Well here is the lowdown on balancing the wheels and tires on the RX-8. These instructions are for both the OEM 16" and 18" wheels with TPMS sensors installed.

Adhesive-type Balance Weight (outer)

1. Remove all old balance weights and adhesive residue.

2. Set the wheel on the balancer, measure the amount of unbalance and location with the mode set for knock-type balance weights.

3. Multiply the amount of unbalance by 1.6 to obtain the balance weight value.

4. Select the balance weight closest to the balance weight value and attach the balance weight on the position indicated on the balancer.

Example calculation of balance weight value. Indicated amount of unbalance: 23 g (.081 oz)

23 g (.081 oz) x 1.6 = 36.8 g (1.30 oz)

Selected balance weight value: 35 g (1.06 oz)

Note: When selecting the balance weight, select one closest to the calculated value
Example: 32.4 g (1.14 oz) = 30 g (1.06 oz)

These weights are installed up against the ridge running the circumference of the wheel just inside the spokes.

5. If attaching tow balance weights, position them so that each is on either side of the position indicated on the wheel balancer.

Caution!
Do not attach weights in a row.
Do not overlap the balance weights
TOTAL weight MUST NOT EXCEED 160 g (5.65 oz)

Knock-type Balance Weight (inner)

1. Measure the amount of unbalance and location with the mode set for knock-type balance weights.

2. Attach a weight corresponding to the measured weight value on the position indicated on the machine.

Caution!
Do not attach three or more balance weights
One balance weight must not exceed 60 g (2.12 oz) and TOTAL of tow balance weights must not exceed 100 g (3.53 oz).

Rebalance wheel and confirm remaining unbalance does not exceed the following on either side. If remaining unbalance exceeds the following specifications then adjust wheel balance again.

16" wheel......outer - 13 g (0.46 oz).....inner - 8 g (0.28 oz)
18" wheel......outer - 10 g (0.35 oz).....inner - 6 g (0.21 oz)

A special thanks to Speed Racer for graciously providing these instructions from the service CD.

I bet the shops are going to charge triple to install new tires for these cars when they wear out.

My dealership just charged me 36 bucks to balance and rotate my tires.

My mother thanks you - my father thanks you - I thanks you - John

Mine charged me $39.95. To finally be rid of the vibration was worth it!

Les Schwaab did mine for free (they do that hoping you'll come back and buy tires from them) but they only balanced them to the nearest 0.5 oz. Given that the inner balance tolerance is 0.2 oz, it's no wonder my car still has a vibration. I guess I'll ask the dealer to do it next week and just pony up the cash.

This is kind of ironic but my dealership actually refused to mount and balance my new set of wheels. They said that a dedicated tire shop would do a better job! :confused:

So I called a few places and explained that the wheels had tire pressure sensors... Each place that I called said that they didn't want to touch them and they all referred me to a local Ford dealership which has one on the top of the line Hunter wheel balancers.

I spent my lunch break and end sum waiting for these guys to mount and balance the tires. I even brought in copies of the TSB and service manual so that they would have step-by-step instructions.

This is kind of funny, it took four of them an hour to read through the instructions and get started on the job. Then it took two guys to stomp the tire on to the rim. I wish I had my camera because one of the technicians was literally jumping up and down on the tire while the other tech was running the machine! I guess my Kumhos must have a wickedly stiff sidewall.

It took them over two hours to mount and balance the wheels. At least they gave me some free entertainment while I waited. :D

But Speed did they get the balance right? Afterall it was you that got the ball rolling by helping me out. I too would find that ironic if yours was not done right but mine was!

When I took my car into the dealer to have a flat fixed under my road hazard warranty, they also could not break the bead and I was forced to strike out on my own to get the repair done.

I had to pay up front and I finaly got my money back today after the repair was done in November.

Well I bought my tires from the Tire Rack and they refered me to an installer. That went great but they did not know how to do the balance correctly.

I drove around for a few months until today, untill you came up with the instructions. It is now rollin' smooooooth!

Actually I don't know if they got it right. The wheels are still sitting IN my car because it was spitting snow today. I'm not quite ready to put the winter tires up for the season but the next dry day I'll swap the wheels just to make sure that every thing is OK.

Wow. We should retitle this thread "Everything you ever wanted to know about balancing the RX-8's wheel but were afraid to ask!" Jeesh. :D

Great info Rotary Nut. Thanks.

One further thing of note: Not all tire shops have the newer "no touch" tire machine. If the wrong machine is used to remove your tires, it WILL hose up your rims pretty badly.

That sounds better! Can I do that?

Never seen a "no touch" machine before. But I have seen some of the newer ones that grip the wheel from the inside but have hard rubber "grippers" and the thingie that goes around the bead to remove the tire from the wheel. This compared to the ones that have the metal feet and such!

Originally posted by Omicron
One further thing of note: Not all tire shops have the newer "no touch" tire machine. If the wrong machine is used to remove your tires, it WILL hose up your rims pretty badly.

What kind of machine is that exactly. Like if I call a shop and say "Do you have a XXXX?"

Thanks.

We have a Hunter GSP 9700 balancer at work. It will do pretty much everything you thought had to be done on a set of tires and then some.

The 9700 can road force the tires meaning that it makes sure that the rim and tire are round when rolling.

to get a better idea of how the 9700 works check out http://www.gsp9700.com

it's a pretty cool machine that really comes in handy when the normal balancer won't take care of a vibration problem.

Ray

My tires were balanced with a GSP 9700 too. You can find a local shop that has one by going to this page (http://128.242.141.111/pub/search/findgsp9700.cfm).

Originally posted by Rotary Nut
That sounds better! Can I do that?

Never seen a "no touch" machine before. But I have seen some of the newer ones that grip the wheel from the inside but have hard rubber "grippers" and the thingie that goes around the bead to remove the tire from the wheel. This compared to the ones that have the metal feet and such!

I haven't seen or heard of a "No Touch" tire machine. However, there are attatchments for some newer tire machines that hold low-profile tires in place while they are installing the tire on the rim. This attatchment is pretty much a neccessity for anything lower than a 50 profile tire. I've messed up a really expensive micheline tire on an older machine, it titaly ripped the bead off the tire! - OUCH! The new attatchments make low-profile tires a non-issue but you better make sure the shop is propperly equiped.

Our shop uses a Hunter TC3000 tire changer for low-profile tires and while it's not the top of the line model with every bell or whistle but it does everything you need to do to get a low profile tire off and on an expensive alloy rim!

Ray

ya but do the guys here that work these machines know how to balance a tire with the air pressure sensors? Get the tire off is only half the fun.

I don't think any shop other than the dealer will know how to properly balance the wheels on an RX-8, 6 or 3 for that matter. The instructions are only found in the shop manual for now at least! My dealer was not even aware there were specific instructions until I showed him the printout that I had.

Does anybody know if the U.K. spec 8 has TPMS? What is the purpose of this? Is it because of a specific problem? I wasn't aware of this feature...

Thanks.

Originally posted by tokenbrit
Does anybody know if the U.K. spec 8 has TPMS? What is the purpose of this? Is it because of a specific problem? I wasn't aware of this feature...

Thanks.

hi tokenbrit,

Nope ...... U.S. only thanks to our government trying to protect us from ourselves :) .

A light on the dashboard informs us if any tire is not within 26 psi to 49 psi - not too useful consindering stock tire pressure is 32 psi. Read more here:Tire Pressure Monitoring System Service Tips (http://www.finishlineperformance.com/rx8/docs/02-002-03.html) . The wheel unit which is installed into each wheel costs ~ US$100 each.

The system would be much more useful if we could get an instantaneous readout of each tires pressure on the dashboard and change the tire pressure alarm range.

regards,
rx8cited

Originally posted by tokenbrit
Does anybody know if the U.K. spec 8 has TPMS? What is the purpose of this? Is it because of a specific problem? I wasn't aware of this feature...

The specific problem was the Ford Explorers with Firestone tires having tire blowouts causing rollovers and other assorted crashes! Seriously, in the investigations of those issues, the US Gov't decided to require tire pressure monitoring systems of some sort on all new vehicles as of some certain date. Canada doesn't require TPMS, so Canadian RX-8s don't have it either.

Regards,
Gordon

So...I would imagine tire shops would need to get good at this sometime in the near future?

one would hope

my lame ass dealer scratched my new wheel

now that i've gone over the "special" instructions for balancing these wheels i'll step out and say that for anyone int he tire industry they shouldn't have a problem balancing these wheels - FOR THE MOST PART.

The reason behind Mazda dedicating these instructions to the book is because companies like Mazda, Ford, Chevy, Nissan etc... all require their dealer service departments to carry a specific minimum list of tools and these tools can sometime by rather antiquated peices of machinery such as tire balancers and alignment machines. these machines probably need some kind of compensating math to figure out the propper balance.

In our shop, as i have stated in another post, we use a Hunter GSP9700 - perhaps one of the best balancers on the market. all of our balance jobs are spun to 0.00 imbalance which has a tolerance of .15oz. Unless the rim is bent, the tire has radial runout, or the tire is out of phaze with the wheel (high spot in tire does not match low spot in rim) we can garuntee that we can solve just about any vibration problem.

Ray

I had a tire replaced and it was $280

$230 for the tire and $50 for labor. They messed up the TPMS sensor. I had to take it back and they replaced the sensor under warranty.

Originally posted by flatso
I bet the shops are going to charge triple to install new tires for these cars when they wear out.

Even though a shop may own a Hunter GSP9700 does not automatically mean that they'll be able to balance the tires properly. I know this from experience because a local shop I went to did an awful job which caused the wheels to shake around 70 MPH. I even brought in the instructions provided by Mazda and they still botched the job and were unable to correct it. So I eventually ended up having it done by my dealer who has an antiquated wheel balancer and everything is fine now.

Ditto what Speed Racer said.

The shop that installed my shop had the same equipment and even after rebalancing the wheels twice there was still vibration. They sad that all my tires may have been out of round and the machine could not compensate for it.

Again thanks to Speed for showing me the light! I brought the instructions that Speed sent me and they (the dealer service dept.) followed them and it is as smooth as glass now.

P.S. On a side note. On Tire Racks survey I screwed up and rated these tires badly because of the vibration before I got the skinny on the balancing issue. I wish I could go back and right that wrong.

Originally posted by Rotary Nut
.....

P.S. On a side note. On Tire Racks survey I screwed up and rated these tires badly because of the vibration before I got the skinny on the balancing issue. I wish I could go back and right that wrong.

Have you tried contacting those wonderful folks at TireRack? I'm sure they could help you fix this.

rx8cited