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Date: 20 Sep 2007 13:03:55
From: damyth
Subject: Shimano compact road brake levers
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Aside from the shim(s) that adjust reach for the Shimano levers, are
there any other functional differences between compact and normal (non-
compact) road levers? Specifically, I'm wondering if there's improved
mechanical advantage in the compact levers, so for a given amount of
lever travel, the brake caliper moves farther (than the normal levers)?
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Date: 21 Sep 2007 05:03:21
From: Qui si parla Campagnolo-www.vecchios.com
Subject: Re: Shimano compact road brake levers
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On Sep 20, 2:03 pm, damyth <mdk.10.dam...@spamgourmet.com > wrote:
> Aside from the shim(s) that adjust reach for the Shimano levers, are
> there any other functional differences between compact and normal (non-
> compact) road levers? Specifically, I'm wondering if there's improved
> mechanical advantage in the compact levers, so for a given amount of
> lever travel, the brake caliper moves farther (than the normal levers)?
No, identical levers, just uses a rubber shim to move the lever closer
to the handlebar.
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Date: 20 Sep 2007 21:26:09
From: damyth
Subject: Re: Shimano compact road brake levers
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On Sep 20, 2:58 pm, "NickP" <some...@nowhere.au > wrote:
> Improved mechanical advantage (ie less finger pressure at the lever for a
> given braking pressure) would be the reverse - less movement at the brake
> caliper for a given movement of the lever.
>
> "damyth" <mdk.10.dam...@spamgourmet.com> wrote in message
>
> news:1190318635.583971.113480@e9g2000prf.googlegroups.com...
>
> > Aside from the shim(s) that adjust reach for the Shimano levers, are
> > there any other functional differences between compact and normal (non-
> > compact) road levers? Specifically, I'm wondering if there's improved
> > mechanical advantage in the compact levers, so for a given amount of
> > lever travel, the brake caliper moves farther (than the normal levers)?
I believe you're confused. There is the mechanical advantage of the
lever itself, and also of calipers. Since caliper remains unchanged
in both cases, we're only talking mechanical advantage of the lever.
If mechanical advantage is defined as "force multiplication," higher
mechanical advantage in the lever implies a greater amount of cable
pull for a given displacement of the lever (compared to one with less
mechanical advantage). That's exactly what you want to happen in
compact brake levers to prevent the lever from bottoming out against
the handlebar (because of the reduced distance).
In other words, because the brake shoes should be a certain distance
from the rim when the brake is not applied, but because of the reduced
travel distance of the compact lever, it's desirable to have the
calipers "close" at a faster rate so the lever is less likely to
bottom out when it's applied.
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Date: 20 Sep 2007 23:23:37
From: Mike Jacoubowsky
Subject: Re: Shimano compact road brake levers
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> In other words, because the brake shoes should be a certain distance
> from the rim when the brake is not applied, but because of the reduced
> travel distance of the compact lever, it's desirable to have the
> calipers "close" at a faster rate so the lever is less likely to
> bottom out when it's applied.
If you're designing for smaller hands with less power, the opposite is
actually true. You need the lever to travel a larger amount relative to the
brake itself moving in a smaller amount (if you want maximum stopping
power). The problem is rarely a lack of travel, although that's often the
perception. The fact that you can forcibly bottom out the lever on the
handlebar doesn't mean that you didn't develop all the stopping power (at
the wheel) you'd ever need, long before you got to that point.
The primary advantage to the "compact" lever is that a smaller hand has an
easier time getting a good grip on it and applying power. Your grip has an
increasing amount of power as you curve your fingers in closer to your palm.
So, for a smaller hand, it doesn't matter if you're talking about reaching
"down" from on top of the hoods, or "across" from the drops. Shorten those
distances and things work better, regardless of leverage involved.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"damyth" <mdk.10.damyth@spamgourmet.com > wrote in message
news:1190348769.187156.218780@k35g2000prh.googlegroups.com...
> On Sep 20, 2:58 pm, "NickP" <some...@nowhere.au> wrote:
>> Improved mechanical advantage (ie less finger pressure at the lever for a
>> given braking pressure) would be the reverse - less movement at the brake
>> caliper for a given movement of the lever.
>>
>> "damyth" <mdk.10.dam...@spamgourmet.com> wrote in message
>>
>> news:1190318635.583971.113480@e9g2000prf.googlegroups.com...
>>
>> > Aside from the shim(s) that adjust reach for the Shimano levers, are
>> > there any other functional differences between compact and normal (non-
>> > compact) road levers? Specifically, I'm wondering if there's improved
>> > mechanical advantage in the compact levers, so for a given amount of
>> > lever travel, the brake caliper moves farther (than the normal levers)?
>
> I believe you're confused. There is the mechanical advantage of the
> lever itself, and also of calipers. Since caliper remains unchanged
> in both cases, we're only talking mechanical advantage of the lever.
>
> If mechanical advantage is defined as "force multiplication," higher
> mechanical advantage in the lever implies a greater amount of cable
> pull for a given displacement of the lever (compared to one with less
> mechanical advantage). That's exactly what you want to happen in
> compact brake levers to prevent the lever from bottoming out against
> the handlebar (because of the reduced distance).
>
> In other words, because the brake shoes should be a certain distance
> from the rim when the brake is not applied, but because of the reduced
> travel distance of the compact lever, it's desirable to have the
> calipers "close" at a faster rate so the lever is less likely to
> bottom out when it's applied.
>
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Date: 20 Sep 2007 21:46:05
From: jim beam
Subject: Re: Shimano compact road brake levers
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damyth wrote:
> On Sep 20, 2:58 pm, "NickP" <some...@nowhere.au> wrote:
>> Improved mechanical advantage (ie less finger pressure at the lever for a
>> given braking pressure) would be the reverse - less movement at the brake
>> caliper for a given movement of the lever.
>>
>> "damyth" <mdk.10.dam...@spamgourmet.com> wrote in message
>>
>> news:1190318635.583971.113480@e9g2000prf.googlegroups.com...
>>
>>> Aside from the shim(s) that adjust reach for the Shimano levers, are
>>> there any other functional differences between compact and normal (non-
>>> compact) road levers? Specifically, I'm wondering if there's improved
>>> mechanical advantage in the compact levers, so for a given amount of
>>> lever travel, the brake caliper moves farther (than the normal levers)?
>
> I believe you're confused. There is the mechanical advantage of the
> lever itself, and also of calipers. Since caliper remains unchanged
> in both cases, we're only talking mechanical advantage of the lever.
>
> If mechanical advantage is defined as "force multiplication," higher
> mechanical advantage in the lever implies a greater amount of cable
> pull for a given displacement of the lever (compared to one with less
> mechanical advantage). That's exactly what you want to happen in
> compact brake levers to prevent the lever from bottoming out against
> the handlebar (because of the reduced distance).
but not if you want to maintain ease of operation, i.e. reduced force
required for a given braking effect. if you decrease the mechanical
advantage to reduce the displacement of the lever, you /increase/ the
force that has to be applied.
>
> In other words, because the brake shoes should be a certain distance
> from the rim when the brake is not applied, but because of the reduced
> travel distance of the compact lever, it's desirable to have the
> calipers "close" at a faster rate so the lever is less likely to
> bottom out when it's applied.
that may be, but as above, it comes at the cost of increased force being
necessary.
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Date: 21 Sep 2007 07:58:20
From: NickP
Subject: Re: Shimano compact road brake levers
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Improved mechanical advantage (ie less finger pressure at the lever for a
given braking pressure) would be the reverse - less movement at the brake
caliper for a given movement of the lever.
"damyth" <mdk.10.damyth@spamgourmet.com > wrote in message
news:1190318635.583971.113480@e9g2000prf.googlegroups.com...
> Aside from the shim(s) that adjust reach for the Shimano levers, are
> there any other functional differences between compact and normal (non-
> compact) road levers? Specifically, I'm wondering if there's improved
> mechanical advantage in the compact levers, so for a given amount of
> lever travel, the brake caliper moves farther (than the normal levers)?
>
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