2017 CX-5 Spare Tire Mod for U.S.

Good on the center bore and bolt pattern. What about offset? Did you try putting the spare on your CX-5 to verify fit?

I did not do a test fit. KIA offset is 46, Mazda offset is 50. Close enough for me and it's just the spare.
 
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I just pulled them off. A little glue residue was all that was left.

I would measure how much thicker your new spare is vs the old one. Since you used a 4" width wheel it may be a little narrower than mine but it may be fine. And I just noticed yours is a '14, so the bumpers may be a different size. Mine were about 2" thick I think.

Nice find on the Kia spare!

You just pulled them off? Remind me never to arm wrestle you! I had a heck of a time and I used a rigid putty knife! (bowdown)

It is just a touch too big for the wheel well even with the blocks removed. I also took out the pad underneath the tire and that got it pretty flush. I have the OEM rigid rubber mat in the back so that stiffened things up too, so all is good. Also, I was able to reuse the regular hold-down spinner, but I had to remove the metal gasket/washer thing that was underneath it. Tire felt snug. Need to drive a bit and see if anything rattles.
 
You just pulled them off? Remind me never to arm wrestle you! I had a heck of a time and I used a rigid putty knife! (bowdown)

It is just a touch too big for the wheel well even with the blocks removed. I also took out the pad underneath the tire and that got it pretty flush. I have the OEM rigid rubber mat in the back so that stiffened things up too, so all is good. Also, I was able to reuse the regular hold-down spinner, but I had to remove the metal gasket/washer thing that was underneath it. Tire felt snug. Need to drive a bit and see if anything rattles.

I guess the '17 wheel well is just a little bit deeper than the previous years for some reason. Maybe because of the Bose sub. Glad it all worked out and I know you probably did this, but make sure you have 60 PSI in that spare for when you need it!
 
I know you probably did this, but make sure you have 60 PSI in that spare for when you need it!
Good advice! It's opposite to road tires that the spare in CX-5 seems to be under-inflated frequently from factory. Mine was only 40 psi when I checked. Small air volume on temporary spare makes the tire pressure fluctuate a lot more due to seasonal changes. But it's a hassle taking the spare out to measure the air pressure. (boom08)
 
Nice write up OP. And pictures do show stark contrast. So you had to buy wheel from Med Mazda then buy tire from tire rack. I'm assuming you had to go to local shop to get it mounted and balanced ? Did you check if tire rack sells the same size wheel so they do everything in one shot so all one has to do is just replace stock and take out the foam spacers.

Also, agree better for the spare tire to be as close to the same diameter of other wheels especially for AWD and the transfer case. Better to use your idea of modded spare especially if you're in a rural area and nowhere near a tire shop. Using original small spare would not be good for AWD system.

Just fyi, never use the spare in any of the front two wheels even with this mod spare. If you have a front flat. Proper way is to take good wheel from adjacent rear, and move to front, use spare on surrogate rear. It's a hassle like changing a flat twice but necessary for good control of front in case of emergency stops and emergency turns.

With the diameter of the 'improved' spare tire being the same as the original tire (or very close to the original tire diameter), why wouldn't you be able to use the spare on the front?
 
I hate the idea of having the incorrect diameter tire for the spare, especially when most other countries get a spare that has the correct diameter. Australia, Mexico, and most of Europe get a 185/80R17, which is still a temporary use spare, but it has an outside diameter of 28.7", which is exactly the same as the factory 225/55R19 (the 17" tires are 28.5" which is basically the same thing). In the US, we are given a tiny 145/90/16, which has an outside diameter of 26.3". A difference of 2.4". This small spare will go 68 more revolutions per mile than the stock tires when in use, which would be more important to AWD owners, but I think could also create problems for FWD if you have to put it on the front. Plus it is so damn skinny I don't trust how long this thing could actually hold up if you needed it to. I'm sure Mazda did this to save the 11.6 LB weight difference, but how much fuel can that save really?

You can't get the 185/70R17 tire available in other countries anywhere in the US. I tried a lot of places and you can't. But I did find a 165/90R17 from Tire Rack that also has the perfect diameter of 28.7". This picture shows the factory tire, the new spare from Tire Rack, and the original spare for comparison. Which spare would you rather use if you were in the middle of nowhere?

Now the best part is that even though it is a much wider and larger diameter tire tire, it will fit in the spare storage area and still keep your floor perfectly flat. Here are pics of the original spare first, and the new, correct size spare second. Bose subwoofer will still fit perfectly.

The only real "mod" you have to do, besides ordering a new spare wheel and tire, is to remove the foam blocks that Mazda installs in the floor board to make up the space created by giving us this incorrect sized tire. So you simply pull off these 2" thick foam pieces in the picture and the rear floor will rest perfectly on the new wider spare.

One final pic of new spare vs original spare.

Parts needed:
17" X 5.5" steel wheel from Med Center Mazda
Weight of original spare and tire 24.4 LB. Weight of new spare and wheel 36.0 LB.

You can also use a true factory aluminum wheel and full size tire and it will fit diameter-wise, but the thickness will raise the floor level about 2.5".

Without the limited slip differentials, available in other countries, this is irrelevant.
 
Got the rim and tire recommended by the OP. Perfect fit in the spare tire well. Removed the foam pads and rear panel cover sits flush. I feel better now that if and when I get a flat I can use it on the front or rear and not damage my drivetrain. Thanx!
 
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I hate the idea of having the incorrect diameter tire for the spare, especially when most other countries get a spare that has the correct diameter. Australia, Mexico, and most of Europe get a 185/80R17, which is still a temporary use spare, but it has an outside diameter of 28.7", which is exactly the same as the factory 225/55R19 (the 17" tires are 28.5" which is basically the same thing). In the US, we are given a tiny 145/90/16, which has an outside diameter of 26.3". A difference of 2.4". This small spare will go 68 more revolutions per mile than the stock tires when in use, which would be more important to AWD owners, but I think could also create problems for FWD if you have to put it on the front. Plus it is so damn skinny I don't trust how long this thing could actually hold up if you needed it to. I'm sure Mazda did this to save the 11.6 LB weight difference, but how much fuel can that save really?
Without the limited slip differentials, available in other countries, this is irrelevant.
For FWD CX-5 even if we dont get limited slip differential but it still can trigger unnecessary action from traction control system due to different tire revolutions. For AWD CX-5 in addition to TCS, theres a clutch pack in rear differential. Any different revolutions from any tires will trigger it to action, and it may get damaged if the load is too heavy!
 
For FWD CX-5 even if we don’t get limited slip differential but it still can trigger unnecessary action from traction control system due to different tire revolutions. For AWD CX-5 in addition to TCS, there’s a clutch pack in rear differential. Any different revolutions from any tires will trigger it to action, and it may get damaged if the load is too heavy!

I love this mod, I think any AWD owners should do this.

This is less of an issue for FWD CX-5s though. You should always mount the spare tire on the rear anyway, so it is not a big deal if the spare tire has a smaller diameter. That said, if you want to go faster than 55 mph or have to drive very long distances, then a properly sized spare would be better. If you only have the smaller spare tire though on your FWD CX-5, even on a road trip, you should still be able to drive at 55 mph max for longer distances until you can get the tire replaced/fixed.
 
I hate the idea of having the incorrect diameter tire for the spare, especially when most other countries get a spare that has the correct diameter. Australia, Mexico, and most of Europe get a 185/80R17, which is still a temporary use spare, but it has an outside diameter of 28.7", which is exactly the same as the factory 225/55R19 (the 17" tires are 28.5" which is basically the same thing). In the US, we are given a tiny 145/90/16, which has an outside diameter of 26.3". A difference of 2.4". This small spare will go 68 more revolutions per mile than the stock tires when in use, which would be more important to AWD owners, but I think could also create problems for FWD if you have to put it on the front. Plus it is so damn skinny I don't trust how long this thing could actually hold up if you needed it to. I'm sure Mazda did this to save the 11.6 LB weight difference, but how much fuel can that save really?

You can't get the 185/70R17 tire available in other countries anywhere in the US. I tried a lot of places and you can't. But I did find a 165/90R17 from Tire Rack that also has the perfect diameter of 28.7". This picture shows the factory tire, the new spare from Tire Rack, and the original spare for comparison. Which spare would you rather use if you were in the middle of nowhere?

-snip-

Parts needed:
17" X 5.5" steel wheel from Med Center Mazda https://www.shopmazdaparts.com/oem-...re-9965025570/?c=aT01NDY1MTcwNSZyPWxheWVyXzE= $119.31
T165/90R17 Kumho T121 from Tire Rack https://www.tirerack.com/tires/tire...m=69R7KH&vehicleSearch=false&fromCompare1=yes $79.10
Weight of original spare and tire 24.4 LB. Weight of new spare and wheel 36.0 LB.

You can also use a true factory aluminum wheel and full size tire and it will fit diameter-wise, but the thickness will raise the floor level about 2.5".

Thanks Bigtex! As an AWD owner who just had a tire scare, but luckily have not had to use the spare yet, I certainly plan to do this mod in the near future.
 
I love this mod, I think any AWD owners should do this.

This is less of an issue for FWD CX-5s though. You should always mount the spare tire on the rear anyway, so it is not a big deal if the spare tire has a smaller diameter. That said, if you want to go faster than 55 mph or have to drive very long distances, then a properly sized spare would be better. If you only have the smaller spare tire though on your FWD CX-5, even on a road trip, you should still be able to drive at 55 mph max for longer distances until you can get the tire replaced/fixed.
Even if you have FWD and put the temporary spare on the rear, the TCS system may apply brake to the smaller spare tire which is revolving a little faster than the other three. We should always remember to turn the TCS off with smaller spare tire mounted but I believe the switch cant turn the TCS off completely.
 
Even if you have FWD and put the temporary spare on the rear, the TCS system may apply brake to the smaller spare tire which is revolving a little faster than the other three. We should always remember to turn the TCS off with smaller spare tire mounted but I believe the switch can’t turn the TCS off completely.

You're not supposed to be driving fast enough to activate the TCS when you're driving with the smaller spare tire. If the TCS system, actually I think it would be the Stability control, if that system is trying to apply brake to the rear tires, that means your CX-5 is starting to spin, which means you are probably driving too fast while using the smaller diameter spare tire. What I'm saying is, you should be driving with caution when you're driving with the smaller diameter spare tire. If you want to drive full speed, even the same diameter spare tire could be a safety issue, because it is not as wide as the rest of the tires on the car.
 
For FWD CX-5 even if we dont get limited slip differential but it still can trigger unnecessary action from traction control system due to different tire revolutions. For AWD CX-5 in addition to TCS, theres a clutch pack in rear differential. Any different revolutions from any tires will trigger it to action, and it may get damaged if the load is too heavy!

The clutch/AWD system will think it is going in circles. IF for some reason the spare diameter results in excess slippage and the clutch gets too hot, it will disengage and light a light on the dash. OTOH, unless there is a lot of slip in the front, there is no reason for the rear clutch to tighten and send a lot of torque to the rear wheels, to cause heat. How rare would it be to have a flat and then have to drive scores of miles through mud or snow creating that small chance of overheating the rear differential and causing it to protect itself?

Very few precautions in the OM.

Irrelevant. But, harmless to change.

View attachment 2016-cx5-owners-manual-flat.pdf
 
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I did not do a test fit. KIA offset is 46, Mazda offset is 50. Close enough for me and it's just the spare.

I ended up purchasing a Kia spare as well. Actually, it is off a 2012 Hyundai Santa Fe but it has the Kumho 165/90r17 tire. I did a test mount and verified that the Kia/Hyundai spare fits perfectly on the 2017 CX-5. To store the spare in the well required a couple of mods. First, the hold down bolt was too short (no Bose) so I used the yellow hold down bolt for the alloy rim combined with metal plate from the original hold down as a spacer. See pic. Also, instead of removing the foam blocks, I trimmed 3/4" off the blocks and the cargo floor lies flat and feels supported. See pic with trimmed blocks. Thanks to minnesotaart for coming up with the idea of using a Kia spare and thanks to bigtex for bringing up the issue with the small Mazda spare.
 

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(drinks)

Oh, and I suppose I should mention that I sold my original CX-5 spare to a guy with a 2013 Kia Optima which came with NO spare, just a "spare tire in a can". I got $30, so the swap cost me $18 and change and the new tire is 3 years younger than the old one.
 
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Sorry to drag up an old(ish) thread, but with these pictures, its perfect for my needs. I am looking for the part numbers please for the 2 x rigid foam packing pieces either side of the spare wheel. I am also looking for the part numbers for the bolt that secures thru the Bose subwoofer and the second bolt that is fitted in the righthand packing piece. I am guessing that this second bolt is longer to secure a standard wheel after a puncture? I have searched the usual parts websites online for a 2017 CX-5 but cannot find a schematic for the spare wheel trunk area anywhere. I have noticed that some posters on here have access to the Mazda US parts schematics and am hoping that somebody can post a schematic of this area with part numbers please. Finally, what size are the foam blocks glued to the underside of the floorboard, 2" x 2" x 2"?
Thank you in advance.
 
Answering my own query here, I got the relevant part numbers; KB7W-68-8MX, KB8A-68-8MX for the packing and 9YA3-00-803, 9YA3-00-805 for the bolts. But there is also an “insulator TK48-56-135A” and I don’t know what it is, suspect it either goes between the sub and the rim or under the wheel itself? Any chance someone with a Grand Touring could take a photo with their sub lifted out of the rim and post it please?
 
I found a full size spare on ebay from a cx7 for about $75. It fits perfectly without any mods.
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