Q about triathlon bikes.

[FrustratedUser]

Why are all thriatlon bikes equipped with 650c wheels instead of the normal 700c?

 

[Brutuskend]

They don't ALL have 650c wheels.

(read I have NO idea.)

 

[saltedeggman]

my guess is that they are more robust 650c's diameter less than 700c

 

[Brutuskend]

Originally posted by: saltedeggman
my guess is that they are more robust 650c's diameter less than 700c

That IS true.

It's also MUCH harder to find 650c tires, and they often cost more....

 

[FrustratedUser]

Originally posted by: Brutuskend

Originally posted by: saltedeggman
my guess is that they are more robust 650c's diameter less than 700c

That IS true.

It's also MUCH harder to find 650c tires, and they often cost more....

I guess so but what is the reason? Why not 700c like on normal roadbikes. There is no difference in the riding.

 

[Brutuskend]

Maybe less wind resistance?

 

[SomeDude22]

Originally posted by: FrustratedUser

Originally posted by: Brutuskend

Originally posted by: saltedeggman
my guess is that they are more robust 650c's diameter less than 700c

That IS true.

It's also MUCH harder to find 650c tires, and they often cost more....

I guess so but what is the reason? Why not 700c like on normal roadbikes. There is no difference in the riding.

smaller wheels go shorter in a revolution then bigger tires

giving them more of a challenge

 

[FrustratedUser]

 

[ElFenix]

i think it's just to frustrate you

 

[FrustratedUser]

Originally posted by: ElFenix
i think it's just to frustrate you

I think I found the answer:

Q. What's the difference between Triathlon bikes and regular road bikes?

A. Triathlon bikes are designed with a different geometry than road bikes. Triathlon bikes are more forward in their seat tubes (between 75-78 degrees) and are set up lower in the front end to provide a time trial position.
A steeper seat tube angle emphasizes the quads more to save the use of your run muscles so that you have more get up and go when you start the run portion of a triathlon. Triathlon bikes come in 650c or 700c wheel sizes. 650c wheels accelerate better and are lighter, having less surface area exposed to the wind than 700c wheels. They are more proportional to riders under 5'10''. 700c wheels have long been the standard in the bike industry. Although slightly larger, 700c wheels offer more comfort and less rolling resistance than 650c wheels and are more proportional to riders over 5'10''.
Regular road bikes have a more slack seat tube angle, from 72-74 degrees, and are set up for all-purpose riding. They are designed to corner, climb, and sprint well. The road bike position is more upright and less aerodynamic than a time trial position. A road bike position uses all of the leg muscles to provide as much power to the bike as possible. A road bike can be converted to a triathlon bike with the addition of a forward seat post and aero bars. Sunrise Cyclery can help you convert your road bike to a time trial machine or set you up with a state-of-the-art triathlon bike by Kestrel.

 

[Brutuskend]

So i was partially right. (The aerodynamics thing...)

 

[Dessert Tears]

This page claims that 700c wheels will not fit on a triathlon-geometry frame due to the 78 (vs 73) degree seat tube angle. I suppose the seat stays could be lengthened to accomodate the change, at the cost of increasing wheelbase length. From their (not-to-scale) diagrams, it looks like the seat tube angle change effectively moves the bottom bracket back and the saddle forward, leaving everything else unchanged.

I found this while looking up whether I could just tell imtim to "google it" in another thread without being a complete jerk.

Google: "bike road difference"

http://www.bikesportmichigan.com/bikes/difference.shtml