Full size spare tire for 2018-20 Mustang GT

[chenga732]

Hi,

I am looking for a full size spare time that fits in the current spare tire space. I saw a post that a 225/50/18 will fit perfectly in the space without the extra height. If anyone a full size tire as a spare, do you mind telling me your tire and wheel size?

thanks

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[Fly2High]

Pete,
Have you measured the depth and width of the wheel well and calculated backwards?

If the depth is , say 8" deep (no idea if it is), that would equate to a 8 x 25.4 = 203 so a 205 wide tire.

Next, you need to determine if you have space for what size rim. If you are like me with the 15" Brembos up front, you will find it easier to get a 19" to fit.

Next, if the wheel well is 27" wide (again, no idea if it is), you would subtract 27 -19 and get 8" for both sides of the wheel for a tire. So only half that will apply to the series. The tire can be no taller off the rim than 4".

So a tire that is 205 wide and (4" x 25.4 ~100mm tall) would be about a 50 series tire (205 *.50 ~ 100 therefore a 50 series).

A 205/50R19 would fit the well if I did not screw up the calculations.

Of course, these are just estimated numbers. I would also leave a little wiggle room.

That is how I would go about it.

Measure your space and we can get an idea from there.

 

[Snakebyte]

A recent poster asked about getting his tire pressure to display on the dash. It reminded me of an issue I had when installing a full size spare in my Mustang. Realizing others have considered full size spares, here is what I learned after several months of frustration.

Disclaimer: I have a 2019 Mustang with a digital dash. That said, I’m not sure how non-digital dashes work with this.

Anyway, the issue centers around Mustang’s TPMS system capability.

• First, the TPMS can only register 4 (four) TPMS sensors at a time.
• Secondly, the TPMS system polls sensors and has no way of identifying a spare tire sensor by position.
• There is a TPMS polling device near the rear axle and of course it was not expecting three tire sensors back there.
• But here’s the most confusing part. The spare tire’s pressure (if a different PSI than the other 4) randomly showed up in the L/front, R/front, L/rear, or R/rear position per the digital dash graphic.

But because I do have 5 sensors total, here’s my approach:

I ensure that all my tires (including the spare) are consistently filled to the same PSI.​

Should I see on the dashboard that there’s an overly low tire, I will initially assume it is one of the four axle mounted ones and check them out individually.​

I frequent the tire pump at Costco about monthly anyway to ensure all 5 pressures are where I want them, so generally whether or not one of the TPMS reading is that of the spare, it doesn’t matter when they all are up to pressure.​

Of course, if the spare tire’s sensor is showing, there’s a risk of a tire failure of one of the 4 axle mounted tires. I’ll accept that risk, as I have a spare anyway.​

So…..If you don’t want confusion between 5 tire sensors, just ensure the full-size spare does not have a pressure sensor in it.

BTW…I tried wrapping a large aluminum foil around the spare tire’s TPMS valve/sensor, but that didn’t adequately block the signal.

Anyway, hope this helps you who have tried or plan to try a full-size spare.

 

[UncleSams_SVT]

I run a spare setup from this company on my GT500. They have many different options depending on what wheel/brake package your car came with.

https://www.automotiveauthorityllc.com/collections/mustang-gt-spare-tire-1

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