I'm looking for a frame and gearing recommendation for a 300-pound, new cyclist. I introduced my brother to cycling and he is addicted. His weight and size are concerns due to the flexibility in today's frames.
For a larger rider what frame material is best? Should he be looking at a carbon, aluminum or steel frame? Should he be looking for a very large bottom bracket? Should stiffness be a priority?
He currently has a 2007 LeMond Alpe d'Huez, which was selected based on his comfort, budget and confidence when riding. When the LeMond is on the trainer, he can see and feel the flex in the bike when he is pedaling, which adds to his concern.
Manufacturers do not provide weight limits on frames, so shopping with safety in mind is a challenge. From his research, he appears to be extremely interested in the Giant Advanced or Specialized Roubaix.
Most road bikes are designed for 185-pound males, but tested to far greater extremes, so strength issues should not deter your brother from pounding out the miles.
Safety should not be a concern if he takes a couple of precautions: First, he will be burning up brake pads and heating his rims when descending steep grades. For this reason, watch the pad wear and choose a wheelset with aluminum rims (Mavic Ksyrium is a great choice), and keep the tire pressure up towards the maximum noted on the sidewalls.
Second, he will be pushing a lot of weight uphill, so suggest that he upgrade his bike with a triple chainring setup. The granny gear will make extended climbs a practical part of his cycling and give him the ability to ride with any group or organized event that includes substantial climbs.
As far as a bike, the Roubaix is a good choice, as is the Giant. Aluminum and carbon are the best choice for frame materials because they offer the best strength and stiffness-to-weight ratios.
The fact that he flexes his frame and components when on the trainer is inconsequential—there is no way to put lateral forces into a frame unless it is bolted to a rigid platform. Once he puts the rear wheel back on and hits the road, his frame will see less lateral stress than a featherweight high-watt climber would inflict upon it.