Dumb gearing question

[Tom]

It's real quiet around here. Wasting time in the other bike pic gallery, I noticed Jerk's C50 had a 36-tooth inner chain ring. This got me to thinking a little.

I normally run a Chorus10 12-25 cluster with 53-39 up front. Last year before the Highlander I ran out and bought a 13-26. It worked fine, but my question is why I didn't slap a 36-tooth on there and leave the 12-25 alone? Low end is lower, I keep the big ring gears I'm accustomed to and there seems to be a decent set of overlaps where low gear/big ring is a lot like high gear/little ring.

[Ahneida Ride]

Tom

There are no dumb gearing questions. Never !!!!!! EVER !!!!

Next to the saddle, Gearing is just as important as fit. Yet seldom is
is it discussed. We all just accept what Crampy and SheManNo dictate.
Serotta does not tell me what frame to ride, They custom build it to
my specifications . Yet the component manufactures mandate our
gearing ! How ludicrious !!!!!! :crap: :no:


Personally, I found 53/42/30 to very unproductive. My current rings
are 46/36/22. The 36 ring with a 13-29 rear provides 10 closely spaced
gears, all of which are highly usable, and keeps my cadence up there.

The 22 is a miracle, for places like the Mohawk trail right below GE RD.
Why suffer ? I spin with a smile. :p

48/38/24 was acceptable, but playing with the TA rings convinced me
the 46/36/22 was optimal.

Why not install 36 and adjust the cassette to your liking. The result is
10 gears all usable !!!!! Really this is a nice feature and is it cool to
watch the chain running up and down the full cassette. ;)

Hope this helps !!!!!

[yarg]

Tom - unless I'm slow this a.m. (very possible after assembling an air hockey table for the kids x-mas present), you can't slap on a 36 ring. Unless you are talking about slapping on a compact crankset (110 bcd), a 38 ring is smallest to go on your 130 bcd crank. I have made up my mind to switch to compact 48-34 and a 12-27 cassette. It will give wider more usable gears for me.

[dcotcamp]

Tom,

If it's a Campy crank, the bcd is 135, and a 39 tooth ring is as small as you can go.

I think 110 bcd cranks are great, and give you the freedom to discover the gearing that works best for the places you ride.

Dennis

[Tom]

Thanks... I keep the crankset I got and simply get stronger.

[Climb01742]

i've also become a fan of 36/50 gearing. for me, 34 left me unergeared on anything but climbs. and a 53 is simply too much gear for this wuss.

[Brons2]

great thread. I am building up my Rivendell and I just couldn't pass up a 12-27 Ultegra 9 speed on Colorado Cyclist for $39.99....they're going in the 40-45 range used on eBay! :rolleyes:

Anyways, I want to pair it with a 46/36 double and 180mm or 185mm crank arms.

I think. :confused:

[JohnS]

great thread. I am building up my Rivendell and I just couldn't pass up a 12-27 Ultegra 9 speed on Colorado Cyclist for $39.99....they're going in the 40-45 range used on eBay! :rolleyes:

Anyways, I want to pair it with a 46/36 double and 180mm or 185mm crank arms.

I think. :confused:
Why the long crankarms? How tall are you?

[Brons2]

6'7".

I'm only going 180mm because I've never gone longer than 175 before. According to Leonard Zinn's site, I should be running 205mm. lol.

Plus, my knees already hurt sometimes. :(

[weisan]

6'7".

I'm only going 180mm because I've never gone longer than 175 before. According to Leonard Zinn's site, I should be running 205mm. lol.

Plus, my knees already hurt sometimes. :(

Trust me, I have ridden with Jimmy, he's a GIANT when he is standing beside me....and did I mention also that sitting behind his wheels is like taking a ride on the bus?? :p

[Brons2]

Trust me, I have ridden with Jimmy, he's a GIANT when he is standing beside me....and did I mention also that sitting behind his wheels is like taking a ride on the bus?? :p

That's funny.

Vern told me the other day he had ridden with you also. You should come out to our Thursday ride at Cele sometime. 6:00 PM, not so sharp.

[weisan]

That's funny.

Vern told me the other day he had ridden with you also. You should come out to our Thursday ride at Cele sometime. 6:00 PM, not so sharp.

Does that mean I get to stay in Marriot? :D

It would be tough for me to do any type of riding past 6...family time.

Oh...forgot to mention, if you need any help with putting things together on the Rivendell, let me know.

[Louis]

I agree wholeheartedly with Tom’s initial post. The bottom line is that the vast majority of crank & cassette set-ups these days have a huge amount of overlap, whether they are double or triple. I’m hardly an expert in the matter, but I believe that to a large extent it’s a holdover from the days when cassettes only had five or six cogs, and to fine-tune your gear-inches for a given head-wind or grade you would be constantly shifting both front and back derailleurs, to get exactly what you wanted. Now that we have 9, even 10, cogs in back you fine-tune just by shifting in back and get nearly exactly what you need.

I hope that eventually Shimano or Campy will develop cranks and chainrings that shift well even though they have very large differences between the rings. That will eliminate the need for triples, but still allow a very wide range of gears. If you do the numbers you will find that on many triple set-ups the big and the small rings overlap in the middle, indicating that the middle ring is technically superfluous. Of course, folks with triples spend most of their time in the middle ring, which tells me that it’s a good starting point. Compact doubles are a step in the right direction, but IMO not the logical end point of the evolutionary process. An even greater gap is better.

If you throw MTB cassettes into the mix, you can go to as high as 32 or 34 in back and get a massive range of gears with perfectly manageable spaces between gears, especially with a 10-speed system.

Just some ideas…

Louis

[Ray]

If you throw MTB cassettes into the mix, you can go to as high as 32 or 34 in back and get a massive range of gears with perfectly manageable spaces between gears, especially with a 10-speed system.
Except that mtb cassettes don't come in 10 speed so you can only mix road and mtb gear if you stick with 9-speed. I run a compact double with 9-speed and sometimes run a 12-34 mtb cassette in the back. I never use the 30 or 34 in typical riding (although I recently rode some hills in southwest VA where I was glad to have them), but I can use every cog up to the 26 with my 48 tooth big ring, which allows me to stay in the big ring unless I'm climbing something fairly tough. I don't mind fairly wide gaps between gears, but for people who like really tight spacing, this probably isn't a great solution.

I sort of doubt that Shimano will go 10-speed with their mtb gear - you don't need the spacing as tight and 9-speed is finicky enough in the dirt. I still run 7-speeds very happily on my mountain bike - much more reliable than 9 and slightly more than 8.

-Ray

[Brons2]

Except that mtb cassettes don't come in 10 speed so you can only mix road and mtb gear if you stick with 9-speed. I run a compact double with 9-speed and sometimes run a 12-34 mtb cassette in the back. I never use the 30 or 34 in typical riding (although I recently rode some hills in southwest VA where I was glad to have them), but I can use every cog up to the 26 with my 48 tooth big ring, which allows me to stay in the big ring unless I'm climbing something fairly tough. I don't mind fairly wide gaps between gears, but for people who like really tight spacing, this probably isn't a great solution.

I sort of doubt that Shimano will go 10-speed with their mtb gear - you don't need the spacing as tight and 9-speed is finicky enough in the dirt. I still run 7-speeds very happily on my mountain bike - much more reliable than 9 and slightly more than 8.

-Ray

There are some custom 9 speed road casettes out there with some fairly large inner rings (34-ish) and I'm sure the same will be true with the 10 speeds, if it isn't already.

Anyways, I was wondering what inner ring you run with your 48 big ring on your compact double. Thanks!

[Ray]

There are some custom 9 speed road casettes out there with some fairly large inner rings (34-ish) and I'm sure the same will be true with the 10 speeds, if it isn't already.

Anyways, I was wondering what inner ring you run with your 48 big ring on your compact double. Thanks!
The custom 9-speed road cassettes borrow cogs from the mtb side of the operation I think. I know Sheldon Brown does this with his 13-30 "century" cassette. I don't know if the rings exist to do this with a 10-speed cassette. Maybe they will someday?

I ride a 48-34 up front. My typical low-gear is 34x27 when I'm running a 12-27 cassette and 34x26 when I'm running the 12-34. While the 12-27 is enough for any of the climbs around here, I still like the 12-34 cassette for what it allows me to do with the big ring, taking it up to the 26 cog easily and I guess I could use the 30 if I really needed to. And on a century or other epic, I never mind having those two extra big cogs in case I need them. I haven't touched them on a local ride this year, but I've never been sorry to have them.

-Ray

[Jeremy]

[QUOTE=Ahneida Ride]Tom
.

The 22 is a miracle, for places like the Mohawk trail right below GE RD.
Why suffer ? I spin with a smile. :p


Hi Anheida,


What crank and BCD are you using that allows you to use a 22T inner. I run a custom 24/38/52 triple that I am happy with, but would like to experiment with a 22/36/50 triple. I use a Specialties TA tripleizer, but it has a 74mm inner BCD that limits me to a 24T low. I want a custom 58/110 BCD triple, but have not been able to create one yet.

Jeremy

[Ray]

[QUOTE=Ahneida Ride]Tom
.

The 22 is a miracle, for places like the Mohawk trail right below GE RD.
Why suffer ? I spin with a smile. :p


Hi Anheida,


What crank and BCD are you using that allows you to use a 22T inner. I run a custom 24/38/52 triple that I am happy with, but would like to experiment with a 22/36/50 triple. I use a Specialties TA tripleizer, but it has a 74mm inner BCD that limits me to a 24T low. I want a custom 58/110 BCD triple, but have not been able to create one yet.

Jeremy
I'm willing to bet its a TA Zephyr, which has an outer bcd of 110 but has both 74 and something smaller (56?) as options for the granny. Using the 74, you're limited to a 24 tooth crank, but the other bolt holes let you go down as low as 20 I believe. I have one of these cranks on my rough stuff / cross bike.

-Ray

[CNY rider]

The custom 9-speed road cassettes borrow cogs from the mtb side of the operation I think. I know Sheldon Brown does this with his 13-30 "century" cassette. I don't know if the rings exist to do this with a 10-speed cassette. Maybe they will someday?

I ride a 48-34 up front. My typical low-gear is 34x27 when I'm running a 12-27 cassette and 34x26 when I'm running the 12-34. While the 12-27 is enough for any of the climbs around here, I still like the 12-34 cassette for what it allows me to do with the big ring, taking it up to the 26 cog easily and I guess I could use the 30 if I really needed to. And on a century or other epic, I never mind having those two extra big cogs in case I need them. I haven't touched them on a local ride this year, but I've never been sorry to have them.

-Ray

This is a really enlightening post (well for me at least). I have a 30/42/53 Ultegra triple on my Legend. This year I also got a LeMond and have a 34/50 compact double with a 12/27 in the back. I'm often frustrated by how limited the gearing seems on the LeMond, with the gear I want always seeming to be a crossover combo. This is an approach I just had not thought of.

Thanks!

[Ray]

This is a really enlightening post (well for me at least). I have a 30/42/53 Ultegra triple on my Legend. This year I also got a LeMond and have a 34/50 compact double with a 12/27 in the back. I'm often frustrated by how limited the gearing seems on the LeMond, with the gear I want always seeming to be a crossover combo. This is an approach I just had not thought of.

Thanks!
It may be worth a try for you. But remember, if you like tight spacing between cogs, you won't like it. I ride a fixie a fair amount and am pretty comfortable at a range of cadences, so I don't mind the big jumps. Also, you have to be satisfied with a 48-12 big gear. More than big enough for me, but probably not for everyone. And, oh yeah, if you ever actually want to USE the 34 cog, you're gonna need an mtb rear derailure.

The setup isn't without it's costs and tradeoffs, but it works well for me.

-Ray

[Brons2]

It may be worth a try for you. But remember, if you like tight spacing between cogs, you won't like it. I ride a fixie a fair amount and am pretty comfortable at a range of cadences, so I don't mind the big jumps. Also, you have to be satisfied with a 48-12 big gear. More than big enough for me, but probably not for everyone. And, oh yeah, if you ever actually want to USE the 34 cog, you're gonna need an mtb rear derailure.

The setup isn't without it's costs and tradeoffs, but it works well for me.

-Ray

Why would you need the MTB derailleur to go 34-34? Surely to go 48-34 you would, but why in the small ring?

[kkasper4]

I have a Record 50/36 on my Ottrott. For the most part I run an 11/23 cassette on the rear (which is very similar to a 12/25 on a 53/39 crank). I just did the Death Ride last weekend, and I used a 13/26 on the rear - which was absolutely necessary for myself. It's obviously easier to switch out the rear cassette than add a triple crank. I have yet to find any downsides to the 50/36 crank, the 11/23 giving me more than enough gears for myself on the flats.

[Ray]

Why would you need the MTB derailleur to go 34-34? Surely to go 48-34 you would, but why in the small ring?
Most road derailures aren't rated to handle a bigger cog than 27 or 28. Some of them will handle more - most'll get you to 30 - but a 34 is freaking big cog that I wouldn't want to bet that a road derailure would handle it. It's not just about chain wrap - it's also the physical ability to get the chain onto that large a cog. I just keep an XT rear derailure on the bike. If there's a performance difference between that and a road derailure, I've never been able to feel it.

-Ray

[Jeremy]

The reason you need an MTB der for a 34T cog is that the upper pivot spring (b-spring) is not strong enough on a road der to pull the upper pulley far enough away from cog to prevent the chain from grinding against the cog. Lower b-spring tensions improve chain wrap but limit the capacity of the der to handle large cogs. There are ways around having to use an MTB der, but it requires customizing the b-spring tension on a road der.

Jeremy