TenSpeedV2

2014 Specialized Crave SL:

Currently setup as a SS mountain bike, 34:17 which seems about perfect for the trails here. What I want to do, and plan on doing, is making it a winter commuter. Will throw on some slicker tires as the weather changes and eventually a studded setup. I would like to gear this more appropriately for the street. So I am thinking about getting a second chain and a chainring and just leaving the 17T on there and rolling it. I don't need anything super high but would like something that will let me build up a little speed on a rather flat commute. Any suggestions? The bike does have an EBB as well.

lkyjoker86

46/17 would work I think.

ggpepper

I ride 42:17 on my Hamilton but I think you would find that too low. A 46 or 48 chainring would be my best guess.

nripin

https://www.surplace.fr/ffgc/

TenSpeedV2

Thanks for that link. That is the best calculator I have seen so far.

IAmSam

Needs gear inches...

TenSpeedV2

I don't need gear inches honestly. I just would like to see what the equivalents are depending on what you use for the rear, i.e. what a 46:16 would convert to with another set up.

hohum

Edit: sorry, didn't read OP

IAmSam

IMHO G/I is the by far best way to give you the comparison you ask for...simple gear ratio doesn't account for variables like wheel/tire size & crankarm length

nripin's link does give development but IMHO it is nowhere near as ez to relate to as gear inches

Check this one out, its got effin everything...Catculator, the Fixed Gear Calculator

SquidPuppet

Thank you, thank you, thank you. That's the slickest and most complete one I've seen. Easy to use and auto results when you change a field.

hardboiled718

Nice link, I like how it displays everything at once, GI, RPMs, speed, etc.

Here's another good one I used to use: BikeCalc.com - Fixed Gear Calculator
I like it because you can bring up several different ratios at one time on a graph

idc

46/17 sounds about right to me although it depends a little on the tire size. If you're running 29ers with studs maybe 44/17 would be better.

Gear inches don't account for crank length.

ThermionicScott 

It's simple math. Dividing the chainring teeth by the cog teeth gives a ratio, which you can multiply by any cog to get the equivalent chainring size (after rounding). So 46/16 gives 2.875, if you wanted to use a 15T cog instead, multiply those two and get 43.125. 43T, bam.

For my fixed-gear, I permanently have a 16T and 18T installed on the flip-flop hub, and I switch between a 42T chainring in the winter and a 45T chainring in the other three seasons. So by using 42/18 in the winter and 45/16 the rest of the time, I'm able to keep using the same chain year-round.

TenSpeedV2

Just based on the fact that this is a 34:17, using the one chain isn't feasible. I would like to go to a 45 or 46 up front so I will need a second one. I don't mind honestly.