Wheel Build Advice Thread

blacksp20

blacksp20

Likes Bikes and Dirt
The Duckmeister said:
Yeah, it's well up there, but must be OK if the manufacturer specs it. I normally build aluminium rims to around 110kgf, sometimes lower if they're particularly light - too much tension makes the rims unstable, as well as more prone to cracking at the spoke holes.
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Would you suggest dropping the tension a little? The printout that was supplied with the rims stated tension should be 120-140kgf, so that’s what I tried to stick to. I checked Spanks site though and it specifies 110-120kgf. What do?!?
 
teK--

teK--

Eats Squid
CHEWY said:
The spokes on the opposite side of the wheel are taking the load in tension. Spokes do not take any compression load.
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When the wheel is in use, the spokes around the bottom of the wheel (let's just say from 7 O clock to 5 o clock) are in compression. Conversely the spokes at the top say 11 O clock to 1 O clock, are in tension.

Thats why when spokes don't have enough static tension they can become totally unloaded when they are at the bottom part of the rotation. This is what causes spokes to unwind and/or fail .
 
N

northvanguy

Likes Dirt
teK-- said:
When the wheel is in use, the spokes around the bottom of the wheel (let's just say from 7 O clock to 5 o clock) are in compression. Conversely the spokes at the top say 11 O clock to 1 O clock, are in tension.

Thats why when spokes don't have enough static tension they can become totally unloaded when they are at the bottom part of the rotation. This is what causes spokes to unwind and/or fail .
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Ok. I'm just not smart or I'm over thinking this.

With straight pull hubs the spoke at 6pm and 12pm how are they doing anything given the knob end can just slide out of the hub.

With j-bend I get it.
 
The Duckmeister

The Duckmeister

Has a juicy midrange
If they're properly tensioned they shouldn't be able to, but if the rim takes a big enough hit it can slacken the spokes enough. Most SP hubs have proper closed holes so the spoke can't escape unless it's broken or fully unthreaded, but some just have slotted lobes with a recess to seat the spoke heads, and these can pop out.
 
S

Shredden

Knows his goats
blacksp20 said:
For those interested in ordering parts from the UK during COVID...
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Hey mate - when you ordered, did you get an email with a tracking number or something? I ordered on the 10th, got an email on the 11th saying "We have finished processing your order" that didn't have a tracking number or anything attached.
 
blacksp20

blacksp20

Likes Bikes and Dirt
Shredden said:
Hey mate - when you ordered, did you get an email with a tracking number or something? I ordered on the 10th, got an email on the 11th saying "We have finished processing your order" that didn't have a tracking number or anything attached.
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Yes I got an email exactly 7 days after my order was processed with a tracking number. If you haven’t heard anything in a few days I’d email Peter at spokes@ryanbuildswheels.co.uk
Expect a few weeks to receive your order though as mine sat for 2 weeks in the UK.
 
safreek

safreek

*******
OK, my wheel dishing has hit a snag.
After the tyre and toob came off and out these little canyons were discovered. Look, I know they probably only have 6 months or so left for the dh but was just curious as to what caused the cracks.
Am I just too much of a big hard bastard or was it shoddy building of the wheel.
I have no idea where the wheel came from but it seemed to be OK when riding
367522
367523
 
PJO

PJO

in me vL comy
safreek said:
OK, my wheel dishing has hit a snag.
After the tyre and toob came off and out these little canyons were discovered. Look, I know they probably only have 6 months or so left for the dh but was just curious as to what caused the cracks.
I have no idea where the wheel came from but it seemed to be OK when riding
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That rim is just old, and has been carrying quite a bit of weight. They are a consumable item, yours is just about consumed. Weakest point is where the valve hole is because there is extra drillium there.
What was once a double wall (and hence strong) rim is now just a single wall rim.
Not going to be long before you hit a rock and the thing folds, I'd bin it before it bins you.
 
PJO

PJO

in me vL comy
Measure the ID and see if it is wider around the valve hole compared to elsewhere, I suspect it is starting to flare out there.
 
PJO

PJO

in me vL comy
What was the cracked rim?
I recently built a 521 rim for the DJ bike and the ERD was 533, reckon the 721 will be the same.
 
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