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Old 05-26-2010, 12:31 AM
wildemere wildemere is offline
Motorized Bicycle Elite Member
Join Date: Feb 2008
Location: Newcastle
Posts: 269
Default Re: Aluminum Frame or Steel Frame?

Lance and his cronies wouldn't spit on aluminium frames, too much energy is lost in the frame flex. Carbon fibre with hollow titanium parts and ceramic bearings is what the racers use. Even crank arms are CF these days. Seen thier wheels? Then their new electronic shifters... Their bikes cost $20,000+ each. They use four or five of them in a long race

Plain, non heat treated aluminium is not good for bike frames, downhill and hard core BMX racers prefer Chromoly or Titanium as aluminium alloy is too soft and it cracks/breaks without much warning.

For Motorized bikes the order of preference for me is:-

Titanium:- Highest strength to weight ratio of any metal, would love to have one!

Chrome Molybdenum Steel:- Used in the high end bikes, famed for its ride quality. Accurate steering and feel.

High Tensile Steel:- Mid level bikes, some cruisers, better than mild steel, rides nicely with a good feel.

Mild or plain steel: Supermarket and kiddie bikes, fairly flexible, rarely fails. poor, uncertian ride quality.

Aluminiun:- These days its mostly a gimmick, at the supermarket level anyway. A good name brand heat treated alloy frame is another thing but but still prone to random failure compared to the other types. More flexible than a good ChroMoly frame

Carbon:- Would be awesome except for the clamping problems and if scratched/scored wil fail in that area.

For motorised applications i think steel is the go. The better the steel the better the ride. Most aluminium frames have too much flex and a poor breaking/failure mode for heavy duty use.

My aluminium shifter bike has signifigant flex in the BB area under full power. Previous steel shifter bikes I built did not have this issue.

I wish for a Titanium frame one day.
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