Hi Harvey. I have a classic GP in my "collection" i.e. in a garbage bag under my back porch, which has English 1.37" x 24tpi threads. And i recently came across a Super Course [w/ the beautiful oval head badge] which had Raleigh 1.37" x 26tpi threads. Who knew? I think Sheldon suggests it's possible to "retap" a Raleigh threaded bb to English - same diameter, you're just kind of mashing/moving threads around. I actually tried this on a Sprite but never got around to building it. I'll dig it up sometime soon and report back. Typically a lot of the 26tpi bb shells are wider than the 68mm English shells, 71 or even 73mm, which complicates things. Personally i've never seen a GP w/ chrome beyond the bottom half of the fork blades. And of course both left and right cups on the GP are typically 26tpi w/ the right [fixed cup] being left hand thread. Salutations. I know you know that. Billy [fan of the low end bikes] Ketchum; Chicago, IL; USA
Billy, thanks for reminding me: If this is a run-of-the-mill Gran Prix, then I would expect that the right BB cup is the infamous Raleigh 26 tpi (?) pipe-tapered unit. Upgrades to "real" or standard BB are rough (although, if memory serves, Phil actually made these adapters, too). In any event, that will be a nice fact to help in ID'ing the frameset.
harvey sachs mcLean va
Billy Ketchum wrote:
> Hi Harvey, Bill, all. My suspicion is that the Gran Prix isn't super
> heavy, although the chrome may add a bit of weight. I'm rather enamored
> of the geometry of British bikes of that era and think it may make a
> very nice rider. {It seems more refined than the Puch made Sears bikes
> which i also have a soft spot for. I'm looking forward to refurbishing
> my Altenburger equipped version.} Especially w/ a set of sprint [sewup]
> wheels. I wouldn't necessarily put a lot of money into it and would
> avoid fenders and racks to keep the weight down. But as i've noted
> before i'm eager to build up a Gran Prix for myself and see how she
> fares. The chrome even w/ patina and flaking is pretty cool. Cheers.
> Billy Ketchum; Chicago, IL; USA.