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Auto Talk => General Automotive => Topic started by: Laconian on July 24, 2019, 07:18:36 PM

Title: Changing tire sizes?
Post by: Laconian on July 24, 2019, 07:18:36 PM
My husband will only buy Michelin (yes I know) so I'm thinking the Defender M/S look great. But our Outback uses 225-60R18 tires, which is a size which has many passenger car options but few M/S SUV/truck options. What are the considerations or tradeoffs when picking a tire that isn't OEM sized? We'd probably have to recalibrate the speedo to reflect the new circumference, but what else do I need to keep in mind?
Title: Re: Changing tire sizes?
Post by: Laconian on July 24, 2019, 07:23:14 PM
Also, is there any margin of adjustment of tire width on a given wheel? Or am I absolutely stuck with 225?

https://www.michelinman.com/tire/michelin/defender-ltx-m-s
Title: Re: Changing tire sizes?
Post by: Soup DeVille on July 24, 2019, 07:41:36 PM
Different tires do have slightly different dimensions in the same sizes.

I very rarely put the same size tires back on. Often the speedometer runs a bit off, but never so much it concerns me.

The station wagon wears the police spec size, which was a couple sizes up, and the Land Cruiser wears the biggest Nittos I could stuff under it without lifting. I think I went 20 mm plus on the Civic.

What I would do is hit up the Subie forums and find what others with your car have run.
Title: Re: Changing tire sizes?
Post by: Soup DeVille on July 24, 2019, 07:44:56 PM
What exact model Outback is this?
Title: Re: Changing tire sizes?
Post by: BimmerM3 on July 24, 2019, 07:45:04 PM
The biggest concern is that the bigger tires will rub against something, especially when turning. But most cars have enough room for some extra rubber. IMO, your best bet is probably to find a Subaru forum and see what other people have done.

It could also affect gas mileage and acceleration to some extent.

Would you consider getting new wheels? It's possible that you may find more options in a similarly sized tire, but different rim size. My Explorer either came with 17s or 18s. The 18s have very few A/T tires in its stock size, but there are tons of options in the stock 17 size.
Title: Re: Changing tire sizes?
Post by: Eye of the Tiger on July 24, 2019, 07:48:25 PM
I like tires.
You could go with a 255/55-18 and have negligible speedometer error.
Title: Re: Changing tire sizes?
Post by: MX793 on July 24, 2019, 07:55:36 PM
Tires have maximum and minimum recommended rim widths.  You'll need to consult the tire manufacturer (Tire Rack also publishes this, as do other major retailers).  It's rare for a manufacturer to fit the widest possible tire for the rim as OEM.  They usually run a size or two narrower.  My Mustang came with 255s on 9 inch front rims, but I run 265s on my race wheels.  I ran 255 tires on 8 inch wheels on my last Mustang.  I'd run wider tires on my current car, but there isn't much space between the tire and the strut.  I'd need to change the offset with spacers or different rims.  On my last one, the front tires would rub the fender liners at full steering lock.  The OE tire size for the wheels I had was 235.  So that's something else to watch out for if you want to fit wider tires on stock rims.

I upsized from 205 to 215 on my Mazda.  205 was kind of an odd ball size at the time and a lot more expensive than 215, which had more options.
Title: Re: Changing tire sizes?
Post by: BimmerM3 on July 24, 2019, 07:56:22 PM
Also, are you more concerned with the M or the S part of M/S? If it's just the S, they sell some all-seasons with the 3 peak mountain snowflake designation, which is more meaningful than M/S anyway.

https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=CrossClimate+SUV&partnum=26WR8CCPSUVXL&vehicleSearch=false&fromCompare1=yes

These are both also listed as all-seasons, but still have the M/S label.

https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Primacy+MXM4+ZP&partnum=26HR8MXM4PXLZP&vehicleSearch=false&fromCompare1=yes
https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Primacy+A%2FS&partnum=26HR8PAS&vehicleSearch=false&fromCompare1=yes
Title: Re: Changing tire sizes?
Post by: r0tor on July 24, 2019, 08:06:37 PM
Crossclimate tires come in the original size and appear to get great reviews
Title: Re: Changing tire sizes?
Post by: 2o6 on July 24, 2019, 08:31:15 PM
I don't think you can actually calibrate speedometers for most modern cars


Just keep in mind that tire circumference is also part of gearing. A change in width wouldn't have as much of an impact as a change in sidewall.


I don't think it would be worth it to go more than say 10mm + width on a passenger car.
Title: Re: Changing tire sizes?
Post by: 12,000 RPM on July 24, 2019, 08:52:48 PM
As long as the circumference is closer it's all good. I think ties lose half an inch of circumference as they wear anyway
Title: Re: Changing tire sizes?
Post by: MrH on July 24, 2019, 08:55:51 PM
https://www.wheel-size.com/calc/
Title: Re: Changing tire sizes?
Post by: giant_mtb on July 24, 2019, 09:17:39 PM
Quote from: 12,000 RPM on July 24, 2019, 08:52:48 PM
As long as the circumference is closer it's all good. I think ties lose half an inch of circumference as they wear anyway

Well. No. They lose circumference over time as the tire wears down. Not many passenger car sized tires are rockin' 1/2" tread to begin with...they'd be bald as shit.  :nutty:
Title: Re: Changing tire sizes?
Post by: CaminoRacer on July 24, 2019, 09:39:44 PM
Quote from: giant_mtb on July 24, 2019, 09:17:39 PM
Well. No. They lose circumference over time as the tire wears down. Not many passenger car sized tires are rockin' 1/2" tread to begin with...they'd be bald as shit.  :nutty:

Well it would be 1/4" tread on each side.
Title: Re: Changing tire sizes?
Post by: Eye of the Tiger on July 24, 2019, 09:41:19 PM
Quote from: CaminoRacer on July 24, 2019, 09:39:44 PM
Well it would be 1/4" tread on each side.

Tires are round, and therefore do not have sides.
Title: Re: Changing tire sizes?
Post by: CaminoRacer on July 24, 2019, 10:07:38 PM
Quote from: Eye of the Tiger on July 24, 2019, 09:41:19 PM
Tires are round, and therefore do not have sides.

U got me
Title: Re: Changing tire sizes?
Post by: Laconian on July 24, 2019, 10:25:12 PM
Quote from: MrH on July 24, 2019, 08:55:51 PM
https://www.wheel-size.com/calc/


How the hell do I know what my rim size and offset are?
Title: Re: Changing tire sizes?
Post by: Laconian on July 24, 2019, 10:26:51 PM
Quote from: r0tor on July 24, 2019, 08:06:37 PM
Crossclimate tires come in the original size and appear to get great reviews

I'm under the impression that those tires are for performance SUV folks who normally drive summer tires and tend to fly into ditches when a quarter inch of snow hits the ground.
Title: Re: Changing tire sizes?
Post by: Laconian on July 24, 2019, 10:29:36 PM
Quote from: Soup DeVille on July 24, 2019, 07:44:56 PM
What exact model Outback is this?

Limited 2.5i
Title: Re: Changing tire sizes?
Post by: Laconian on July 24, 2019, 10:29:55 PM
Quote from: 2o6 on July 24, 2019, 08:31:15 PM
I don't think you can actually calibrate speedometers for most modern cars


Just keep in mind that tire circumference is also part of gearing. A change in width wouldn't have as much of an impact as a change in sidewall.


I don't think it would be worth it to go more than say 10mm + width on a passenger car.

235/60R18 sound gud to you? That's +10 over 225.
Title: Re: Changing tire sizes?
Post by: Galaxy on July 25, 2019, 12:09:47 AM
What does BFGoodrich offer? They are part of Michelin.
Title: Re: Changing tire sizes?
Post by: Laconian on July 25, 2019, 12:18:42 AM
Quote from: Galaxy on July 25, 2019, 12:09:47 AM
What does BFGoodrich offer? They are part of Michelin.

Oh vraiment...
Title: Re: Changing tire sizes?
Post by: Laconian on July 25, 2019, 12:36:14 AM
Nope, gotta be Michelin.
Title: Re: Changing tire sizes?
Post by: MX793 on July 25, 2019, 03:59:26 AM
Quote from: Laconian on July 24, 2019, 10:29:55 PM
235/60R18 sound gud to you? That's +10 over 225.

You'll be 1.6% larger, which is minimal.  That's like 1 mph at 60.
Title: Re: Changing tire sizes?
Post by: r0tor on July 25, 2019, 05:22:51 AM
Quote from: Laconian on July 24, 2019, 10:26:51 PM
I'm under the impression that those tires are for performance SUV folks who normally drive summer tires and tend to fly into ditches when a quarter inch of snow hits the ground.

crossclimate tires are in a new "all weather" class of tires... They are like all seasons but perform much closer to dedicated winter tires in the snow/ice
Title: Re: Changing tire sizes?
Post by: SJ_GTI on July 25, 2019, 06:07:09 AM
Quote from: Laconian on July 24, 2019, 10:29:55 PM
235/60R18 sound gud to you? That's +10 over 225.

IMHO, without know all the specifics of your car/wheels, this is the simplest, best solution. It is EXTREMELY unlikely (like, less than 0.00001%) that 235/60R18 wouldn't fit a wheel that used 225/60R18 from the factory. MX793 already explained in detail so I won't go in to the whys and hows again.
Title: Re: Changing tire sizes?
Post by: MX793 on July 25, 2019, 07:57:41 AM
Struggling to wrap my head around why you would want to put truck tires with a highway tread on an Outback.  In terms of grip, a highway tread M+S truck tire won't really perform any better than an M+S all-season passenger tire.  They use similar tread patterns, so it's not like you get a more open, grabbier tread pattern.  What the truck tire gets you is a more heavily reinforced casing with extra radial belts designed to deal with heavier loads that a truck or cargo van may carry.  This also typically results in a stiffer tire that will compromise ride quality on a passenger vehicle.  You also tend to pay more for the higher load rated construction.  Unless you are hauling/towing, I'd stick with a passenger tire.
Title: Re: Changing tire sizes?
Post by: veeman on July 25, 2019, 08:06:06 AM
Your husband is from France if I remember correctly.  Now I understand the insistence on Michelin.  Vive la France!
Title: Re: Changing tire sizes?
Post by: BimmerM3 on July 25, 2019, 10:24:31 AM
Quote from: Laconian on July 24, 2019, 10:26:51 PM
I'm under the impression that those tires are for performance SUV folks who normally drive summer tires and tend to fly into ditches when a quarter inch of snow hits the ground.

They have the "3 peak mountain snowflake" certification, which is more meaningful than "M/S". "M/S" is basically just based on tread design. The mountain snowflake symbol requires actual testing.
Title: Re: Changing tire sizes?
Post by: r0tor on July 25, 2019, 10:36:06 AM
Yes, crossclimate are the tires you want
Title: Re: Changing tire sizes?
Post by: Galaxy on July 25, 2019, 11:06:59 AM
Michelin CrossClimate SUV is available in 225 -60 R18. It is rated as an all season tire that goes beyond M+S with the Snowflake symbol.
Title: Re: Changing tire sizes?
Post by: 12,000 RPM on July 25, 2019, 12:32:11 PM
Quote from: MX793 on July 25, 2019, 07:57:41 AM
Struggling to wrap my head around why you would want to put truck tires with a highway tread on an Outback.  In terms of grip, a highway tread M+S truck tire won't really perform any better than an M+S all-season passenger tire.  They use similar tread patterns, so it's not like you get a more open, grabbier tread pattern.  What the truck tire gets you is a more heavily reinforced casing with extra radial belts designed to deal with heavier loads that a truck or cargo van may carry.  This also typically results in a stiffer tire that will compromise ride quality on a passenger vehicle.  You also tend to pay more for the higher load rated construction.  Unless you are hauling/towing, I'd stick with a passenger tire.
Agreed, any all seasons in the stock size should do.
Title: Re: Changing tire sizes?
Post by: Eye of the Tiger on July 25, 2019, 12:51:48 PM
I like heavy truck tires because I can blow through potholes drift into curbs without being put out.
Title: Re: Changing tire sizes?
Post by: shp4man on July 25, 2019, 01:44:12 PM
Speaking of truck tires, I need to replace the tires on Blue. I'm thinking 700x15LT 6 ply commercial tires like the ones it came with.

(https://d2gvvn2873sxv5.cloudfront.net/RKxDHxX52Mbje1dQuaMfuwz3tfk=/x480/tiregallery/2270/_3.jpg)
Title: Re: Changing tire sizes?
Post by: Eye of the Tiger on July 25, 2019, 03:52:04 PM
Quote from: shp4man on July 25, 2019, 01:44:12 PM
Speaking of truck tires, I need to replace the tires on Blue. I'm thinking 700x15LT 6 ply commercial tires like the ones it came with.

(https://d2gvvn2873sxv5.cloudfront.net/RKxDHxX52Mbje1dQuaMfuwz3tfk=/x480/tiregallery/2270/_3.jpg)

I bet you can find some nice bias ply trailer tires with whit walls. :lol:
Title: Re: Changing tire sizes?
Post by: MrH on July 25, 2019, 03:52:34 PM
Quote from: Laconian on July 24, 2019, 10:25:12 PM
How the hell do I know what my rim size and offset are?

Offset doesn't matter if you're keeping the same wheels. You can get the wheel size from that site too.
Title: Re: Changing tire sizes?
Post by: 2o6 on July 25, 2019, 05:06:05 PM
I feel like the added width + aggressive truck tire is really going to destroy fuel economy. I mean, it doesn't really snow in Seattle, and how often do you really go up to ski in the mountains?
Title: Re: Changing tire sizes?
Post by: MX793 on July 26, 2019, 04:04:53 AM
Quote from: 2o6 on July 25, 2019, 05:06:05 PM
I feel like the added width + aggressive truck tire is really going to destroy fuel economy. I mean, it doesn't really snow in Seattle, and how often do you really go up to ski in the mountains?

There's nothing particularly aggressive about a highway tread.  They're designed to give better fuel economy than an A/T tire for people who don't got off road with their trucks.  Basically the type of tire you get on a cargo van like a full size Transit.
Title: Re: Changing tire sizes?
Post by: Laconian on July 30, 2019, 03:28:24 PM
Got the CrossClimates ordered for 185 a tire from Discount Tire Co. Not bad :mrcool:

TireRack wanted $215 per tire.
Title: Re: Changing tire sizes?
Post by: CaminoRacer on July 30, 2019, 03:37:07 PM
Discount Tire is the only tire shop that I like as much as I like Tire Rack.
Title: Re: Changing tire sizes?
Post by: Laconian on August 05, 2019, 07:50:47 PM
Maybe it's just the fact that they're new, but my initial impression of the CrossClimates is that they drive really nicely. The tires bite in hard and quickly when I make a turn. Previously, there was a certain amount of scrubbing before the car would start to change direction.
Title: Re: Changing tire sizes?
Post by: Laconian on August 07, 2019, 10:12:06 PM
Lovely, lovely tires. Oh boy. Very quiet on the freeway, with almost scarily low rolling resistance. Tire roar is gone, replaced by wind buffeting. I can't wait to rack up some a statistically significant number of miles so that I can compare average fuel economy with the previous tires.
Title: Re: Changing tire sizes?
Post by: 12,000 RPM on August 08, 2019, 04:50:03 AM
Takes about half a year to really see with the season change and gas blend switching

Hopefully you see an improvement

I am absolutely loving getting 30-40% better gas mileage in the TLX... to the point that I'm hesitant to throw the 20s from the Optima on
Title: Re: Changing tire sizes?
Post by: Laconian on August 08, 2019, 12:05:04 PM
Oh, you got a TLX? Nice :cheers:
Title: Re: Changing tire sizes?
Post by: r0tor on August 08, 2019, 02:01:09 PM
Good to hear the crossclimates worked.

I'm completely stump on what to put on the Giulia when the time comes. Really no other choice if I stay with an all season run flat.  While I drove the RX8 with no spare and no run flats, the though of a flat on my daily commute is frightening with high speeds and no real shoulder to the highway.  Tons of choices for dedicated summer and winter tires though.
Title: Re: Changing tire sizes?
Post by: Eye of the Tiger on August 08, 2019, 02:21:57 PM
Quote from: r0tor on August 08, 2019, 02:01:09 PM
Good to hear the crossclimates worked.

I'm completely stump on what to put on the Giulia when the time comes. Really no other choice if I stay with an all season run flat.  While I drove the RX8 with no spare and no run flats, the though of a flat on my daily commute is frightening with high speeds and no real shoulder to the highway.  Tons of choices for dedicated summer and winter tires though.

R compound. Resistance is futile. Mileage is irrelevant. Weather is irrelevant
Title: Re: Changing tire sizes?
Post by: 12,000 RPM on August 08, 2019, 07:53:54 PM
Quote from: r0tor on August 08, 2019, 02:01:09 PM
Good to hear the crossclimates worked.

I'm completely stump on what to put on the Giulia when the time comes. Really no other choice if I stay with an all season run flat.  While I drove the RX8 with no spare and no run flats, the though of a flat on my daily commute is frightening with high speeds and no real shoulder to the highway.  Tons of choices for dedicated summer and winter tires though.
Get some real tires and a fix a flat kit