Q: How light is too light?

Discuss light weight issues concerning road bikes & parts.
Imaking20
Posts: 1622
Joined: Fri Nov 18, 2011 5:19 am

by Imaking20

A: 131 grams

Image



At least now we know..
Current:
T2

Retired:
Blue | Project C6.0 | Felt AR FRD | Colnago C59 NERO | 2014 S-Works Tarmac | S-Works Venge | Wilier Cento Uno SL | Tarmac SL2

by Weenie


AZR3
Posts: 713
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

Well that sucks!

Imaking20
Posts: 1622
Joined: Fri Nov 18, 2011 5:19 am

by Imaking20

Yeah, finally glad the road is 14% in front of my house. This happened one pedal stroke from the driveway. Would have really sucked for this to happen out on the road..
Current:
T2

Retired:
Blue | Project C6.0 | Felt AR FRD | Colnago C59 NERO | 2014 S-Works Tarmac | S-Works Venge | Wilier Cento Uno SL | Tarmac SL2

AZR3
Posts: 713
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

Guess I can give that a hard pass, was looking into one but I’ll take SRAM’s reliability over saving a few grams

FreaK
Posts: 847
Joined: Sat Aug 27, 2005 5:57 am
Location: mOntreal

by FreaK

I'd be really curious to have looked at the failure surface right after it happened. I wonder to what degree there was a flaw in the manufacturing rather than design.
it's actually possible to come to the conclusion even before realising it makes no sense at all
-
tymon_tm

TobinHatesYou
Posts: 1880
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

FreaK wrote:
Sat May 05, 2018 3:37 pm
I'd be really curious to have looked at the failure surface right after it happened. I wonder to what degree there was a flaw in the manufacturing rather than design.

IMO it’s a design weakness. The single alloy cog on the SRAM Red cassette interfaces directly with the freehub driver splines. The single-piece dome that makes up the rest of the cassette has its own interface as well. No matter what cog you’re in, it is directly driving the hub.

The two alloy cogs on the Rotor UNO cassette are riveted onto the steel dome and don’t have their own splined interfaces. This means all your pedaling torque is transferred through the rivets.

FreaK
Posts: 847
Joined: Sat Aug 27, 2005 5:57 am
Location: mOntreal

by FreaK

Ooooh, that's an interesting engineering choice. The basic Shimano freewheels are now just a stack of riveted cogs driving one of the smaller cogs. So I guess it's not an absurd method, but it sure does demand properly sized and sufficient numbers of rivets.
it's actually possible to come to the conclusion even before realising it makes no sense at all
-
tymon_tm

TobinHatesYou
Posts: 1880
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Dura-Ace cassettes had carrier/rivet failures with alarming frequency actually. For some this would manifest as a squeak...for others the carriers would just self-destruct. There was even a silent update to the design that added additional rivets.

See this BR post: https://bikerumor.com/2014/06/06/shiman ... -creaking/

IMO the SRAM XG-1190 has the best overall design from a strength-to-weight standpoint. My only problem with it is the shape of the teeth on the smaller cogs making things a bit noisier.

tpmcman
Posts: 1
Joined: Sun May 06, 2018 12:51 am

by tpmcman

Omni-Lite TI stuff seems to work well for me. Find it on ebay all the time. rear cassette seems sturdy as Im 185 and romp on it. No problems after about 200 mi

pdlpsher1
Posts: 1717
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

I just read Shimano's response to the re-design of the DA cassette. Too funny. Japanese's way of doing business is to never admit fault. DA's cassette problem is well documented and yet they refuse to take blame. I find the following line quite funny...yeah, a creak is not a noise, lol.
Nick Murdick Shimano Lead Technical Instructor wrote:
Sat May 05, 2018 11:28 pm
Of course, if the joint between the carrier and the cog starts to fail it will make noise but that’s different from a creak.

wingguy
Posts: 4198
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

Ah to be fair that's not what he said though, is it? It's basic set theory - every creak is a noise but not every noise is a creak.

But yeah they do have a habit of sending out silent redesigns without publically stating there was ever a problem.

User avatar
micky
Posts: 4778
Joined: Thu Sep 21, 2006 8:57 pm
Location: Vicenza
Contact:

by micky

Just out of curiosity, do you have a picture of the failure?

Imaking20
Posts: 1622
Joined: Fri Nov 18, 2011 5:19 am

by Imaking20

Image

I've got a DA9k cassette as my backup now and it does have issues with creaking in certain cogs under higher load. Ordered another XG1190.
Current:
T2

Retired:
Blue | Project C6.0 | Felt AR FRD | Colnago C59 NERO | 2014 S-Works Tarmac | S-Works Venge | Wilier Cento Uno SL | Tarmac SL2

wingguy
Posts: 4198
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

So it's actually the steel dome itself that has failed rather than a connection between two seperate parts of the cassette?

Imaking20
Posts: 1622
Joined: Fri Nov 18, 2011 5:19 am

by Imaking20

Correct. The steel between two cogs sheared. Looking at it now in two pieces, that area is very, very thin - and frankly a stupid design. I think the steel cage needs to be thicker OR the rear of the cage should actually interface with the splines. As it is, only the front of the cassette actually engages on the splines and the rear floats - leaving the burden of strength completely on the steel cage. Which, obviously, is folly.
Current:
T2

Retired:
Blue | Project C6.0 | Felt AR FRD | Colnago C59 NERO | 2014 S-Works Tarmac | S-Works Venge | Wilier Cento Uno SL | Tarmac SL2

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post