I just bought one of these sausage shaped Sidewinder easy fit inner tubes
from here
Sidewinder Easy Fit Inner tube - for 24 and 26 inc
I fitted it to the back wheel of my wisper and it took about 2 mins to fit...just been out on the bike and it seems normal to ride...
Will report back if there are any problems.
NB The box says they are made for Halfords...so you might find them there too...

from here
Sidewinder Easy Fit Inner tube - for 24 and 26 inc
I fitted it to the back wheel of my wisper and it took about 2 mins to fit...just been out on the bike and it seems normal to ride...
Will report back if there are any problems.
NB The box says they are made for Halfords...so you might find them there too...