semi-compact gearing?

[mosca]

I've been contemplating a new gearing setup, wondering if anyone has any advice before I take the plunge:

I'm currently running a normal 53/39 front with a 12-23 10speed cassette. I'm thinking of swapping rings to a 50/38, keeping the same non-compact crank. Also, to preserve the highest gear ratio, I thought to swap the 12t cog for an 11t cog, keeping the rest of the cassette the same, giving me a 11-13-14-15-16-17-18-19-21-23 cassette.

My reasoning is this: I normally ride the big ring with mostly the 17-18-19 cogs in flat or near flat riding, but my knees are not what they used to be and I'm trying to spin a bit more. Going to a 50t ring will give a better chainline in those ratios by allowing me to ride one cog higher than before, and will also provide one lower gear before dropping down to the small ring (I normally never use the two largest cogs w/ the large ring). I realize swapping the 39 for a 38 is a very small change, but it will provide slightly better spacing of the ratios and a slightly lower low gear. Swapping the 12t cog for an 11 would get the high ratio back and still allow me to keep the 18t cog, which I would use frequently. It leaves a big gap between the two highest gears, but I don't tend to do a lot of fine tuning in that range anyway, mostly just jam up to the highest for a quick downhill sprint now and then. I would say currently the 13t cog sees very little use.

So any thoughts, experiences, or feedback of any kind would be most appreciated. Thanks!

[bigbill]

My commuter has a 39/48 setup with a 12-23 cassette. I spin out at around 32 mph, so it is not a downhill cruisemissile, but it does the job when I commute. I did have a 39/50 and it was ok, but the 48 gives me the ability to spin for a couple of miles in the morning and then stick it in the big ring for the remainder of the ride. Same thing on the way home. A 39/50 and a 39/48 shift very well due to the small difference in rings. I find myself in the 48X16 most of the time which is almost a straight chain line. I use Salsa rings on an old DA crankset. The salsa rings are cheap, so you could buy a 48 and a 50 and find your happy place. The only downside I could see is the loss of top end speed on descents. With a fendered commuter with a rack and bag, I don't really intend on doing any high speed descents anyway.

[JohnS]

I run Campy so I can't use a 38 but I do run a 48 in front with a 12-25 in back. I'm a spinner and I normally do a full tuck on downhills so i don't miss the high gearing.

[flydhest]

Like John, I run Campy and have a 13-29 cassette on my spring bike. 53-13 is a plenty fast gear and 39-29 is a plenty low gear.

Why stick with a cassette that has a 23?

[fiamme red]

.

[fiamme red]

My commuter has a 39/48 setup with a 12-23 cassette. I spin out at around 32 mph, so it is not a downhill cruisemissile, but it does the job when I commute.Then you're spinning out at about 100 rpm. (I'm assuming you have 700c tires.)

[NateM]

Ignore this if you are talking Campy. I think on the Shimano cass that the 11 tooth starter cog nestles into the 12 making it impossible to go 11-13.Maybe someone else in the know can chime in before you spend the $. I ended up going 11-12-14,and missed the 13.

[wdlewis]

Thanks for asking this question because the answers will be helpful in fittting out my new Ottrott.

The bike shop has recommended the Record Compact crankset at 36-50 and the sprockets at 12-25. They also said there were front rings available at 38 and 40 for the small ring and 52 for the front. I also have the option of a second back wheel with a taller gearing.

My concern is to protect old (62) knees and avoid having to shift the front end too much.

[bigbill]

Then you're spinning out at about 100 rpm. (I'm assuming you have 700c tires.)

I am big bill, that is as fast as I want to spin. About means about.

[bigbill]

Thanks for asking this question because the answers will be helpful in fittting out my new Ottrott.

The bike shop has recommended the Record Compact crankset at 36-50 and the sprockets at 12-25. They also said there were front rings available at 38 and 40 for the small ring and 52 for the front. I also have the option of a second back wheel with a taller gearing.

My concern is to protect old (62) knees and avoid having to shift the front end too much.

IMHO, if you do go compact, 36/50 is the way to go. A 14T drop works better with the FD. You can adjust the FD to do a 16T drop, it is just easier with the 14. I normally ride with a 11-23 and a 36X23 takes care of everything around here. Swapping out for a 12-25 should handle the steeper/longer stuff.

[mosca]

Why stick with a cassette that has a 23?

Basically because I like to have the close ratios in the middle of the cassette - it's where I do a lot of my riding. I was so happy to go to 10spd just so I could have the 18t cog on the 12-23! The 23t low gear has been ok for 99.9% of my riding - I'll probably get a 12-27 cassette to throw on if I ever get into more extreme climbing.

I ended up going 11-12-14,and missed the 13.

That sounds like it would work for me - how do you like it?

[christian]

I got a compact crank, because I wanted low gears for hilly vacations (eg Alps, Dolomites). I immediately purchased a 110bcd 39t ring, which works well in NYC.

- Christian

[NateM]

I use the 11-12-14 setup when I need to get down hills faster or ride with groups,which these days isnt often. I am using a 36/46 compact and a 12-27 for everyday riding which is mostly solo and slow.

[palincss]

My concern is to protect old (62) knees and avoid having to shift the front end too much.

You already know what gears you mainly use. Plot out some various chainring and sprocket combinations and see where the crossover points occur. If you spend a lot of time going between two close gears in the middle of the range and to get from one to the other you have to do a chainring shift as well as going up or down 2 or 3 in back you definitely will not be happy.

I've yet to find any gear calculator better than Sheldon's.
http://sheldonbrown.com/gears/