Just finished swapping the wife wheels on her old storm 3. Put some tubes in the front (after digging that awful solid fill foam out!) and stuck some temporary tyres and tubes on the rear 3.50x8 (I think they were for wheelbarrows) £11 the pair with four tubes and what an absolute transformation it has made to the chair! No more jarring and bouncing over cracks and stones. Absolutely amazing and all for around £20
Thanks for this site BM its a trove of knowledge!