I am upgrading my classic road bike to ten speed (x3 so a 30 speed) and my question has to do with re-using my existing chainrings. All three were replaced over the last twelve months, but I didn't specify a need for compatibility with a ten speed chain when I bought them (because I hadn't thought about the ten speed option then).

I am putting on a 105 triple rear deraileur, a 12-27 105 cassette and Dura-Ace SL-7800 downtube shifters. This works out to be quite a cheap upgrade. I will continue to use my old front derailleur, especially since the SL-7800 shifters are friction only for the front anyway.

So does anyone know if my chainrings will be a problem?

Phil.

Most chainrings will work fine with a 10-speed chain. In my understanding, the outside diameter of the chain is narrower to be able to use it on more closely-spaced cogs, but the inside diameter of the chain is the same. I'm quite sure your chainrings will be no problem.

I like your new setup, btw. If I lived in a less rolling-hilly area, I'd still be running downtube shifters. So simple. As it is, I've got bar-end shifters. But I miss the mechanical simplicity.

Thanks.

I have never used anything except down tube shifters and this will be my first experience with indexing shifting, although the SL-7800 can be switched to friction mode :)

I hope to have the bike assembled this weekend if the remaining parts arrive in time. I shall post my thoughts on indexing shifting and maybe even a photo or two!

Btw, my chainrings are 24t/34t/47t so that will give me a nice dura-ace/105 touring bike with a range of gearing from about 24 gear inches to about 106 gear inches, and 30 speeds (with the usual big overlap between chainrings). Interestingly, I get only a few extra useful gears compared to my old 15 speed (5x3) half-step plus granny setup.

Phil

Yeah, your bike sounds pretty good. I've got a 50/36/24 chainrings mated with a 12-26 (9-speed) cassette. I've not touched my small chainring since putting this together. On today's hilly 30-mile ride, the lowest gear I touched was the 36-21. I've got gearing for sustained mountain climbs, but I live in a rolling area.

You note that you only add a few useful gears, but I suspect you'll enjoy having more closely-spaced, easily-accessible gears for the exact grade you're on, or headwind you happen to face at the time.
(That said, I just built up a fixed-gear bike...)