2018 PRO thread

Questions about bike hire abroad and everything light bike related. No off-topic chat please

Moderator: Moderator Team

User avatar
Calnago
Posts: 6222
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

LeDuke wrote:Can anyone explain why 2x is more “efficient”?

Seems “faster” has been retracted already. Let’s hear why “efficient” is the word of the day.

With data and citations, please.


Sent from my iPhone using Tapatalk
I think I explained it quite well. If you didn’t get it, then you never will.

I see some others above talking about the mechanical efficiencies. While there is that, what I was trying to explain in my earlier post was also about efficiencies to the rider from having two distinct “ranges” of gears, closley spaced within each of those ranges.

Citation: Me, Common Sense, and Experience.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

maquisard
Posts: 1906
Joined: Thu May 01, 2008 8:51 pm
Location: France

by maquisard

Calnago wrote:
Mon Jun 18, 2018 6:43 pm
Citation: Me, Common Sense, and Experience.
:thumbup: - Love that quote

by Weenie


User avatar
tymon_tm
Posts: 2421
Joined: Tue Sep 05, 2006 4:35 pm

by tymon_tm

spdntrxi wrote:
Mon Jun 18, 2018 5:56 pm
Besides why is the burden on 2x to prove anything.. it should be on 1x to prove it's for lack of a better term.. "better"
the fact 1x relieves few folks of having to "think about shifting their FD" is enough IMHO

/sarcasm
kkibbler wrote: WW remembers.

thePrince
Posts: 115
Joined: Sun Jun 16, 2013 1:09 am

by thePrince

When you get to a 14 or 15 speed drivetrain, you can end up with more at the top-end, more at the bottom-end, and with fewer big jumps in gear ratios when shifting. And check out the gear ratios when climbing...much smoother shifting in the 1x example. So I'm not sure why you would want a 2x11 system when you can have even more in a 1x15 system. Obviously the pro teams hate 1x11 today, and they should. But I can't imagine pro teams, or pro riders, wanting a FD in the future as we get to 14 or 15 speeds.

In other words, it's not the 1x that is the problem, it's x11 that is the problem.

Image

User avatar
LeDuke
Posts: 1183
Joined: Sun Oct 07, 2012 2:39 am
Location: Front Range, CO

by LeDuke

maquisard wrote:Presumably because 2x setup allows for a straighter chain line at either end of the cassette. A diagonal chain line cross loads the chain increasing driver train losses.

https://www.cyclingpowerlab.com/Drivetr ... iency.aspx
And right above that, they note that riding in a larger cog is more efficient. Which is what you have to do with a 1x system, of course. A 34x17 would be less efficient than a 40x20, for example.

“Efficiency is higher when using larger sprockets because the chain benefits from a less extreme radius of rotation – chain links going around corners cause greater frictional power losses. The take away here is that if you can achieve the same gear using a large chainring + larger sprocket combination than a small ring + smaller sprocket combination it is a worthwhile consideration. The efficiency difference between an equal gear that involves the 24 sprocket and the 13 sprocket can be worth 1-2 watts when riding in the 200-400 watt range.”


Sent from my iPhone using Tapatalk

User avatar
LeDuke
Posts: 1183
Joined: Sun Oct 07, 2012 2:39 am
Location: Front Range, CO

by LeDuke

romanmoser wrote:https://ride.diamondback.com/friction-p ... rivetrains

Frictions on 1X with clutch compared to 2X without clutch
From that link:

“Based on the above data, our 52-11/32 or 54-11/36 setups are not going to have measurably more friction than a comparable 2x11 setup. And, given that we know that a 2x11 is really more like 14 gears rather than 22, it doesn't give up all that much in the way of ratios either. If you want to run 1X, the facts about friction certainly shouldn't dissuade you.

CONCLUSIONS
Ultimately, the frictional losses provide two distinct and somewhat surprising conclusions. The first is that, from a frictional standpoint, typical 1X setups pay no significant penalty vs comparable 2x setups. The second, and perhaps more surprising thing, is that you want to run as large a front chainring and as wide a range cassette as possible.”


Sent from my iPhone using Tapatalk

maquisard
Posts: 1906
Joined: Thu May 01, 2008 8:51 pm
Location: France

by maquisard

Until the chain falls off

Marin
Posts: 2816
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

In my experience, it falls off much less than with 2x

maquisard
Posts: 1906
Joined: Thu May 01, 2008 8:51 pm
Location: France

by maquisard

You should ride for Aqua Blue Sport then!

User avatar
tymon_tm
Posts: 2421
Joined: Tue Sep 05, 2006 4:35 pm

by tymon_tm

thePrince wrote:
Mon Jun 18, 2018 11:00 pm
When you get to a 14 or 15 speed drivetrain, you can end up with more at the top-end, more at the bottom-end, and with fewer big jumps in gear ratios when shifting. And check out the gear ratios when climbing...much smoother shifting in the 1x example. So I'm not sure why you would want a 2x11 system when you can have even more in a 1x15 system. Obviously the pro teams hate 1x11 today, and they should. But I can't imagine pro teams, or pro riders, wanting a FD in the future as we get to 14 or 15 speeds.

In other words, it's not the 1x that is the problem, it's x11 that is the problem.

Image
OK, I feel kinda convinced 15sp might be nice in terms of gears. two issues though: the smaller one - chain would bend like a mofo, and the bigger one - it doesn't exist. actually, with perfectly working fds, I don't see even a point in developing this stuff.

sure, 12sp has just landed (after 11sp has been laughed off by many years ago) and I'm very inclined to get one for myself (although I'd like a cassette with both 16t and 18t so just gotta wait). how many years before Campag and Shim start wondering how to rock that money cradle again and throw another cog? like I said, when it's here, then the we can talk if 1x is in fact 'better'. today it's not. it's simpler, sure, but also narrowes down your gear choices to a point I find it useless for my amateur riding. hell, I can't imagine being forced to race on that thing.
kkibbler wrote: WW remembers.

Marin
Posts: 2816
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

maquisard wrote:
Tue Jun 19, 2018 12:28 pm
You should ride for Aqua Blue Sport then!
No I don't like disc brakes on road bikes.

IchDien
Posts: 280
Joined: Mon Nov 05, 2012 12:23 am
Location: Veneto

by IchDien

Image

Old Dura Ace ridden to 2nd place in the ITT of the tour de suisse. The second time we've seen a sunweb rider doing this, no?

bruno2000
Posts: 668
Joined: Fri Jun 17, 2005 4:11 pm

by bruno2000

Is it only an old crankset?
Sometimes they also use an old frontderailleur.
Look at Foorme's roadbike.

User avatar
Miller
Posts: 1302
Joined: Thu Sep 21, 2006 8:54 pm
Location: Reading, UK

by Miller

IchDien wrote:
Tue Jun 19, 2018 2:05 pm
Old Dura Ace ridden to 2nd place in the ITT of the tour de suisse. The second time we've seen a sunweb rider doing this, no?
ITT bikes don't get raced as often as the road bikes so perhaps don't get refreshed as often. There's a Pioneer power meter embedded in that chainset, another reason not to throw it away.

As for 14 or 15 sp at the rear, that's not going to happen any time soon. Campag have once more managed to retain compatibility with the existing hub spline pattern in their move to 12sp but can that trick be pulled off with 13, 14, or 15sp? I doubt it. So that move, if/when it happens, means new hub designs and probably new frame spacing standards. So there's something to look forward to.

C36
Posts: 252
Joined: Fri Mar 03, 2017 3:24 am

by C36

Miller wrote:
IchDien wrote:
Tue Jun 19, 2018 2:05 pm
Old Dura Ace ridden to 2nd place in the ITT of the tour de suisse. The second time we've seen a sunweb rider doing this, no?
ITT bikes don't get raced as often as the road bikes so perhaps don't get refreshed as often. There's a Pioneer power meter embedded in that chainset, another reason not to throw it away.

As for 14 or 15 sp at the rear, that's not going to happen any time soon. Campag have once more managed to retain compatibility with the existing hub spline pattern in their move to 12sp but can that trick be pulled off with 13, 14, or 15sp? I doubt it. So that move, if/when it happens, means new hub designs and probably new frame spacing standards. So there's something to look forward to.
Wider cassette (can’t imagine adding 25% speeds and not using wider hubs) = longer chainstay (well that is already the case with disc brake hubs, but could imagine adding few more mm) and will likely have more chain wear (chain angle and less contact area).
Whoever claim few post above than 11ps chains do not wear faster, needs to refresh his memory, wear significantly more than 9sp and “more” than 10sp, similar for cassettes (elite-team méch are a good source since they do not replace those components as frequently as pro who do preventive pet replacement).


Envoyé de mon iPhone en utilisant Tapatalk
Last edited by C36 on Tue Jun 19, 2018 5:11 pm, edited 1 time in total.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post