Wednesday, February 16, 2005

Spectrum on Big Rider Geometry.

Spectrum on Big Rider Geometry.

Tom Kellogg is another builder whom I have had some e-conversations with about building a frame for my big frame. He is very knowledgeable and I believe is another excellent builder who can accommodate the Clydesdale class. Spectrum is highly recommended and his work is top notch.

William

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Bicycle Geometry for Big Riders
When a tall cyclist looks for a bicycle there just aren't that many options available. You can try a local bike shop but the chances are you and the dealer will quickly become frustrated. Stock frames just aren't designed for big riders so you can forget the fit kit run through. You are beyond the kit's realistic size limits anyway as they are designed to get a beginning cyclist into an entry-level bicycle. If you are serious about cycling and are a tall cyclist Spectrum strongly suggests you investigate a Custom frame. You may not buy it from us (even though we think you should) but Custom is still your best option.

So what should big riders look for in a bicycle frame? Lets start with what they shouldn't do. They should not look for a frame that is simply a bigger version of a production frame. The reasons deal with strength and ride quality. As frames (and their tubes) get longer, the stresses put onto the tubes are increased not only because they are longer, but also because the rider is usually heaver and stronger. The tubes are also more highly stressed because the rider farther from the ground. Big production frames often beef up tubing to compensate. Bad idea! Simple beefing up of the frame tubes will cause the frame to loose its resiliency.

Just as critical as expert material choices is the knowledge required to make a large frame fit and function as well as a standard sized frame. Simply expanding the size of the frame results in a frame that works like a truck. There are a myriad of adjustments that a builder must make to larger frames to make them work properly. Front-end geometry changes may be required to compensate for a longer wheelbase. Rear-center and front centers may require adjustment with changes in seat angle or rider center of gravity. While most large riders require shallower seat angles than smaller riders do, this is not always the case Therefore getting fitted properly is critical. Keep in mind that small changes in seat and head angles have disproportionally large effects on larger frames. If you are confused or just have questions about fit, call me. After you've got the fit nailed down, you have to consider materials. For big riders who tend to eat equipment (you all know who you are) Titanium is an excellent choice. It stands up to abuse better than any material out there and it won't rust either. You can consider Aluminum and Carbon but both have serious drawbacks especially for a larger cyclist. If you are looking for a bicycle that will last longer than a few seasons, consider the fatigue numbers associated with aluminum. Aluminum frames accumulate fatigue over the miles. That fatigue will eventually result in failure. Another problem with many of the aluminum frames now is their lack of vertical compliance. Aluminum frames offer a stiff ride but they do so at the expense of comfort.

Carbon frames are often more comfortable than Aluminum but strength is a serious consideration. Under ideal conditions, composites offer significant weight to strength advantages. Some of the current composite frames on the market work very well. But the real world does not offer ideal conditions very often. If you are a rider who does not expect to crash, be hit by a car, or damage your frame, then carbon may be for you. For a larger rider, the biggest drawback to composite frames is their unavailability. There are one or two custom builders working in composites who can build large frames, but the sources for these frames are severely limited. In short, we suggest that tall cyclists look around for a while and consider options. If you are ready to buy a Custom Frame, we suggest Titanium for strength, durability and ride quality, and steel for its beauty, solid functionality and value. But take your time! If you should decide to go Custom and you choose Titanium, your search should be easy as there are only a handful of us out there. Just look through the "marketplace" sections of The Ride and VeloNews. Talk to your riding friends to find out what they know about other builders, and give Spectrum a call if you want to find out what sets us apart.

If you need some help, print out the Buyers Checklist from this site and start comparing now

1190 Dorney Road, Breinigsville, PA 18031-1123 phone:1-610-398-1986 . www.spectrum-cycles.com