I am new to TT's and I have a Disc wheel question. I have converted an old road bike to a TT bike with a Disc wheel from EBAY. I am having problems getting air into the tire. The cutout on this disc is very small and my pump does not fit into the hole. I looked at the pumps in the bike store and the "heads" all look the same size. If I keep moving and bending the value stem it will evenually cause a leak. Does anyone else have this issue?