I need an explanation. Help!

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I am looking for replacement tires for my Fusion. While expensive, I've decided on Michelin Primacy MXM4 tires in my stock 235 /45 R18 size. However, there are two choices for the same tire with a few small variations. While I am aware that some OE tires have unique compounds, for the specific vehicle vs the same tire for general vehicles, this doesn't seem to be the case. The difference is pressure, width, and tread depth. Below are the specs differences between the two. Can someone explain these differences (other than the obvious). How should this affect which set I should get?
Since tires are probably one of the most important items you can put on your car, I want to make sure I get the best fit.

1. 235/45R18 94V
Maximum Inflation Pressure: 51 PSI
Tread Depth:9.5/32"
Tread Width: 8.5"



2. 235/45R18 94V
Maximum Inflation Pressure: 44 PSI
Tread Depth:8.5/32"
Tread Width: 7.9"
 
Are you sure you're looking at the exact same tire? The maximum inflation pressure difference of 51PSI vs 44PSI indicates to me that one might be an XL tire with a higher load rating.

A quick check on michelinman.com, they show that there's a 235/45R18/XL 98W (16144) and a 235/45R18 94V (14644), although the tread depths don't quite match what you found. Your door placard should indicate whether you need an XL tire or not.

Edit:

I clicked the PDF on Michelin's site, they list two models in the 235/45R18 size:
Code:


70631 235/45R18 94V 55,000 Mile BSW 500/A/A 7.5" - 9" 9.3" on 8" 26.3" 790 8.5 1477@44 24.91 lbs

16144 235/45R18/XL 98W 45,000 Mile BSW 500/A/A 7.5" - 9" 9.3" on 8" 26.3" 790 8.0 1653@50 25.22 lbs


https://www.michelinman.com/upload/michelin_us/specifications/specs-primacy-mxm4.pdf

I would get the non XL tire unless your car specifically calls for it.
 
There are 4 versions of that tire made?

the 2 you list plus a honda model and a tesla model


I'm guessing one is Standard load and one is XL.

just looking at the specs I'd buy the one with deeper tread and more tread width.
 
Most differences btwn two "like" tires are usually speed rating W vs V neither of which are needed on a fusion
 
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Originally Posted By: dbias
Most differences btwn two "like" tires are usually speed rating W vs V


Both are V rated. I will be ordering a tuner shortly, so V-Rated tires are a priority. This will not only add to HP/TQ, but remove the stock limiter.
 
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Originally Posted By: jcartwright99
Can someone explain these differences (other than the obvious). How should this affect which set I should get?
That's odd. Did you try asking TireRack this question?
 
Originally Posted By: Quattro Pete
Originally Posted By: jcartwright99
Can someone explain these differences (other than the obvious). How should this affect which set I should get?
That's odd. Did you try asking TireRack this question?


Not yet. I may have to give them a call.
 
I'd take the one with 9.5/32 over the one with 8.5/32

TR lists four MXM4's in the size 235/45-18
The OE Honda one has the full 10/32 and a different tread.

Also remember that you will not be inflating them to the maximum pressure, be it 44 or 51 psi. They will most likely be inflated to the stock spec 32 or whatever is listed on the placard. At stock spec inflation pressure, there is no difference. It only comes into play if you need the extra load capacity of the XL tires where you would inflate them to 51 psi. In that case, get the Tesla tires with their XL load capacity (and W speed rating).

But the Premier is still probably a better tire than any of the OE MXM4's (they are still used as OE tires, but it is an old design that Michelin stopped making for the aftermarket). The Goodyear Weatherready and Vredestein Quatrac 5 are also good options with their 3-peak all-season tires.
 
Different inflation PSI on the same size tire are usually about the construction of the tire. Maybe in this case, even though there seems to be no difference in the load rating, there are more sidewall plies on on vs the other? Or else the specs are simply wrong. Check with Michelin, not Tire Rack, and see what comes up.

Also make sure you are viewing the same wheel width; it affects the tire width spec.
 
Having a closer look at the TireRack links you posted:

The candidate No1:
... with 9 and 5/32 tread dept has a wear rating of 500. That is a very long tread life spec, so I don't think the tread depth should be an issue in any way.
1477lbs maximum load @ 51 psi
Tire weight of 25 lbs
7.5~8" wheel width spec, measured at 8" giving a section width of 9.3" and a tread width of 8.5"
26.3" overall diameter, made in France or USA

Candidate No2:
... with 8 and 5/32 tread depth has a wear rating of 500, so equivalent expected life.
1477 lbs at maximum load 44 psi. This seems to imply a higher load rating at lower pressure. You will (or should) be inflating to the door card spec but if the two specs are not a typo by either Tire Rack or Michelin, this implies a higher load rating at the door card psi since the difference would be higher vs Tire No1
Tire weight of 25 pounds, implies no difference in the construction
7.5~9" wheel width spec, measured at 8" giving a section width of 9.3" and a tread width of 7.9".
26.3" overall diameter, made in USA only.

The second-to-last line tell the story here. These are seemingly different profile tires. The second tire can be fitted to wider wheels, and when fitted with the same size wheel (8") has a slightly narrower contact patch. The second tire is more suited to wider wheels while the first may be "stretched" on a 9" wheel.

Even though the profile doesn't show in the main spec (the tire size and profile ratio) they still don't sit the same on the same width wheel.

Now, this seems in disagreement with the other specs (same overall diameter, for example) so I would check that the numbers Tire Reck presents in the full spec are correct.
 
Originally Posted By: Johnny2Bad
Having a closer look at the TireRack links you posted:

The candidate No1:
7.5~8" wheel width spec, measured at 8" giving a section width of 9.3" and a tread width of 8.5"
They both show 7.5" - 9" rim width range. Not sure where you saw 7.5" - 8".
 
if there is no difference in the model number or item number theres a big chance its a typo or older data and you end up getting the typical item anyway even if you ordered from the other link.

Its the same situation of people getting excited when they saw an ad for pennzoil ultra with the black bottle graphic used, but it ends up just being an old pic.

I've also had this happen on some parts where they have autosubstituted the superceded part.
 
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Michelin's website shows 3 tires in size 235/45/18 with the same part number (14644). Odd.

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I'm wondering if the tire with the lower tread depth and narrower tread width is an older OE tire - one that was replaced.

Best guess, it was the Tesla version, because the depths and tread widths are very similar - and now the Tesla version has that foam insert (labeled Acoustic Tech)

So I think the OP should buy the other one. That seems to line up more with the rest of the tire line.

Oh, and in case the OP (or anyone else) is unfamiliar, it is common for vehicle manufacturers to have specs that are totally different than what the tire manufacturers would do on their own - specifically rolling resistance. So it's not a surprise that a Tesla would have less rubber in the tread as tread rubber contributes a lot of rolling resistance.

And it is also common for tire manufacturers to have an aftermarket spec tire available in the exact same size/design/speed rating - (although it is more common that the replacement tire not exist while the OE tire is in production.)
 
Originally Posted By: CapriRacer
I'm wondering if the tire with the lower tread depth and narrower tread width is an older OE tire - one that was replaced.



on tirerack's site there are 4 listed.. one is tesla oem and one is honda oem.

the 2 tires the OP listed are not oem tires (unless its an error)
 
Originally Posted By: Rand
Originally Posted By: CapriRacer
I'm wondering if the tire with the lower tread depth and narrower tread width is an older OE tire - one that was replaced.



on tirerack's site there are 4 listed.. one is tesla oem and one is honda oem.

the 2 tires the OP listed are not oem tires (unless its an error)


Except that if a tire is no longer supplied as an OEM, but used to be, is it an OEM or not? - and should Tire Rack label the tire as an OE thereby creating some confusion? Granted that there is confusion now, but I think it would be worse if the former Tesla OEM was labeled as a Tesla OEM. People are likely to order the tire without the foam when they should have ordered it with.

So in some respects, I think this is an error.
 
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