Both are top quality and perhaps 'built' to stronger specs. than the 'standard industrial specs' because of their inbuilt 'safety and quality factors'. Once you KNOW the belt quality/size/rating, etc. you can 'set up an account' and order from www.granger.com for probably the BEST prices, etc.: http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=v-belt&op=search&Ntt=v-belt&N=0&sst=All&cm_mmc=PPC%3A+Google-_-TPN+-+Power+Transmission-_-V-Belts-_-v-belts%7C-%7C100000000000001057372&cm_guid=1-_-100000000000001057372-_-4804980983

URL for ascertaining Vee Belt specs. (a UK site, so sorry, its in abominable 'metric' values). http://www.roymech.co.uk/Useful_Tables/Drive/Vee_belts.html

Here's a URL that you can download the *vee belt specs*., etc. http://www.grahamrubber.com.au/grp13/13SpecJP.htm