I have a small nail pointing out of my rear tyre. May not go down when i pull it but need to do it when i know i am near a place that can repair or replace in Hammersmith London. Anyone know of a good place in Hammersmith W6 or near by? Anyone tried removing the rear tyre before on this bike? is it easy? Anyone recommend good multi compound tyre (hard middle, soft outer)? Is it safe to still ride if nail does not cuase tyre to go down? Is it safe to still ride hard if repaired if right in middle center of tyre? Many thanks, Matthew