Has the quest for lighter and lighter gone to far?

[ianrauk]

Someone on the telly (don't recall who ... Eurosport I think ... in the past couple of days) said that one of the objections to discs is that they get very hot and could be dangerous in a crash. Dunno if that makes any sense.

Cookson said that the Lugano charter would be revisited when he was elected. I'm sure there is much murky dealing with manufacturers going on there.

You certainly wouldn't want to touch a disc brake rotor after a long descent or heavy braking .

 

[StuAff]

You certainly wouldn't want to touch a disc brake rotor after a long descent or heavy braking .

Oh yes, on the Fridays' LonJOG the stoker of the tandem decided to check the temperature of its rear disc brake with her hand...ouch.
Pro tour teams' issues with discs include that risk, the problem of varying standards (rotor size and fitting, axle standards...) and its effect on wheel changes and neutral service needs, what happens if some teams are on rim braked bikes and others on discs..
They'll be coming to road racing sooner or later though.

 

[400bhp]

The OP is talking bollox.

What matters is the centre of gravity.

 

[Fab Foodie]

Conventional bikes, with a rider on board, are inherently top heavy and always have been.

Especially mine ....

 

[bigjim]

It never happened when dual pivot brakes came in, and if you ever rode with single pivot you'll know the difference in stopping power between the two were planets apart.

Don't agree I find properly maintained and adjusted single pivots just as efficient as a dual pivot.
I quote -
"The sole purpose of the dual pivot brake is to guarantee centering,
nothing more. The dual pivot is half centerpull and half sidepull and
has the problem that the short arm sweeps up into the tire as
centerpulls do, requiring pad adjustment as they wear. You may have
noticed that dual pivot brakes always remain centered and cannot track
a wheel with a broken spoke. This is an advantage?"

 

[Smokin Joe]

Don't agree I find properly maintained and adjusted single pivots just as efficient as a dual pivot.
I quote -
"The sole purpose of the dual pivot brake is to guarantee centering,
nothing more. The dual pivot is half centerpull and half sidepull and
has the problem that the short arm sweeps up into the tire as
centerpulls do, requiring pad adjustment as they wear. You may have
noticed that dual pivot brakes always remain centered and cannot track
a wheel with a broken spoke. This is an advantage?"

We'll agree to differ, IMO single pivot brakes were crap.

 

[bigjim]

IMO single pivot brakes were crap.

At least tell us why.

 

[snorri]

I believe the quest for lighter and lighter has gone to Farr.


IGMC

 

[Flick of the Elbow]

The quest for lighter and lighter has been achieved through making everything ever more fragile. When I started following the sport in the 80's you hardly ever heard of things breaking apart from in crashes. Now just about every day in the Tour you see riders calling for a new bike because their chain has snapped or their rear mech has sheared off, the other day we saw what looked like a riders bars suddenly shearing off, we've seen seatposts and saddles break off on a number of occasions too. And as for the braking limitations of carbon rims, they shouldn't be allowed anywhere near a peloton.

 

[Smokin Joe]

At least tell us why.

They just didn't have the stopping power of DP. When I switched from single pivot to dual (Both Ultegra) the difference was the same as going from drums to discs on a car.

 

[TheJDog]

I've just built my new bike to about 7.5kg (59cm) and it was "relatively cheap". You could build a weight limit bike for far less than £2k. The current weight limit means that the TDF etc. 'advertising' probably doesn't advertise the light bikes very well, and so the big bike manufacturers are probably pushing for a decrease in the limit.

My bike doesn't feel twitchy at all. I have ridden lighter bikes, and I don't really agree that they become dangerous the lighter they get. I've never ridden on a set of 1kg wheels, though, which might be where the twitchiness comes in...

 

[bigjim]

They just didn't have the stopping power of DP. When I switched from single pivot to dual (Both Ultegra) the difference was the same as going from drums to discs on a car.

They actually do. They are very powerful used properly. The current vogue is for bars to be much lower than the saddle. We therefore ride more on the tops and brake from there. On older bikes the bars were more or less level with the saddle and we spent more time on the drops. We therefore braked from the drops and had a high mechanical advantage with single sidepull brakes.
People like Jobst Brandt were recently hurtling down Alpines passes using single sidepulls without any problems.

 

[TheJDog]

Newer SRAM aero brakes are single pivot, albeit with a 'lever' modification to give them a bit more advantage.