It should be apparent to most of us, that frame builders often go through great lengths to put together a frame which can seemingly do it all. Things such as head tube, seat tube angle, chainstay. seatstay. and top tube lengths all play a dramatic role in terms of how comfortable the bike feels for the rider, how well he is able to balance his weight between the rear/front axle, as well as the overall balance achieved between handling and stability. For example, the head tube angle tends to be on the slacker side (68-71 degrees) for mountain bikes, which results in slightly less precise steering, but improves stability. Road bikes tend to have a more aggressive head tube angle (about 74 degrees) which sets the fork further in front of the frame, increasing steering precision, albeit at the expense of overall stability. Seat tube angles on mountain bikes tends to be angled fairly aggressively backwards to increase the amount of weight towards to rear axle, setting the rider backwards for a more stable angle of attack during climbing scenarios. However, angle the seat tube too far backwards, and this will compromise the amount of weight the rider places over the handlebars, causing a light front end which may result in the rider flipping over. chain stay lengths tend to be increase due to the introduction of larger 27.5/29" rims. This helps to increase stability at speed due to a longer wheel base, and helps balance the weight better to prevent the handlebars from lifting up during climbs. A shorter chainstay can help to improve liveliness on technical trails. Furthermore, you may have heard of the terminology trible, or double butted frames. This essentially means that the diameter and shape of the tubing differs according to the amount of load being placed onto each respective tube. For example, the down tube and chain stays tend to take the most stress from riding, especially at the welding points. Consequently, this area of the frame tends to have thicker, stiffer tubing in place. The top tube and seat stays are usually a different shape. to allow for a little bit of forgiveness, so that vibrations and small imperfections in the terrain can be more or less absorbed before they reach the contact points of the rider.

After studying the frame geometry of my bike, a 1998 GT Zaskar LE, it is apparent to me that the engineers strived to achieve a good overall balance between polar opposites, light weight versus overall strength, stability versus handling precision, climbing versus descending, etc. The bike clearly excels on long, tough climbs, where i feel like the overall geometry and stiffness of the frame results in a high percentage of my efforts being converted directly to forward momentum. I never have to get out of my saddle no matter how steep the grade is. I just snatch and lower gear, keep up a good cadence at the cranks, and power my way up. However, with all this in mind, stability on steep hills do not seem to be affected.

With GT's triple triangle frames, the seat stays are welded to both the top tube and the seat tube. This obviously results in a more rigid frame, without needing to result in extra tubing stiffness. The end result in a punishingly stiff frame which also happens to be very light. my XL frame (23" seat tube), fully equipped, weighs in at just 21LB. That is very impressive for any aluminum mountain bike in my opinion. By allowing the top tube and seat stays to intersect further up in the frame, this results in a long top tube and chain stays without making the entire wheelbase of the bike ridiculously long. You are able to easily shift your weight forwards or backwards depending on what sort of riding you are doing. The end result, is a very well balanced geometry that strikes a great balance. The riders weight is set further back without necessarily impacting front end stability.