Shimano shifters

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Anonymous's picture
Anonymous

A friend wants to change his triple (Shimano 105) to a compact. Will he have to change the shifters as well. Are there other issues to consider?

Anonymous's picture
Christian Edstrom (not verified)

No, he won't have to change shifters. He will need to get a double-specific front derailleur for good shifting performance. The IRD Compact-specific derailleur might be a good choice.

Oh, and has he looked at the gear charts very very very carefully? I consider myself a reasonably adept cycling technician, and I bought a compact only to find it fairly hateful. So he should consider that.

To me, a compact is only useful for an A21+ rider who lives where it is mega hilly...

- Christian

Anonymous's picture
don montalvo (not verified)
high end...

...what's the highest gear on a compact? i used to get by with a 52x13 or 52x12 but now that i'm heavier, flats/decents are easier...53x11 is a necessity. i thought compacts topped of at 50 on the front? seems like an a21 rider in a hilly area should get a smaller inner ring (like a 39) and a wider cassette (one with a 26).

don

Anonymous's picture
An anonymous cow! (Christian Edstrom) (not verified)

You need a 53x11 but Eddy Merckx was ok with a 52x14? Yeah, ok, I believe you. How's the EPO treating you? Wicked headache, much?

Funniest. Post. Ever.

- Christian

Anonymous's picture
don montalvo (not verified)
i doubt eddy rode a compact 50t front

:-)

Anonymous's picture
An anonymous cow! (Christian Edstrom) (not verified)

A 53x11 (what you claim to need) is 126.6 gear inches.

A 50x11 (highest gear you can get on a compact) is 119.5 gear inches.

A 50x12 (highest normal gear on a compact) is 113.9 gear inches.

Eddy Merckx's highest gear (52x14) when racing was 97.6 gear inches.

No offense Don, and I don't know you from Adam, but I bet you can't turn a 126 inch gear over on the flats at 100rpm for 300 yards. If you could, you'd be Tom Boonen! :)

PS: May I draft you on our next ride?

Anonymous's picture
<a href="http://www.OhReallyOreilly.com">Peter O'Reilly</a> (not verified)
Thanks for the laugh; though yer missin' a little something...

"""Funniest.  Post.   Ever.""
"

Anonymous's picture
don montalvo (not verified)
doh!!!

"...wait..a...minuuuuTTEEEEEEE...that's ME! wait...no, that's not me...i don't have a tan...argh!!! must be the crca podium guy...

a fat guy in his briefs...hmmm...this photo elicits a very BAD, visceral response ... :)

don"

Anonymous's picture
An anonymous cow! (Christian Edstrom) (not verified)

Pietro, Complementi!

Awesome! :-)
- Christian

Anonymous's picture
jc (not verified)

I've been using a compact for 2 years now, 34/50 with 12-25 cassette.
What did you find hateful about your set-up?

Anonymous's picture
An anonymous cow! (Christian Edstrom) (not verified)

I'm slow and I suck, so I spend a lot of time cross-chaining in my 50-17, when I'd be better off on a 39 inner.

A compact to me is only useful if you're buff and strong and can ride anything around here in the 50t and only use the 34 for absolutely horrendous, Tre Cime de Lavaredo-spec, gut-busting climbs.

Additionally, the 34t is totally useless for the flats, of course.

Basically, if you're riding the 50x17, 50x19, or 50x21 then, well, you're probably better off on a triple.

I'm swapping my inner for a 39, to get a 50-39. There ain't nothing around here I can't climb in a 39-25 anyway. And, as I said, I suck.

- Christian

Anonymous's picture
DvB (not verified)
I can't believe I'm doing this . . .

". . . but I'm going to have to disagree with the Anonymous Cow on this one.

Let me preface by saying that I think Christian is an absolutely fabulous source of cycling information, and I know in advance that a post by him will contain thoughtful, informed, intelligent, and sensible advice. I can't think of a single previous post of his with which I've disagreed.

HOWEVER . . . I think compacts are a really good idea for most riders -- regardless of one's ability or local terrain. Just my opinion, but it seems to me that with a compact you gain much while losing very little. Yes, if you stick with a typical 12-25 cassette, you lose a bit of high gearing. So if you're spun out at, say, 150 RPM, you'll max out at only about 49 mph with a compact vs. 51 mph with a traditional 53-tooth chainring. I'm fine with that. (You could of course avoid this ""problem"" entirely by swapping to a cassette with an 11-tooth small cog.)

On the other hand, you gain a lot of useful low-end gearing. You're right, there's nothing around here that most reasonably fit cyclists can't climb with a 39-25 -- but there's more to climbing than just getting up the hill. It's nice to have the option to spin if you want to. And even with a 34-25 low gear, 80 RPM will get you about 8.4 mph -- not a bad average pace on Little Tor, for example. I'd much rather climb Little Tor at 80 RPM than the 60 or 70 RPM that I needed with my old 39-23 combo. Sure I got up okay, but I hated every minute of it. And hey, if I want to slog out a climb at 60 RPM, I still can, just by upshifting a few gears.

I only just installed a compact setup, so a lot of what I'm writing is at this point theoretical -- I may wind up hating the whole thing once I've lived with it for a while. But I have a feeling I'll be sticking with it. I'll let you know!

--DvB

P.S. I'm just DYING for a link to some pictures of buxom European podium girls. Does anyone have any idea where I might find such a link?"

Anonymous's picture
An anonymous cow! (Christian Edstrom) (not verified)

Doug,

It's the crossover on the flats that sucks. If you can't turn a 50x16 or higher _all_ the time on the flats, you'll hate it. Actually, I think you're strong enough not to need to crosschain on the flats, so I actually think you'll like it. Doesn't work for me though.

So yeah, the absolute ratios are good - in effect giving up a >100 gear to get a <40 gear. And it's great for steep hills.

But the fact that the cruising gears for a weakling like me are in the crossover range sucks... If you cruise at 18-20mph, ugh.

- Christian

Anonymous's picture
don montalvo (not verified)
a rides...

"...i remember we used to cruise in around an 80"" gear. the 50 should allow this, especially with a 26 in the back...lots of 60-70"" gears.

don

"

Anonymous's picture
<a href="http://www.OhReallyOreilly.com">Peter O'Reilly</a> (not verified)
What cassette are you using?

I ride with a 12x27 - 34/50 and spend most of my miles (>66%) riding in the 50x17, 50x15. One of the benefits of such is that I have a really nice, as in almost perfectly straight, chainline.

The only time I'm in the small ring is for the hills. The 50 tooth up front allows me to ride the flats and near flats in the big ring. For rollers, I'm usually only shifting the front derailler, too while in the 17 tooth rear. Your tooth experience may vary....

Anonymous's picture
An anonymous cow (not verified)

I ride with a 12-25 10sp, and I spend most of my time in the 50x15, 50x16 or 50x17 as well. The chainline in the 50x17 is not good though.

If I were a smidgen stronger, I think it would be ok. As in, I'd never use a gear lower than 50x16 on the flats.

Anonymous's picture
<a href="http://www.OhReallyOreilly.com">Peter O'Reilly</a> (not verified)
50x17 is nearly perfect chainline for a 9 speed 12x27

The 17 tooth cog is in the middle of the cassette and the chainline is nearly straight as could be. As a result, my chains last longer than expected.

One thing I do miss is the 16 tooth cog. I really notice the jump from a 17 to a 15 tooth gearing. Short of upgrading to 10 spd, I'd gladly trade my 12 tooth cog for a 16 if it were readily possible.

Anonymous's picture
"Chainwheel" (not verified)
Gears

"""Yes, if you stick with a typical 12-25 cassette, you lose a bit of high gearing. So if you're spun out at, say, 150 RPM, you'll max out at only about 49 mph with a compact vs. 51 mph with a traditional 53-tooth chainring.""

At those speeds, it's better to tuck and coast.

""And even with a 34-25 low gear, 80 RPM will get you about 8.4 mph -- not a bad average pace""

Assuming you have the aerobic capacity to climb a steep hill that fast. Low gears aren't a magic potion. I agree it's nice to have the option of spinning instead of grinding up a steep hill at 35 rpm. But the work required is the same.

""Chainwheel""
"

Anonymous's picture
Training Wheels (not verified)
TRUE - It's all about the ENGINE - NOT the Gears (nm)
Anonymous's picture
oops (not verified)

:)

Anonymous's picture
don montalvo (not verified)
fsa notes on compact cranksets
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