I need some help from the dually owners out there. My 1997 F350 DRW has 16x6 alloy rims on it and I have a couple of questions about mounting the wheels.

I seems that my rear wheels (inside and outside) are indexed by a small metal rod on the inside rim that fits into a corresponding hole in the outside wheel. I am sure there is a name for that thing so please help me out if you know what it is called. This means that the 2 wheels can only mount if the rod is lined up with the hole. I have also noticed that my other truck, a 2007 F350 DRW, has a hole in the rim where the metal indexing rod would be but it is missing on both sides. This means I can rotate the outside wheel any number of lug positions in relation to the inner wheel. When I got the 2007, I could not air up the inside wheel because the holes were not lined up with the inner valve stem. I took the outside wheel off and rotated it so I could reach the inner wheel's valve stem and put it back on.

However, after doing that, I now have a vibration. I have had all 6 tires balanced and they had no problems getting them balanced and the runout was within specs so I know the individual wheels are balanced. I suspect that the vibration is due to fact that I moved the outer wheel in relation to the inner wheel. A friend of mine told me that he had the same problem on his Dodge truck so he jacked up the rear axle on both sides, started the motor and ran it up to 60-70 mph then shut it off and and pulled the outside wheel off and rotated it one lug nut and tested it again. He kept doing that until the vibration went away and he now says it rides smooth as glass without any vibration.

Has anyone had to do this and what were the results? And WTH is that little indexing rod called?

 

It is an indexing pin. My truck has short hoses that go from the valve stem to a bracket
attached by axle bolts. The hoses make for easy access to check the tire pressure. If it were not the pins it could be difficult to get the hoses oriented properly. I don't know how it would be on wheels without extension hoses.

When you say that the pin is missing, was it not installed at the factory or does it look like someone removed then?

I don't understand why the balance issue would be there. In my mind the orientation would not make a difference. Have you talked to your favorite tire store about it?

Steel wheels are "Hub Centric". That means the wheels are centered to the axis of rotation by the hub rather than the lug nuts and studs. They do this by having a tight slip between the wheel and the hub. On the dually trucks that I seen there is an area adjacent to the flange that centers the drum and the wheels. Since the alloy wheels are thicker than steel, I don't know how the outer wheel would be centered because the area for centering on the hub is not long enough to reach it. So whatever method of centering the alloy outer wheel may be off causing vibration.

 

On a similar note, can someone tell me the bore diamater of the indexing hole, as well as the center hole of the rim?

 

Thank you! This is really helpful.

It doesn't appear that the indexing pin was ever there but there is no way to know. I have yet to take it back to the tire store since the wheels were balanced but I may have to do that.

The inner wheel on all Ford duallys is steel so the difference in thickness of the steel wheel might be just thin enough to allow the alloy wheel to be hub-centric as well. Personally, I thought all Ford truck wheels were hub-centric, including alloys. I do know that the lug nuts have flat washers built in that spin and that the manual says to put a drop of oil between the washer and the nut when installing the wheels. But they also say NOT to oil the threads (bit of common sense there).

I read on a Dodge forum that some of their wheels are lug-centric and that they use 2 conical lug nuts (on opposite sides) to center the wheel on the studs and then tighten up the other lug nuts that are flat once the wheel is centered on the studs. This might be something I try.

I agree with you that the sole purpose of the indexing pins are there to allow access to the inner valve stems.

It also makes sense that if 2 wheels are perfectly balanced independently, that they should still be balanced regardless of orientation to each other on the vehicle. My buddy who suggested the test method to me said that he agrees but finds that that is not always the case. If the run-out on the tires is bad then perhaps regular spin balancing wouldn't catch that. I'm not sure if the tire shop road force balanced the tires before re-installing them but I'll call them to check.

From what I have researched, most rims are marked by the manufacturer to identify the point on the rim with the most run-out and the tire manufacturers put a dot on the tire to identify the area with the most run-out. This provides the tire tech with reference points to road force balance the tires and allows them to rotate the tire on the rim to minimize the vibrations.

I have also read that installing the wheels so that the valve stems are 180 degrees from each other will help minimize vibration. The explanation provided was that the valve stem weighs more than the metal removed from the rim to make the hole for the valve stem so that creates an imbalance. I think that is where I will start when I work on it this weekend. I wish my compressor was a little bigger so I could use an impact wrench to remove all the lugs. As of now, I'll have to do it manually.

 

Idk about runout dot but there is a dot on tires to mark the heaviest part so you can match with the valve stem. The Alloys are hub centric to my knowledge. I have six Alcoa's on my 88'.

 

That's interesting about 6 Alcoa's. My '97 and '07 have steel inner wheels. Are your rims polished on both sides?

 

I have not kept up with polishing any of my alcoa's. If you do polish make sure to keep them coated with an aluminum protector because you are removing the protective layer.

Truck came with inner steels but this is also pre factory alcoa. I picked up a Chevy set and modified them to fit. Run for probably 25k miles now with the modded Chevys on the inners.

Run Stainless steel valve stem extenders from NAPA on the inners with the mounts from the SLIME brand rubber houses because the mounts from the SS ones are cheap pot metal.

 

97 and older used the indexing pin to line up a hand hole with the inner valve stem. I always cut mine off

99+ they did away with the indexing pin(maybe they figured people got smarter)

As for you vibration, it sounds like you have a bent wheel, or axle, or both

 

So, I got anxious the other day and jacked up the rear axle on both sides and conducted a visual inspection of the tires and wheels. I ran the engine up to 65-70 mph and observed the wheels from the side mirrors with a 500W work light behind the wheels.

When I first bought this truck, I soon realized that the front driver's side rim was bent when I went to have the tires balanced due to this vibration. The tire tech informed me that my aluminum rim was damaged and needed to be replaced. I was nearly a 1,000 miles from home hauling my truck camper so I went to a Ford dealer to purchase a new Ford rim. It was a Saturday and the junkyards were all about to close and many weren't open wouldn't be until Monday. I had to get to my destination so I bit the bullet and bought a new rim.

Long story short, whatever the PO did to damage the front rim may have messed up the rear tires on the same side (DS). I don't think the rims are bent because I got out of the truck and watched the rim closely looking for static (up and down) and dynamic (side to side) runout. It appears that the inner and outer rims are fine but that the tires are bad. The steel may be separated in them or just bent.

I recorded a video of the tires and wheels spinning here:


Both the inner and the outer wheels wobble out of phase with each other. They have both been off the truck and are probably indexed in different ways than they were when the damage happened. It could very well be the rims but I'm hoping it is just the tires. You can see more of the vibration if you watch the shadows cast by the wheels. The passenger side seems okay and doesn't vibrate. You can see the camera start to vibrate at higher speeds if you watch closely.

I have an appointment on Monday to get the tires looked at and I will show them this video.The tires are a cheap value brand Chinese-made tire called Milestar Grantland's in 245/75/17E. They aren't a premium tire so this could also be a manufacturer's defect. I can't find 2 of these tires locally so I will have to order them online or just replace all of the tires. I am trying to sell the truck so I don't want to put too much money into it but having 6 tires all the same brand is something I look for when I buy a truck.

I appreciate all of the tips and info. I hope that replacing tires fixes this. I do not want to buy more rims!

 

So, I got anxious the other day and jacked up the rear axle on both sides and conducted a visual inspection of the tires and wheels. I ran the engine up to 65-70 mph and observed the wheels from the side mirrors with a 500W work light behind the wheels.

When I first bought this truck, I soon realized that the front driver's side rim was bent when I went to have the tires balanced due to this vibration. The tire tech informed me that my aluminum rim was damaged and needed to be replaced. I was nearly a 1,000 miles from home hauling my truck camper so I went to a Ford dealer to purchase a new Ford rim. It was a Saturday and the junkyards were all about to close and many weren't open wouldn't be until Monday. I had to get to my destination so I bit the bullet and bought a new rim.

Long story short, whatever the PO did to damage the front rim may have messed up the rear tires on the same side (DS). I don't think the rims are bent because I got out of the truck and watched the rim closely looking for static (up and down) and dynamic (side to side) runout. It appears that the inner and outer rims are fine but that the tires are bad. The steel may be separated in them or just bent.

I recorded a video of the tires and wheels spinning here:


Both the inner and the outer wheels wobble out of phase with each other. They have both been off the truck and are probably indexed in different ways than they were when the damage happened. It could very well be the rims but I'm hoping it is just the tires. You can see more of the vibration if you watch the shadows cast by the wheels. The passenger side seems okay and doesn't vibrate. You can see the camera start to vibrate at higher speeds if you watch closely.

I have an appointment on Monday to get the tires looked at and I will show them this video.The tires are a cheap value brand Chinese-made tire called Milestar Grantland's in 245/75/17E. They aren't a premium tire so this could also be a manufacturer's defect. I can't find 2 of these tires locally so I will have to order them online or just replace all of the tires. I am trying to sell the truck so I don't want to put too much money into it but having 6 tires all the same brand is something I look for when I buy a truck.

I appreciate all of the tips and info. I hope that replacing tires fixes this. I do not want to buy more rims!

 

There two things I don’t go cheap on: tires and battery. There is no assurance that if you got a new same brand that it would be any better. There are several used tire shops around here. You could install the tire the way it was before you got the vibration.

 

My tire shop balanced the tires and the vibration subsided a little but the wobble is still there. New alloy rim on order. I am going to attempt to use the spare as the inner steel rim. There's shouldn't be anything wrong with that rim because I don;t think the tire has ever been used.

My ABS light came on last night briefly but went out when I re-started the truck. Now I have to search on here to see what might be causing that. I just had the rear brakes completely rebuilt so they might have messed up something.

It's always something...

 

That is interesting. I’ve seen 3 or 4 duallys including my own that had spares that have never been used. Mine is so old and cracked that I’ll replace it someday.
You might want to check your spare before using.

If your spare is attached to the bracket like mine was be prepared for several hours of frustration to get it off. I have a thread on it on this forum. It might help you in doing your job to read it before starting your project.

when my ABS light came on I removed and reseated the connector on the rear axle several times and that seems to have fixed it. If it happens again I’ll spray it with contact cleaner.

 

My spare comes down fine. I used it briefly when I discovered that the front DS rim was bent and damaged. The tire itself isn't in great shape, but it would get the job done. I was surprised that the winch worked so well lowering the spare. The whole truck is in really good shape.

I intend to do the same thing for my ABS. The TSB I read on the issue says to check the connection first since that is likely the culprit and not the sensor.

 

I'm surprised there was a winch on a '97 F-350. As far as I know, that didn't come from the factory until at least '99. People periodically ask about retrofitting a spare tire winch onto these trucks. It would sure make it easier if they had come that way from the factory.