dirkp

I'm trying to get a line on winter tires for my 8. (I don't actually have the 8 yet; I figured I'd better solve the snow tire problem first because lack of snow tires would be a dealbreaker for me. ) So, I've been doing the research and run into a couple of questions. I apologize if these are stupid questions - I'm not a tire expert.

1) I was told by a salesguy at tirerack that it's possible to re-use the factory TPMS on 17" tires. The impression I've gotten from the forum is that this isn't possible. Can the original sensors be reused? If not, why? Are they permanently attached to the wheel?

2) It seems like the concensus is that 18" tires are preferable to 17", mostly because with 18" tires, you can reuse the existing wheels and TPMS sensors. Is that correct? If so, it seems to me that the smarter move for me would be to wait until spring to get an 8 , then get 18" snow tires next October, which would save me $1K or so on wheels and sensors. Opinions?

Thanks in advance for any help!

WHealy

Well I’m a newbie myself, but my information is that you can move the sensors from wheel to wheel. I think you just have to be sure they fit the specific wheel. Check here for the TSB on it. Today when I was calling around to get my snow tire package options, each place wanted to move the sensors for me. Didn’t make any sense since I’m going for the 17” with dedicated wheels to winter tires. (So I guess I’m not in the consensus) So I also spent some time tracking down sensors and they are costly IMO. But that’s the way I plan on doing mine to minimize the labor needed to make the switch.

As for the cost ... it will be there next year too, maybe with a price increase. Jump on in, the waters fine!

Gord96BRG

Dirk,

1) The transmitters can be remounted onto compatible 17" wheels.

2) No, the consensus is by no means that 18" winter tires are the way to go.

Do a search here in the Tires/Wheels forum and the Canada regional forum for 'winter tires', you'll find plenty of good discussions about which tires, wheels, etc. to use. You can always just ignore the TPMS light you know, and run wheels without the pressure transmitters, as several owners are doing. To change over 18" tires twice per year gets expensive, especially when extra care is needed to avoid damaging the pressure transmitters. I posted a cost analysis a month or more ago ( in this thread (9th post) ) that proved that if you were going to keep your RX-8 longer than 3 years, then it was cheaper to buy a separate set of 17" wheels with 17" winter tires than to buy a set of 18" winter tires to change to/from twice per year.

Regards,
Gordon

dirkp

Gord96BRG,

First, I want to thank you for all the tire advice you've posted. Your nagging everyone to get snow tires every time the subject comes up is probably the biggest reason I've decided to get tires now rather than "wait and see"; I'm sure you've saved me some headaches.

I did read your cost analysis (and the replies) and it seems like the $250 savings over 4 years comes with 2 caveats:

1) You have to be willing/able to swap out your tires yourself twice a year. Never having had snow tires before (previous cars were FWD/AWD with all seasons and have done OK), I'm a little reluctant to swap tires for the first time on a $30K+ car. If you have the tires swapped at a tire shop, some of that cost savings will be wiped out. I'm going to call a local tire shop tomorrow and find out the cost differential.

2) As you mentioned, you have to be willing to live with the TPMS light in the winter.

With those factors, I'm not sure the decision is cut and dry. Am I missing something? Is there more to swapping tires than changing a flat? (I feel kinda stupid even having to ask the question)

Again, Gord96BRG, I appreciate your contributions to the forum. I feel like I've learned something from you and I definately take your opinion seriously.


As an aside, I was going to mention the speedo/odo inaccuracy as being a disadvantage of 17" tires, but I see that the 225/50/17's that tirerack recommends have an error of only 0.44%. I don't understand how the error can be that small; anyone feel like taking a crack at enlightening me?

Thanks!

WHealy

My understanding is that even though you change the wheel diameter, you also change sizes on the tire. These tire change shrink or expand the sidewall size. It's the tire circumfrence that is used in the spedo. So, by correctly adjusting the sidewall, you can get close to the same outer tire size.

Hope that helped.

I found this much clearer explination on Tire Rack ...

dirkp

For what it's worth, I talked to my local tire shop. If I go with the 18" tires, swapping wheels and mounting the summer tires in the spring will cost me $36. I'm inclined to go that route and not have to deal with the TPMS light.

jonalan

...per tire?

oldguy

dirkp and others,

I agree with Gord that the long term cost savings associated with buying snows mounted on wheels and changing them yourself makes sense. This is the first car I have tried this on. I changed the tires tonight (Blizzak LM-22's on Kazera KV-Z 17" rims painted grey to match my titanium body) and had no trouble. It took about 1 hour and the only special tool I used was a torque wrench. Bring on the snow!

WHealy

I'm with Gord96BRG on this one too. I think perhaps the only thing he might have missed in his analysis was the fact that the tire store that does the work for you would probably have limited experience driving rotarys. So to me, the chance of flooding damage makes the separate tires available for me to switch makes it “priceless” in my opinion. Of course I plan on putting a note on the steering wheel explaining flooding any time I take my car to a non Mazda dealer!

TreknMazda

If you have someone swap tires on the factory 18" wheels, a word of caution....
When I had to have a punctured tire replaced, the tire machine and mechanics caused considerable cosmetic damage to the wheel. So much so, that the sevice manager gave me a new one from their demo car. The machine put a scrape in the finish 1/3 around the edge of the wheel. The pry bar-type tool to lift the tire over the rim broke thru the wheel finish to bare metal in at least four different spots from 1 to 2 inches wide. IT was very difficult for them to break the bead of the 18" tire. By the way, most places will charge extra for 18" and larger beacuse of time/effort involved.

So, make sure you check your wheels with the shop before AND after a tire swap. Maybe I was just unlucky this time, but I intend to point out the condition of my wheels to any future tire changers before they start and caution them about damage.

dirkp

Nope, $9 per tire, $36 total. There are definite pros & cons to either approach in my book. It would cost $72/year + the tire cost differential to have the TPMS sensor working. I don't have an exact tire comparison handy, but the tire cost differential seems to be around $25 per. I agree that the TPMS system is nearly worthless, but having the light on constantly would be annoying. The question is whether it's $100/year worth of annoying...

The point about a tire place possibly flooding the engine is well taken. A note on the steering wheel is a good idea. When I take mine in, I'll also make an appointment so they'll work on the car soon after I arrive. That way the engine will be warm for the trip into the bay and I'll be there for the trip out.

So, is swapping wheels as simple as jacking up each tire, taking off the lug nuts, replacing the wheel, and putting the lug nuts back on? Could I rotate the wheels when I do this or does that require balancing?

jonalan

You have a little more faith in Mazda dealers than I do.

RXhusker

Swapping tires was easy (and I have never even changed a flat tire before in my life -- my 8 has inspired me to be a do-it-yourselfer). I bought a floor jack at wal-mart for $20 and a torque-wrench from tirerack with my wheels for $23. Took me about 45 minutes to change over the wheels -- my 7-yr. old son helped and we had a fun time.

I was also worried about the warning light but the advantages of getting a dedicated set of winter wheels swayed me that way (that and looking at the rims on my Volvo that are getting beat up from having the Blizzaks put on every winter -- didn't want to see my 8's 18" rims getting abused).

The TPM light only comes on after 15 minutes -- most of my trips it doesn't even come on and honestly after a week I don't even notice the warning light when it does come on -- it doensn't stay on but kind of goes on and off with a several second delay.

I have not regretted going with the Winter rims -- my 18's are detailed, covered in plastic and waiting for the warm weather. Thinking about getting them polished over the winter for a little different look next year.

dirkp

RXhusker -

Is swapping the tires just a matter of jacking the car up, removing the lug nuts, and replacing the tire? No balancing, etc.? If you buy a tire/wheel combo from tirerack, they mount the tire to the wheel? How tight do you torque the lug nuts?

Also, can somebody chime in with an opinion on rotating the summer tires when re-installing them? Besides actually mounting the tire, is there anything else that needs to be done?

Sorry for the naive questions, but you guys are starting to convince me that this is the way to go and I want to make sure I understand what I'm getting myself into.

alamike

I keep hearing people say that they would be annoyed by the TPMS light on all the time. How would that be any more annoying than your head lights are on, Main Cruise Control, Bright Lights or Cruise Active indicators. My TPMS indicator does not flash, it is just on and blends in with the rest of them. Besides it's almost Christmas, just think of it as decorating your dash for the holidays.

Gord96BRG

Exactly right - the wheels are balanced when you receive them, so just bolt them on, torque to 75 or 80 lb-ft, and you're set. (Actually, torque them, drive for a day or two, then re-torque to the same value)

Quote:

Also, can somebody chime in with an opinion on rotating the summer tires when re-installing them? Besides actually mounting the tire, is there anything else that needs to be done?

That's exactly what I do - rotate the tires F<-->R from the position they came off (do not cross L to R in the rotation pattern, just front to rear and rear to front). Nothing else is required!

The other factor in this that was hinted at by someone is cosmetics - a wheel that has tires dismounted/mounted twice per year (like the OEM wheels if you use 18" winter tires and swap them with the summer tires) is going to get pretty rough looking after a few years, with lots of chips and scratches around the outside of the rim.

Regards,
Gordon

rx8cited

hi alamike,
Do you have TPM sensors on your wheels?

rx8cited

snowbound

Dirk, I'm in a similar situation to you (don't yet have RX8, lack of winter tire/wheel/sensor solution could be dealbreaker, expecting snow), and I've been following these conversations. In another thread, there was talk about the legality of using wheels without TPMS sensors. I finally dug up the NHTSA doc. What did I find (based on my interpretation)?

- All cars as of 11/1/2003 are supposed to have some sort of TPMS system, either direct or indirect.
- To knowingly disable a TPMS is illegal, but...
- Installation of non-standard wheels and tires are allowed, and there is no requirement that the TPMS work on all replacement wheels.

So, by my reading, there's a hole in the rule that allows us to put on whatever rims we want, and without the sensors.

This means I can get my RX8 sooner. :-)

My source for the above info:
http://www.nhtsa.dot.gov/cars/rules/...e.html?name=#B

The actual paragraph about using non-standard rims:

NHTSA notes that 49 U.S.C. 30122 prohibits manufacturers, distributors, dealers, and motor vehicle repair businesses from knowingly making inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. The agency has determined that if such a business installed on a vehicle aftermarket rims that are not identical to the original rims, or tires that are not of the same size recommended for use on the vehicle by the vehicle manufacturer, the business would not violate the make inoperative provision. However, if such a business knowingly renders a vehicle's TPMS inoperative while rotating the vehicle's tires or installing tires that are of the same size recommended for use on the vehicle by the vehicle manufacturer, and does not repair the TPMS, the business has violated the make inoperative provision.


Ah, christmas on the dashboard...

I'm still gonna check out who's put on 17" rims and the TPMS's... but that's another thread.

rx8cited

Hi DSpaeth,
Other people without the sensors have reported the TPMS light flashing - which is what the Owner's Manual states would happen on page 5-26.

Interesting that yours is staying on - which is what would happen if you had sensors and the tire pressure was too hi or low (it also says the buzzer would go off, but yours is not going off).

Are you running your snow tires with 36 PSI cold as recommended in the RX-8 owner's manual (normal tire PSI + 4.3 PSI for snow tires ~ 36 psi).

regards,
rx8cited

dirkp

OK, I'm convinced. I (finally!) picked up my 8 last night; I'll get 17" tires and wheels ordered in the next day or 2.

Has anyone had any trouble with any of the recommended wheels on tirerack.com fitting properly, clearing the brakes, etc.? I'd be interested in any wheels that are confirmed to fit the 8 OK and (obviously) any that have problems. I assume tirerack sends new lugs along with the wheels if needed?

Also, the torque wrenches I see on tirerack only appear to have the wrench; do standard sockets fit the wrench or do I need a new set?

Thanks for the education guys; I'm kind of excited about getting the new wheels now!

jonalan

I bought the 17" Kazera KZ-Vs from TireRack. They fit perfect. I did receive all new lug nuts, which were an interesting shape, and a socket specifically designed for the lugs.

I have my own torque wrench, so can't help much. Just be sure to match the wrench to your sockets. Most wrenches use either 3/8" or 1/2" sockets.

ObjeX

I purchased the 225/50/QR17 Bridgestone Blizzak WS-50's from Tirerack and put them on MM Evo5 rims. Can't say enough good things about the Tirerack team. I put the car on jacks, swapped the tires, torqued 'em down, and went for a drive. :D

The snow tires w/rims are the same PHYSICAL size (or darn close to the eye) as the stock 18" Potenza's. Caliper clearance is not an issue either - there is plenty of room. I'm REALLY glad I listened / read the threads here and went with the 17" tire / rim combo. Thanks Gordon - you've posted A LOT of useful information that was really helpful to me.

The car feels good on the road - both city and interstate. I did not see the TPMS light come on, but only drove for 10 minutes per stop. I am glad to hear that it comes on intermittently after 15 minutes of continuous driving. Thanks for the heads up on this thread.

I am looking forward to the St. Louis winter now that I'm fully prepared for it!

rx8cited

Good point. I was rushing to put my M3 snow tires on before our first snowfall when I realized that the stock wheel lug nuts are 21mm - a size I did not own - doh! :o - so I had to make a quick trip to Sears to pick one up for the torque wrench. (Side note: the sales guy kept trying to mate standard sockets with my lug not lock, even though I told him 21 mm metric - sheesh! I told him it was for a Japanese car - he commented he always buys American!)

So be sure to check your lug nut size (21mm for stock lug nuts) for a matching socket for the torque wrench.

I got lucky and finished up about 30 minutes before the snow started - I hope this might save someone else from that last minute "no socket surprise"!

regards,
rx8cited