Real spare tire for the 2020 GT500

[protraxduner]

I only found two Spare Tires: Continental-SCONTACT-T145/60R20 @ $215 And Pirelli-Spare Type-T155/65R20 @ $135!!!

You are not looking for a designated 'spare' tire but a regular tire with OD similar to stock that will fit 8" wide rim. And likely won't fit in spare tire well. Spare tire well is approximately 7" deep by 26.5" OD

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[50 Deep]

I only found two Spare Tires: Continental-SCONTACT-T145/60R20 @ $215 And Pirelli-Spare Type-T155/65R20 @ $135!!!

With this being a full size wheel you would want a full size tire. Enabling you to still drive the car as normal with no mileage limitation.

Something like the Pilot 4S 235/40/20. It has. 27.4” overall diameter compared to the 27.5” diameter of the OEM 315. You can do this with any brand tire or type as long as you keep the overall diameter close.

 

[kilobravo]

T: Would a lower profile tire than a 40 be able to keep the OD under 26.5"? (Thanks, Tony.) NBD, I'll probably just keep the spare in the bed of the truck along with the electric jack and lug wrench but, it sure would be nice to be able to carry the spare. I could live with it being an inch or so higher raising the floor a bit and I think I could fabricate a floor brace of some sort.

Just wondering and BTW, invoice remitted.

KB

 

[protraxduner]

T: Would a lower profile tire than a 40 be able to keep the OD under 26.5"? (Thanks, Tony.) NBD, I'll probably just keep the spare in the bed of the truck along with the electric jack and lug wrench but, it sure would be nice to be able to carry the spare. I could live with it being an inch or so higher raising the floor a bit and I think I could fabricate a floor brace of some sort.

Just wondering and BTW, invoice remitted.

KB

My measurements was rough and at bottom where it tapers and rounded. It appears people have put 27.3 diameter spares in the well. So depending on tire actual roundness and real measurements may actually fall in. Probably best to try and put real wheel/tire in there and see if it falls in and bottoms out or wedges. In any case its going to stick up past floor cover

 

[Surfergeek]

Looking at the diameters of the 35 series tire it’s around 26.5”

that’s 7/10 smaller than the front 305 and 9/10 than the rear 315.

I am thinking that’s too much of a size difference, especially if it were run on the rear?

 

[kilobravo]

Jared: That may be why T suggested a 40.

KB

 

[50 Deep]

T: Would a lower profile tire than a 40 be able to keep the OD under 26.5"? (Thanks, Tony.) NBD, I'll probably just keep the spare in the bed of the truck along with the electric jack and lug wrench but, it sure would be nice to be able to carry the spare. I could live with it being an inch or so higher raising the floor a bit and I think I could fabricate a floor brace of some sort.

Just wondering and BTW, invoice remitted.

KB

Good question. I would say stay close to the original diameter as possible just to prevent Torsen Issues. However, this is all a game of chance. Circumference issues only really matter if you blow a rear tire. Which is a 1/4 probability. If you do not plan on taking the car cross country then a blow out around probably wont have you driving on the spare long enough to make a difference if the size is slightly off. But it could be a major convenience if it means it fits in the spare well.

I would let your driving habits dictate how you proceed with the tire.

Looking at the diameters of the 35 series tire it’s around 26.5”

that’s 7/10 smaller than the front 305 and 9/10 than the rear 315.

I am thinking that’s too much of a size difference, especially if it were run on the rear?

I do not know how sensitive the system is. But like I mentioned above I would let driving habits dictate the tire. If you are taking long drives that might require 100 + miles to get home then keep that tire size closer. Bombing around town, I do not think you have as much to worry about.

 

[kilobravo]

Not being a wheel or tire engineer, I didn't know how much difference in diameter the car could handle, T when I suggested a lower profile. But your comment about Torsen effects makes perfect sense.

It would be "NICE" if I could keep the spare in the well but the truth is, I can just as easily keep it in the truck and just phone the better half to come rescue me with the wheel and tire.

BTW, I think the probability of a rear flat is 1/2. <grin>

KB

 

[16Kobra]

just keep the spare in the bed of the truck along with the electric jack and lug wrench

KB

Really, Lug Wrench???

I have one of these in my trailer, great option for changing tires.

https://www.homedepot.com/p/RYOBI-O...nIA60x0WwlrPiiQJSaMaAtJGEALw_wcB&gclsrc=aw.ds

 

[kilobravo]

I like cordless for many things, Jim but remember, I have the CR wheels so the old man wants to be careful with them.

These are the two things I've ordered for my rescue kit:

 

[Melmark93]

You are not looking for a designated 'spare' tire but a regular tire with OD similar to stock that will fit 8" wide rim. And likely won't fit in spare tire well. Spare tire well is approximately 7" deep by 26.5" OD

Googling around for small/narrow 20" tires, I found Nitto NeoGen 225/30-20. It has an OD of 25.3,
a width of 8.82 and fits a 8" rim. An 8"x20" rim w/ a spacer to move it out past the caliper might
be shade tree engineered as a "get you home solution". A rim with small enough offset might work by itself.

 

[kilobravo]

Yes, it might, Mel, but Terrance (@50 Deep) has a few of us hooked up with a wheel that will work front and rear, (as long as we're careful I presume,) but more than good enough to get you home. For me, that's the prime directive. Just having the wheel and tire ready to go in an emergency gives me enormous piece of mind even if it won't fit in the spare well. Quickly available is all that is required.

KB

 

[gfcobra04]

The 315-30/20 has a theoretical dia. of 27.441”
A 20x8 wheel with a tire 235-40/20 has a theoretical dia of 27.402”
These tires fit that bill:
https://m.tirerack.com/tires/TireSe...rearWidth=255/&rearRatio=40&rearDiameter=17#0

 

[Surfergeek]

I think it’s clear the 235/40 is the best fit diameter wise.

but what I don’t know is how much diameter difference the torsion can take and for how long?

the convenience of having the tire drop into the well would be nice. It doesn’t seem that the 27.4” is going to drop in.

I was hoping someone here more knowledgeable than I could chime in on the diameter differences and the torsion.

Going to have to take some measurements once the wheels arrive.

Example of an use case for me: each summer NorCal Team Shelby does a cruise from Sacramento to Lake Tahoe, it’s a multiple hundreds of miles drive / round trip for me and usually involves overnight stay extension. Could I just throw the spare in the trunk and be way safer than not having it? Yes! But if Incould drop it in the well and keep more room for luggage would that be better? Yes!!! Either way it’s a huge improvement over the current which is might get stuck hundreds of miles from home, require a ride on unknown tow truck, unknown tire repair shop, and depending on local stock if the tire can’t be repaired.

 

[Surfergeek]

I like cordless for many things, Jim but remember, I have the CR wheels so the old man wants to be careful with them.

These are the two things I've ordered for my rescue kit:

recently stocked my glovebox with this exact thing on my Shelby, my C5, and my F150, all with signature wheels Indont want messed up!

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