Try going down to a 2.1. I have a riding mate that weighs 220 lbs and he uses Panaracer Fire XC's at 50 psi front and rear on a Hardtail and no problems. Then on the Tandem we use 2.1's at 60 psi and we have an all up weight of 400lbs on that thing. When we were using 2.3's- we were getting side wall damage, no grip and a lot of drag. And as to durability- This thing eats tyres. 500 miles before the tread goes and that is if they last that long

For those of you talking about cars- If you are talking wheelbase- it should be Longer. Wider would refer to Track- Distance between the wheels on the same axle.