nextreme

Hi Everyone,

I'm looking at converting my '95 Rocky Mountain Fusion into a tourer, and would like to install drop handlebars.
To do so, my idea is to install rapid fire shifters (Shimano SL-M310) on the tops of the drop bars, positioned
where you often find the small brake levers on cyclocross style bikes (about 1" away from the stem).

So my question is, will the SL-M310 fit on a drop bar with a 31.8mm diameter clamp size ? I already have these
drop bars so I'd like to reuse them.

If not, is there something else I could use for my existing derailleurs (3x7 Shimano STX-RC) besides bar end shifters (not crazy about those).

Thanks
Steven

(You can see my bike specs here)

Andrew R Stewart 

You know a photo of the actual shift levers would help us help you. I suspect you'll find that your shifters are made to clamp onto a 22.2 bar diameter. Depending on the clamp's design one might be able to open it up and, using a much longer bolt, get it to fit on your drop bat. But I also suspect that this won't work.

Additionally while the rear der is cross compatible with road bike shifters the front isn't. So going to road shifters will likely result in poor front control. There is a reason why bar end levers are still around... Andy.

SkyDog75

The bar's center section is 31.8 mm, but once you get out past the center bulged section, its diameter likely drops to 23.8 mm, which is the diameter road bike brake levers are designed to fit. Both of those are bigger than 22.2 mm, which is the diameter of the mountain bike bars the SL-M310 shifters are meant to fit.

If you want thumb shifters and a drop bar, you've got a few options. Paul Thumbies are available in a 31.8 mm diameter. They're adapters that'll let you use road bike downtube shifters as thumb shifters. Or you could use a flat bar with drop-style bar ends.

Raiden

How about butterfly bars, or some sort of bar end/extension for your mtb bars? There exist bolt on bar ends that mimic drop bar curves.

nextreme

Thanks for the responses everyone, I actually found a user manual for the Altus SL-M310 and it says "Use a handlebar grip with a maximum outer diameter of 36 mm". Here's a link to the pdf.

I'm quite surprised it can be mounted on a handlebar with such a large diameter, am I understanding it correctly ?

Bill Kapaun

Your link leads to a ST-310.
Maximum GRIP diameter is probably germane to brake lever travel.

SkyDog75

"Handlebar grip", not "handlebar". If you use a grip with too large a diameter, it'll prevent brake lever travel. The handlebar itself is still 22.2 mm.

nextreme

Ah yes, I get what they mean by grip diameter now, and its the wrong shifter model altogether.

thanks