What gearing for a singlespeed?!

tremayne Posts: 378
edited May 2011 in Road buying advice
I have a couple of fixed bikes. One for commuting/generally tooling around and one for racing time trial. My commuter runs a 48t front which can pretty much be considered same as your 49. My commute is either 20 for 42 mile roundtrip. In summer I switch to the longer one. Some hills and deffo not flat. I've experimented and like you, the bike arrive with an 18 on the rear. I've got down to a 13, did a few weeks and realised I was simply going to give myself a hernia on the climbs. Bulk of last year was a 14, but when I was a bit under-the-weather early this year I upped to 15t. I'm close now to switching back to 14t but would never bother with 13t again.

Simple advice - experiment. But from 18, I'd at least drop to 15 or 16.

For info - my average commute will be from 19 to 21 mph average, with no traff lights, traffic stops etc.



  • markos1963
    markos1963 Posts: 3,724
    A 49/18 won't spin out at 15mph. I have 48/18 on my bike and can manage to cruise at 20mph ok with a short sprint up to 28mph without spinning out.
    I would have thought for Bristol 49/18 might even be a bit high(unless your commute is along the Bath/Bristol cycleway) I wouldn't fancy taking on Park St on that set up.
  • appletrees
    appletrees Posts: 327
    My commute is an undulating just under 11.5 miles each way, with 2 good-ish hills in each direction.

    I use 48x18 in the winter, then 48x16 and will shortly up to 48x14 for the summer.

    I use the commute as the bulk of my training for TT's, despite the last 2.5 miles being traffic laden town...

    On the 48x14 I did it in just over 28 mins in the summer (on a garmin, so no allowance for traffic lights etc, just start on leaving work and stop when I get home).

    When you're used to the gearing, you should be able to spin at well over 20mph on 48/49 x 18, but I'd be more inclined to go 16 and see how it feels.
  • andy_wrx
    andy_wrx Posts: 3,396
    I've heard a 3:1 gearing recommended a few times for fixed, and my 47 x 16 is about that, or 79"

    On the track I use 51 x 16 or 86", but the track is flat, no stop-start, etc

    You do ask about singlespeed rather than fixed - I guess you could easily run lower gearing to allow you up hills, then freewheel down
  • tremayne
    tremayne Posts: 378
    Not a bad idea to start on ss. However, chances are you will be drawn to the 'dark side' of fixed at some point!
  • Monty Dog
    Monty Dog Posts: 20,614
    49x18 gives a 74" gear which you actually might struggle with on longer inclines - depends on your strength, fitness and pedalling style. FWIW "spinning-out" on fixed/SS is somewhere in excess of 150rpm whereas 15mph is a paltry 75rpm or so.
    Make mine an Italian, with Campagnolo on the side..
  • As above - experiment. Rear cogs are cheal and easy to swap over. As for spinning out - learning to handle a higher cadence will come surprisingly quickly and benefits your leg speed so, if you race, your sprint.
  • I've got a gear inch of about 74 and it's fine for Bristol. I can get up most of the hills in Bristol on that gearing (I only got about a third of the way up Marlborough hill though). That gearing ought to get you to the high twenties before you spin out.