12-17-2008, 09:08 PM
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#11 (permalink)
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EcoModding Lurker
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Its to do with the tensile strength of carbon fiber and the low coefficient of thermal expansion
Wheels get hot they also get shock so you want a strong material that has a bit of give in it, carbon fiber is just too stiff to be reliable in the application of a wheel. When the wheel gets a heavy impact and the tensile strength is exceeded the wheel will explode rather than get bent like a normal alloy.
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12-18-2008, 12:27 PM
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#12 (permalink)
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Quote:
Originally Posted by Christ
Do those have tires on them?
I saw somewhere... (might have been a joke) latex compound bike tires... very low weight rating, but they were supposedly LRR tires for bikes..
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I think they do, since they're tubulars. Lightweight is good for climbing, but you get better momentum for flat course and downhill with a slightly heavier wheel, as long as the weight is at the rim and not the hub.
Saw a gimicky looking thing a while back that was basically weights on springs you attach to the wheels. At low speeds, the mass is near the hub for better acceleration. At higher speeds, the mass is closer to the rims for better momentum. Interesting concept and apparently, on the right course, can increase average speed.
But back to carbon fiber: carbon fiber failing is pretty high on the FAIL scale, far more so then the metal alloys.
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12-18-2008, 02:43 PM
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#13 (permalink)
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Moderate your Moderation.
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Quote:
Originally Posted by i_am_socket
At higher speeds, the mass is closer to the rims for better momentum. Interesting concept and apparently, on the right course, can increase average speed.
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This was also a concept that was used for a variable gearing system on bikes. I never personally saw one in use, but I saw them displayed at the local bike shop when I was a kid, and it didn't seem like too many people bought into it.
Faster you went, larger the rear sprocket would get... only in final gear though, and it had extra sets of teeth that would fill in the gaps to keep the sprocket "round" so the chain wouldn't leap.
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12-18-2008, 05:52 PM
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#14 (permalink)
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38 time NHRA/IHRA Champ
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Quote:
Originally Posted by aerohead
I attempted to locate a single wheel over the wrecking-lot parts-locater network for an Earth-Day exhibit and never scored.I understand that they weigh only about 8-pounds.Should one of your race friends want to part with one of the "ruined" wheels,I might purchase one for future exhibits.For street use they might have been okay,as they did receive DOT certification.From a mass standpoint they're quite remarkable!
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I don't think they were that light or all the really fast Shelby/Dodges would scarf them up for use on their cars in place of the Borbets.
E-mail me your name, address, and phone number. I will put a feeler out on the two national forums and send your info ONLY to those that have rims available.
ataylorracing@comcast.net
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12-18-2008, 05:54 PM
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#15 (permalink)
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38 time NHRA/IHRA Champ
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I meant the fast Shelby/Dodge drag racers, not road racers.
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42 time NHRA/IHRA drag race champ
05 SRT4-12.17@117 mph on DOTs-31.0 mpg-SOLD
96 Geo Metro-3 banger-60.1 mpg-SOLD
95 BMW M3-13.41 @ 106 mph-31mpg-SOLD
77 Chevy Monza with 350/350-FOR SALE
84 Horizon-1880 lbs-29 mpg
95 Neon-43 mpg
99 Z28-10.80 @ 127 mph-27.1mpg
2011 Prius-62.1 wife's
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12-18-2008, 10:44 PM
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#16 (permalink)
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Thanks to all who posted.
There are some valuable points for further consideration there.
Pete.
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12-18-2008, 10:52 PM
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#17 (permalink)
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Moderate your Moderation.
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Quote:
Originally Posted by ATaylorRacing
I meant the fast Shelby/Dodge drag racers, not road racers.
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The rarity of them, and relative difficulty to replace, might be a good reason they don't use them.
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12-18-2008, 10:59 PM
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#18 (permalink)
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Hi,
The Britten V1000 had handmade carbon fiber everything -- the wheels were constructed in a "skin & bone" method, with carbon fiber:
The whole bike was just 138kg (305 pounds):
Britten Motorcycle Company
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12-19-2008, 02:39 AM
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#19 (permalink)
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carbon fiber also isnt good with "shock" nor is it flexible.
i hear alot of the monocoque design cf bikes disintegrate after harsh use.
but i know they make carbon fiber sidewalled tires. not cheap stuff, and they only come in low pros i believe.
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12-19-2008, 03:56 AM
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#20 (permalink)
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Quote:
Originally Posted by achang1
i hear alot of the monocoque design cf bikes disintegrate after harsh use.
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hear from whom?
i saw a guy repeatedly pick his cf bike up over his head and throw it to the ground in a fit of anger after flatting on a first lap escent and losing contact with the pelaton - the bike took it all in stride
awesome material
i ride with many people and unless it's a big crash, i've never heard of frames going
i have witnessed cf fork failures but that's a pretty demanding job
i have a set of these wheels, but have been too busy to try them out
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