Ive had my R10 since there inception......I'd say I put air every 6 months....I've bought new front wheels w/brakes after 7 years....the rubber can dry rot on the back wheels also which makes them leak air.. just go on their site and buy new ones & you'll get another 10 years with them they have a good parts supply.....I use the cart EVERY DAY in all weather.
http://www.rocknrollercart.com/parts.php

My only complaint is I wish they would make a better system with a quick release lever on top of the handle to close the cart instead of always having to bend down to squeeze the cable release !!!
http://www.rocknrollercart.com/blog/

There are allot of choices but the R&R to me is still the best for a musician gigging. http://www.rocknrollercart.com/downloads/R-Trac-Wheel-Press-Release-12-1-10-All-models-color.pdf
http://www.handtrucksrus.com/index.aspx?src=googleLWhts&gclid=CJqthM2PlaYCFaE65QodUC3h mg



[This message has been edited by Dnj (edited 12-30-2010).]