Wheel Dish Question
 

Forgive my ignorance, but I have a question about wheel dish...

Over time, the dish of my 700 road bike wheel has moved 2mm away from the drive side. The wheel is straight and true, and functions properly, and there is plenty of room inside the frame for the tire. My question is whether or not I should go to the trouble to re-dish the wheel, or just let it be.

Two millimeters off center would be enough for me to re-dish it. Either the drive side spokes are too loose or the non-drive side spokes are too tight.

Flip your wheel over in the frame and see if it is 2mm over the other way. If it is, most likely your wheel needs to be dished, perhaps due to spokes de-tensioning? After flipping the wheel over and it's still 2mm off in the same direction, then it's not your wheel. Check your dropouts/frame alignment.

Maybe the drive-side spokes had more change as the spokes "set" because they're higher tension - so they loosened more than the non-drive-side spokes? I don't know what the mechanism is.

You'd likely be fine to not re-dish the wheel - your frame's tracking will be slightly off, but not much or meaningfully so.

However, I'd re-dish if I were you, too, partly just because I'm on the perfectionist side of things.
To judge spoke tension, get a tensionmeter or use this handy rough guide by tone:
http://www.bikexprt.com/bicycle/tension.htm
This is debated (recommended by Sheldon Brown in his wheelbuilding article) but I've found it consistently useful.
If you need to get a tone from your computer, you can use the Java Tuner.

Wow! I am all for doing it right, but sometimes I wonder about the intolerances for reasonable tolerances in cycling. :D

Stan,

I just picked up my ruler to see how much 2 millimeters is, and I just have to ask, other than seeing a difference with a dishing gauge, how would this misalignment manifest itself during riding, or is it strictly to even the tension? Would it make a difference to you if it was 2 mm the other way versus this way?

I personally true and dish my wheels to within 0.5mm and then retrue and redish when they drift themselves back out to about 1.0mm. I believe this is pretty much the standard. An untrue or poorly dished wheel almost always has a few spokes that are a little slack and "just along for the ride". A properly tensioned wheel is stiffer, more durable, and often more responsive under acceleration. Having the front and rear wheels in the exact same plane will improve a bike's handling too.

To me it sounds like the spoke heads on the drive side weren't set into their holes when the wheel was built and worked themselves in over time. Although I've yet to see it on one of my 32h or 36h 3X wheels, some drive side spokes will also stretch a bit. It's possible that you may have lost enough drive side tension to have the LBS check it with a tensiometer. My preferred LBS will usually check it for free and true a wheel for $5. I think a complete retensioning runs about $15 but I do virtually all my own wheelbuilding so I'm kind of guessing on that one.

If the frame's straight and spokes are tight, I think I would see if a washer has somehow migrated from the non-drive to the drive side during some maintenance activity, or just switch/insert some myself before I started dishing.

My 2mm off-center reading came from my truing stand, so I know it's the wheel.

But this brings up a good point. Is it the wheel itself that needs to be true, or does the wheel just need to be centered in the frame?

2 mm is quite a bit. have you reversed the wheel on the stand to make sure it's the dish that is off or the stand?

The wheels I've built with all Revolution spokes (2.0-1.5-2.0) have continued to pull off dish as the driveside rear spokes have stretched. The rim moves over about 1/2 mm per year. I'm gradually running out of threads and will either take a chance on loosening the non-driveside spokes or replace the driveside spokes with Competition spokes (2.0-1.7-2.0).

Al

+1 to re-dishing

It will only take you like 2 minutes unless you have threadlocked aluminum nipples. I could re-dish a rear faster than I could swap out a punctured tube. Very easy job.

Not having a wheel dished in the rear can have advantages. Some add a spacer on the Non-Drive just for that reason.

Plus is Less Spoke breakage.

The only real problem you will have is the rear caliper. It will move to the far left and you may have a problem centering it. For my 35yrs at this. You want it to be as close to center of your Brake Bridge {where the caliper bolts into.} For this is the part that really counts.

Update:

I double checked my truing stand, and the center line was off center a bit...and the dish was now off by almost another millimeter...meaning the dish was off around 3mm, favoring the non-drive side.

I went ahead and re-trued the wheel. I loosened the non drive side around 1/8 of a turn, and then tightenened up the drive side a little bit at a time until the wheel was centered, and then trued the wobble out of it.

So, I have no idea where I'm at in terms of tension on either side, but it's a 36 spoke wheel, so I'm just going to ride it and see what happens.

When I dropped the wheel back into the frame, the tire was centered perfectly.

AL1943
Are you going to ride the Tour of Payne this year???

I hope to. That's a good one, well organized, one of my favorites along with the D.A.M. JAM.

Al

A good test is to flip it on the truing stand to see if it "stays" centered.

The risk of reducing the tension on the non-driveside is the increase in spoke flexure at the hub can cause the spokes to break in the "J" bend. For $55 - $60 the Park Tension Meter is a good investment.

Al

Al1943,

Yes, I filipped the wheel on the stand, and it was centered both ways...so I know both the gauge and the wheel are centered.

Your point about the reduced tension on the non-drive side is a good one, and I'll have to check that out.



Thanks everybody for your replies, they are much appreciated!

Maybe we will run into each other there. What is the D.A.M. Jam???
Thanks....