Help a first-time aftermarket wheel customer with questions before purchase!
 

Hey everyone! I've been reading and re-reading the tire 101 thread, as well as checking fitments and designs of wheels in the Wheels Gallery here on the FT86Club forums (big thanks to DarrenDriven for maintaining the gallery).


Since I lack both the tools and technical ability, I will be having a local performance shop perform the installation of both the chosen wheels / tires, as well as an Eibach Pro spring kit, netting a 1” drop on each corner.

After looking over many designs / widths / heights, I've finally decided on a set of 17x8 OZ Ultraleggeras in Black, as these have the look I desire, but are lighter than the stock wheels, and the 17” diameter should help minimize the amount of rotational inertia I'll be adding to each corner, but I have numerous questions on installation concerning TPMS, speedometer, rubbing, etc.

According to the fitment guide on Tirerack.com, the "recommended" tire size for this wheel is 235/40-17. Unfortunately, there aren't a lot of options for this tire size, especially in the high performance summer tire area (there are mostly “Extreme” summer tires). Would jumping to a 235/45 tire cause any issues with rubbing with a 1” drop? Is there another tire size any of you could recommend to me that would fit the OZ wheels?


I understand that increasing the aspect ratio of the tire will raise the height of the tire, adding rotational inertia, effectively slowing the car down. Also, the added height can also cause the speedometer to become inaccurate. Can any performance shop adjust the calibration of the factory speedometer to match the new tire / wheel combo?


And lastly, I see that TireRack offers the option of purchasing a new set of TPMS sensors. Is this going to be required for use on the Ozs? I noticed that if I elect to choose this option, TireRack will install the new sensors on the wheels before they are shipped to me. Does this mean that the performance company will have to do anything special when installing the wheels? I know that they'll be able to help me get the flush look I desire, but I wasn't sure about the TPMS system.


I've never purchased a set of aftermarket wheels / tires for any car, so I appreciate any and all advice you guys can offer to me! Thanks!

Adding height to the tire is also going to change gearing and will change the reading on your speedometer/odometer, definitely try to stay as close to factory height as possible. Maybe change the width to get better tire selection instead of height?

I am running a 17x8 +35 wheel, but i have 225/45/17 tires. I am nowhere close to rubbing, and i have an even more aggressive drop than you will have.

Hope this helps. It looks like youve done your research. The speedo difference cant feasibly be adjusted. as far as TPMS i would recommend just transferring your stock ones from your old wheels if you really care (i left mine out.)

Your best tire options are:

215/45/17 (I'm running this on 17x8 currently)
225/45/17 (good prices and selection)
235/40/17

If I were you, I'd stick to 225. 215 looks a little stretched on 17x8. The difference in diameter with 225 is minimal (~1 mph off at 60).

You'll need to buy sensors if you want TPMS to work. Your dealership will charge to program the TPMS codes. Or you can transfer the sensors from your OEM wheels. You can also run without TPMS.

Skip new TMPS sensors. Reuse your old ones or don't use them at all.

235/40 is indeed an awkward size with little tire selection; go 225/45. You shouldn't run on this setup with an offset anywhere in the 40s. It might be close (cm), but not close enough to rub even under full compression and lock.

Just about any performance tire will be heavier than the stock tire; you are dropping weight from the wheels as well, so remember that. Even if the wheel/tire assembly weighs the same as stock or even 1-2lb more per corner you've increased grip and contact patch by such a large amount that the weight's not a big deal. The more money you have to play with, the lighter wheel you can get. My wheel/tire combo dropped ~4lbs per corner and the wheels weren't too expensive IMO. Cheaper than Volks by many hundreds.

With the lack of a TPMS system, wouldn't the ECU be programmed to throw a perpetual tire pressure error on the dash?

Yes, but you won't fail inspection anywhere (I don't think it's a requirement to pass inspection/emissions) and it's not a CEL either. It's just an idiot light that's annoying; piece of black electrical tape fixes this.

I read somewhere that you can also have the tire shop break the bead on your old wheels and pull your existing TPMS sensors to stick in your new wheels. This means you won't have to worry about getting them set up and should just work. (Someone correct me if I'm wrong, that's what I'm planning on doing with mine)
Also make sure that you don't need tuner lug nuts to fit the wheels and hub-centric spacers.

Yerp. Took out stock TPMS sensors from stock wheels when mounting winter tires. Remounted TPMS sensors to summer wheels when I got the tires put on.

I don't see any mention of this in TireRack's literature on the wheel itself. There is some information about included hardware, though, but don't think this is what you mean:

"The following wheel-specific hardware will be included with your order at no additional charge.
(4) Required centering ring
(20) Required lugbolt for vehicle (black)"

Btw, I appreciate everyone's help so far! I'm new to tires / wheels / suspension modifications, and I find it easier to learn when I just ask questions

The stock lugs and wheels have that cone shaped seat. Aftermarket wheels have that same cone shaped seat so you should be fine.

The TPMS sensor isn't necessary at all. It's a good indicator on when you need to pump up your tires, but you should be consistently checking your tire pressure to ensure they are properly inflated. You'll just get a light indicator on the dash that doesn't go away until you mount a wheel with the TPMS on. Losing the TPMS doesn't affect any characteristics of the car in anyway. :)

Even without the TPMS sensors the light is somewhat wonky. It won't illuminate right away if it doesn't detect sensors - it'll wait a bit, something like 30 miles, before it'll start flashing at you and then turn on completely.

If you don't drive more than 30 miles a day normally you'll hardly ever see the light.

235/40 tyres will throw your speedo off by more than 3%.

My question is what if I went alot off the stock wheel setup, how do I fix that? And what TPMS SENSORS?