Any question answered...

http://www.dotbike.com/ProductsC137.aspx?db_src%3dinternal%26db_med%3d11%26db_cam%3dDAC
Thanks for that. I have bought my daughter a Bianchi with 24" tubulars (the rims are a little dented and out of true) which i would like to replace with clinchers as i saw TFG had rims available for £15 each but they are 540s which seems to suggest that they are wheelchair rims and thus reduces tyre options somewhat. I will measure the rims tomorrow as it is elsewhere due to birthday suprises and all that. Any further guidance or suggestions would be gratefully received. At the moment I think sticking with the tubulars may be best. So maybe i need new rims?