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PostPosted: Sat May 17, 2014 9:11 pm 
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Sure, 186 g is a ton of weight, but I meant its doubtful switching from standard to compact will save anywhere near that much, will it?

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Posted: Sat May 17, 2014 9:11 pm 


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PostPosted: Sat May 17, 2014 9:33 pm 
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Location: Loveland, CO
gitsome wrote:
Sure, 186 g is a ton of weight, but I meant its doubtful switching from standard to compact will save anywhere near that much, will it?


It won't be 186 g. In SRAM's case it's about 30 g. I'm not sure about Shimano or Campy.

I do like the fact that with a compact crank I'm able stay in the big ring longer or avoid shifting down to the small ring on rollies.


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PostPosted: Sun May 18, 2014 12:06 am 
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I just think using whatever gear combo is best for your power and revs efficiency outweighs 30-100 g of weight. For instance when I switched to compact I regretted it regardless of weight change I did not like the combo w the 11-25 rear tho by now Im used to it etc etc.

Sees like the choice of stand or compact should be based on pedaling and terrain rather tan relatively minor weight savings. Just my opinion. But I do love the WWism of it~ Lots of respect for the thought!

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PostPosted: Sun May 18, 2014 6:49 am 
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I went from 53/39 crank (came with full super record kit) to ultra torque compact 50/34, then purchased 52/36 stronglight CT2 for campy compact 113 BCD. Cassettes came with 12-29 SR, but also purchased 11-25 chorus (as i thought I needed the 11 when running compact 50), and recently added 12-25 super record and Tiso Ti 11-27 (I like the options of being able to purchase individual cogs and mix and match)

I'm more grinder than smasher, similar terrain. So like the lower rpm 90-95. But I definitely never could do 53/11 combo. My legs just can't power it.

Best combo so far is stronglight 52/36 11-25. Only on weekends when going for steeper mountain roads, the back to campy original 50/34 chainrings and bring two wheelsets shamal ultra with 12-29 and meilenstein with 11-25 depending on wet/dry.

Bottomline, I never regretted converting to compact, now I have two options of running compact or mid-compact from the same crank! Sold the standard crank since. Even built another bike with super record compact set from the get go. And never thought about the fact I don't change to small chainring as much as I used to.

Edit: chain length are the same between both compact or mid-compact. To be precise mau have to be 1 link less or more. But not noticeable and chain slaps is non existent when properly adjusted. Weight wise, front compact and standard cranksets differ by 22gr only. I'm sure cassette is lighter too as you mentioned


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PostPosted: Sun May 18, 2014 12:22 pm 
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gitsome wrote:
Sure, 186 g is a ton of weight, but I meant its doubtful switching from standard to compact will save anywhere near that much, will it?


This also includes moving from a 2010 rotor 3d+ to the new campagnolo over torque comp ultra advertised at 563 grams, upgrading to ceramic bearings, and moving to a lighter cassette

If everything is as advertised I should be dropping 150+ while hopefully getting better front shifting


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PostPosted: Sun May 18, 2014 12:28 pm 
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gitsome wrote:
I just think using whatever gear combo is best for your power and revs efficiency outweighs 30-100 g of weight. For instance when I switched to compact I regretted it regardless of weight change I did not like the combo w the 11-25 rear tho by now Im used to it etc etc.

Sees like the choice of stand or compact should be based on pedaling and terrain rather tan relatively minor weight savings. Just my opinion. But I do love the WWism of it~ Lots of respect for the thought!


I get this argument, but after pouring over the gear ratio tables over and over again, I can get an identical range, ( slightly expanded actually with a 16 tooth spread up front instead of 14 on the standard). And I think that my normal gears will all me in hue he big ring now instead of at the high end of my small ring/ low Enid of my big ring. Also gear ratios will be much closer with the smaller cassette.

It all looks my good on paper I'll let you know in a fewer week if I'm happy or not!


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PostPosted: Sun May 18, 2014 8:05 pm 
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I actually dropped the 34 front ring for a 36. The front shift was necessitating a 3 or 4 gear shift at the back to maintain cadence, going to the 36 means it's (usually) only 2. Similar to a 53/39.


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PostPosted: Wed May 21, 2014 6:06 pm 
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Joined: Sat Nov 02, 2013 10:17 pm
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I never want to give up gear inches ... saving weight? It's more important to figure out where you need the pulling power. I wouldn't let weight of my cranks get in the way over that. Using a Rotor Flow 3D+ 53-38 with an 11-25 on a 14 lbs 14 oz setup. No real complaints.


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PostPosted: Thu May 22, 2014 11:35 pm 
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If you're going to go compact, why don't you just get the rotor compact spider and some rings?


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PostPosted: Fri May 23, 2014 12:10 am 
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pdlpsher1 wrote:
Although the crank doesn't spin very fast we're talking about rotational weight savings here. When I dropped 186g. by upgrading the crank I noticed the weight savings immediately after leaving the driveway on a level road.


Cyclists get compact cranks to go up hills because they aren't strong enough and/or refuse to train for. Compact cranks are not purchased to make the bike lighter. Since you don't have tough hills the hill reason isn't there. You may also wind up loosing top speed on the flats with the new gear choice.

Personally, I would never go compact as I don't do well with high cadence pedaling.

Again , you may find that the weight benefit of compact is far outweighed by the gearing. Is the goal to ride faster or to have a lighter bike?

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PostPosted: Fri May 23, 2014 1:40 am 
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fromtrektocolnago wrote:

Cyclists get compact cranks to go up hills because they aren't strong enough and/or refuse to train for. Compact cranks are not purchased to make the bike lighter. Since you don't have tough hills the hill reason isn't there. You may also wind up loosing top speed on the flats with the new gear choice.

Personally, I would never go compact as I don't do well with high cadence pedaling.

Again , you may find that the weight benefit of compact is far outweighed by the gearing. Is the goal to ride faster or to have a lighter bike?


Funny I keep hearing the gear ratios, but by switching to a smaller cassette I can get another area for significant weight loss while maintaining my gear spread, in fact my highest gear is a bit higher and my lowest is a hair lower.

So the whole, compacts= slow argument really isn't holding water for me except for the 11tooth cog has more friction than a 12 for your highest gear argument, I'll see how that plays out for me. As the new crank is in and will get installed tomorrow.

By the way I'm moving from a 12-27 and a 39-53 crank to a 11-25 with a 34-50 crank. Run the numbers if you I don't believe me. Since I use the granny gear on about one out of every 5 rides, I could probably move down to the 11-23 cassette and be ok 99.9% of the time.


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PostPosted: Fri May 23, 2014 4:16 am 
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Location: Loveland, CO
mjduct wrote:
Since I use the granny gear on about one out of every 5 rides, I could probably move down to the 11-23 cassette and be ok 99.9% of the time.


You don't want to go too small of a cluster in the back. There are benefits keeping the rear cluster at 11-25 or 12-27. The larger cluster allows you to run a 50x23 or 50x25 combo on a less-steep climb or rollies. I'm running 50/34 and 12-27. On fast group rides I'm in the big ring (50) most of time despite the lumpy terrain. Shifting the FD wastes time and energy as you would have to shift the RD at the same time. Keeping the chain on the big ring enhances power transfer (this is subjective but I could feel it...the big ring is much stiffer than the small ring), reduce chain friction, reduce misshifts, saves energy by not having to reduce power while shifting the RD, etc. With my setup I have a wide speed range from 13mph to 35mph on the big ring. This is akin to a 1x10 setup on the mountain bike drivetrain :mrgreen:

In a nut shell there's a lot more to just looking at gear inches.


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PostPosted: Fri May 23, 2014 3:22 pm 
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good points pdlpsher1

heres what I'm coming from:

------39-----53
12---85.4---116.1
13---78.8---107.1
14---73.2---99.5
15---68.3---92.9
16---64.1---87.1
17---60.3---81.9
19---53.9---73.3
21---48.8---66.3
23---44.6---60.6
25---41.0---55.7
27---38.0---51.6


here' what I'm going to (special thanks to Sheldon Brown for the calculator):

-----34------50
11---81.2---119.5
12---74.5---109.5
13---68.7---101.1
14---63.8---93.9
15---59.6---87.6
16---55.8---82.1
17---52.6---77.3
19---47.0---69.2
21---42.5---62.6
23---38.8---57.1
25---35.7---52.6

I'm really never more than 2-3 gear inches off from my old setup to my new setup... I don't know if I could justify in my mind the large ring being stiffer than the small ring, seems counter intuitive, more material, larger area to bend= less stiffness. Do you have some evidence that proves that? I would be interested to see it...

I typically power over rollers and small hills in the gear I hit them in, everyone says I surge, but I maintain speed and cadence in these spots. I prefer to think that they sag!

For large hills, I typically shift into my small ring/ small end of the cassette at the end of the approach when I can let off the power without much loss in momentum, then hit the hill with a decent amount of speed (usually around 25) and then I can move through my rear cluster at me preferred cadence (95-105) as I wear down without having to shift the front.

(edited many times to get the gear charts to read right, formatting on the reply page doesn't = what it looks like on the topic page)


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PostPosted: Fri May 23, 2014 3:39 pm 
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Joined: Tue Nov 11, 2003 9:47 pm
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Location: Santa Cruz, California, USA
> Keeping the chain on the big ring enhances power transfer

Chainrings don't flex at all in the direction the force is on. Certainly not enough to feel.

Some large 110mm BCD chainrings can flex sideways but if that's a problem at all it's a problem when shifting. I've used a lot of different 50t 110mm BCD chainrings and have not noticed any flex induced shifting problems. I think that's a theory that is unproved. Proponents may be mistaking slightly warped chainrings for flexing chainrings.

The biggest drawback to the 50/34 compact is having to shift an extra cog in the back when shifting the front rings, and slightly slower front shifting from small to large ring. That bothers some people but most learn to deal with it.

I'd carefully add up the weight savings before embarking on a conversion to compact purely for weight. It's not that much difference. OTOH if you need low gearing it's the way to go- better than a 130mm BCD crank and huge cassette.


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PostPosted: Fri May 23, 2014 9:08 pm 
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Location: Sweden
Talking about saving energy while promoting maximum chain crossing is just ridiculous. The energy lost in drive train friction with big-big is just huge.

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Posted: Fri May 23, 2014 9:08 pm 


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