Sunday, October 14, 2007

Karls 69r

I've been bantering back and forth with Karl on his Viento 69r and thought it would be cool to share his thoughts on the bike, and his setup.
Living at the base of the North Shore Mountain I don't get an opportunity to different setups like this because its go up... and then go down... theres not much roll in our part of the world. I really want to try one of these out next time I go to Bootleg and I'm going to make sure Linden [our Colorado rep] has a 69r in his aresenal of demo bikes.
Basically a 69r, for those of you who don't know, is a bike with a 26" wheel in the back and a 29" up front.

Anyway heres what Karl had to say

I think this is the best pic from last week, it definitely emphasizes the larger front wheel. As for a bit of history...
Until 2007 I raced Xterra Triathlons, with my best finish being 6th amateur over-all at the 2006 World Championship in Hawaii. I also was racing singlespeed cross country and endurance events. I always have had amazing support from my wife and kids, however, this year there are too many other activities and responsibilities, so racing has taken a back seat.
This is why I was looking for an 'all-mountain' bike in the spring and decided upon the Banshee Viento. After riding it with various amounts of travel on the front end I finally settled on 115mm as the best feel and performance for my style of riding. As for my style, I like to take smaller (up to 3 or 4 foot) drops and climb and descend as fast as my conditioning and skills allow. That is where the 29er front wheel comes in. While on a ride with Terry Pitman, the owner of the Bike Shop in Henderson, Nevada, Terry recommended the larger wheel size because of the terrain that I typically ride and the way I ride. We talked about all of the benefits including the larger footprint, the beneficial angle of attack that is created by the larger wheel when rolling over obstacles on both the climb and the descent, the faster rolling tire at speeds and the greater control that the larger wheel provides.
That is when we put the 29er wheel on with the Reba 29er fork with 85mm (or maybe 80mm) of travel. Because of the larger diameter wheel paired with less travel of the fork the overall head tube angle barely changed and did not cause any adverse handling affects for 'cross county' riding. Plus I still have the quickness and acceleration of the 26 inch rear wheel. I have definitely noticed the advantages of the larger front wheel, especially on steep rocky descents where the 26 inch front wheel gets 'knocked around' by the larger rocks, the 29er wheel rolls right over. One more benefit that resulted form the larger front wheel is a higher bottom bracket (it is now 12.5 versus 12 inches with my previous setup), however, my center of gravity in relation to the entire frame is lower. It is similar to the models of the compressed suspension and how the frame sinks between the wheels. If you look at the added height of the front hub in relation to the height of the bottom bracket you see that the frame is 'sitting' within' the wheels.
Of course, this whole experiment would not have worked without the right frame. Because of the the geometry of the Viento, primarily the standover height and headtube designed to accommodate forks from 3-6 inches it worked.
I know I said racing has taken a back seat, but this coming weekend, Oct. 20th, I am going to test the setup at the 12 Hours of Bootleg hosted by All Mountain Cyclery. I am going to race the solo category which will give me plenty of miles on the 69er, many more at one time than I have had a chance to do so far.
Anyway, when I am ready to invest in a full-suspension frame I want to do the 69er setup on a Banshee Pyre. After looking at the geometry of the Pyre I think it would work and result in the same benefits and provide the perfect all mountain bike for both trail riding and racing.