Commuting - My cranks suck. Help me choose new ones.

My current cranks are el junko old shimano. I want to upgrade. I don't know much about cranks ie the bolt pattern size etc. I do know that i want to put a 20 tooth chainring on. Currently, I have a 24 as the smallest. It would help greatly to have the 20 when pulling my bike trailer full of groceries uphill. I think I have seen a 20 tooth with a bolt pattern size of 58mm. Preferably, I would like to buy cranks that would fit that chainring. I would prefer Ultegra quality. Does 58mm only fit mtn bike cranks? Can I use mtn bike cranks on my hybrid? Its actually a road frame, but I have built it as a hybrid.


Thanks in advance for your assistance.

Shimano used to make a system called Microdrive. I have no idea what the teeth count was, but the rings were small. Might be what you're looking for.

vegan,
I do not see a problem with using MTB cranks. You do of course have to consider your front der. However alot of cyclocross bikes for example use MTB parts. In doing so you can downsize the front chainrings.
Late,'
I am unaware of shimaNo having a "system called microdrive", however Suntour made a components with that name on them.

What cassette are you running in back? If you already have a 24 up front swapping cassettes would be an easier way of getting a few less gear inches. Don't get me wrong, I am a big fan of low gears and of trying new stuff. In fact as an experiment I just took a 110/74 bcd triple crank and put a 24 small ring, 44 on the middle position, and a chainring guard on the outside. My thinking was that the 44 will serve for all my totally flat local riding while the 24, with a 28 in back, will handle just about anything else in the world. I've got to tell you, the 24, even cross chained to the current small cog, 14, is almost too low to be of use.

I'd like to throw in a suggestion, not about bolt patterns or chainwheel sizes... but if you're doing an upgrade, I'd throw out that you might want to go ISIS (or Octolink) (new BB and crankset)... I did that and I love it so much better than the tapered ones- maybe its just pyschological.. but they seem much stiffer and don't slip or creak as much.. <shrug> $.02 inserted. No more quarters.

I'd like to throw in a suggestion, not about bolt patterns or chainwheel sizes... but if you're doing an upgrade, I'd throw out that you might want to go ISIS (or Octolink) (new BB and crankset)... I did that and I love it so much better than the tapered ones- maybe its just pyschological.. but they seem much stiffer and don't slip or creak as much.. <shrug> $.02 inserted. No more quarters.


what are isis and octolink? what are there websites?

Most modern quality cranks use a splined bottom bracket fitting, not the tapered flats. Shimano have their own standard, and lots of independants use the ISIS standard.
I fitted a Shimano LX crank and splined BB to my touring bike. It works fine. The road triple mech works with the 24-46 rings, but you probably need an MTB mech to use really small rings.
LX is a good enough quality for most uses, and is probably best value in the Shimano lineup.

ISIS is short for International Standard Interface System. This refers to the interface of the b.b spindle and the crank arm. Octalink is the tradenmark name shimaNO gave thier spile b.b spindle. Bottom line they are both a spline setup, with funky names.

vegan,
I do not see a problem with using MTB cranks. You do of course have to consider your front der. However alot of cyclocross bikes for example use MTB parts. In doing so you can downsize the front chainrings.
Late,'
I am unaware of shimaNo having a "system called microdrive", however Suntour made a components with that name on them.

I think Shimano just called them "compact cranks" (as they're still called today) but they were mated to HyperDrive-C (C for compact) cassettes. Although, knowing Shimano, they probably named the whole system something like CompactDrive. The concept is the same as SunTour's MD I believe.

I think TA sells a 20T chainring in a 58 BCD.

So instead of changing the 24 chainring, I should just go to a nine speed cassette? Then I would have to change my rear de-railleur shifter too. Would I have to change my rear de-railleur? (its a deore LX). The chain would have to go as well. Anything else? I think I may as well replace the whole frickin' drive train!

If i just changed the cranks to that which accepted a 20T chainring I wouldn't have to replace everything.

Do most mtn cranks accept 20s or which ones specifically?

Thanks again!