checking the dish on a rear wheel
 

I'm truing my rear wheel. It's really dished to the cassette side. However, most of the spokes on the cassette side seem to have less tension overall.

Is this normal?

This may be obvious but 'dish corrections are made to center the rim in the bike' or centered between the 'face of the locknut on the axle'. If you are saying that the rim is offset from center toward the DS then either the NDS spokes need to be tightened to pull the rim toward the NDS, or the DS spokes need to be loosened to allow rim to move toward the NDS. Which one depends on actual tension readings.

When you say "It's really dished to the cassette side", how much do you mean. 1mm is considered acceptable as rim offset from the locknut face. More than that and it should be reduced by appropriate tightening or loosening to move the rim closer to the center.

The DS spokes should end up having approx 70% higher tension than the NDS due to the steeper angle of spokes on that side. If your wheel has lower tension on the DS than on the NDS it's not tensioned correctly.

I made a mistake in my original post.

The rim is offset toward the NDS (by about 2-3 mm)

The DS spokes have way more tension than the NDS.
So I'd have to either loosen the NDS even more and/or tighten the DS much more?

It's the other way around, NDS side has abt 70% of DS tension. This is valid for many Shimano rear hubs. Campy can be worse (56% NDS tension). Shimano MTB disc hubs can be better by being very narrow between the spoke flanges..

I stand by my statement
"The DS spokes should end up having approx 70% higher tension than the NDS."

Read what I said It's the same as you said dbac.
The DS should be 70% higher - the NDS has about 70% of DS tension.

Depending on the hub, that may be true.


I don't know how you're counting, but I can't get the math to translate like that.

If DS is 100% and NDS is 70%, then DS isn't 70% higher than NDS.
If NDS is 70% of DS, then DS is 143% of NDS, or 43% higher.

Let's do it with numbers: Using the DS as a reference, and assigning it (arbitrarily) the tension of 50. 70% (0.7 x 50) gives a NDS tension of 35.
Using the NDS as a reference and putting the DS 70% higher would put it at 59.5 - not 50.

Using the NDS as a reference the DS tension is 43% higher(35 x 1.43 = 50)

It's just an approximation not an exact figure. Big deal!

Setting 40-something% to 70-something% is indeed an approximation. And a sizeable one at that...

+1

Assuming that the DS is the cassette side. Those spokes will always have more tension that the NDS side due to the angle difference.

Very interesting theoretical argument going on in this thread, but I still don't understand your question? Are you asking if its normal to have the DS spoke tension much higher than the NDS? If so, yes, its normal.

If you are asking whether your wheel is properly dished, then you have to use a dish tool to measure it, or measure the distance from the rim to one brake pad, flip the wheel over in the dropouts (so the cassette is on the left side of the bike) and see if the distance you measured is the same when the wheel is flipped.

I'm not arguing that, I'm saying that NDS being 70% of DS doesn't equal DS being 70% higher than NDS.

if I have 5 apples and you have 10:

You have 200% of my apple quantity.

I have 50% as much as you.

(but, is there a math type in the house....do we say)

you have 100 percent more than me?

I have 50% less than you?

Assuming that your wheel is tensioned enough, the easiest way to check the dish of the rear wheel, is to put the wheel in backwards, and compare its position in the frame with its position when correctly installed. if your wheel is properly dished, then the wheel should sit in the same position regardless of which direction it's installed. Because I'm assuming that you don't own a tensiometer, I can just say with a conventional wheel you should have more tension on the drive side. Exactly 25.19762% :)

100% correct. I was just making sure that it was clear that the cassette side will have more tension.
Ride safe.