I'm interested in building up a bike for commuting/utility/general jackassery with one chainring and an 8 or 9 speed cassette. Are any of you running "one by..." setups? What gear ratio are you using (chainring and smallest cog/largest cog)

I'd love to see some pics and stats about your one by setups for inspiration.

Thanks in advance.

I'm thinking about doing this same thing. I have an older Cannondale road bike with a 53/36 combo up front. I find the 53 tooth ring completely useless for what I typically ride for. I can't just take it off though, as the chainring bolts are long and hold the two rings together. I would like to put a dummy ring with no teeth, maybe made out of plexiglass, in place of the 53, to help avoid any grease on the pants.

My current 1x9 setup (check the link in my sig) is a massive pain in the arse (39x11-34 9sp with a friction-shifting, long-cage Deore). Throws chains all the time (almost daily) and I haven't fully diagnosed the cause yet. I do not recommend the use of wide-range pie-plate cassettes in this sort of a configuration.

The bike was MUCH happier with a 36x11-28 8sp setup.

You will want a chainring with tall teeth, possibly a bash guard, and also a Chain Watcher or similar to keep the chain from throwing. I have also been told that short-cage road derailleurs are better than mountain ones for this.

+1 on the chainring items. Chainring doesn't need ramps for shifting, so something made for the FG/SS market will work. Short-cage derailleur makes sense, you are covering a smaller range (23t for 11-34 cassette) than the design spec for,say, a Shimano SS cage RD (27t).

I've done the reverse, converting a 1x9 (Bianchi Castro Valley frame) to a 2x9 (using old parts from my road bike). Needed a clamp-on braze-on derailleur mount to use my braze-on derailleur, and had to kludge a cable stop on the lower seat tube for the front derailleur cable and secure housing along the full length of the down tube. If unsuccessful, I would have set up a 42 or 39t single chainring with bashguard and chain fang.

Cool. Thanks for the input.

Right now I'm planning on using an IRO track crank (because i have it in my parts box) and SRAM X.9 equipment in the back has been highly recommended.

I need a new frame choice though. I was all set on the Nashbar X Cyclocross frame until I discovered that it uses 130mm rear spacing which is a PITA if I want to run disc brakes without building up (more expensive) custom wheels. I need to find a new frame (maybe just a 29er MTB frame) so I can run disc brakes with an off-the-shelf wheelset.

I've got a sweet De Bernardi SL that I ran single-speed for a while, but it was destroying my knees, so I switched it to 1x9 for a while. I was using a 42 Ultegra chainring paired with a 12-27 cassette. However, I soon found that I was shifting more with the 1x9 setup than was with 2x9 on my other bike I use for commuting. My commuting route is very hilly, and I often shift to the big ring on big downhills and the flick the FD back to the little ring, so it involves relatively few shifts. With a 1x9, I was shifting up and down through a range of gears on many of the hills. Ultimately, I switched the back to a 2x9 with the classic 39/53 chainring and 12-27 cassette. It doesn't look as cool as it did S/S or 1x9, but my knees are much happier.

I ride an old GT cyclocross bike with cheap 42t Sugino chainring (no ramps or pins) on the inner position with a Spot chainguard on the outer position. I also use a Third-Eye chainwatcher. I'm running a 12-28 Ultegra, 9-speed cassette with Dura Ace short cage derailleur and Dura Ace bar-end shifters.

I've raced cyclocross with this set up for years, and I don't recall ever having thrown the chain.

The gearing is optimized for cyclocross, so it tends to be a tad low for fast commuting, but good for riding in general.

Here's a photo of it in the Cyclocross forum from way back: https://www.bikeforums.net/showthread...=1#post3112098

here you go 1x8

Sram 12x34 cassette
Campy veloce bb and crank it is a double with the 39 chain ring on the outside. Chain line is ok but not perfect...but hasn't been a problem
sram chain
have not had problems with chain coming off....but I don't jump it much
Deore xt derailer........yes the chain should be longer it looks goofy but work fine.
el cheapo sunrace thumb shifters....work great (I used trigger shifters in first version...didn't like.. the thumb is great)
Nitto stem and handle bar.
new long reach brakes
700c sun cr18 rims on deore hubs
brooks b17
plante bike fenders....soon to be replaced with the sliver german ones who name escapes me right now
wald folding baskets
rack I had laying around
Frame and seat post are remaining original items from 82 Niskhki....I bought new

In "The Dancing Chain", there are line drawings of several 1x3 derailleur setups from the 1930s that are fitted with little chain guides over the chainwheel to prevent tossing the chain. In the 1960s Fred DeLong took some high-speed pictures of a 1x set up on a stand in a shop to understand why it happens. The new millennium, and it's still being "discovered".

The other way to keep from tossing the chain on a 1x set up. This technique has been working well since the 1890s.

Best,
tcs

My commuter 1x9 is 41 x 11-23 with bar-con shifter and Ultegra short cage RD. I use a Ngear Jump Stop and Salsa crossing guard on the crank, but I've never had issues with the chain jumping. The bike came stock fixed, and I ran it that way for a year or so. Kept the crank when I switched to 1x9.

What is going on at the rear axle there?

I wonder if my chain isn't still a link or two too long. It seems to throw in the 7-8-9 (high gears) end of the cassette. One would think that the Deore would take up the slack, but maybe not...

I have a Salsa Casseroll singlespeed that I converted to 1x10 running sram rival. 48x 12/26 using the stock crankset and gear. I have never needed a lower ratio. I occasionally coast one one long hill, not because I couldn't spin with it, but just because I don't feel the need to kill myself on the commute.

I don't use any guards and haven't dropped a chain in several thousand miles. If I built another commuter tomorrow I would go 1x10 again. I put probably 6000 miles on my Las Cruces and never shifted into my small ring. I was running a 50 front ring with the same ratio 9-speed rear.

I've yet to take any pics of the casseroll.

my 'One by.' I'm running a 13-30 7 speed cassette with a 40 tooth chainring. LX long cage derailer (it was on the bike before) and a suntour power ratchet shifter (actually the front shifter, mounted upside down. The rear is on my GF's 1X9). The handlebars are a moded wald 8095, bend to make the sweeps almost parallel to the top tube.



The chainguard is a 45 tooth chainring, previously shark-toothed to death, that had an unfortunate accident with a grinding wheel. it actually does a great job of keeping my pants from getting caught in the chain, but it turns out it does a lousy job of preventing derailment. For the first 100 miles or so my chain kept jumping off, and I couldn't figure it out. After very carefully watching the chain, I realized the chainguard was catching it, and deflecting it just enough to cause derailment. A few mm spacers and it was solved, not a single derailment issue since. Oh, there's nothing to stop derailment on the inside.



Trust me, I've tried to derail it. The shifter is just at my thumb, so the temptation to shift is great. I've gotten into the habit of shifting way down at stop lights, and starting up in such a low gear that I pop a small wheelie. I'm sure this is enhanced by the upright riding position (yeah, the handlebars are a little lower than the seat, but the reach is almost nothing, so I end up rather upright). Even shifting fast as I can from one end of the cassette to the other, I can't derail the chain. I'm sure it's just some variant on chainstay length, derailer tension and a little bit of voodoo.

I was using an old cro-mo Trek MTB with 3 x 6 setup. I always needed to use the granny ring to climb a couple of hills on my way to work. Just before the Fall season, I got an old aluminium Cannondale for Winter commute. I set it up with 3 x 8, thinking it would be just like the Trek. As it turns out, with the additional 2 larger cassette in the back, I only use the largest chain ring for the whole commute. I want to convert to a 1 x 8 setup. So I will be following this thread with a lot of interest.

IGH.

tcs

Some great bikes and great inspiration being posted here. Thanks to all who've offered advice and pictures!

This Fuji Cambridge VI isn't a bike I ride. I got it at a fund raising rummage sale in bad condition. I fixed it up and am trying to sell it. I did ride it for about a week when my main commuter bike was out of commission. I even pulled a heavily loaded trailer with it, up a steep hill.

It's a six speed.

I find that "1 by ..." is less than ideal, because chainline swings heavily from one extreme to the other.

My previous street bike was a mountain bike modded for urban riding. Among other changes, I took off the front derailleur and the smaller chainrings, and put a tighter cluster in back so I had a 48x12-26. I did not have chain-drop problems (maybe once or twice riding over train tracks).

My current street bike is a singlespeed.

That what I thought it was, but for some reason my mind expected a singlespeed with some kind of magical chain tensioner.

I might as well be running 1x. I haven't left the middle chainring in probably 2 years.

Maybe my chain was just too long, still. I took two more links out of it today and it rode like butter (no, not mushy and yellow!) this morning.