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- Plano, Texas, USA
I personally would prefer to use T155/90 D18 as the spare for our AWD CX-5 just to match supposedly the factory spec.
And haven't thought about the benefit of having 2 spares for "X" pattern DIY rotation.
2017 CX-5 Spare Tire Mod for U.S.
- Thread starter bigtex
- Start date
And haven't thought about the benefit of having 2 spares for "X" pattern DIY rotation.
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- 2016 CX-5
actually yrwei52 I think OP mod matches closer to CX-5 grand touring wheels, you can double check my math:
CX-5 grand touring 19" wheel diameter using OEM 225/55 R19
22.5cm/2.54 = 8.858 (conversion)
8.858 x .55 aspect = 4.87 (sidewall height)
overall wheel diameter = (2 x 4.87) + 19" = 28.7 " diameter
Bigtex mod 17" wheel diameter using 165/90 R17 from Tirerack
16.5cm/2.54 = 6.496 (conversion)
6.496 x .90 aspect = 5.85 (sidewall height)
overall wheel diameter = (2 x 5.85) + 17" = 28.7 " diameter
MAZDA OEM 18" spare using T155/90 D18
15.5cm/2.54 = 6.102 (conversion)
6.102 x .90 aspect = 5.49 (sidewall height)
overall wheel diameter = (2 x 5.49) + 18" = 28.98 " diameter
GJ-Molestor
Banned
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- 2011 BMW 528i, 2015 Mazda 6, 1995 Nissan Maxima Manual
If you think Mazda is cutting corners, you should remember that they are one of the many brands that offer a tiny cheap spare tire and then there are brands like BMW that dont even come with a spare or tire kit in the first place!
If incorrect tire diameters is in fact bad for your AWD system, I suspect its only for increased periods of time because the spare tire is meant to be used for a short time only. Mazda isnt the only one cheaping out like this!
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- Plano, Texas, USA
Calculation aside, here's the spec of overall diameter from all OE tires used on Mazda CX-5 and supposed T155/90D18 spare for CX-5 AWD. Dunlop Space Miser T155/90D18 113M tire is the spare found in CX-7 AWD and 1st-gen CX-9 AWD. They're all within reasonable 0.4" tolerance on overall tire diameter.
[table="width: 500, class: grid"]
[tr]
[td]Mazda CX-5 OE Tires[/td]
[td]Size[/td]
[td]Overall Tire Diameter[/td]
[/tr]
[tr]
[td]Yokohama Geolandar G91A[/td]
[td]225/65R17 100H[/td]
[td]28.5"[/td]
[/tr]
[tr]
[td]Toyo A23[/td]
[td]225/55R19 99V[/td]
[td]28.9"[/td]
[/tr]
[tr]
[td]Yokohama Y870B[/td]
[td]T145/90D16 106M[/td]
[td]N/A (26.3" estimated)[/td]
[/tr]
[tr]
[td]Dunlop Space Miser[/td]
[td]T155/90D18 113M[/td]
[td]28.5"[/td]
[/tr]
[/table]
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- 2016 CX-5
Yep, confirming what Yrwei52 said, I just checked and I'm surprised to see the small 26.3" diameter T145/90 R16 spare
in my '16 CX-5 AWD GT with 19" wheels. i chock this up as another Mazda penny pinching with disregard to customers' cost of future repairs.
I have owned AWD in the past and it's extremely important for AWD systems to have all the same diameter wheels, mismatched wheels will cause stress on the transfer case and cause premature failure......
I thank Bigtex and Yrwei52 to bringing this to our attention.
As they said, we all know the spare is only to be used for short trips but there's a chance you might be in the middle of nowhere with no auto shop near, no way I'm going to use mismatched tires on the AWD system...and another plus that Batmancx suggested, 2 spares will help with tire rotation.
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- Plano, Texas, USA
You said earlier we should get correct-sized spare. Mazda or Mazda North American Operations apparently planned to use larger T155/90D18 as the spare for CX-5 AWD originally like CX-7 and CX-9 AWD hence the spec at thier USA website. But someone had decided to cut pennies and use one-size-fit-all spare for all CX-5's, which I believe it's worse than not giving one to all AWD CX-5 owners. The AWD system will get heavy stress on clutch pack immediately once you put a much smaller spare and TPMS and TCS warning lights would be on. As bigtex said, we may need to drive over 150 miles to find a tire shop who is capable of fixing the flat properly on our CX-5 in Texas.
No, this's the first time I encountered this issue giving a much smaller diameter spare than road tires on an AWD vehicle. My 1987 VW Vanagon Syncro、1998 Honda CR-V AWD both offer a full-sized and same alloy wheel as the spare. Mazda has been providing correct-sized temporary spare in the past on CX-7 and CX-9 AWD's, the spec at their website shows the larger-sized spare for CX-5 AWD too, why is the production change?
I believe giving a correct-sized spare is important. But giving an incorrect-sized spare sometimes is worse than giving you a Fix-a-Flat can as it will give AWD owners more risk ruining an AWD system. As for BMW my 2000 BMW 528i does come with a full-sized spare with the same alloy wheel like the road wheels. The newer MYs don't come with a spare, but at least BMW moves the heavy battery into the spare tire well to balance the weight for performance reason.
Just FYI, if you decide to go the 18" spare wheel route, it is a narrower wheel and tire, so instead of simply removing the foam blocks mentioned earlier, you may need to trim them down the appropriate amount and leave some attached to where the rear floor rests on the new width spare. I personally like the 17" wheel option because you can go with a 165 width, which gives you a little more rubber on the road, and because of the wheel width, you only have to remove the foam blocks instead of cutting them down to fit. I have not tried the 18", so not sure how it will fit exactly. Also, the 17" option gives an exact diameter match of 28.7", but anything real close will be much better than the almost 2.5" difference in the stock spare if you need to use it.
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- Plano, Texas, USA
I agreed with you getting T165/90D17 temporary tire is a better alternative as a spare for our CX-5 AWD with the reasons you mentioned. And may I add a couple of more reasons for you: the tire with that size has more choices and is cheaper too. At Tire Rack, T165/90R17 116M Kumho T121 weighted 18 lbs costs $79.10 each and T165/90D17 116M Kumho T131 weighted 15 lbs costs $75.22 each; whereas T155/90D18 113M Dunlop Space Miser, and that's the only tire for that size available, weighted 16 lbs costs $109.46 each.
BTW, any reason why you chose Kumho T121 instead of Kumho T131?
I second this sentiment, better to not give me a spare tire if it's the wrong size and give me a false sense of security. I think most AWD owners wouldn't even know they are driving around with mismatched spare. Wrong wheels on AWD is a recipe for damaged transfer case, hell even not rotating tires or tightening lugs without a torque wrench is enough to cause stress on the transfer case like the gen 1 CX-9's.
I think it had a slightly wider tread width, maybe 1/2", that I thought would be beneficial.
On another note, if you have the bose subwoofer, there is a hold down bolt that goes through the center of the unit that sits on top of the spare and holds both the speaker and the spare in place. It looks like this (sorry for the huge pic):
With the wider 17" steel wheel, the bolt is not long enough and will barely grab any threads if you can get it to grab at all. I lengthened the threads with a coupling nut and some threaded rod. Size you need is M8 X 1.25. You can cut a piece of the threaded rod to the length you will need, but you will have to experiment to get the right length and probably need to file the cut ends a little. Once you have it, use some blue loctite and let it sit overnight to set up and you should be good to go. If you make it a little long, you can use some washers between the bolt head and the bose speaker to make up some room. I used a couple of hose washers and it works great.
Attachments
It is about 6 3/4". The coupling nut is about 1 1/4" and it would be better if you could find one a little shorter, but then you might need to snip some of the threads from the original bolt to make room for the new threaded rod. If any of that make sense?
On my setup, the coupling nut hits before the bolt is fully tightened, so I just used a few rubber hose washers between the bolt head and the speaker and then when I tighten everything up, it is very snug against the speaker.
On my setup, the coupling nut hits before the bolt is fully tightened, so I just used a few rubber hose washers between the bolt head and the speaker and then when I tighten everything up, it is very snug against the speaker.
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Hotpocketdeath
Member
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- Future CX-5 Diesel
Greetings. New to the forum and plan on getting a CX-5 Diesel when it comes out. I currently drive a VW TDI, so the VWGate issue is dropping a large pile of cash in my lap for me to switch over.
I have a background in machining and welding from the Army, and I would have chosen a different route. Ideally, I would cut the bolt and lengthen it to the needed size and weld it to length.
But another method I would choose is to cut off the threaded portion of the bolt. Then drill and tap the solid portion and insert the threaded rod into your new hole with additional length. To adjust bottoming length, you can just add a nut to the end, which can give you a smaller incremental length increase without needing to add washers to the top. This would require a little more technical how-to, but I think would be better in the long run.
But I do appreciate you finding this information. I go scuba diving as often as I can and I have some heavy steel tanks I carry. They've cause issues with my TDI, but using the spare tire as reinforcement for their weight would help out a lot.
Sounds like a great way to do it as well! I was just using readily available parts and trying to provide a quick, easy fix for those without welding equipment or a drill press. The CX5 diesel should be awesome.
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- 2016 CX-5
I found a Dunlop Space Miser T155/90D18 113M tire off a wrecked '14 1st gen CX-9 at a local junk yard, the spare was practically brand new never used, junkyard wanted $65, I thought it was a good deal, so I bought it..... it fits perfectly in my 16 CX-5, no need to take off or cut the foam smaller, fully plug and play mod....
Bigtex is right, when you see it in person, the size difference is startling, I can't believe Mazda approved this, the 145/90 R16 would not be good for the AWD system
I wonder what the new CX-9's AWD get for spare tire sizes....
you have to see it in person, the size difference is very noticeable
155/90 R18 fits perfectly in 2016 CX-5
cargo floor is flat without any modification, just drop in new wheel and screw on, pure plug and play
the larger wheel now takes up the empty space where I used to put my heavy duty emergency orange triangles, and with cargo space at a premium, I didn't want the triangles up in the cargo area, I wanted them to remain in the hidden spare tire compartment, so I cut a little of the foam to the left of the spare, that extra foam was useless and doing nothing and just taking up precious space. Now everything fits nice and neatly and ready for any emergency.
Thanks Bigtex for the heads up on the mismatched spare.
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- Plano, Texas, USA
I envy you finding a wrecked '14 CX-9 AWD which is rare for the MY! In Texas very few CX's are AWD and I had to special order ours. It would be impossible to find a late 1st-gen CX-9 AWD in our salvage yards! Have you checked the date code on your Dunlop Space Miser T155/90D18 113M? Since it's from a 2014, it shouldn't be more than 4 years old.
I thought T155/90D18 should be a better "fit" for our need as a spare for AWD since it had been planned by Mazda as the factory spare for CX-5 AWD at certain point indicated on thier website. Now you have one and have verified there's no need to trim the foam block down which is great!
2nd-gen CX-9's have bigger road tires, 255/60R18 107H or 255/50R20 104V, and the spare is one (small) size fit all, T155/90D17 101M.
you mean Bigtex's picture ? that's the new Bose subwoofer that comes with 2017 CX-5 GT's
that new for 2017, 2016 and previous years don't have
so it looks like 2nd-gen CX-9's also have a mismatched spare issue also, their given spare is 28" diameter and their main wheels are 30" diameter :
https://www.mazdas247.com/forum/showthread.php?123861573-2016-CX-9-AWD-spare-tire-size&p=6539972
I'm not an expert on these things so can't comment on the reliability of using these small spares and what's the maximum distance they're allowed to be used without damaging the AWD system.....
but I did find that mismatched revolutions is not good: https://www.lesschwab.com/learn/article/replace-all-4-tires-on-your-awd-vehicle
Mazda is giving us CX5 and CX9 AWD owners difference in diameter of 2 inches!!! what gives ?
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