Groupset for a tt bike?

Discuss light weight issues concerning road bikes & parts.
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Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

I have osymetric waiting to go on. I have Ultegra di2 on a propel advanced I could swap over. I was considering a sram force cx1 1x10 or 11. Is there an option I'm missing? I kind of want to stay mechanical since I've done 10+ hour rides before. Osymetric 1x10/11 is appealing. There's nearly 0 sram support in Japan. :|. It currently has first gen 10 speed Ultegra on it.

by Weenie


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Miller
Posts: 1230
Joined: Thu Sep 21, 2006 8:54 pm
Location: Reading, UK

by Miller

Out of interest, how does mechanical shifting relate to 10 hour rides? I would expect an e-shift battery to last that long :-) Are you really going to do 10 hour rides on a TT bike anyway?

Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

Miller wrote:Out of interest, how does mechanical shifting relate to 10 hour rides? I would expect an e-shift battery to last that long :-) Are you really going to do 10 hour rides on a TT bike anyway?

10 hours so far is longest so far this year. Last year did nearly 2 days straight. But that was on a folding bike that was 40 pounds unloaded and only 7 speeds. Being able to take the weight off my palms is nice. Longest ride on the tt bike so far was only cut short by a pedal that sounded like it was going to explode.
With a bucket cap and full messenger bag I was aero as a brick despite being nearly horizontal to the top tube. :lol:

Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

Nobody? No opinions? No suggestions? No campy or bust nutters? No di2 will show you the light followers?

Dalai
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Joined: Wed Dec 15, 2004 10:54 am
Location: Melbourne, Australia

by Dalai

It's Weight Weenies. Which is the lightest?

olebole
Posts: 133
Joined: Thu Mar 31, 2011 3:42 pm

by olebole

I'm building a 1x11 setup with Ultegra 6800 and an oval n/w chainring. Not worried about dropping the chain on paved surface

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Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

What I'm wondering is if a clutch derailleur will make a difference with osymetric. Obviously of regular derailleurs red's lightest. Clutch derailleurs has shimano's xtr being lightest but not compatible with bar ends. Force cx1 rr is 265g. GX 2.1 is 269g at half the price. About 300$ for di2 bar ends.

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Miller
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Joined: Thu Sep 21, 2006 8:54 pm
Location: Reading, UK

by Miller

Raccooningtanuki wrote:Nobody? No opinions? No suggestions? No campy or bust nutters? No di2 will show you the light followers?


I have Campag EPS on my TT bike and love it but e-groups are optimised for the groupset, not for mix and match. You've said you don't even have local support for Sram so I don't imagine your local shops know much about Campag.

As you've stated you want a one-by Osymmetric set-up you're not in well known territory. Chain retention will certainly be a worry.

I do see why people want single chainring setups but I'm not convinced. A dropped chain ruins your race, I'm no fan either of the wide range cassettes implied by a single front ring. A double front ring more or less eliminates chain drop worries, especially with a chain catcher fitted, and it's more practical in the gear range offered. Sometimes I ride out to events or train on the TT bike and I like to have a lowish gear to get up a hill.

But you should get what you want.

Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

I have Campag EPS on my TT bike and love it but e-groups are optimised for the groupset, not for mix and match. You've said you don't even have local support for Sram so I don't imagine your local shops know much about Campag.

As you've stated you want a one-by Osymmetric set-up you're not in well known territory. Chain retention will certainly be a worry.

I do see why people want single chainring setups but I'm not convinced. A dropped chain ruins your race, I'm no fan either of the wide range cassettes implied by a single front ring. A double front ring more or less eliminates chain drop worries, especially with a chain catcher fitted, and it's more practical in the gear range offered. Sometimes I ride out to events or train on the TT bike and I like to have a lowish gear to get up a hill.

But you should get what you want.

The Ultegra 6600 was finicky until I switched it back to friction. Half the problem is probably a sram cassette too. Ordered a inner 44t. I'll decide a route once I see how the shifting goes. Di2 just for the front to deal with o-rings seems like overkill.

junchen
Posts: 340
Joined: Fri Jun 12, 2015 6:21 pm

by junchen

Consider absoluteblack oval narrow wide single chainring and a sram force 1 rear derailleur. The narrow wide chain ring and clutched force 1 derailleur helps in chain retention. The sram force 1 rear derailleur is compatible with 10 or 11 speed sram shifters. End of the day it's a mechanical bike - I'm sure your bike shop would be able to assist u in simple tuning or installation. As for warranty issues, it should be easily resolved if u buy from the major online bike shops.

Having said that, I'm sure ur sram bike will stand out in the land of shimano.

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Cheetahmk7
Posts: 69
Joined: Sat Aug 20, 2011 2:09 am

by Cheetahmk7

Does it need to be UCI compliant? If so go electric as it gives you more length as the the measuring point for the TT bar end is the tip of the gear lever in a horizontal forward position.

audiojan
Posts: 772
Joined: Fri Jan 27, 2006 1:38 pm
Location: New Hampshire

by audiojan

I wouldn't do without my Campy EPS on my tri bike... electronic shifting makes such a big difference
"Suddenly the thought struck me; my floor is someone elses ceiling" - Nils Ferlin

spdntrxi
Posts: 1420
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

love electronic on TT bikes. My TT bikes lasted 2 weeks before I switched to Di2 from mech

alcatraz
Posts: 728
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Sure a 1x setup would be lighter but if you are interested in efficiency a 2x would give you smaller crosschaining angles while preserving a wider gear ratio interval.

I don't know about you but I don't like the crosschaining noise that is eating up my watts :-).

/a

by Weenie


Raccooningtanuki
Posts: 58
Joined: Mon Aug 22, 2016 7:30 am

by Raccooningtanuki

Update:
Installed the big ring with the small 36 from the original crank using 4 bolts from a sram red crank. Snitched the 11 speed chain too since I didn't want to wait for the 10 speed links and since it was on a 11-28/53t with a medium cage it was just about right. Unluckily the 6600 derailleur won't go high enough so I took it off. Short ride moving around the middle of the cassette hasn't dropped the chain. Just need to hunt down a spacer for the front derailleur.

Considering weight savings. If I just went with bar ends or would a bar end and sprint shifters be lighter? Bout 100g at least could be saved by doing 3t brake levers instead of di2 STIs.

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