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important to use washers between spoke nipples and single-wall eyeletless alloy rims?
I'm using a NOS Araya single-wall (twin hollow) rim to replace a Sun Mistral rim (similar construction, except with single - obviously - eyelets) on a wheel in which the hub and spokes are in good shape. The sun rim is bent.
Anyway, the important info is that I'm building a dished rear wheel with a 36-hole Araya single-wall rim without eyelets. 14g straight-gauge spokes. I'm pretty confident in my wheelbuilding skills, where equalized tension is concerned, etc. The spoke nipples sit directly against the aluminum, but I could use washers to spread out the force of the spoke nipples against the rim. This would be important specifically on the drive-side spokes, which are higher tension, because of the possibility of the spoke nipples causing cracks in the rim. The rim itself is relatively lightweight - 488g - for a 27" single-wall rim. What do people think? I don't know much about building with washers between spoke nipples and the rim bed, other than the theoretical benefits that I can see reasons for in my mind. |
My experience is that single wall aluminum rims don't last very long - especially the rear rims. They are easily damaged.
I wouldn't put too much time or money into them. |
Spoke washers are intended to be used between the spoke and the hub. They are not intended to go into the rim socket. If you don't have eyelets, put a little grease on the inside of the rim drilling so the nipples will turn easier when tensioning.
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Originally Posted by NJWheelBuilder
Spoke washers are intended to be used between the spoke and the hub. They are not intended to go into the rim socket. If you don't have eyelets, put a little grease on the inside of the rim drilling so the nipples will turn easier when tensioning.
Dan Burkhart www.boomerbicycle.ca |
mike: I've seen plenty of single-walled aluminum rims that lasted a long time, even without washers as I've described. What is the method of failure that you've usually seen?
NJWheelBuilder: I'm familiar with the tiny washers that go between the spoke head and the hub flange, and I should have been more clear about that in my original post. I'm talking about washers that sit on the spoke bed underneath the spoke nipple, and help to spread out the force of the spoke tension over a wider area of the rim's un-reinforced spoke bed. Dan: I take it you mean that intentionally-designed nipple washers are oval on the outside, but still circular on the inside diameter to fit cleanly around a spoke nipple. I've seen wheels built with just run-of-the-mill (round outside profile) washers, and if they're narrow enough there is still room in the spoke bed for them despite not having an ovalised profile. I agree with you that this sort of thing could start a flame war... except that not enough people are familiar with the issue to get it going :) |
Originally Posted by timcupery
I agree with you that this sort of thing could start a flame war... except that not enough people are familiar with the issue to get it going :)
The Arayas will be fine without washers. I have yet to see one fail by having a nipple pull through. Just don't crank 'em up to more than about 90-95 kg/f. Those things have plenty of meat in the spine.... |
Here are a couple of pictures of round washers between spoke nipple and rim bed. Not wheel that I built, and this wheel did it only on the drive-side. It gave me the idea, got me wondering, etc.
You can see that they'd ideally be oval on the outside profile, not round, because they sit exactly centered in the rim bed and not offset to one side as the spoke-holes in the rim bed (and thus the nipples) are. http://www.unc.edu/~cupery/pics/bike...ith_washer.jpg http://www.unc.edu/~cupery/pics/bike...ith_washer.jpg |
Originally Posted by timcupery
mike: I've seen plenty of single-walled aluminum rims that lasted a long time, even without washers as I've described. What is the method of failure that you've usually seen?
NJWheelBuilder: I'm familiar with the tiny washers that go between the spoke head and the hub flange, and I should have been more clear about that in my original post. I'm talking about washers that sit on the spoke bed underneath the spoke nipple, and help to spread out the force of the spoke tension over a wider area of the rim's un-reinforced spoke bed. Dan: I take it you mean that intentionally-designed nipple washers are oval on the outside, but still circular on the inside diameter to fit cleanly around a spoke nipple. I've seen wheels built with just run-of-the-mill (round outside profile) washers, and if they're narrow enough there is still room in the spoke bed for them despite not having an ovalised profile. I agree with you that this sort of thing could start a flame war... except that not enough people are familiar with the issue to get it going :) Dan Burkhart www.boomerbicycle.ca |
Originally Posted by BikeWise1
LOL. Since when has being ignorant stopped a flamer around here?:D
The Arayas will be fine without washers. I have yet to see one fail by having a nipple pull through. Just don't crank 'em up to more than about 90-95 kg/f. Those things have plenty of meat in the spine.... Glad to hear that I can go ahead and build the wheels up without washers. It's a bit cleaner that way. Do you agree with Dan that there's no tested-engineering benefit to nipple washers? Incidentally, Jobst Brandt does refer to "rims that use washers" on page 54 of The Bicycle Wheel. He presumes that rims without eyelets will use washers in the wheelbuild, as a default course of action, to spread out the forces but also to prevent the spoke nipple from galling the aluminum rim. The walls of lightweight aluminum rims are too thin to support concentrated from spoke nipples directly. Steel eyelets are crimped into the spoke holes of aluminum rims to reinforce them and to prevent nipples from galling the rim when they are tightened. Good hollow cross section rims have steel sockets, held in place by crimped eyelets that distribute spoke loads to both the inner and outer bed of the rim. This method of spoke support permits thinner walls and lighter rims. Rims without sockets to distribute loads to both walls often crack around their spoke holes with use. Steel washers can be used instead of sockets, but these are uncommon because even thick ones are relatively low in bending strength compared to a deep socket. Therefore, washers must be nearly as heavy as sockets to carry the same load. Since only one wall of the rim supports the washers, this wall must be thick enough to give the same strength as a thin wall of a socketed rim. Rims that use washers are only lighter than rims with sockets when weighed without their washers. |
Originally Posted by timcupery
You're right that ignorance doesn't stop flaming, but I guess it's got to be a subject that people have some knowledge of, or at least feel some investment in. My guess is that most people look at "washers between spoke nipple and rim bed" and get a big "whatever" in their head, as it's such a scarce topic.
Glad to hear that I can go ahead and build the wheels up without washers. It's a bit cleaner that way. Do you agree with Dan that there's no tested-engineering benefit to nipple washers? Incidentally, Jobst Brandt does refer to "rims that use washers" on page 54 of The Bicycle Wheel. He presumes that rims without eyelets will use washers in the wheelbuild, as a default course of action, to spread out the forces but also to prevent the spoke nipple from galling the aluminum rim. Dan Burkhart www.boomerbicycle.ca |
Originally Posted by Dan Burkhart
Let's be clear. I did not say there are no engineering data on this, I merely said my opinion was not based on any. I'm sure there are volumes of it somewhere.
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Yes, use washers. Eyelets in rims spread out the force and lessen the chance of rim fracture at the hole, washers will also spread out the force.
Many years ago when I worked at an LBS, we always used washers on rims with no eyelets. |
Originally Posted by BikeWise1
Just don't crank 'em up to more than about 90-95 kg/f. Those things have plenty of meat in the spine....
I'd use the washers or a different rim. Al |
Originally Posted by timcupery
You're right that ignorance doesn't stop flaming, but I guess it's got to be a subject that people have some knowledge of, or at least feel some investment in. My guess is that most people look at "washers between spoke nipple and rim bed" and get a big "whatever" in their head, as it's such a scarce topic.
Glad to hear that I can go ahead and build the wheels up without washers. It's a bit cleaner that way. Do you agree with Dan that there's no tested-engineering benefit to nipple washers? Incidentally, Jobst Brandt does refer to "rims that use washers" on page 54 of The Bicycle Wheel. He presumes that rims without eyelets will use washers in the wheelbuild, as a default course of action, to spread out the forces but also to prevent the spoke nipple from galling the aluminum rim. The applications that would require nipple washers typically are super lightweight aero rims without eyelets. The sub-300gm aero tubular rims without eyelets typically need them. The 240gm FIR and 220gm Ambrosia rims I've tried came with alloy washers that are actualy triangular in shape to fit into the deep aero section of the rim and provided a flat surface on top for the nipple to sit. Weight of these washers added 10gm to the rim. |
Originally Posted by Dan Burkhart
I would have thought from your handle that you would know there are spoke washers and nipple washers. Nipple washers are oval shaped, whereas spoke washers are round. I am sure this is one of those topics that could start a glorious dedate or even a flame war. Suffice it to say, it is my opinion, based on absolutely zero engineering data, (other than the seat of the pants variety,)that there would be some benefit to using nipple washers for re-enforcement in a single wall rim if you don't mind the added(negligable) Weight.
Dan Burkhart www.boomerbicycle.ca |
No
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Originally Posted by timcupery
Here are a couple of pictures of round washers between spoke nipple and rim bed. Not wheel that I built, and this wheel did it only on the drive-side. It gave me the idea, got me wondering, etc.
You can see that they'd ideally be oval on the outside profile, not round, because they sit exactly centered in the rim bed and not offset to one side as the spoke-holes in the rim bed (and thus the nipples) are. http://www.unc.edu/~cupery/pics/bike...ith_washer.jpg http://www.unc.edu/~cupery/pics/bike...ith_washer.jpg Round washers were used on the drive side only because someone didnt have shorter spokes. |
Originally Posted by San Rensho
Yes, use washers. Eyelets in rims spread out the force and lessen the chance of rim fracture at the hole, washers will also spread out the force.
Many years ago when I worked at an LBS, we always used washers on rims with no eyelets. Using them wont hurt but they really arent needed. |
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