Tyre pressure

+ 1 as paris1 states: Door jam is manufactures recommendation for best all-around pressure with regards to safety, handling and wear. Ed
 
That fabulous little book called the owners manual...

Thanks. Must be new info for the 18s. It's not in the 17 manual. Not even a mention of running 17"s [except Mexico], or anything about snow tires at all.

I asked because it sounds strange to me. Why would one run them so much higher? Maybe they're thinking that 17's are in a sort of high load situation? I don't get it. Any ideas?
 
Where did you find that recommendation?

It was mentioned to me on another thread. I looked high and low in the owners manual but finally found it (for my 2018) on page 3-54 "Winter Driving" where it says under the topic of "Snow Tires" : ..."Inflate snow tires 30 kPa(0.3 kgf/cm2, 4.3 psi more than recommended on the tire pressure label (driver's door frame), but never more than the maximum cold-tire pressure shown on the tires."
 
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Why would one run them so much higher? Maybe they're thinking that 17's are in a sort of high load situation? I don't get it. Any ideas?

Here's Tire Rack's explanation:

Several vehicle manufacturer's owner's manuals recommend operating winter tires several psi (typically 3-5) higher than their recommended pressures for summer and all-season tires. While none of them actually provide the reason why, there are several scenarios that would support the practice.

First and foremost is that winter tires feature more aggressive tread designs, softer tread compounds and are often molded with deeper beginning tread depths than summer or all-season tires. While the combination of these design elements allows winter tires to remain more pliable in sub-freezing temperatures to provide more traction in snow and on ice, it often results in tires that have somewhat reduced responsiveness to driver input. The 3-5 psi higher recommended inflation pressures increase tire stability and help offset the reduction in responsiveness.

Additionally ambient air temperatures in winter typically range 40- to 50-degrees Fahrenheit colder than typical summer temperatures for the same location. The lower ambient temperatures allow tires to be more efficient at radiating heat and the tires will run cooler, building up less hot tire pressure. In this case, the 3-5 psi higher recommended inflation pressure increase helps offset the reduced hot tire pressures resulting from less heat buildup.

And finally, all tire pressures are intended to be measured cold, which means when the tires are at the same temperature as the air outside. Unfortunately, unless you park your vehicle outside or in an unheated, detached garage, and measure its tire pressures first thing on dark, cold mornings, the influence of attached garages or higher ambient air temperatures later in the day often means that drivers are actually measuring tires that are not completely cold. In this case the 3-5 psi higher recommended inflation pressure increase helps offset the reduced tire pressures associated with the conditions in which the tire pressures are typically measured.
 
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Thanks. Must be new info for the 18s. It's not in the 17 manual. Not even a mention of running 17"s [except Mexico], or anything about snow tires at all.

I asked because it sounds strange to me. Why would one run them so much higher? Maybe they're thinking that 17's are in a sort of high load situation? I don't get it. Any ideas?

Been in every manual since at least 2014....

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Thanks kdaug and madar for the references. I stand corrected.
I guess the one tire rack explanation kinda sorta makes sense if one doesn't know how to check pressures.
 
My label says 35psi for 19's
Yes, for gen-2 CX-5 with 225/55R19 Mazda reduced its tire pressure recommendation to 35 psi for US market. If OP is in other country Mazda would give several different tire pressure recommendations based on different load and driving speed.

I always put 2~4 psi more than US-only one-psi-fit-all manufacture recommended tire pressure.
 
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Yes, for gen-2 CX-5 with 225/55R19 Mazda reduced its tire pressure recommendation to 35 psi for US market. If OP is in other country Mazda would give several different tire pressure recommendations based on different load and driving speed.

I always put 2~4 psi more than US-only one-psi-fit-all manufacture recommended tire pressure.

Are you putting in this extra 2~4 psi in winter tires...if so you are doing exactly as Mazda recommends. If this extra PSI is in your summer/all season tires why would you increase this pressure above what Mazda recommends on the inside door label?
 
I bumped my Toyo 19's from 35 to 38 psi and the steering is a little better as well as a softer ride over road seams. Overall very pleased.
 
I bumped my Toyo 19's from 35 to 38 psi and the steering is a little better as well as a softer ride over road seams. Overall very pleased.

I would have thought that increasing the PSI above that recommended by Mazda would make the tire stiffer and therefore producing a harder ride over road seams.
 
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I would have thought that increasing the PSI above that recommended by Mazda would make the tire stiffer and therefore producing a harder ride over road seams.

Increasing the PSI will make the ride feel stiffer. It's just a fact. Some, as it seems, like that feel.
 
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