suspended mass is a concern.
The R&T frame geometry was developed under the following premises:
1- 29" bikes up to now have had a bigger BB drop (distance from the wheel axles level to the BB) and still they had higher BB height to the ground than 26" bikes. That decreases the distance between the rider's center of gravity and the wheel axles level, thus decreasing the the rider's center of gravity leverage on the wheels. This results in the rider having to apply higher side forces to lean the bike for cornering. As a result, the bike is more "selfstable". On the other hand, the higher BB meand the rider's centre of gravity is higher too, this resulting in a more critical response to side leaning or fore-aft atittude. In other words, once we reach the point in which the rider's weight has enough leverage to cause the bike to react to side leaning or fore (steep descents)-aft (steep climbs) progression, the bike reacts more in a quicker and harder to control way.
Example: We climb a very steep section. Usually 29ers have very good traction and allow us to climb easily. Suddenly a rock or root rises a bit more the front wheel. The rear wheel still has grip but the rider's COG reaches the point where all wight in upon the rear. The bike suddenly losese steering and even tends to fall backwards. That procces happens more progresively when the rider's COG is lower. Same for steep descents in which we suddenly find a hole in our way. For tight corners in which we need a high grade of side leaning, a lower COG makes for a more progressive transition from tire sliding to full drift. Mind you tires are siliding all the time while the bike (any vehicle actually) moves, and they are able to grip like that, then they start to skid or drift, which means a very low drag coeficient. Usually a drift that starts with a hight degree of side leaning ends in a side toss.
2- 29ers tend to have a very long wheelbase. This adds up to the selfstability effect, making more side leaning or handlebar twisting needed for the same cornering radius (there are equations that explain this, but i'll try to keep it simple by now) 29ers tend too to have a higher distance between the rider's COG and the rear wheel axle due to long chainstays. To compensate this and avoid the front axle to carry too much precentage of the overall weight, they usually have slacker headtube angles, but that also adds up to the effect of needing more handebar twist and side leaning to corner.
So we decided to design a 29er that has
-Low BB
-Short stays (430mm)
-Same mechanical trail than most racing 26ers, which meant a headtbe angle bteween 72 and 72.5º dependig on size.
All this makes for a bike that keeps the advantages of larger wheels (larger contact patch, better attack angle for a give obstacle height, better absbtion, higher tire efficiency due to less angular speed,...) but with what we think is a geometry that is better suited for the experienced rider.
The definitive frame has way larger clearance and will be take 2.3"/58.4 mm tire. Clearance of a tire this size to seat tube will be between 15 and 20 mm.
I hope this, and the attached pics of the full titanium vesion clarifies the matter.
