
• #2452
Is there a formula for working gear ratios ?
Can you do division (calculators are allowed in this exam)? Then you're good to go.

• #2454
All is I know is that I have a 17 on and it's gets me all but the steepest of stuff. Is there a formula for working gear ratios ?
Front teeth / Back teeth gives you the ratio.
I'd guess you'll be on something between 40/17 giving you about 2.4 turns of the rear wheel for one turn of the pedals and 48/17 giving you 2.8.
There are plenty of websites with the various gearing measures programmed in for calculation. See http://www.bikecalc.com/gear_ratios 
• #2455
.

• #2456
Good good keanulooser

• #2457
48/17!
How many times people?!
Ratio of the Gods.

• #2458
If Prime/Coprime gearing does help with wear (https://news.ycombinator.com/item?id=2406562) how come 47T or 49T chainrings seem much more rare than 48T?

• #2459
How many times people?!
Ratio of the (flat) Gods.
ftfy.

• #2460
I MAKE AGREEMENT.
(London Cambridge London is flat.)How many times people?!
Ratio of the Gods.
ftfy.

• #2461
New sprocket so went down a tooth to a 52/18. A minor tweak but it feels quite significantly better to me.

• #2462
What ratio would you guys recommend for a slightly flabby, unfit 46yr old. Converting a Raleigh Scorpio on a really tight budget to SS, so using the existing inside ring of 42 what would you recommend for the back?? Would 16 be ok?!

• #2463
perfect x

• #2464
Cheers noisier :)

• #2465
Running a 46/15 and in East Mids. Looking at 48/17 and 48/15 though as I now have a fixed/fixed hub..

• #2466
perfect x
Aye. 42x16 is the out of the box ratio for lots of off the peg fixed bikes. You'll run it for a while, think you need bigger, then realise it's actually the perfect compromise for stop/start town riding and the odd undulating country ride.

• #2467
It's pretty flat where I intend riding apart from the hill back up to my house so sounds good

• #2468
Running a 46/15 and in East Mids. Looking at 48/17 and 48/15 though as I now have a fixed/fixed hub..
For riding on the street 48/1917 is probably more useful.

• #2469
I started riding the street using 48/17 (pretty flat), but quickly progressed to 48/16, then 48/15. Am now using 48/14, which is probably where I stop, but it's cost me £20 a cog for every change.

• #2470
And to think that's £60 in the wrong direction...

• #2471
n/a

• #2473
This is my everyday gear; I have a 15T on the other side, but I'm on the track every week and I'm basically lazy.

• #2474
n/a

• #2475
Been riding 49/17 but can barely hit 30 for a few secs, am wondering whether i should drop to 48/17 slightly lower ratio but same patch wise which doesnt really matter to me as I cant skid?
.