Morning All,
Question before I begindetermine if my front hub is centered in the rim.
From my straight edge do I want to measure to the bearings or will I get good info measuring to the surface of the hub where the spokes mount. I ask because on the disc side the wheel bearing protrudes a hair, maybe a 1/6" or so. On the opposite side we have a recess where the speedo drive sits. Should I pull the bearing that protrudes and measure to the edge of the opening.
I figure if I measure to like points on either side of hub I will get good data in regards to centering.
Am I missing anything?
Thanks,
Bucaman

 

A couple of questions back to you first.....
Are you using the existing rim, or building a new wheel with a new rim?
The reason I ask is because it will make a difference in the 'dimension' you use. Yes I know that is confusing.

Maybe I can make things clearer. If you look at a factory service manual you will notice that the distance given for a 1974 using a standard rim is 1/4 inch from the inside surface of the disc (rotor) to the rim edge on the brake side of the wheel. (A 1973 is a bit different and the same dimension for that is 1/8 inch)

Now this is all different if you are installing a new rim on a wheel build.
The point I am trying to make is this:
On a wheel with a disc brake, the location of the rotor is what sets the position of the wheel between the forks. Then the rim ic centered inside of that location. Clear as mud I am sure. Sorry.

The bearing sticking out has no real bearing on centering the hub on a disc brake wheel, but rather this is set by the disc rotor location and then you work from there. I sure wish I had the words to make this more understandable and less confusing.
On a drum brake the hub is centered between the forks and then the rim gets centered over the hub. A bearing sticking out here does have an effect on the measurement along with any spacers used. But in the end, the spacer(s) and the bearing stick should result in the hub being centered between the forks.
Disc brake is located by the location of the rotor. There I go repeating myself for the third time.
pg

 

Pinion,
Not a new lacing job. Just looking to center what I have right now. It is not a factory wheel. It is a Excell wheel. Never has looked right.
I have rotor off. Using a straight egde across the rim to the surface where the nipples 'nubs" are, on one side I measure 1.520" and the other 1.260". The smaller dimension is on the rotor side. In my mind that puts the rim offset to the rotor side.
This is the offset I have witnessed with the assembled wheel on the bike since I bought it the bike. All the clearance I had was on the side opposite of the rotor. If I shift the rim away from the rotor and keep all the spacers in order the rotor will be where I need it to be.
I am only looking at a shift of about .125". This should give me a dimension of approx. 1.400" on each side.
Am I making any sense?
Bucaman

 

I am dealing with a '74...

 

Yes you make very good sense.
The difference between the two measurements is roughly 1/4 inch.
I agree with you on shifting the rim away from the rotor side 1/8 inch. This will leave the rim centered between the forks, your rotor will be in the correct place to fit into the caliper and you should be set.

I suggest you mount the wheel in the forks and make an indicator out of a piece of wire, placing it close to the rim edge ( 1/8 inch air space would be perfect) to give you an idea of how far you are moving the rim away from the rotor side. That way, when the rim moves over 1/8 inch the wire will screech against the rim all the way around.

Then start at the hole for the tube stem and loosen the first nipple on the rotor side i/2 turn. Next nipple is on the opposite side so tighten it 1/2 turn. Next nipple is on the rotor side.... loosen 1/2 turn, advance to the opposite side......tighten 1/2 turn, etc all around the 40 spokes. Then see what the wheel looks like for being centered. You may have to do another 1/4 turn on each nipple, or if a 1/2 turn was too much in the beginning, go back a 1/4 turn the other direction on each nipple.

If the rim is an aftermarket then what happened was whoever built this wheel did not center it properly over the hub, since you say it has been like that since you got the bike.
pg
.

 

PG,
I think I have it.
I pulled it over as I described and it appears to be where I need it. It now measures within .010" both sides and it looks right. Next I will true it on a stand. I will let you know after I mount in the the front end.
Next I go after the rear wheell. I suspect I have the same thing going on with it. It is a 16" wheel and if the same guy laced it he did the same thing.
Thanks,
Bucaman

 

Great! Good to hear you got it pulled over.
The last wheel I built I was determined to get the total side to side runout as small as possible. Ditto for the radial runout.
The end result was .011 side to side and the same for the radial runout.
Normal tolerance for this is .020 for each direction. I just wanted to see how much better I could get.

A lot of guys have this problem of a rim that is not balanced over the hub.
Instead of talking about adding washers and bending fender struts all they have to do is just what you did.
Work on the spoke adjustment and watch the rim move over as you go around the wheel.
As I always say...... This is the only way to correct a wheel that was incorrectly laced up.
And so I say to you.....Good Job... well done!
pg

 

I think you can get a spoke wrench from the same place P.G is reccomending he get his wheel Bucannen I think or you can just goggle it in,I happened on their site and they have spokes ,rims ,hubs and tools for the job.

 

Absolutely! Bucannan would be a good place to get a wrench. Just make sure to get the proper sized one and they can even help with that.

Oh, congats on the FLH and having the little woman happpy lagunatic!
pg