There not belted as such but they have a Honeycomb internal structure instead of using inner foams, that supports it VERY well, they feel like there made of solid rubber only they don't weight enough.
I taped my road rages but they still ballooned a little at the sidewalls where you can't tape em, and they squirm about a ridiculous amount under cornering. I can't detect any kind of distortion on the Medial Pro Tarmac IIs either ballooning or in corners, they really are infinatly better if you can get your hands on them. I've not tried the OFNAs but they can't be worse than the roadrages, they really are [expletive deleted].
Oops I almost forgot there is a downside to them, they are a fair bit lower profile than the RoadRages, the peaks on my eagletree went down by 10-12 Amps and I lost a few MPH top speed, my 45 shore ones seem to grip better tho (there available in 25,35,45,60 shore) so acceleration hasn't suffered, I will be getting that speed back and more with LiPo soon so I haven't regeared but a bigger pinion could be used, if you want to check on Brian's Calculator my calipers make the Tarmac IIs 3.769" and the RoadRages 4.3165"
There has been a for sale sign pulled up and laying on the pavement at the end of my road for a couple of weeks now, so I thought I would be a good boy and tidy up the terrible litter, I took it home with me and a couple of minutes with a saw and the cyno produced this, it's just my style, lots of good entertainment for no financial outlay and little effort.
Now there is no excuse, go and clean up your neighbourhood.
It turns out that my buggy jumps quite well even with 12 cells over on one side if I hit the jump straight it flies straight