Road bike wheels are generally 700c size, although the smaller sized 650b size are available on some smaller sized frames. Irrespective of size, the two can be found as carbon or alloy options. The R5 is rigid, although not as well stiff—the Goldilocks of climbing bikes if you can. Poise, https://cervelo-e-bike80234.topbloghub.com/32749831/tandem-bicycle-an-overview