How much braking power is lost with long reach brakes?
08-15-14, 06:13 AM
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How much braking power is lost with long reach brakes?
My stepson has an old steel Schwinn touring bike that he loves but the 20+ year old wheelset (a higher end vintage set with aluminum rims that I believe came off a Miyata) has seen better days. I'm trying the decide between buying or building another 27" wheelset or upgrading him to a 700c set that I already have and cold setting the frame from 125mm to 130mm to accept a 9sp cassette. I've done the 9sp conversion on a number of older steel bikes and have no problem there, but I'm wondering how much his braking will suffer if I have to go to long reach brakes. Obviously he's not racing or anything like that, but he is a Clydesdale at 6'2" and 235# and rides some moderately hilly areas and city traffic, so I want him to have decent stopping power. Anything will be an improvement from the stock 1970s Schwinn calipers with WalMart pads that are on there now. I've got a pair of old RX100 dual pivot brakes that appear to have enough reach, but the pads will be at the furthest end of the adjustment slot.
So I'm looking for opinions and insights. What do you think would be better, a 27" wheelset with normal brake reach but other limitations such as tire selection, or a 700c wheelset with longer reach brakes?
So I'm looking for opinions and insights. What do you think would be better, a 27" wheelset with normal brake reach but other limitations such as tire selection, or a 700c wheelset with longer reach brakes?
08-15-14, 06:27 AM
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I've used "short reach" (37-47 mm) and "long reach" (47-57 mm) brakes on various bikes as needed and never seen any significant difference in power or modulation. As long as the brakes are sufficiently rigid and use good pads, you should have no problems. Those RX-100 long reach are almost identical to the 105 dp long reach calipers I have on one bike and the should work well. The 700c wheels will be easier to find good tires for and those are the ones I'd use.
08-15-14, 06:40 AM
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If you already have all the stuff, why not give it a try and carefully test ride it. If things are a bit iffy, then you can buy something new, but why spend money before you have to?
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08-15-14, 06:51 AM
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when comparing
modern dual pivol long reac brakes
or mdplrb
with
modern dual pivot short reach brakes
or mdpsrb
there is little or no difference
i believe
but correct me if i am wrong
that
if the pad slot of mdplrb is x percent lower
than the pad slot of mdpsrb
then the actuation arms are also x percent longer
so
if all other things
besides distance from mounting bolt to brake track
are equal
then braking will be equal
comparing old single pivot brakes
to mdplrb or mdpsrb
there is a wide performance difference
and
if you compare an old single pivot brake
with the pad at the top of the slot
to
the same brake
with the pad at the bottom of the slot
there is a wide performance difference
and i think you get a similar difference
when comparing dual pivots
with pads at their highest
to dual pivots
with pads at their lowest
but the baseline of braking is so much higher
you probably still have decent brakes
although i have never done a 27" to 700c conversion
on a bike with dual pivots
so i am not sure of this
so my recommendation is
if you can use either mdplrb or mdpsrb
use the ones
that allow you to have the pads
higher in the slots
which in essence
means
use long reach brakes
modern dual pivol long reac brakes
or mdplrb
with
modern dual pivot short reach brakes
or mdpsrb
there is little or no difference
i believe
but correct me if i am wrong
that
if the pad slot of mdplrb is x percent lower
than the pad slot of mdpsrb
then the actuation arms are also x percent longer
so
if all other things
besides distance from mounting bolt to brake track
are equal
then braking will be equal
comparing old single pivot brakes
to mdplrb or mdpsrb
there is a wide performance difference
and
if you compare an old single pivot brake
with the pad at the top of the slot
to
the same brake
with the pad at the bottom of the slot
there is a wide performance difference
and i think you get a similar difference
when comparing dual pivots
with pads at their highest
to dual pivots
with pads at their lowest
but the baseline of braking is so much higher
you probably still have decent brakes
although i have never done a 27" to 700c conversion
on a bike with dual pivots
so i am not sure of this
so my recommendation is
if you can use either mdplrb or mdpsrb
use the ones
that allow you to have the pads
higher in the slots
which in essence
means
use long reach brakes
08-15-14, 07:11 AM
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08-15-14, 07:11 AM
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I just put a new Nashbar long reach caliper on the rear of my 1993 GT Timberline after switching over to 700c wheels. It was a whopping $17.99 and feels great. In my case, the pads have to be as far down as possible and it is a significant improvement over the old u-brake that was on there.
08-15-14, 08:51 AM
#7
Banned
you can measure the flexing of the longer reach, vs the shorter. .. do some science.. its math not an opinion ..
BTW the 27" rim is just 4mm larger radially than a 700c 630, vs 622 Diameter .. r= 1/2D
BTW the 27" rim is just 4mm larger radially than a 700c 630, vs 622 Diameter .. r= 1/2D
Last edited by fietsbob; 08-15-14 at 08:55 AM.
08-15-14, 09:34 AM
#8
Really Old Senior Member
About a year+ ago, I was in a similar situation for a 70's Takara road bike.
The existing rear brake would reach a 700c wheel, but the brake mounting bridge was pretty skinny/twisty. For that reason, I stayed with 27" wheels.
The existing rear brake would reach a 700c wheel, but the brake mounting bridge was pretty skinny/twisty. For that reason, I stayed with 27" wheels.
08-15-14, 12:31 PM
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I have RX100 long reach on several bikes, and Ultegra short reach on another, all with Kool Stop salmon pads (highly recommended!). Can't say that I could tell the difference just by feel, and ANY dual-pivot will be a huge improvement over what you have now.
More modern levers will also help, but not as dramatically as the calipers.
More modern levers will also help, but not as dramatically as the calipers.
