Subject: Re: 29" same as 700c? Posted by: Al on August 02, 2006 at 08:08:14: In Reply to: 29" same as 700c? posted by sam on August 01, 2006 at 10:48:09:

Message: >Hi. I want to mount cyclocross clinchers (700 x 30c) tires on 29'er disc rims, but am being told I cannot. . Are these sizes identical, or does one have a larger bead seat diameter? Thanks. Yes, the 29er rims are 700c ... but, the 29er rim's bead-to-bead may be too wide for a 700-30 tire to seat properly -- like putting a narrow 700-20 on a 622-17 rim. Without actually having laid my eyes on a 29er rim, I'm going to guess the 29er rims has the width of a "hybrid" tire rim (what is that, about an inch?) with about a 20mm bead-to-bead dimension (i.e., 622-20?). I think the thought is that you would be running a low pressure (65PSI, or less?) tire instead of about 85PSI ... So, you possibly could use your 700-30 tires, but a bead-to-bead of 15mm (e.g., MAVIC Open Pro / 622-15) or 17mm is probably better AND it is probably best to lace up a different pair of rims ... but, I guess I would give your tires & current wheels a try on a non-technical trail/roadway, particularly if your 29er rims are 622-17 (which should be more-than "okay" for 700-30 tires).