Bicycle Mechanics - Ideal Spoke Tension

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brianappleby
01-05-08, 05:01 PM
I'm building my first wheel. Where can I find the ideal spoke tension for the wheel?

32 spokes
2.0mm straight gauge steel
Velocity deep V-rim
surly medium flange rear hub

It's a rear track wheel so dishing is symmetrical.


Sheldon Brown
01-05-08, 05:11 PM
I'm building my first wheel. Where can I find the ideal spoke tension for the wheel?

32 spokes
2.0mm straight gauge steel
Velocity deep V-rim
surly medium flange rear hub

It's a rear track wheel so dishing is symmetrical.
Symmetrical wheels are SUPER strong, so the tension is much less critical than for a derailer type wheel. I'd probably go with somewhere around 100 kGf.

However, if you haven't already bought the cheap spokes, I would suggest going for butted spokes. They're really not that much more expensive, and they will build a more reliable wheel. Straight gague spokes are a false economy. Also, go for stainless, not plain steel.

Sheldon "Penny Wise..." Brown

waterrockets
01-05-08, 05:14 PM
You can email Velocity and they'll get back to you w/in hours during the week. Rim manufacturers determine spoke tensions. Luckily, I emailed them on this same rim, and they said that for the Deep V they recommend 105-110kgf for the front and 110-115kgf for the rear drive side. I'm not sure why they recommend lower for the front though. Maybe because only one side of the rear is doing all the work, or higher DS tension means higher NDS tension, which is probably healthier.

I would just build it to 110kgf on all spokes front and rear. Those wheels will last forever. I was almost disappointed at the tremendous durability as it eliminated the need for building replacement wheels. Thank goodness I got a PowerTap hub to get me out of that rut :)


operator
01-05-08, 05:41 PM
Yep, deep v's while heavy are super strong.

brianappleby
01-05-08, 05:50 PM
wow, thankyou for the prompt and informative responses.

New question. The wheel is out of round (flat spot) by about 1mm directly above the weld joint. The out of roundness is too localized to fix with spoke tension. Is this acceptable, or should I ask for a replacement rim?

The spokes may very well be stainless, but they're definitely straight gauge. I will be rebuilding this wheel in a matter of months, and will buy new (butted) spokes then. I laced the wheel incorrectly a few times, so they have been bent around more than I'd like.

Mr. Brown, your wheelbuilding article is what I was following before, and as I built the wheel. Thanks so much for providing such a helpful resource.

well biked
01-05-08, 06:10 PM
New question. The wheel is out of round (flat spot) by about 1mm directly above the weld joint. The out of roundness is too localized to fix with spoke tension. Is this acceptable, or should I ask for a replacement rim?

If it's just 1mm, I wouldn't worry about it. Peter White addresses this very issue on his website, regarding Velocity and Mavic rims, and says that if it's 1mm or less, it's okay. Scroll down to the "how true will your wheels be?" section:

http://www.peterwhitecycles.com/Wheels.asp

bailcash09
01-05-08, 06:12 PM
However, if you haven't already bought the cheap spokes, I would suggest going for butted spokes. They're really not that much more expensive, and they will build a more reliable wheel. Straight gague spokes are a false economy.

How do butted spokes build a more reliable wheel? I know they are probably worth the extra money because the disadvantages aren't great, but aren't plain gauge spokes stronger/less flexy? I don't have a whole lot of wheel building experience, but everything I've read and even simple reasoning suggests that plain gauge should be stronger. What are the advantages butted spokes offer other than weight savings that makes for a "more reliable wheel"?

well biked
01-05-08, 06:14 PM
How do butted spokes build a more reliable wheel? I know they are probably worth the extra money because the disadvantages aren't great, but aren't plain gauge spokes stronger/less flexy? I don't have a whole lot of wheel building experience, but everything I've read and even simple reasoning suggests that plain gauge should be stronger. What are the advantages butted spokes offer other than weight savings that makes for a "more reliable wheel"?

Butted spokes flex in the middle section more, and therefore don't flex as much at the elbows, which is where spokes usually break-

bailcash09
01-05-08, 06:16 PM
Butted spokes flex in the middle section more, and therefore don't flex as much at the elbows, which is where spokes usually break-

Ah. Thanks

J T CUNNINGHAM
01-05-08, 06:41 PM
Both Frank J Berto, 'COMPLETE GUIDE TO UPGRADING YOUR BIKE',

and

Jobst Brandt, 'THE BICYCLE WHEEL',

agree that double butted spokes are superior to

straight gauge for the above mentioned reason.


Regards,
J T

Sheldon Brown
01-05-08, 09:03 PM
How do butted spokes build a more reliable wheel? I know they are probably worth the extra money because the disadvantages aren't great, but aren't plain gauge spokes stronger/less flexy? I don't have a whole lot of wheel building experience, but everything I've read and even simple reasoning suggests that plain gauge should be stronger. What are the advantages butted spokes offer other than weight savings that makes for a "more reliable wheel"?See:

http://sheldonbrown.com/wheelbuild

All the best,

Sheldon

waterrockets
01-05-08, 09:22 PM
+100 to Sheldon's (and others) points about double butted advantages.

The only disadvantage is that a given wheel will be more laterally flexible with double butted spokes. This is not a problem on wheels that aren't fashionably short on spokes.

brianappleby
01-05-08, 11:41 PM
waterrockets, I find this hard to believe, evidence?

Since the tone of my question can't be conveyed over the internet, I will elaborate.

Although I have very little experience with actual wheelbuilding, I've done a lot of research on the physics & geometry behind how bike wheels work.

I understand how a thinner (in the middle) spoke could be more flexible in stretching/compression, but that will affect stiffness across the board (tangential, lateral, torsional).

I don't see how spoke thickness, or especially spoke butting will change only the lateral stiffness of a wheel.

Not trying to be rude, just an honest question,

B.

p.s. I finished the wheel and it's true and symmetric and (mostly) round and the tension is pretty even. I'd post pictures but you really don't need to see another deep V with 32 3x spokes...

thanks again for all the help though.

waterrockets
01-06-08, 10:42 AM
If the rim is to move sideways, spokes will have to get longer on the other side. Thinner spokes will lengthen easier, and double-butted spokes are thinner in the middle. It's not an issue at all with a 32h Deep-V :)