Compact Crank

gbrandon said:

As an alternative to a granny gear I am considering a
compact crank. Any recommendations? Currently running a Shimano Ultegra 53/38 and 30/13 cogset.😕

It depends how much you want to spend ...

I presume you currently have a square taper, 8-speed crank ... is that right?

Did you want to change the BB, also?

What about the cassette?

What gearing are you trying to achieve?[indent]30/27 = 1.111

38/34 = 1.118

34/30 = 1.133

34/27 = 1.259

[/indent]There are several USED options if you want to continue to use a square taper BB -- primarily, using a variety of older MTB triples which have a 110BCD ...

You could use a 4-arm (104BCD) MTB crank, sans granny, with 48/32 chairings:

[indent]32/30 = 1.066

[/indent]FSA cranks are a good value ...

Yes, 8 speed, square taper. Prefer not to change BB if possible. After all, I don't want to spend an amount that will cost me almost as much as an mid tier bike with a triple (a consideration, but I really like this bike for all around riding in Pennsylvania). As far as gearing, as low as reasonably achievable, remember, I manage to use a 38/30 currently and it meets my needs 80% of the time.

alfeng said:

It depends how much you want to spend ...

I presume you currently have a square taper, 8-speed crank ... is that right?

Did you want to change the BB, also?

What about the cassette?

What gearing are you trying to achieve?[indent]30/27 = 1.111

38/34 = 1.118

34/30 = 1.133
34/27 = 1.259

[/indent]There are several USED options if you want to continue to use a square taper BB -- primarily, using a variety of older MTB triples which have a 110BCD ...

You could use a 4-arm (104BCD) MTB crank, sans granny, with 48/32 chairings:

[indent]32/30 = 1.066

[/indent]FSA cranks are a good value ...

gbrandon said:

Yes, 8 speed, square taper. Prefer not to change BB if possible. After all, I don't want to spend an amount that will cost me almost as much as an mid tier bike with a triple (a consideration, but I really like this bike for all around riding in Pennsylvania). As far as gearing, as low as reasonably achievable, remember, I manage to use a 38/30 currently and it meets my needs 80% of the time.

Maintaining the square taper BB gives you a lot of options, but, most involve buying a "used" crank & relying on the prior rider having properly removed it from the bike so that the tapers are in "good" condition ... so, you are actually limited in what is available.

Personally, I would opt for an OLD, 5-arm XT-type crank (either from eBay OR a "friend" who has an old MTB) with 110BCD and just not mount the granny ... and, adjust the gearing accordingly with "new" chainrings which give you the ratio range you want ... price is usually based on "cosmetic" condition (presuming, again, that the tapers are in good condition). 34t is the common minimum size (a 33t available for the mega-bucks).

The so-called "compact" 5-arm 94BCD cranks are "okay"; but, the largest chainring readily available (and, THAT is not so much so ... quite a special order item) is a 46t ... a 48t may be available; but, the cost of chainrings with more than 42t for that size spider is probably pretty high. I think the minimum is a 30t ... maybe, smaller.

If you restack your cassette so that it has an 11t smallest cog (available separately from you local bike shop ... but, I don't know how much your LBS would charge ... might be less expensive to get a "new"/replacement cassette on eBay OR they may only charge you a few dollars!) , then you could use a 44t "compact" 5-arm ring and get close to the same high gear you have with the 13t cog; and, go with a 30t (or, smaller) inner ring.

IF your 13t cog is threaded on and not held in place with a lock-ring, then your can't use an 11t or 12t smallest cog, BTW.

You really need to decide how high-and-low (mostly low, I guess) you want the gearing to be AND be willing to wait for the crank to come along on eBay ...

BTW. Your current rear derailleur's cage may not be long enough to take up all the slack when you are using the smaller chairing if you are also using one of the smaller cogs ... not a particularly big deal.

gbrandon said:

Yes, 8 speed, square taper. Prefer not to change BB if possible. After all, I don't want to spend an amount that will cost me almost as much as an mid tier bike with a triple (a consideration, but I really like this bike for all around riding in Pennsylvania). As far as gearing, as low as reasonably achievable, remember, I manage to use a 38/30 currently and it meets my needs 80% of the time.

Any specific reasons for not changing the BB? You're going to have a hard time finding a compact that works with the Shimano square taper. Performance Bike has the FSA Gossamer with BB for $150, and if you search around you might even find it cheaper.

What are your reasons to converting to a compact? Given the fact that you have 30t cogs on the back, I'd imagine a regular double crank would suit you just fine.

I went to a compact crank last September for a hillclimb TT and now ride it all the time. Basically, it's all about cadence. Forget all the macho stuff like, "Real men hammer the mountains in the big ring." It's all about figuring out how you climb best and what cadences allow you to make the maximum power climbing. I am a spinner and I hate it when my cadence drops below ~75rpm. I was limited in how high I could get my cadence on grades >6% with a standard double crank, so I changed to a compact crank (FSA 50/34) and now use a variety of cassettes depending on the topography of the event. I run a 13/29 for rides with lots of climbing and I can run an 11/21 for flat courses, and several options in between. Changing cassettes is quick and simple and requires few tools, plus cassettes are pretty cheap as compared with cranks. I doubt if I will ever need to put my standard crank back on.

Consideration to convert in lieu of a granny. Most (80%) of the time my current setup is fine but when the hill exceeds 12% grade I find myself wanting that "one lower gear" that isn't there.

That and the fact I'm getting OLD and the knees and quads ain't what they used to be......

badkarma said:

What are your reasons to converting to a compact? Given the fact that you have 30t cogs on the back, I'd imagine a regular double crank would suit you just fine.

No reason not to go with the granny if its cheaper and easier for you...
I'm 28, and am able to stick with the fast bunch on my local club's group ride. and have a triple on my bike. and I am happy with it. properly set up, it will shift smoothly and get you pedalling up a vertical wall.

gbrandon said:

Consideration to convert in lieu of a granny. Most (80%) of the time my current setup is fine but when the hill exceeds 12% grade I find myself wanting that "one lower gear" that isn't there.

That and the fact I'm getting OLD and the knees and quads ain't what they used to be......

Trying to avoid having to change shifters/derailleurs.

FREDBLACK said:

No reason not to go with the granny if its cheaper and easier for you...
I'm 28, and am able to stick with the fast bunch on my local club's group ride. and have a triple on my bike. and I am happy with it. properly set up, it will shift smoothly and get you pedalling up a vertical wall.

artmichalek said:

Any specific reasons for not changing the BB? You're going to have a hard time finding a compact that works with the Shimano square taper. Performance Bike has the FSA Gossamer with BB for $150, and if you search around you might even find it cheaper.

FSA Gossamer is a good crankset. A 50-34 compact gets you about two gears at the bottom while losing a gear at the high end over a regular 53-39.

With a 34-30 gear, you should be in great shape for those tough climbs.

Apologies for jumping in to someone elses thread but I am considering a compact crank to add a couple of extra gears for those longer / steeper climbs. Current set up is a 2004 Ultegra Double (9 gear cassette). Any suggestions in terms of compatible compacts - preferably without running to carbon prices

Bevuardo said:

Apologies for jumping in to someone elses thread but I am considering a compact crank to add a couple of extra gears for those longer / steeper climbs. Current set up is a 2004 Ultegra Double (9 gear cassette). Any suggestions in terms of compatible compacts - preferably without running to carbon prices

I think you could let your budget be your guide ...

The Ritchey compact crank is highly regarded and uses an Octalink BB; but, it is fairly expensive ... about $170 at EXCEL SPORTS.

For the price of the Ritchey, you could certainly by an FSA with either an ISIS or possibly a MegaExo version if you shop around.

You can certainly get a 12-27 cassette if you aren't already using one AND also a 37t (yes!) 130BCD chainring from Warhawk Industries (about $50!?!).

The Ultegra 6500 rear derailleur can handle a larger cog than 27t, BTW ... it depends on how long the dropout hanger is.

I would opt for the FSA MegaExo, FWIW.

The Shimano "Compact" crank is a good choice if yoiur budget can swing it.

Another choice is a 104BCD XT/LX crank with a 48t "touring" ring ...

alfeng said:

I think you could let your budget be your guide ...

The Ritchey compact crank is highly regarded and uses an Octalink BB; but, it is fairly expensive ... about $170 at EXCEL SPORTS.

For the price of the Ritchey, you could certainly by an FSA with either an ISIS or possibly a MegaExo version if you shop around.

You can certainly get a 12-27 cassette if you aren't already using one AND also a 37t (yes!) 130BCD chainring from Warhawk Industries (about $50!?!).

The Ultegra 6500 rear derailleur can handle a larger cog than 27t, BTW ... it depends on how long the dropout hanger is.

I would opt for the FSA MegaExo, FWIW.

The Shimano "Compact" crank is a good choice if yoiur budget can swing it.

Another choice is a 104BCD XT/LX crank with a 48t "touring" ring ...

Thanks AlfEng - I'll look into these options
🙂

Hello experts!

I'm also thinking of switching to a compact crankset to deal with the mountains with more cadence. My current crank setup of the R/B is 53/39 (FSA) with 13/25 cogset (Campy), 10 speed. I'm using a Dura Ace 7700 front derailleur and Campy-Record rear derailleur.

My budget is $200.

What would be the recommendation of the brand of compact crankset?

I would perfer not to the change the cogset and front derailleur....
- Will I be losing lots of the high gear range for not changing to a 11/23 cogset?
- Will my front derailleur work with the compact crank set?

Sorry for all the questions but will appreciate your reply

Will 🙂

4wu said:

.... My current crank setup of the R/B is 53/39 (FSA) with 13/25 cogset (Campy), 10 speed.
- Will I be losing lots of the high gear range for not changing to a 11/23 cogset?
🙂

Currently you have 53/13 top = 4.08. So a 50/12 top = 4.16 & therefor you would have a slightly higher top then before. So 11 rear not req.
Edit - Your existing 13 may leave you a little short though

Thank you so much for your response. As I'm pretty new to the concept of compact crank. Can you explain to me what does 4.08 and 4.16 means in terms of measurement?

😕

Albert 50 said:

Currently you have 53/13 top = 4.08. So a 50/12 top = 4.16 & therefor you would have a slightly higher top then before. So 11 rear not req.
Edit - Your existing 13 may leave you a little short though

gbrandon said:

As an alternative to a granny gear I am considering a compact crank. Any recommendations? Currently running a Shimano Ultegra 53/38 and 30/13 cogset.😕

I like my compact crank just fine, but I needed a new crank anyway. If your only objective is a lower low, a MTB derailleur and cassette is a cheaper way to go. 9-speed road shifters will shift 9-speed mtb derailleurs no problem, then you can have a 38x34 low gear.

4wu said:

Thank you so much for your response. As I'm pretty new to the concept of compact crank. Can you explain to me what does 4.08 and 4.16 means in terms of measurement?

😕

One crank revolution will be 4.08 wheel revolutions in that gear.

There are plenty of sites which have a comprehensive list of gear ratio calculations. I personally like to work them for myself.
Divide front teeth# by rear teeth# X by wheel roll out [ weighted curcumference] i.e. 53 divided by 13 = 4.0769 multiplied by 2.115 [which is my weighted roll out of my 700 x 25mm rear tyre cause that is where my comp magnet is] = 8.622 Metres which means that for every 360 degrees [one revolution] of your crank arm your bike has moved 8622mm.[or for a typical 23mm front weighted rollout around 2095 X 4.0769 = 8541mm.]
8813mm is roll out of my 25 tyre in 50/12
8135mm is roll out of my 25 tyre in 50/13
So i would travel 678mm less per crank rev in those respective gears.
OK, plenty of people will tell you about "gear inches" but they are pretty well meaningless to most folk were as "roll out" can be understood at a glance.
If my maths are wrong someone please correct me.