Worn out hoods

On 15/10/16 07:48, wrote:
On Friday, October 14, 2016 at 9:56:31 AM UTC-7, Doug Landau wrote:
On Thursday, October 13, 2016 at 11:10:32 PM UTC-7, James wrote:
On 14/10/16 11:25, Doug Landau wrote:
How many miles does it take to get to wear out the rubber hoods on Ultegra 9 speed?



How long is a piece of string? I mean, how rough are your hands? How
much weight do you put on the hoods? How much riding do you do hanging
on to the hoods? What constitutes worn out?

I'd rather know why a sachs chain now lasts only 1200 miles where it used to go 2000

Think about this - a chain used to drag really hard if you went to extremes - low/high or high/low. Now testing laboratories show that there's no measurable difference when you do this.

This would suggest to me that chain sides are thinner now than in the past so the chain is less rigid. This also would mean that there is either more play in the bearings to begin with or the steel in the rollers is softer than before so that it can flex.


I thought the biggest difference was when they stopped riveting the side
plates together, allowing the side plates to float a little on the pin.
This allows much more flex to the side, and also decreases bearing
surface area - thus quicker wear but better capacity to handle more
sprockets.

--
JS

"Doug Landau" wrote in message ...
How many miles does it take to get to wear out the rubber hoods on Ultegra 9 speed?

In my experience they do not wear out. I have worn out the internals of a right hand shifter and its hood was still in good condition. My guess is, that like most rubber products, their lives might be governed more by exposure to sun light rather than hand wear.

We are not overly blessed by strong sunlight in the UK and my bikes are stored in doors.

Graham.

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On 10/14/2016 8:10 PM, James wrote:
On 15/10/16 07:48, wrote:
On Friday, October 14, 2016 at 9:56:31 AM UTC-7, Doug
Landau wrote:
On Thursday, October 13, 2016 at 11:10:32 PM UTC-7, James
wrote:
On 14/10/16 11:25, Doug Landau wrote:
How many miles does it take to get to wear out the
rubber hoods on Ultegra 9 speed?



How long is a piece of string? I mean, how rough are
your hands? How
much weight do you put on the hoods? How much riding do
you do hanging
on to the hoods? What constitutes worn out?

I'd rather know why a sachs chain now lasts only 1200
miles where it used to go 2000

Think about this - a chain used to drag really hard if you
went to extremes - low/high or high/low. Now testing
laboratories show that there's no measurable difference
when you do this.

This would suggest to me that chain sides are thinner now
than in the past so the chain is less rigid. This also
would mean that there is either more play in the bearings
to begin with or the steel in the rollers is softer than
before so that it can flex.


I thought the biggest difference was when they stopped
riveting the side plates together, allowing the side plates
to float a little on the pin. This allows much more flex to
the side, and also decreases bearing surface area - thus
quicker wear but better capacity to handle more sprockets.


True roller chain connects the two sideplates with a sleeve.
The rivet runs inside that sleeve, the roller outside. That
system gives longest life but with minimum sideplay.
https://www.machineseeker.com/pic/la.../2950798-3.jpg

Starting with the Sedisport c.1978 the sideplates are
interrupted with a lip. The two sideplate lips support the
roller and a rivet connects the sideplates. That system is
lighter, cheaper to make and has much more sideways slop
which is good for derailleur systems. The wear is however
significantly faster as Jobst elucidated here frequently.

http://www.khurramhashmi.org/khurram...gtuyb_f9-2.jpg

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971