Unfortunately I have never seen direct numbers. I think Superdave posted some a while back. What your really looking at comparing is two equal size gearing combo. a 50 X 11 compact and a 56 x 13. These give almost the same speed at the same cadence. With the 50 X 11 the chain is angled and wrapped around smaller curves. This definately will result in power loss, particularly going from the 11 to the 13. How much is hard to tell. A researcher named Alan Lim might have some answers.



Styrrell

Does anyone use a 14-25 or 15-27 with a 54 or 55.
Cullen

Alan Lim laughed at recreational riders like us buying big rings larger than 53.

Do we really want to emulate the gear selection of Time Trialers (this has come up a couple times)? We have this small issue of a warm down run...

It all comes down to speed (driven by watts, weight and aero), preferred cadence, and pacing strategy (I will NOT push 300watts to go 35mph when I could rest completely and go 32mph).

ot

Hello, Again read my posts. The specific case I was referencing is a rider who went 2:15 or so on a flat course. Hardly recreational. I also sated that its more important to have not sacrifice your low gear.



Styrrell

My experience,

I rode 55/42 11-23 at Muskoka this year and was .2 km/h faster than Dev Paul on 50/34. Didn't overly affect my run, Dev was less than a minute faster and I set a PB on the 15k run. However, I kept thinking at my next race with sharp 42/23 climbs "why the hell am I running this gearing" after reading Dev's posts. Now the compact is on and I am just as fast with more gears to chose from and my quads aren't smokin on tough little climbs.

My next two 15k club TT's on the compact and a rolling course were '45 and '51 seconds faster than when I had the 55/42. I attribute most of the time gains to having the extra gearing and a smaller rpm drop per shift.

Now if I could only learn to swim :)

considering that triathletes ( long distance) always have to hold back on the bike AND the fact they can't match the peakpower of roadies, I advise a 50- 34/36 or 50- 38 ( if you don't have compact)



I rode a 345 Watt averages non drafting Oly , had the fastest time an never used my 11. I rode a 50-38, and 11-23
I did not use the 38 as well. I can still ride my "big" ring where others can not, also an advantage

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http://www.wimdedoncker.be

I think everyone posting any sort of gearing about their own bike also needs to post whether they have 700c or 650 wheels and their pedaling style. I know a fellow racer who has 650's and mashes- he rides a 58t big ring. I am on 700s and I tend to spin- I ride with a 53 big ring. I THINK a 56/42 on 650s is equal to a 53/39 on 700's. This really needs to be taken into account.

well i'm upgrading to a 55 or 56 (i've got a 53/39 11/23 setup 700c). In my last races i only rode on the 11 and 12 and still i had had the feeling i could have ridden on a bigger gear.

I ride a 54/39 FSA and haven't had any shifting problems. I use a 12/25 for training and flatter races and 12/27 for really hilly courses. I also have 700c wheels. I had a 55/39 on my previous bike and will probably get a 55 tooth ring for this bike next season. Like Elwood, I blast the downhills and I spin out on almost every big descent since switching to the 54. In flat 1/2 IMs I usually ride at about 85-88 rpms.

OK.......all you wussies...: ) the heck with the 12-23 and stuff. I ride a 54/42 with a 12-19. OPPSSS.....I live in Florida with the only hill as a bridge!! : )

I do ride a road bike with a 53/39 and my tri bikes with the 54/42 and my largest cassettes are 12-21. I even have a 12-18, 7 speed straight block, for the days I feel very fast!!

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Paul

I'm starting to get a good feel for why the Slowtwitch DNF rate was so high in the ST v. TNO challenge ;-).

ot

"but of course there would be an annoying jump from one ring to the other."

Not so's you'd notice. The front shifts cleanly, and I downshift going up a hill so the big drop from 56 to 39 doesn't really cause too much grief. If there's only a slight gradient change, I'll do a double shift but it's rarely necessary.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

CE,

You're on a 56 - at our age. Holy crap!

A 50/34 compact works best for me. Guess I'll need Viagra a long time before you do. :-)

BTW, I don't buy the spinning downhill arguement with a 56/12. Betcha I can go just as fast tucking aero and coasting.

"You're on a 56 - at our age. Holy crap!"
- - At my age I can't spin my arthritic hips fast enough to keep up with anything less!

"A 50/34 compact works best for me. Guess I'll need Viagra a long time before you do. :-) "
- - Before I worry about lead for my pencil, I need to find someone to write to...

"BTW, I don't buy the spinning downhill arguement with a 56/12. Betcha I can go just as fast tucking aero and coasting."
- - I'll take that bet. Ever seen 72 mph show up on your speedo? And btw, that's 56/11

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

"Ever seen 72 mph show up on your speedo"

My speedo is in kph and 72 mph translates into about 118 kph. What were you doing ? - Falling off a cliff!

I'll have to check on analytic cycling but even with a 56/11 to get 118 kph you've got to be turning 150+ cadence.

You obviously aren't a masher. :-)

"even with a 56/11 to get 118 kph you've got to be turning 150+ cadence."

It equates to about 180 rpm. I think I lost control of the pedals at 165 or so and continued to accelerate downhill. There was a very tense moment as I rounded a very soft, high-speed curve. There was just a small bump in the road - hardly visible - but enough to get me airborn... This squid came very close to inking his shorts.

I've determined that that will be my all time high speed and I have no intention of every trying to go there again. I tried to figure how that might have been a miscalculation, but one of the guys riding behind me said he registered 63 and I was pulling away from him.

I can spin as high as 180 on a spin bike or CT, but only for a matter of seconds.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

(under cough:) bullshit ;-)

It's not that hard.. I've watched a buddy of mine spin at 180 for a few secs.

I'm teasing the old man...

"(under cough:) bullshit ;-)"

Watch it. The last time you tangled with me you ran away with your tail between your legs.

Three things you should know before you start dissin' me on this:
1- I'm a spin instructor
2- I've been biking longer than you've been alive
3- My current bike, a 2000 Trek, has over 75,000 miles on it

As the saying goes my dear, better to remain silent and be thought a fool than to open your mouth and erase all doubt.

Now run away, or I shall taunt you yet again...

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Old man I think you're confusing me with someone else :-)

how many teeth do cock rings have?

You're baaaaaaaaaaaaaack...

Knowing what I know now about how I ride, I think it was damned near a crime for my coach to have me on a 56 years ago. I dropped down from a 54 to a 53 this past year and noticed improvement in my range of gearing as well as performance. I never spin out in a 53-11, and I'd stop pedaling before I did.

Now on the other hand, for the last 15 years I've been riding on a 42 small ring. Never had anything else on, never. But I've been noticing lately that no one seems to ride a 42 any more, so just today I picked up a 39 to experiment with. I imagine thats going to be quite a change.

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Elivis needs boats.

"Old man I think you're confusing me with someone else :-)"

Nope. Check your outgoing PM entitled "line crossed." I assume you swallowed the balance of your Xanax while writing it. The accusations were childish, as I detailed in my response, which you chose not to answer. When you make accusations like that, you need to defend them or apologize. You did neither.

So no, I won't ever confuse you with anyone else.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...