39x24

zorkmundsson

This might be an utterly stupid question, but I'm assuming numbers like this are to do with the relationship between your front ring and rear cassette? are they the number of "spikes" (check me out with my lingo) that each ring has?

for what it's worth, i just counted said spikes on my inner front ring and "lowest gear" at the back. got the number above (39x24). comments?

tunney

39x24 - yip the first number refers to the number of teeth on the front, the second the number of teeth on the back. The lower the number on the front and the higher the number on the back the easier it is to pedal

As for comments on 39x24 - first thing I'd said is you've miscounted Campag and Shimano don't do a 24 as the biggest ring. Odds are its a 25-12 cassette, most common on road bikes. I've a 23-11, a 25-12 and a 27-12 - depends ont the terrain.

zorkmundsson

tunney wrote: »

39x24 - yip the first number refers to the number of teeth on the front, the second the number of teeth on the back. The lower the number on the front and the higher the number on the back the easier it is to pedal

As for comments on 39x24 - first thing I'd said is you've miscounted Campag and Shimano don't do a 24 as the biggest ring. Odds are its a 25-12 cassette, most common on road bikes. I've a 23-11, a 25-12 and a 27-12 - depends ont the terrain.

thanks tunney, appreciate it. just had another look, and my front "inner" ring is definitely 39. however, i wouldn't assume it's shimano or campagnolo; in fact, it's prob some no-name brand never heard of. bike was astonishingly cheap, in all senses.
as for the back, should i be counting the "smallest" ring (outer) or "largest (inner)?

cantalach

zorkmundsson wrote: »

thanks tunney, appreciate it. just had another look, and my front "inner" ring is definitely 39. however, i wouldn't assume it's shimano or campagnolo; in fact, it's prob some no-name brand never heard of. bike was astonishingly cheap, in all senses.
as for the back, should i be counting the "smallest" ring (outer) or "largest (inner)?

For your highest gear, you quote the teeth count on the big ring (on the outside, unless your bike is very strange indeed) times the teeth count on the smallest sprocket in the cassette, e.g. 53x11, 50x12.

For your lowest gear, you quote the teeth count on the smallest ring (on the inside) times the teeth count on the largest sprocket in the cassette, e.g. 39x25, 34x25, 30x25, etc.

blorg

39 is the most common inner ring size on a standard road double chainset (e.g. the front two rings.) So you haven't miscounted there. tunney is suggesting that you may have miscounted the 24 as the largest cog on the back (it is possible that you have a 24 largest cog at the back but 23 and 25 are far more common.)

Sheldon Brown's site has a handy Gear Calculator that converts these combinations into useful numbers for comparisons.

AndyP

God be with the days when gears were spoken about in inches.

kenmc

AndyP wrote: »

God be with the days when gears were spoken about in inches.

Yeah but womens' definition of inches are smaller than mens'