Figuring the proper ratio?
 

Hello! I am looking into a singlespeed to serve as an alternative to my regular geared one. I'm wondering how one goes about deciding just what ratio / gear inch to shoot for? Is it trial and error, or is there some methods / experiences that translate out well? I have heard that the "ideal" for flat areas in gear inches is somewhere around the height of the rider, in inches, but that seems awfully convenient. One would think you'd want something lower than that ideal, due to hills and winds.

Also, that was in reference to geared bikes, where I've heard it's harder to maintain the same RPM's as a single, which might complicate things.

M.

it all depends on how fast you can spin comfortably. also, hills, drops, etc.

i started out 48x15, which was rough for a first timer in my case. i am comfortable right now with 48x17. Davis is not too hilly, but when i travel to my parents place, i can get up the hills and down them pretty well.

easiest thing to do is try a few cogs (they're cheaper than multiple chainrings). find what's good for you.

So, taller riders are stronger than shorter riders ? Man, that explains why I need to use such a low gear.

Start off around 65-70 gear inches and give it some time to get use to it before switching to different gear inches.

My bike is the 3 G.I. taller than I am... guess I need a new cog... :-/

Basically yes, trial is the order of the day here. If your area is flat and you like going fast, bigger gearing rules the day. Hilly terrain, or modest fitness levels (nobody is judging you) will warrant lower gear choices. If you have a multi geared bike, you can use that to get a rough idea of where to start, by looking at your favourite gear choice.

It's way easier to spin out going downhill than it is to push a monster gear uphill.

Ride your geared bike around without shifting. Go for several rides, trying a different gear each time. Find one that you feel comfortable holding for an entire ride. Count the teeth and shoot for something in that range.

1. Shoot for a gear you could ride anywhere, anytime as a base goal. Not a gear you can ride hard for 2 miles on dead flat or whatnot. There are times for bigger or smaller gears (riding dead flat or on a track, doing a hilly long ride, whatever). Shoot for something you are comfy with wherever.

2. "Comfy wherever" means you can hold a decent cadence in whatever is normal riding for you. I shoot for >90 rpm on small hills and flat, which is my terrain.

3. Bigger GI will make you stronger (provided you are spinning it and not mashing along at 50 rpm) and faster, but what about endurance? I put on a taller GI (not a lot, say plus 4 GI) thinking it'd make me stronger vis a vis the 68 GI where I was spinning the heck out everywhere. Guess what? the smaller GI lets me go farther. So what if I can spin the "big" gear for 2 miles at a decent cadence -- if you run out of gas at mile 12. When I went to taller GI I was really going faster, til I ran out of energy.

You choose the perfect ratio now. In twelve months time, if you've bothered to think about your technique and fitness, it may well be wrong, particularly if your riding habits have changed. Then again, it may not have. Mate, it's trial and error but most importantly, it's all about reading your body. Forget the numbers. If you feel over geared, add a tooth to the rear. If you think you could go a higher gear, try one tooth less. These parts aren't expensive ... unless you're buying White Industries, which you don't need to do until you're comfortable that you've found the right gearing (and not even then if the truth be known).

With brakes, I like to aim for 67-71 gear inches. Without brakes, 63-65. I prefer the lower end of each. I think trial and error is the best way to figure your preferences out.

Everyone's right. It's a bit of trial and error. I have a flip-flop hub with a 44T chainring and have a 17T freewheel and a 16T fixed cog. I live in DC so it's pretty flat (besides going up Capitol Hill) and I love the 44T/16T setup for the city. The 44T/17T was fine, also. However, if there's a lot of hills where you are, go with more teeth on the rear.

I like 48/17 I've changed ratios a bunch, and always come back to it

Solution is to ride your bike.

same

Any lower and I get bored of spinning like a maniac downhill and any higher I worry about my knees going uphill