700c and 29er are the same diameter, although 29er mountain bike rims will usually be wider than road rims. If in doubt look for the ETRTO number - for a 26" mountain bike wheel the measurement will be 559. Somewhere on the tyre it will probably say something like 559x45; 622 is the ETRTO for road bike (700c) tyres.
In other words, if it's a 622 tyre you can fit it to road / cyclocross / 29er 700c rims. But the widths need to be roughly compatible. Balloon tyres will not fit on a Pro Tour bike...!
ok cheers for that makes it a lttle more leyman terms for me
the tyres on the wheels are 37-622 so with wot your saying these are 700c road bike if i understand corect ? the full tyre size reads, ( 37-622 128x15/8x13/8 ) (700x35 HS307.) if those figures help with any other questions from people,
thanks again for the help
I havent got a clue on what i need....but
im sure someone will be along shortly to sell me something i dont need.