with our wholesalers, we have to spend £150 to get free postage. thats the only constraint, usually a pair will do.
dont know if I said at the time, Busters (M&P) usually beat our suppliers prices , and they get them from the same supplier.
you could look here..
http://www.tyreleader.co.uk/motorbik...20-60-17/?m=25
could also look at the original size , think it should be 120-70/17