Front mechs are the worst idea in the world.

[Bats]

That says more about the chainrings than not having a front mech. All that ££££ and the front mech is the only thing stopping chains going walkabout? singlespeeds must be walk on water holy magic!

Wrong! it says more about idiots using 8/9/10 speed blocks running with an extreme chain line on the outer rear sprockets with a single chainring & wondering why their chain comes off.

Sturmey archer do a nice line in chainsets that have guides all the way around the ring to stop it coming off. Come to think of it so do most bikes in argos. Perhaps he should've had a go on a zinc with chinese tuff wheels.

 

[bagpuss]

Cure for this .

1/ pull a bank job.
2 go and spend £600 on a Swiss hub . {Rohloff} :xmas-big-grin: :xmas-big-grin:

 

[mattr]

Cure for this .

1/ pull a bank job.
2 go and spend £600 on a Swiss hub . {Rohloff} :xmas-big-grin: :xmas-big-grin:

then watch as it eats its own insides when it gets wet. (Ok, when it gets submerged.......)

And IIRC Millar asked for the front mech to be removed, to save weight. Unfortunately, he was also using a conventional chain ring (ramps and pins) rather than a track ring, which is what you need if you want to run a single ring for road/cx. I very much doubt the mechanic was fired.

 

[stringfellow1946]

Cure for this .

1/ pull a bank job.
2 go and spend £600 on a Swiss hub . {Rohloff} :xmas-big-grin: :xmas-big-grin:

then watch as it eats its own insides when it gets wet. (Ok, when it gets submerged.......)

And IIRC Millar asked for the front mech to be removed, to save weight. Unfortunately, he was also using a conventional chain ring (ramps and pins) rather than a track ring, which is what you need if you want to run a single ring for road/cx. I very much doubt the mechanic was fired.

Why or how would he run a 1/8 track chainring with a 1/8 chain on a 9/10 speed narrow rear cassette? Also both would increase weight, which you say HE was trying to save.
I'm 95% sure that the Mechanic or maybe it was one of the sporting directors was fired because of the chain unshipping incident. After all IIRC he would have been in Yellow & that on the TDF Means loads of TV coverage world wide, massive plus extra publicity for all the sponsors Etc, without touching on the extra money it brings into the team especially if he'd held the jersey for a few days as is the Norm. Anyway it don't get away from the fact that if you run a single chainring without a front mec (or now maybe a chain saver) & you use 8/9/10/11 speed rear cassette the chain will without fail unship at some point.

 

[Bats]

You should probably let everyone who does that know then.

As it is, the world is full of singles that aren't 1/8th wide. What do you think they put on 5 speed bikes?

 

[mattr]

Why or how would he run a 1/8 track chainring with a 1/8 chain on a 9/10 speed narrow rear cassette? Also both would increase weight, which you say HE was trying to save.
I'm 95% sure that the Mechanic or maybe it was one of the sporting directors was fired because of the chain unshipping incident. After all IIRC he would have been in Yellow & that on the TDF Means loads of TV coverage world wide, massive plus extra publicity for all the sponsors Etc, without touching on the extra money it brings into the team especially if he'd held the jersey for a few days as is the Norm. Anyway it don't get away from the fact that if you run a single chainring without a front mec (or now maybe a chain saver) & you use 8/9/10/11 speed rear cassette the chain will without fail unship at some point.

:facepalm: track rings come in both widths. No one got sacked.

 

[stringfellow1946]

Cure for this .

Unfortunately, he was also using a conventional chain ring (ramps and pins) rather than a track ring, which is what you need if you want to run a single ring for road/cx. I very much doubt the mechanic was fired.

Agreed track rings are available in both 1/8 & 3/32both but please explain what the ramps & pins have to do with the chain unshipping? when its on the outer sprockets of a 8/9/10/11 speed cassette, because they are on the inside of the outer chain ring to aid the movement of the chain from the inner ring to the outer ring.

 

[mattr]

Unfortunately, he was also using a conventional chain ring (ramps and pins) rather than a track ring, which is what you need if you want to run a single ring for road/cx. I very much doubt the mechanic was fired.

Agreed track rings are available in both 1/8 & 3/32both but please explain what the ramps & pins have to do with the chain unshipping? when its on the outer sprockets of a 8/9/10/11 speed cassette, because they are on the inside of the outer chain ring to aid the movement of the chain from the inner ring to the outer ring.

it's not the ramps and pins specifically, but the shorter and shift profiled teeth that go along with it. Soon as you get a side loaded chain going past a shift gate, it's coming off.

 

[stringfellow1946]

OK just found this on http://en.wikipedia.org/wiki/David_Millar
His attempt to win the prologue in central Paris in the centenary Tour of 2003 ended when his chain dropped off 500 m before the finish. He lost by 0.14 s to Brad McGee. Millar had ridden a bike without a front derailleur.[n 2] He blamed his directeur sportif, Alain Bondue. "It wasn't a problem with my chainring; it was a problem with my team," he told journalists at the finish. He said Bondue had tried to save a few grams by removing the derailleur. Bondue said he had told Millar to use a front derailleur after other riders had similar problems.[17][18] Bondue was demoted to logistics manager.[18]
like I said "Sacked" as director sport!!
AND not the mechanic as I first said, my humble apologies to the mechanic.

And this also might be an interesting read for some people thinking of doing the same thing!! http://fernandoj.wordpress.com/2013/08/ ... erailleur/

 

[stringfellow1946]

You should probably let everyone who does that know then.

As it is, the world is full of singles that aren't 1/8th wide. What do you think they put on 5 speed bikes?

Did I ever at any time mention 5 speed freewheels?? & come to think of it nor did you, IIRC your original post that started this thread was referring to a 6 speed freewheel.