(unrelated question ...H and I have been arguing over how long we can use or BOB Duallie with the twins. You are still using yours right? And your two are 4?)
I was actually thinking about this today ..now that the weather is nice and my daughter has asked a few times for it. But, they will have to get out and run some too, because now they are 5 and there is no reason for them to not get some exercise. The last time we ran it was perhaps 3-4 months ago? They were still 4.
I believe the weight limit is 100 pounds. They are 42# and 45# so I am getting very close to exceeding the limit (especially when you factor in any body weight I may add to the stroller). But its so used that I don't plan on reselling it, so I may as well run it into the ground.
I guess I will test the stroller and see exactly what the upper bounds are. I will update you on my findings!