Single chainring - why not?

[thejen12]

I'm so happy with my new custom bike (Mango Passion!, in the image gallery), that I'm going to order another one because I can't live with just one bike. I gave away my stock commuter/backup-bike recently because it still causes me pain, whereas my custom doesn't.

So I'm going to order a titanium bike with the same geo as my new S&S coupled steel steed. It will have a rack and full fenders and will primarily be a commuter, and a backup-bike for when the steel one is in the shop or it looks like rain. I've been trying to decide what drive train to put on it. The steel bike has Ultegra 9-speed triple, and I've always been happy with that. However, I ran my previous commute bike with only one chainring up front for a short time and really liked the simplicity of it. It also allows a narrower Q-factor, which I will want on this bike because I want to run mtb shoes and pedals on it instead of road shoes and pedals.

If this bike is also going to be a backup-bike, it needs to be able to climb hills. (Notice how I put that responsibility on the bike, not the engine! ) I debated and debated and finally came up with a plan to put one 41-tooth chainring on the front, and an 11-34 XTR 9-speed cassette on the back. This will give me an equivalent of the triple's 30/25 low gear for the climbs and 52/14 high gear for the descents. It means fairly big jumps in between, but while I'm commuting I can just pretend it's a single-speed and stay in one gear if I don't like the jumps.

I think the pros to this plan are that it keeps things simple, quiet, light, narrow, and easier to clean for a rain bike. (I also think it sounds like fun, something different to try.) The cons are that it has big jumps between the different gears, and I'll lose some gearing on the high end. Are there other cons that I have missed? It seems like I don't hear of many (any?) people doing something like this, although single speeds are all the rage now.

By the way, my old commute bike was a 7-speed with a 12-28 cassette, so I had kinda big jumps there, as well. It wasn't quite as nice as my 9-speed 12-27, but it wasn't all that bad. Also, I prefer 167.5 cranks, but will use 165s if I have to. I don't know if a compact crank set would come in either of those, but somehow compact cranks just don't turn me on anyway. I would definitely go with the Ultegra 9-speed triple if not the single chainring - I spend most of my time in the 42-ring of the triple.

Comments welcome, thanks!

Jenn

[PBWrench]

I recently added a single speed to the stable: 42 in front and 16 in the back. I'm managing reasonable hills and couldn't be happier. Good luck.

[mosca]

My old town bike had an 8 speed cassette with single ring. One downside was that the chain would occasionally bounce off the ring due to lack of front derailler. Also, the chainline was not usually as good as with a double ring, if you're the type to be bothered by such things.

I'd focus on maximizing function for a commuter bike. If you want simplicity, the best solution is a custom fixed gear

[RPS]

Originally Posted by mosca

My old town bike had an 8 speed cassette with single ring. One downside was that the chain would occasionally bounce off the ring due to lack of front derailler.

I had the same problem a few times with a single ring. A fixed front derailleur solved my problem but after a while decided to reinstall the cable and small ring.

[Waldo]

Jen,
Another Rex, then? I'm off to see Steve for a fit next week.

[thejen12]

Originally Posted by vlad luskin

Jen,
Another Rex, then? I'm off to see Steve for a fit next week.

I couldn't be happier with my Rex! I'll be scheduling some time with him as soon as I get back from my tour, in a couple of weeks. Mostly to discuss braze-ons and such, I don't think I need much of a fitting for this second one.

I'm sure you'll love your new Rex!

Jenn

[thejen12]

Originally Posted by mosca

My old town bike had an 8 speed cassette with single ring. One downside was that the chain would occasionally bounce off the ring due to lack of front derailler.

I was wondering about that! What about a bolt-on chain-guard thingy that I see on some bikes? I think it bolts on outside the chainring - I'm not sure if it's for single-speeds, or something else.

Thanks, Jenn

[stackie]

Why not consider an internally geared hub? The Shimano Alfine grouppo is supposedly the bomb. Then, you will be able to tension the chain such that chain hop will not be a problem. Hub is supposedly bombproof and you get generator run lights.

Jon

[rpm]

Jen--

Here's another option. I'm going to refit one of my bikes that has an Ultegra 30-42-52 and 12-27 triple with a Ritchey cyclocross 38-48 double crankset and the same cassette. This will give me the gears that I really use with a simpler setup and fairly small jumps. This setup would give you pretty much the same high and low as you're planning without the pie plate cassette, big jumps, and chain loss issues.

[justinf]

I ran my Surly commuter as a 1x9 for over a year and loved it. It's a singlespeed now which is also cool but I may take it back at some point.

Honestly in Charlotte I could ride with a 50T ring in front everywhere on every road bike. I literally never use the small ring, it's just too flat.

[mosca]

Originally Posted by RPS

I had the same problem a few times with a single ring. A fixed front derailleur solved my problem but after a while decided to reinstall the cable and small ring.

Yeah, there's a point at which the single chainring option loses its elegance and you might as well have the extra gears, imho.

[11.4]

What you describe makes it a bit easier to maintain, especially after bad weather. And I'd definitely recommend you install cyclocross chainring guards (see www.cyclocrossworld.com for a good selection, as well as all kinds of intermediate-sized chainrings). You can install a ring guard on each side (with longer chainring bolts) or just install one on the outside and then put a chain-catcher (dogfang) on the seat tube to catch a chain that falls off inwards. Frankly, I've never lost a chain yet on the road -- you may occasionally lose one carrying the bike up stairs or whatever, but not on the road. The chainring guard on the outside for road use is really just to keep grease away from you a bit and to dress up a standard double-chainring crankarm.

You can definitely do a close-ratio front (39/46 is my own favorite with a standard crankarm). Getting rid of that front shifter, however, gets rid of a cable routing to the front shifter plus all the hardware associated with it. You can use a top-tube routing for the rear derailleur (across the top tube and down the right seatstay) which keeps the down tube clear of cables. It makes cleanup easier.

As for gearing, you're commuting and you can always use the cadence training, right? You could do something closer than what you describe and probably be just fine. Figure out the lowest gear you need and don't worry about pushing it too far on the high end -- you can coast, you can spin, or you won't be in the gear anyway. When you ride a fixed gear you really end up learning this one in a hurry. (You say you want to take it easy on hills or I'd simply suggest a fixie or a single rear freewheel -- not for aesthetics but because it is the easiest to maintain as a commuter.) If you pick up a compact front crankset, you can put a smaller chainring on such as a 34 or 36 and then work with a closer-ratio cassette. This might give you the better shifting intervals you're looking for.

You could conceivably consider the approach Rivendell came up with: two chainrings on front, two side-by-side White Industries cogs on a single freewheel in the rear, and be able to mix and match them at will. You might check out their site just to see what they do. The limitation is of course gearing range. The advantage of not having a rear shifter is that you don't have anything there to get knocked around, and of course it's easier to keep clean. But while I ride fixies a lot of the winter, I don't push them on people who have other ideas about how to ride.

[gdw]

I used a 34t front ring with an 11-30 8 speed cassette and short caged derailleur on an old Bridgestone MB-3 for a couple years without problems on or off road. I shortened the chain and fitted an outer guard made from an old 42t ring to keep from dropping the chain to the outside. I just cut off the teeth with a hacksaw and ground the outer edge till it was smooth. It worked great. You can use one of those chain deflectors/guards to prevent the chain from dropping to the inside although it wasn't an issue with a short caged derailleur. Pay attention to the chainline, a 9mm shorter bb spindle was ideal for the Ritchey crankset used, and it will work great.

[thejen12]

Originally Posted by rpm

Jen--

Here's another option. I'm going to refit one of my bikes that has an Ultegra 30-42-52 and 12-27 triple with a Ritchey cyclocross 38-48 double crankset and the same cassette. This will give me the gears that I really use with a simpler setup and fairly small jumps. This setup would give you pretty much the same high and low as you're planning without the pie plate cassette, big jumps, and chain loss issues.

Yes, but I really like riding in the 42 on my triple. I think if I had a 38-48, I'd be wanting to switch between the small and the large chainring all the time. The 42 on my triple is one reason I like it so much better than when I had a 39-52 double.

Jenn

[thejen12]

Originally Posted by 11.4

As for gearing, you're commuting and you can always use the cadence training, right? You could do something closer than what you describe and probably be just fine. Figure out the lowest gear you need and don't worry about pushing it too far on the high end -- you can coast, you can spin, or you won't be in the gear anyway. When you ride a fixed gear you really end up learning this one in a hurry. (You say you want to take it easy on hills or I'd simply suggest a fixie or a single rear freewheel -- not for aesthetics but because it is the easiest to maintain as a commuter.) If you pick up a compact front crankset, you can put a smaller chainring on such as a 34 or 36 and then work with a closer-ratio cassette. This might give you the better shifting intervals you're looking for.

Thanks for the ideas. I love cadence training on my commute! But, as a backup bike, I'd still like to be able to ride in the hills - I'm talking hills that are 5-8 miles of 6% to 8% steady grade, climbing 2000+ feet per hill. I know a lot of you cats can do that with smaller gears (I used to, myself), but I'm not there yet. I make liberal use of my 30/27 now! As I get stronger, I can downsize the cassette or upsize the chainring....

I'll check out the website you posted, too - thanks!

Jenn