Like to make my '75 Grand Prix a little more versatile, especially in the climbing department. It has the original, cottered, three pin, Stronglight double up front and a Maillard 14-28 freewheel out back with Huret derailleurs.

From what I've read, converting to a triple is wrought with problems due to proprietary threading and the bottom bracket width. Not to mention the fact that I like the retro crank look.

The other option is changing the freewheel out for one with a wider range. Harris Cyclery has just the ticket... a 13-34 Shimano, Megarange seven speed.

What all would be involved with the switch? Is it just a matter of swapping the freewheels, maybe dishing the wheels and spacing the frame, or is it more involved than that? Will the derailleur work right? Maybe there's an option I'm not considering?

Any advice would be greatly appreciated!

If you can find a compact 6-speed freewheel with the gearing range you want, you won't have to bother with respacing the frame. Your rear dropout is 120mm, which can accommodate up to a compact 6. Anything larger and you'll have to do some stretching and mounting on a larger axle.

Changing to the 7 speed megarange involves redishing and respacing, as well as cold setting the frame.

You'll get the biggest bang for your buck by replacing the freewheel with the Ultra 6 as USAZorro suggests, and changing the front crank (or at least the inner ring). For better hill climbing potential, swap out the existing crank for something like a 48/38 MTB crank and have at it....

John D.

Or, if you don't mind the big jumps between gears, You can get an old Shimano or Suntour 14 - 34 five speed freewheel.

First, figure out how much lower bottom gear you want. Second, assess how important it is to you to have small ratiometric steps in your gear progression. Third, count the teeth on your chainring set (I am guessing 52-40, but it could be 52-39, 52-42, or something else). Finally, decide how high a top gear you really need.

When I originally built the Peugeot UO-8 for my wife, I had a 52-42 TA crankset and wanted to give her a good climbing gear on a starving grad student budget. I custom-built a 16-18-21-24-32 freewheel, which gave her most of the benefits of the very popular 52-42 / 14-16-18-21-24 gearing combination, plus a 35-inch granny gear.

Here's another trick -- if you can find a 7-speed freewheel whose smallest cog is threaded into the second-smallest, you may be able simply to remove the top cog and use the remainder as an "ultra" 6-speed, which just might fit your current rear hub and axle, particularly if you lose the spoke protector or "pie plate."

6 speed width freewheel would be the largest you could go -7 will not fit due to spacing as advised. Due to the age of the bike it is really not worth it to change to a triple-too much involved money wise and parts fit wise. Great bike, but don't put a ton of money in it.