~80 mm brake reach? How terrible would it be (650B conversion)
03-30-21, 04:38 AM
#1
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~80 mm brake reach? How terrible would it be (650B conversion)
So I'm considering to do a 700cc --> 650B conversion, and calculated the needed brake reach to be near 80 mm:
Dropout to brake bridge is 370 mm, so 370 mm - (622 mm / 2) = up to 59 mm reach with 700cc wheels which is already pretty much. With 650B it would be 370 mm - (584 mm / 2) = 78 mm. Am I doing this right?
I have my eyes on a pair of old Shimano centerpulls that have a reach up to 95 mm, but I'm concerned about braking efficiency with such long brake arms :/
Read about some guy who had reverted back to 700cc because he didn't feel safe with the braking efficiency he got with unnamed super long reach brakes.
Dropout to brake bridge is 370 mm, so 370 mm - (622 mm / 2) = up to 59 mm reach with 700cc wheels which is already pretty much. With 650B it would be 370 mm - (584 mm / 2) = 78 mm. Am I doing this right?
I have my eyes on a pair of old Shimano centerpulls that have a reach up to 95 mm, but I'm concerned about braking efficiency with such long brake arms :/
Read about some guy who had reverted back to 700cc because he didn't feel safe with the braking efficiency he got with unnamed super long reach brakes.
03-30-21, 05:57 AM
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Tektro makes some long-reach, dual pivot calipers. With decent pads they provide adequate stopping power. I used these when I converted my wife's bike to 650B:
03-30-21, 06:18 AM
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Can I ask what the conversion is for? Is it to allow a change of tire format?
I am usually down at 24" wheels, so the reasoning behind big wheel changes is like something from the moon
I am usually down at 24" wheels, so the reasoning behind big wheel changes is like something from the moon
03-30-21, 07:12 AM
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I believe long-reach brakes are built to work similarly to short reach brakes from the point of view of the rim and levers.
If you were to, say, modify short reach brakes to move the pads further from the pivots they won't work well, but using brakes as they were designed will be fine.
Also, the wheel size is 700C, not 700cc - cc is a unit of volume (cubic cemtimeter, aka millilitre), the C is an indicator of which of the 700 mm diameter wheel sizes you have. There used to be 700A B and C. Just as you are looking to use 650B, you can also get rims and tires in 650 A or C sizes.
If you were to, say, modify short reach brakes to move the pads further from the pivots they won't work well, but using brakes as they were designed will be fine.
Also, the wheel size is 700C, not 700cc - cc is a unit of volume (cubic cemtimeter, aka millilitre), the C is an indicator of which of the 700 mm diameter wheel sizes you have. There used to be 700A B and C. Just as you are looking to use 650B, you can also get rims and tires in 650 A or C sizes.
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03-30-21, 09:50 AM
#5
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I believe long-reach brakes are built to work similarly to short reach brakes from the point of view of the rim and levers.
If you were to, say, modify short reach brakes to move the pads further from the pivots they won't work well, but using brakes as they were designed will be fine.
Also, the wheel size is 700C, not 700cc - cc is a unit of volume (cubic cemtimeter, aka millilitre), the C is an indicator of which of the 700 mm diameter wheel sizes you have. There used to be 700A B and C. Just as you are looking to use 650B, you can also get rims and tires in 650 A or C sizes.
If you were to, say, modify short reach brakes to move the pads further from the pivots they won't work well, but using brakes as they were designed will be fine.
Also, the wheel size is 700C, not 700cc - cc is a unit of volume (cubic cemtimeter, aka millilitre), the C is an indicator of which of the 700 mm diameter wheel sizes you have. There used to be 700A B and C. Just as you are looking to use 650B, you can also get rims and tires in 650 A or C sizes.
03-31-21, 08:33 AM
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If you can find an old set of Weinmann 750 center-pulls, they would have enough reach. Plenty of power too.
