Hubs, spokes, rims and angles

Everything about building wheels, glueing tubs, etc.
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RocketRacing
Posts: 828
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

I have some 56mm rims, and carbon ti x hubs. Apparently they have wide spacing for the spokes (drive side to non drive side), allowing some pretty stiff bracing angles.

Tri hubs are far more narrow, with shallow spoke spacing.

Stiffer is better right? But can your hub be too wide for a deep rim? An 80mm rim would have some crazy spoke angles.

Is there a rule of thimb? Were the xhubs designed for a shallow rim?

by Weenie


Jugi
Posts: 525
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

I bet there is no right answer to the question "how wide bracing angles are wide enough" but, wider equals stiffer and stiffer is better in general.

Play around with this tool, it will demonstrate the differences quite well: http://kstoerz.com/freespoke/

Most carbon rims have a specified bracing angle limit (or a suggestion for best angle) which should be respected.

RocketRacing
Posts: 828
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Jugi wrote:
Sat Jul 13, 2019 8:52 am
I bet there is no right answer to the question "how wide bracing angles are wide enough" but, wider equals stiffer and stiffer is better in general.

Play around with this tool, it will demonstrate the differences quite well: http://kstoerz.com/freespoke/

Most carbon rims have a specified bracing angle limit (or a suggestion for best angle) which should be respected.
I had no idea about the bracing angle until i thought about it one day. I suspect i am pushing it on my 56mm wheels with x-hubs.

alcatraz
Posts: 2145
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Lateral bracing is limited by the flange spacing.

Torsional bracing can be customized with the lacing pattern.

If you have too wide bracing your rim needs to be drilled with that in mind. Otherwise you'll get bent spokes and cracked nipples.

It's an interesting thought you present. Is a deeper rim more laterally stiff or a shallower rim? Sure the deeper rim has better bracing angles but more forces act upon the rim itself.

What do you mean by a tri-hub? Triplet? Some are normal hubs with triplet drilling (bad geometry some might say?) and some are triplet specific with very wide bracing on the nds side. Interestingly if you want to run a genuine triplet hub you might need special rim drill angles. If you can settle for "fake" triplet any standard rim will likely do. I've run "fake" triplet successfully. I don't complain over it.

RocketRacing
Posts: 828
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

alcatraz wrote:
Sun Jul 14, 2019 11:55 am
Lateral bracing is limited by the flange spacing.

Torsional bracing can be customized with the lacing pattern.

If you have too wide bracing your rim needs to be drilled with that in mind. Otherwise you'll get bent spokes and cracked nipples.

It's an interesting thought you present. Is a deeper rim more laterally stiff or a shallower rim? Sure the deeper rim has better bracing angles but more forces act upon the rim itself.

What do you mean by a tri-hub? Triplet? Some are normal hubs with triplet drilling (bad geometry some might say?) and some are triplet specific with very wide bracing on the nds side. Interestingly if you want to run a genuine triplet hub you might need special rim drill angles. If you can settle for "fake" triplet any standard rim will likely do. I've run "fake" triplet successfully. I don't complain over it.
I am just a mess with the Terminology. Learning as i go. By “tri hub” i mean “triathalon ideal hub” or a hub with very narrow flange spacing, presumably to keep bracing angles within spec for very deep aero rims, and to keep spokes as hidden as possible to minimize drag. The cost is lateral stiffness.

by Weenie


bm0p700f
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Location: Glermsford, Suffolk U.K
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by bm0p700f

Deeper rim are stiffer in every way than shallow rims

Carbon ti hubs dont have high bracing angles
They have the ideal geometry for 11 speed hubs.

Tri hubs that's a joke right. You can build good wheels witha deep rim with a 80mm deep rim. Hubs with narrow flange spacing are garbage. I now the kind you mean. They make dt swiss road hubs look like they have wide spacing. Such hubs exist because someone has faulty logic and then sells them based on that faulty logic.

I own a set of 88mm deep tubular laced to dur ace hubs. 12 spoke. The bracing angle is extreme and yet there is no unsavory bend at the nipples.

Tri hubs give me a break. They have been invented to sell triathletes kit they dont need complete e
With faulty logic reasoning.

With deep rims you can reduce the non drive side to centre spacing a bit but anything below 33mm is utterly futile.

A high non drive bracing angle is helpful as it reduces brake rub with deep rims.

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