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Old 08-21-2010, 04:53 AM
Chalo Chalo is offline
Motorized Bicycle Senior Member
Join Date: Aug 2010
Location: Texas
Posts: 78
Default Re: Strengenthing my new cruiser

Originally Posted by BarelyAWake View Post
erm... Hate to throw fuel on the fire - but a triangle is most definitely the "strongest geometric shape" w/o a doubt or debate - arches do come in a close second, the only problem being it's heavily dependent on where the load is... and a bike frame isn't ideal loading for your typical arch (thus the added supports in a cantilever).
Arches are for compressive materials; trusses are for materials that can take both tension and compression. Trusses are more efficient (hence the availability of two-pound bike frames in the real world).

In the end, the above isn't if a Cranny needs be "beefed up" because it's a cantilever - when it comes down to it, it's a budget bike and that's the only problem. I'd no sooner trust a budget diamond frame than a cantilever as it's not the geometry that is the root of the problem, it's the lack of quality materials and welds evidenced by actual failures and not just theory.
I dunno, man-- I've seen a lot of reeeally cheap and horrible traditional Indian, Chinese, and Mexican bikes that have nothing on the Cranbrook materials-wise, and whose frames aren't any heavier, but which still last long enough to be handed down from one generation to the next. The difference is design, both overall and in the details.

There is no doubt in my mind that you could motorize a Chinese Flying Pigeon and it wouldn't bust up multiple times within a short period like Kevlarr's Cranbrook has. And it ain't because the bike is expensive, meticulous, or high quality.

"When I see an adult on a bicycle, I do not despair for the future of the human race."
H.G. Wells
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