medium/low gearing for road bike (double chain ring)
 

Hey All,

I'd like to put together a bike using a road bike frame (something like a Surly Pacer) with a medium (not too high, not too low) gear range. I have a road bike with high gears and a touring bike with a triple chain ring with very low gears.

I'd like to put something together with a double chain ring and a normal road front derailleur and road rear derailleur. I'd like to have 700cc tires and a medium to low gear range for riding the hills. I have occasional soreness in my left knee and would like to keep the required torque down so I can avoid aggravating the knee.

I've seen some Shimano cassettes that have a 28 tooth sprocket. Would this cassette work with a normal compact road crankset (50/34)? Also, is it possible to have a compact crankset with slightly smaller chain rings (maybe a 44/30)? Or could I use a Mountain Bike double compact crankset (44/30) for the front and still use a normal road front derailleur and a 10 or 9-speed rear cassette with a road rear derailleur?

Can the chainrings on a Shimano compact crankset (Ultegra) be changed to a slightly smaller set of rings?

I like how the double chainring cranksets shift. I was thinking of putting together something with a steel road frame and a moderate gear range so I could use it for riding the hills of NH, commuting and for fitness. I'm not too worried about the high end gear range. I'd like to achieve a moderate range (maybe around the low 30's in gear inches) for the low end of this bike so I can spin up the hills and put less stress on my knee.

What drivetrain configuration would you recommend if I'd like to keep a double chainring set with road-style front and rear derailleurs? I would be using bar end shifters (friction for the front derailleur and indexed for the back) for the bike.

Thanks in advance

Based on your current hill climbing experience, I suggest calculating the lowest gear you would like to have, along with desired high gear. That will then give a starting point for suggestions. For instance, my low gear is a 39 x 25, and high is 53 x 12. There are a variety of ways to get the same gears, but that works for me because I prefer a tight-ish ratio for the type of riding I do.

The smallest chainring you can put on a "compact" (110BCD) crank is 33T and usually the smallest reasonably-priced one is the 34T. I've often thought that a 46/34 double with a 12-28T cassette would be a great starting point for most people*. That's 32-101 gear inches if you're using 700x25 tires.

You should play around with this site if you haven't already: http://www.gear-calculator.com


* More appropriate than the common 50/34 crank with 11-something cassette that gives you a 120" high gear and makes you cross-chain for the usable combinations...

These sites may give you some ideas to get started:
http://store.velo-orange.com/index.p...ts/cranks.html they have a 48 X 34 double on sale

http://www.rivbike.com/Cranks-Chainrings-s/41.htm even lower at 40 X 32 and 40 X 26

Here's a gearing calculator which allows you to graphically compare two drivetrain choices: http://www.kstoerz.com/gearcalc/compare/

You could lower your gearing if you went with a 26" wheel. I recently built up a bike as a commuter and used a frame with the clearance for either 700c or 26" wheels. The key being disc brakes. A typical compact crankset combined with wider range gearing (11-28 for example) and 1.25" tires on 26"rims would give you a 111" high and 30" low. Just throwing some ideas out there.

Why are you obsessed with a "road" FDER?

Get one that matches the rings.

What I did on my Cannondale road bike to make it more hill friendly along with old guy friendly was to put a mountain triple on it minus the granny. In my case it was a 44,32 and in doing that the 32 is centered on the cassette better and the 44 is centered on the smaller cogs, keeping cross chaining to a minimum. You could go with whatever rings and cassette suit you best. In my case I have a 13-24 (7 sp) cassette. So my gear inches run from 35 to 89. You could improve on that quite a bit with a 9 or 10 speed cassette.

It’s not as pretty as the 52,42 that was on it but my knees are much happier.

If he's using brifters, a road fd is the only one that will index properly. If he's going to use friction shifting (dt, barends, etc) any fd will work.

It does say near the end of the post that the OP will use bar ends for shifting.

Hey All,

thanks for the replies. I talked to my LBS and he said that I could easily put a 11-28 tooth cassette and use a compact crankset (34 tooth smaller chainring). I made a spreadsheet and that would give me a 33.5 gear inch, which should be pretty good for riding the hills.

I have nearly the same,44/34/14-28 and its ideal for my casual around town/errand/grocery getter bike. Its an old triple mtb crankset using only the top two, no granny needed.

When considering a crankset with small chainrings be sure that the front derailleur can be lowered enough. Many of the popular road frames offered now, especially carbon fiber frames, have "braze-on" type derailleur hangers that do not allow the derailleur to be lowered enough to work with a big ring smaller than 48 or 50.
This should not be a problem with a clamp-on FD if the seat tube has a constant diameter in the area of the clamp.

My steel disc jamis has a 22in low and 117in high with its 48 36 28 VO crank and 11-34 cassette with LX rear derailleur and tiagra shifters with 28c tires. I use it for everything including loaded to ultralight touring, hills, centuries, commuting, gravel adventures w fatter tires, etc. the gearing is a bit extreme, cause I got skinny weak legs, but can spin up a wall on the jamis

Hi mattntp

Thanks for the post. I have a triple chain ring on my touring bike and love the low gears. I can also spin up a mountain and stay seated on the saddle for the duration of the climb!

I have a road bike with 53/39 front, 34-11 x 9 MTB cassette on the rear and that pretty well covers it all. I am not a racer or so highly trained and knowledgeable that I need super close gearing.

Don in Austin

Today I am riding a Ti road bike with a 48/34 chainring double, and a 12-27 cassette. This is on rolling terrain, and I find I spend a lot of time using the front derailleur. So on the flats I'm in the 48 ring, and otherwise in the 34 for the frequent climbs.

If I needed lower gearing, then I would go to a 30 in the back. A mid-cage derailleur would handle this. Shimano used to offer their XTR and XT mountain derailleurs in mid-cage; the 9-speed versions of these would be compatible with Shimano STI shifters.

A double with a big difference was straight forward with TA Cyclo-Tourist cranksets,
a friend had a 50-28 on his british bike, on our SF to SD Cali coast trip

White ind has a Clever crankset the Big ring has 5 slots so has the option
of a variety of Bolt circle inside rings as long as there are 5

http://www.whiteind.com/cranks/roadcranks.html

inner: 24-38, outer 38-52