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Q: Shimano cantilever straddle cable length?
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. I can pick one of several fixed straddle cables. Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? Does that mean the geometry won't be quite right when switching to another rim? I checked the Sheldon stuff but don't have enough experience to pick the right one. Thanks! Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html |
#2
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Q: Shimano cantilever straddle cable length?
On Oct 18, 8:41*am, somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. *I can pick one of several fixed straddle cables. *Which one? Use the one it comes with and work from there. Chances are that a normal canti with an average sized rim like that will work pretty well with the average sized linkage included. ;-) Cheaper and better, IMHO, are the Tektro CR720s on that same page. They come with an adjustable straddle setup. Stock pads are better than Shimano. Only reason not to use them would be clearance issues as they stick out a bit. Set em up so the yoke makes about a 90 degree angle. See how you like that first, then lengthen or shorten as desired. |
#3
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Q: Shimano cantilever straddle cable length?
somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. I can pick one of several fixed straddle cables. Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? Does that mean the geometry won't be quite right when switching to another rim? I checked the Sheldon stuff but don't have enough experience to pick the right one. Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html You want the size which ends with a 90-degree angle as the pads touch. That varies by brake stud position and rim width. Some brakes allow lateral pad adjustment which can help to get that just right with various LinkWire sizes. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#4
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Q: Shimano cantilever straddle cable length?
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:
somebody wrote: I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. I can pick one of several fixed straddle cables. Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? Does that mean the geometry won't be quite right when switching to another rim? I checked the Sheldon stuff but don't have enough experience to pick the right one. Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html You want the size which ends with a 90-degree angle as the pads touch. That varies by brake stud position and rim width. Some brakes allow lateral pad adjustment which can help to get that just right with various LinkWire sizes. That's it. The brakes came with two different straddle cable sizes; the previous owner worked at a shop and must have swapped in what worked on his bike. That means I can try each and check the angle. How are Shimano straddle/yoke cables measured? Is it base on the length that sticks out of the middle? Thanks! |
#5
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Q: Shimano cantilever straddle cable length?
On Oct 19, 3:41*pm, somebody wrote:
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote: somebody wrote: I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. *I can pick one of several fixed straddle cables. *Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? *Does that mean the geometry won't be quite right when switching to another rim? *I checked the Sheldon stuff but don't have enough experience to pick the right one. Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html You want the size which ends with a 90-degree angle as the pads touch. That varies by brake stud position and rim width. Some brakes allow lateral pad adjustment which can help to get that just right with various LinkWire sizes. That's it. *The brakes came with two different straddle cable sizes; the previous owner worked at a shop and must *have swapped in what worked on his bike. *That means I can try each and check the angle. How are Shimano straddle/yoke cables measured? *Is it base on the length that sticks out of the middle? Thanks! How are Shimano straddle/yoke cables measured? Is it base on the length that sticks out of the middle? That’s good question! After measuring several straddle links, I’ve come the conclusion that it’s the length of exposed cable from where it exit’s the center device to where it disappears into the lead casting @ the other end. It isn’t the same as the C-C distance, & therefore not usable in trig calculations. However it isn’t necessary to do any trig calculations to try to get the optimum length. As Andrew so succinctly pointed out the goal is to get the length such that the straddle cables make a 90 deg or slightly smaller angle when the pads hit the rim. That’s w/ the angle measured @ the point where the line from the pivot point of the brake arm intersects the cable attachment, w/ the cable running to the center device as the other line making the angle. However, so far so I know it’s usually impossible to get a 90 or 90 deg. angle w/ the “narrow” or “up right” type of cantilevere arms. The angle usually ends up more oblique that 90 deg. Therefore the idea is to get an angle that is as close to 90 deg. While still clearing the tire, fenders, racks, etc. It’s quite easy to get this 90 deg. or w/ the older style wide cantilevers such as “Paul’s”. The idea of using straddle links in lieu for a single straddle cable was to keep the straddle cable from getting caught on Mt.B. tire knobs & tossing the rider over the bars in case of the primary brake cable severing. I don’t think this is much of a problem w/ relatively smooth road tires, & therefore use a plain straddle cable on road bikes for the greater ease of optimizing geometry. The use of non threaded brake pad posts (or smooth posts) allows one to extend the pads of upright arms further from the brake arm to improve the angle of the straddle cable to brake arm. Doing this, however brings on other problems. These are increased chance of brake squeal, & the difficulty of adjusting smooth arm pads. In my experience the rotating tabs that set toe-in & all the other pad adjustments, are made of plastic that has to be torqued very tight. This torque causes the plastic to deform creating a crease where the pad post is. This isn’t so bad when it is the 1st time the brakes are set up, but subsequent adjustments make it just about impossible to keep the pad post from being captured by this crease. There are work arounds, but are a pain too. I don’t remember all the smooth pad posts I’ve worked on. There may be some that don’t have these adjustability problems. I would appreciate knowing which, if any, they are. |
#6
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Q: Shimano cantilever straddle cable length?
jay wrote:
On Oct 19, 3:41 pm, somebody wrote: On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote: somebody wrote: I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. I can pick one of several fixed straddle cables. Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? Does that mean the geometry won't be quite right when switching to another rim? I checked the Sheldon stuff but don't have enough experience to pick the right one. Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html You want the size which ends with a 90-degree angle as the pads touch. That varies by brake stud position and rim width. Some brakes allow lateral pad adjustment which can help to get that just right with various LinkWire sizes. That's it. The brakes came with two different straddle cable sizes; the previous owner worked at a shop and must have swapped in what worked on his bike. That means I can try each and check the angle. How are Shimano straddle/yoke cables measured? Is it base on the length that sticks out of the middle? Thanks! How are Shimano straddle/yoke cables measured? Is it base on the length that sticks out of the middle? That’s good question! After measuring several straddle links, I’ve come the conclusion that it’s the length of exposed cable from where it exit’s the center device to where it disappears into the lead casting @ the other end. It isn’t the same as the C-C distance, & therefore not usable in trig calculations. However it isn’t necessary to do any trig calculations to try to get the optimum length. As Andrew so succinctly pointed out the goal is to get the length such that the straddle cables make a 90 deg or slightly smaller angle when the pads hit the rim. That’s w/ the angle measured @ the point where the line from the pivot point of the brake arm intersects the cable attachment, w/ the cable running to the center device as the other line making the angle. However, so far so I know it’s usually impossible to get a 90 or 90 deg. angle w/ the “narrow” or “up right” type of cantilevere arms. The angle usually ends up more oblique that 90 deg. Therefore the idea is to get an angle that is as close to 90 deg. While still clearing the tire, fenders, racks, etc. It’s quite easy to get this 90 deg. or w/ the older style wide cantilevers such as “Paul’s”. The idea of using straddle links in lieu for a single straddle cable was to keep the straddle cable from getting caught on Mt.B. tire knobs & tossing the rider over the bars in case of the primary brake cable severing. I don’t think this is much of a problem w/ relatively smooth road tires, & therefore use a plain straddle cable on road bikes for the greater ease of optimizing geometry. The use of non threaded brake pad posts (or smooth posts) allows one to extend the pads of upright arms further from the brake arm to improve the angle of the straddle cable to brake arm. Doing this, however brings on other problems. These are increased chance of brake squeal, & the difficulty of adjusting smooth arm pads. In my experience the rotating tabs that set toe-in & all the other pad adjustments, are made of plastic that has to be torqued very tight. This torque causes the plastic to deform creating a crease where the pad post is. This isn’t so bad when it is the 1st time the brakes are set up, but subsequent adjustments make it just about impossible to keep the pad post from being captured by this crease. There are work arounds, but are a pain too. I don’t remember all the smooth pad posts I’ve worked on. There may be some that don’t have these adjustability problems. I would appreciate knowing which, if any, they are. It's not just knobby tires. A transverse will grab any tire and likely injure (kill?) the rider in the event of a failed main wire. It's good practice to ensure there's a mudguard, lamp bracket or something between transverse and tire on a non-LinkWire setup. You can argue helmets but not this. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#7
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Q: Shimano cantilever straddle cable length?
On Oct 20, 6:30*pm, AMuzi wrote:
jay wrote: On Oct 19, 3:41 pm, somebody wrote: On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote: somebody wrote: I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. *I can pick one of several fixed straddle cables. *Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? *Does that mean the geometry won't be quite right when switching to another rim? *I checked the Sheldon stuff but don't have enough experience to pick the right one.. Adjustment: http://www.sheldonbrown.com/canti-trad.html#yoke The brakes: http://www.sheldonbrown.com/harris/c...ers/index.html You want the size which ends with a 90-degree angle as the pads touch. That varies by brake stud position and rim width. Some brakes allow lateral pad adjustment which can help to get that just right with various LinkWire sizes. That's it. *The brakes came with two different straddle cable sizes; the previous owner worked at a shop and must *have swapped in what worked on his bike. *That means I can try each and check the angle. How are Shimano straddle/yoke cables measured? *Is it base on the length that sticks out of the middle? Thanks! How are Shimano straddle/yoke cables measured? *Is it base on the length that sticks out of the middle? That’s *good question! After measuring several straddle links, I’ve come the conclusion that it’s the length of exposed cable from where it exit’s the center device to where it disappears into the lead casting @ the other end. It isn’t the same as the C-C distance, & therefore not usable in trig calculations. However it isn’t necessary to do any trig calculations to try to get the optimum length. As Andrew so succinctly pointed out the goal is to get the length such that the straddle cables make a 90 deg or slightly smaller angle when the pads hit the rim. That’s w/ the angle measured @ the point where the line from the pivot point of the brake arm intersects the cable attachment, w/ the cable running to the center device as the other line making the angle. However, so far so I know it’s usually impossible to get a 90 or 90 deg. angle w/ the “narrow” or “up right” type of cantilevere arms. The angle usually ends up more oblique that 90 deg. Therefore the idea is to *get an angle that is as close to 90 deg. While still clearing the tire, fenders, racks, etc. It’s quite easy to get this 90 deg. or w/ the older style wide cantilevers such as “Paul’s”. The idea of using straddle links in lieu for a single straddle cable was to keep the straddle cable from getting caught on Mt.B. tire knobs & tossing the rider over the bars in case of the primary brake cable severing. I don’t think this is much of a problem w/ relatively smooth road tires, & therefore use a plain straddle cable on road bikes for the greater ease of optimizing geometry. The use of non threaded brake pad posts (or smooth posts) allows one to extend the pads of upright arms further from the brake arm to improve the angle of the straddle cable to brake arm. Doing this, however brings on other problems. These are increased chance of brake squeal, & the difficulty of adjusting smooth arm pads. In my experience the rotating tabs that set toe-in & all the other pad adjustments, are made of plastic that has to be torqued very tight. This torque causes the plastic to deform creating a crease where the pad post is. This isn’t so bad when it is the 1st *time the brakes are set up, but subsequent adjustments make it just about impossible to keep the pad post from being captured by this crease. There are work arounds, but are a pain too. I don’t remember all the smooth pad posts I’ve worked on. There may be some that don’t have these adjustability problems. I would appreciate knowing which, if any, they are. It's not just knobby tires. A transverse will grab any tire and likely injure (kill?) the rider in the event of a failed main wire. It's good practice to ensure there's a mudguard, lamp bracket or something between transverse and tire on a non-LinkWire setup. You can argue helmets but not this. Agreed--and link wires don't make you look like a Fred, either! |
#8
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Q: Shimano cantilever straddle cable length?
On Oct 18, 7:41*am, somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex DM-18 rims. *I can pick one of several fixed straddle cables. *Which one? Is it related to rim width, where we want length that produces a specific angle based on brake model? *Does that mean the geometry won't be quite right when switching to another rim? *I checked the Sheldon stuff but don't have enough experience to pick the right one. Thanks! Adjustment:http://www.sheldonbrown.com/canti-trad.html#yoke The brakes:http://www.sheldonbrown.com/harris/c...ers/index.html Use one of these and give the one piece things the heave-ho. http://www.bikeman.com/Cyclocross_St..._Carriers.html |
#9
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Q: Shimano cantilever straddle cable length?
On Oct 21, 8:49*am, Qui si parla Campagnolo
wrote: Use one of these and give the one piece things the heave-ho. http://www.bikeman.com/Cyclocross_St..._Carriers.html My touring bike has cable carriers like that, but with a built in quick release lever. They're handy. I'd like those on our tandem, since I switched to levers with no quick release, but I've been unable to locate any. Anyone know where I can get them? - Frank Krygowski |
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