deadly downtube

Hey there. I have a cyclocross frame I want to make into my commuter bike, and I was debating going with a single chain ring in the front versus a double.

I already have a 10 speed double ultegra crankset, would it be possible to install a single 9 speed chain ring on that? Or two 9 speed rings?

Would chain line be much of a factor to consider if I just use a single chain ring?

My rear cassette would probably be a 11-32 range, and I'm a strong rider, riding around oakland/berkeley, and san francisco, so there would be some serious hills, does anyone want to recommend what size chain ring to put in the front if I go with a single ring? That 10 speed crankset previously had a 39/53 setup, would it be compatible to install 2 rings that are a bit smaller like 36/48?

thank you!

nwbikeman

You would need a compact crank 36/50 or mountain bike crank to get that ring size. Here in Seattle I have several employees doing 1 by 9 or 10 using a 34 tooth chain ring with the mountain bike crank, 1 with 9 speed and 1 with 10 speed. The 1 10 speed bike is using a chain guide but I am not sure if it was mandatory, and about to change to a new Shimano 11/36 cassette on the mountain bike. Me I want all rings for all variations of terrain.

FBinNY 

As NWbikeman pointed out, it isn't a 9s vs 10d issue but one of chainring size and crank BCD. TMO the smallest chainring possible with the 130BCD of your Ultegra crank is 38t. So if you were OK going 38/48 you'd be fine, but if the 36t were critical to your needs,you'd need new crank arms.

As far as 9s and 10s goes, it's a difference in the 1/2mm range in chainring separation and not going to be a problem.

If you go with a single up front, needing a chainkeeper depends on how rough the service is. For road use, usually no problem, but for cyclocross or offroad use, the bouncing around will tend to ping the chain off and you'll want a keeper, or a bashwich to keep it on.

Also for 1x9 use try to buy a chainring made for that use. Those lack the shift gates, or cut down teeth of normal outer rings, and are less likely to drop a chain when using the inner cassette sprockets.

deadly downtube

Thanks for the great info folks! 38 and 48 tooth would be just fine for me, I think I might as well just go with double gears in the front, since I have everything necessary except the chain rings. I'm not even sure why I wanted a single ring now. Elegance? bah! Sounds more like a hassle with an ugly chain line. Any recomended brands of chain rings? Or where to order them from? I feel like if I go to the LBS they always charge so much for replacement gears. thanks!

operator

This is NOT true. 9s and 10s SHimano rings are speed specific. You will get *extremely* poor shift performance.

deadly downtube

oh wait, was someone telling me I could use 9 speed rings and 10 speed rings at the same time? that's crazy talk imo.. but it is OK to use 9 speed rings on a 10 speed crankset right? my rear cassette is of course 9 speed. I like 10 speed on my roadie with STI's, but my g/f uses 10 speed and bar end shifters and I don't like the feel of it.

Oysterboy

I was looking at Jenson USA (or maybe Price point) a while back, they were selling some FSA titanium rings for a pretty good price

deadly downtube

I've never even heard of titanium chain rings, do they last longer than aluminum rings? sounds painstaking to machine the ramps and pins..

Nerull

Titanium tends to wear faster in metal-metal contact.