Correct spoke tension, 2019 Rad Rover rear wheel?

[PCeBiker]

On the bike, I will put a zip tie on the frame and trim it so it just brushes the rim,

Yeah, that's what I do.
You can always attach zip ties somewhere to make pointers out of them.
I like to use the center of the tread. I figure that's what counts the most.

Pythagoras said that meant the radial distance was 248.7mm.

Pythagoras also said,..

OMG !!
If I had to learn the Pythagorean Theorem all over again, it would take me a month of studying to straighten a wheel.

I used to be able to calculate the fourth derivative of a function.

Lately I have a hard time counting out change.

 

[PCeBiker]

I think that balancing lateral tension doesn’t matter with 13 and 12 gauge spokes,
They don’t have enough elastic stretch to let the rim move.
With greater elastic movement, they may require preloading (tensioning).

I bet I got some of that lateral tensioning going on with my 12 gauge spokes ??

The spokes are torqueing over sideways to tension the spoke.

 

[spokewrench]

I bet I got some of that lateral tensioning going on with my 12 gauge spokes ??

The spokes are torqueing over sideways to tension the spoke.

View attachment 186115

The tension (the vector sum which includes lateral tension) should be along the spoke. The nipple should tip to line up with the spoke. The one on the right looks right. The other two don't seem to line up. Are those two spokes bent at the rim end? Are they in the wrong hub holes?

 

[spokewrench]

Yeah, that's what I do.
You can always attach zip ties somewhere to make pointers out of them.
I like to use the center of the tread. I figure that's what counts the most.

View attachment 186114





OMG !!
If I had to learn the Pythagorean Theorem all over again, it would take me a month of studying to straighten a wheel.

I used to be able to calculate the fourth derivative of a function.

Lately I have a hard time counting out change.

I remembered the Theorem because it's useful. The diagonal of a rectangle is the square root of the sum of the squares of the sides. For a 3 x 4 rectangle, the sum is 3sq + 4sq or 25. The diagonal is the square root, or 5.

For a spoke, I wrongly called the distance at right angles to the lateral distance the radial distance because I forgot that a spoke doesn't point to the axle. The Theorem saved me a lot of trial and error by letting me calculate how far to turn the nipples.

I have trouble counting change, too, especially without my spectacles. Remembering my PIN number frees me from trying to figure out a handful of coins.

 

[spokewrench]

Yeah, that's what I do.
You can always attach zip ties somewhere to make pointers out of them.
I like to use the center of the tread. I figure that's what counts the most.

I measure at the rim by putting a finger against fork or chain stay and turning the wheel. If runout is more than 1mm, I'll know it. I'll measure with a caliper and use tape to mark the rim sector I need to move.

Riding, I may see runout as I look past the front fender to the center of the tread. Maybe it just means bicycle tires aren't perfect.

 

[PCeBiker]

Are those two spokes bent at the rim end?

Every spoke is bent at the rim/nipple.
I stuck my camera in the spokes to take pictures,..

I figure that the rim isn't designed for the boost spacing along with shorter spokes going to the motor.
(A mid-drive or front wheel has longer spokes.)

The nipples can't pivot in the rim holes to aim sideways with all that Pythagorean stuff to aim towards the hub holes, so the spokes have to bend.

However,..
It's kinda working !!??
Instead of the spokes being pretensioned by being stretched, they are being pretensioned like a torsion rod.

It helps if you a Vado first then stare at your wheel for hours observing and thinking.
Forget all the silly math stuff.
It's too hard to remember anyway.

 

[PCeBiker]

I remembered the Theorem because it's useful. The diagonal of a rectangle is the square root of the sum of the squares of the sides. For a 3 x 4 rectangle, the sum is 3sq + 4sq or 25. The diagonal is the square root, or 5.

I do remember enough to know that the angles of the spokes on a front wheel form an isosceles triangle, but because of the dishing on a rear wheel, the spokes form an irregular triangle.

The Theorem saved me a lot of trial and error by letting me calculate how far to turn the nipples.

I would've just winged it,.. tightening every second spoke a ¼ turn and loosening the others ¼ turn.
Just keep going around and around until the rim moves over 5 mm.

It helps if you a Vado first.

The spinning wheel starts looking pretty trippy.

I have trouble counting change, too, especially without my spectacles. Remembering my PIN number frees me from trying to figure out a handful of coins.

I just tap and go now.
Way easier for me.
No counting at all, and if I forget my birthday or name or something, I can just look it up on my phone.

My name is on my bank card too, so it's easy to find out who I am.

 

[PCeBiker]

Riding, I may see runout as I look past the front fender to the center of the tread. Maybe it just means bicycle tires aren't perfect.

Yeah, I do the same thing and that's why I true the whole wheel including the tire, instead of truing the rim.

I figure it's having the tire square and true where it hits the pavement that counts.

 

[spokewrench]

Yeah, I do the same thing and that's why I true the whole wheel including the tire, instead of truing the rim.

I figure it's having the tire square and true where it hits the pavement that counts.

I figure if the rim's fine, I'm not going to alter it for the tire. What if I repair a puncture and mount the tire in a different rotational position? What if I get a new tire?

An item on automobile tire runout says it's okay if radial runout is <.125" and lateral runout is <.10".
It says the causes of tire runout are manufacturing variation, wear and tear, improper installation, and impact damage.

I wonder if maybe the bead isn't seated quite evenly. Maybe I should ride at 5 psi and reinflate.

 

[spokewrench]

It worked. On one bike, the rim was true, but one section of tire was off by 3mm. It seemed to be installed correctly because the bead seemed evenly seated all the way around. Still, I deflated from 50 to 8, rode 200 yards, and re-inflated. No more tire runout!

The next time I patch a puncture, I'll have to get somebody smarter than me to mount the tire!