I have a retrax pro in my 2013 2500 with 6ft bed and was able to get my ATI 30 gal tank under the bed cover canister. The bed rail height on my Ram is basically the same as the Chevy but can't find an answer on the canister size for the 8ft version vs my 6ft version. Is anyone running the Retrax in the Ram with 8ft bed that can give me the distance to the bed from bottom of the canister. There are a couple of other options that have smaller canisters (Roll-N-Lock and Pace Edwards) but I have no one that has one of those to confirm if it is as good as the Retrax.