Tire pressure for the Falken Wildpeak Trail

rockethead26

2019 CX-5 Reserve
:
N. Arizona @ 7000'
Hi all,

Just changed to 18" wheels from my OEM 19" and added the Wildpeak 235/60 R18. The Falken is smaller, has a taller sidewall and is wider than OEM.

Running right now at 37 psi which is where I ran the OEM Toyo A36 which is 1 psi over recommended.

Here's the questions.

1) Does changing tire size/width necessitate modifying the tire pressure used? Is the recommended tire pressure for a car for the OEM tires or for any tire used on that vehicle?

2) Those of you running Wildpeak Trails, what pressure are you running?

Thanks,
Jim
 
Simply use the recommended tire pressure printed on the tire.
Ooooooo, I'mma have to disagree with that. Pressure stamped on the side of the tire is a MAX allowable for MAX load rating. Gonna be way too much for application on the cx5.

The results of using max pressure will be (IMHO) ...
It'll ride like Fred Flintstone on stone wheels.
You'll have terrible uneven tire wear
Traction will be far less.
Efficiency (mpg's) should be a little better with less rolling resistance.
 
HighFlyer and Dunhillmc, Yeah, I knew not to use the max number.

I did read that one could use 10% less than the max number to start and if that's too harsh remove a little at a time until it's suitable, but never below the Mazda recommended number.

I also found this How to Figure Out Tire Pressure guide from Toyo which uses tire loading tables for old and new tires and the OEM recommended pressure on the OEM tire as a start.

Just curious what other Wildpeak Trail drivers are actually using.

Thanks!
 
If you want similar comfort level as the OE tires, you can calculate like this...

vehicle weight (in lbs) = 4 * (contact patch area in inch square) * PSI
i.e. contactPatchArea*PSI should remain the same.
Since you increase the width of tire, the contactPatchArea is now larger.
You can reduce PSI to compensate it.
Going from 225 to 235 increases patch area by 4.44%.
You can reduce PSI from recommended 35PSI down to 33.5PSI.
You should get about the same ride comfort.
You may adjust from there (+ or -).
 
If you want similar comfort level as the OE tires, you can calculate like this...

vehicle weight (in lbs) = 4 * (contact patch area in inch square) * PSI
i.e. contactPatchArea*PSI should remain the same.
Since you increase the width of tire, the contactPatchArea is now larger.
You can reduce PSI to compensate it.
Going from 225 to 235 increases patch area by 4.44%.
You can reduce PSI from recommended 35PSI down to 33.5PSI.
You should get about the same ride comfort.
You may adjust from there (+ or -).

Thanks, Ceric. I hadn't seen that method in my searches. As fairly uneducated in this topic, I was expecting psi to go up since I had a taller sidewall than the OEM, but it seems the load inflation tables seem to agree with you on the lower number, although I can't seem to find the correct table that has the 235/60/r18 tire with an XL load index to match loads with my OEM tire at 35 psi. It appears the differences in aspect ratio do not come into play in your methodology.

It's also weird that I thought of increasing tire pressure before I started researching because the Wildpeaks felt just a tad soft even though I knew the additional rubber on the Falkens would make it feel "more comfortable". I do like the more comfortable, but don't want to sacrifice too much handling.

I'm going to try reducing the psi down to the original recommended 35 from 37 where Discount Tire put them and then maybe to 34, close to what you calculated. Curious now.

Thanks again,
Jim
 
I'm running 36 psi. The tire construction, actual loads and your preference for impact harshness and steering response will dictate tire pressure.
 
Thanks, Ceric. I hadn't seen that method in my searches. As fairly uneducated in this topic, I was expecting psi to go up since I had a taller sidewall than the OEM, but it seems the load inflation tables seem to agree with you on the lower number, although I can't seem to find the correct table that has the 235/60/r18 tire with an XL load index to match loads with my OEM tire at 35 psi. It appears the differences in aspect ratio do not come into play in your methodology.

It's also weird that I thought of increasing tire pressure before I started researching because the Wildpeaks felt just a tad soft even though I knew the additional rubber on the Falkens would make it feel "more comfortable". I do like the more comfortable, but don't want to sacrifice too much handling.

I'm going to try reducing the psi down to the original recommended 35 from 37 where Discount Tire put them and then maybe to 34, close to what you calculated. Curious now.

Thanks again,
Jim
Jim,
My simple calculation was based on vehicle weight support by tire pressure (PSI).
Other factors come into the play here to your preferences.
Diff makes of tires, side wall thickness, etc.
Some people prefer lower PSI to increase contact area for traction ... etc.
Others prefer higher PSI to increase MPG.
All need to be considered.
 
Last May, we had a family gathering in the FL panhandle. There were rumours of fuel shortages. I ran my previous set of Geolander G015s at 51 psi and babied the car. It got over 33 mpg (33.6 on the computer) on the trip south. Since there was no fuel shortage, we ate a hole in the wind returning north! :cool: Pick your pressure by your needs.
 
@rockethead26 What psi did you end up with? I recently went from 19s to 17s, Falken Wildpeak AT Trails, 245 vs 225 (old) width, and much taller sidewall. I have been running 34 psi - They were installed with 37psi which was too stiff.
 
@cx5boo333 I ended up at 34 psi as well. I didn't go any lower than that as they felt good there, one step down from 35. Been loving these tires in the 3 feet of snow we got over the last 3 weeks.

Winter Storm January 2023 (12).JPG
 
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