Yeah, that's the funny thing. You list the 17's as 31 lbs, their website lists them at 25. I do see they list the 20's as 40lbs...which is significant. The 18's though are listed at 29, which might be more the ticket.
Edit:
http://www.amazon.com/gp/product/B00..._cd_al_qh_dp_i
This lists SHIPPING weight at 36Lbs, which means that they're probably closer to 34-35 lbs...if it's accurate.
http://www.amazon.com/Worx-Triad-Off...triad+black+17
This lists shipping weight at 33 lbs. And I have a hard time believing that a 3" bigger wheel only has 3 more Lbs of shipping weight.
Wish I had warehouse access & a scale.