balloon tyre 
noun
A large tyre containing air at low pressure for travel on soft or uneven surfaces.The staff were very helpful and most difficulties were easily overcome, though we really needed a 4 x 4 wheelchair fitted with balloon tyres for the desert!...
- We've got these three-wheelers with balloon tyres.
- I said ‘Yes, they used to call me balloon tyres’, because I'm not a tall man as you can see, but I got my legs strong, because I knew to be a runner you had to have something.
Derivatives
balloon-tyred
- ‘Each day, with a backpack full of instruments, we rode across the salt on balloon-tyred motorbikes to the centre of the lake,’ says Ms Campbell.
- The maximum speed was approximately 30 km/h, considered by the designers to be a speed that would not impair the life of a standard balloon-tyred bicycle.
- They were able to negotiate the surface of the Lake with three-wheeled balloon-tyred Honda buggies and they had radio communication with Muloorina Station.