If you have a dually and rotate the spare to the front you could probably use the spacer but it is not essential. For those that do not know, the spare is on a steel rim with offset as an inner dually needs to be. This brings it in closer on the hub, but nothing rubs.

my guess, and only a guess, is that the spacer may be required for some non-oem rims and probably all wider than oem rims to be used with larger tires. Could also be a balancer that works with multiple truck brands with different hub and wheel dimensions, with (my guess) gm needing the spacer, ford not.

lay the balancer inside your rim. Lays flat? No spacer needed on the outside of the balancer. Now put spacer on hub. Lay flat against the hub? AND no rubbing when you spin the hub? If ok on both, no space needed on the inside of the balancer. Put your rims/tires on over the the balancer, tighten and torque the rim properly and away you go!

in various weather conditions I can hear mine with windows down when on a slow roll. Just swishing of the beads/materials inside the balancers.

you will love the extended mileage you get out of a tire. It will not help mpg. It will not help much if the alignment is off with too much or little tow.

I found that if most of my driving is with a heavy 5er, which it is, I wear front tires on outside even when alignment is within in spec. I ask alignment place to set at far end of range and that works. Have done this on two 450’s and a 350 dually. I got 87k miles out of oem Goodrich tires on the 2015 350. Rears were even across but down to 1 above minimum. Fronts were ok, but swapped all 6 out for the ford version of the oem goodrich tire.

 

Ordered. I'm curious to see if they eliminate the "phantom" vibration I get at highway speeds. Sometimes it shows up, other times it doesn't. Craziest thing I've ever tried to sort out.

 

I painted the Centramatics and installed them today. I can 100% recommend them. They completely eliminated ALL vibrations on my truck, all the way to 95 MPH. Absolutely worth the price !!!

 

I installed these yesterday with the spacers. I put about 100 miles on them the same day. All I can say is WOW!! I am blown away with the improvement in the ride quality at highway speeds. Why anyone with a 3/4 ton truck or bigger doesn't use these is really missing out. I also installed a Bilstein steering stabilizer at the same time. Not sure it was a combination of the two or not but the ride is on par or better than many passenger vehicles. The $225ish spent on Centramatics is worth its weight in gold.

 

Installed mine a week ago on my F-350. Had a very minor shake with my winter tires at highway speeds. Only really noticed because my water bottle would rattle. All gone now. Just feel the rough roads now! I didn't need any spacers. Used the set with the little offset on the front, and flat ones on the rear.

Was planning on taking them off for the summer since they apprently make a noise, but even with windows down, I can't hear then. At least not over the noise of the tires on wet pavement, or sound of snow. Well probably leave on all year now.

 

I immediately noticed the same with my water bottles and sun visor!!! I do know that the fronts were stamped with the letter 'A' and the rears were stamped with the letter 'B' per their mounting instructions. I only faintly heard them at low speed with the window down until they balanced. Cannot hear them at all with the windows up.

 

This forum is great for making my truck better, but bad for my bank account. Haha. I just ordered a set. I am extremely OCD about little vibrations and while my new truck doesn't have any yet, I know they will come as the tires wear. Hopefully these work as advertised.