SIGforum
Tire Gurus - a question
November 07, 2019, 07:44 AM
tsmccullTire Gurus - a question
Had snow tires installed on my Silverado yesterday. Door sticker says 30 psi fronts, 35 psi rears. Checked this morning and both fronts and rears are 35 psi. Not sure if that was intended, or the installer just missed the fronts being 5 psi less than the rears.
Other than a slightly harsher ride, any pros (or cons) to leaving the snow tires on the front 5 psi over Chevy’s recommendation?
November 07, 2019, 08:13 AM
El Cid 92Prob not a huge issue.
Likely, the manufacturer is thinking lower pressure up front to get a larger contact patch between the tire and the road/ice. That will enable better steerage.
If you're not in cold temps yet... I'd just leave it as you'll get a drop in pressure with temps... ie Boyle's Law.
Just my random thoughts.
Andrew
Duty is the sublimest word in the English Language - Gen Robert E Lee. November 07, 2019, 08:20 AM
ChowserI always run slightly higher anyways.
My door says 33/41 and I'm always at 35/43. With my summers and my winters.
Not minority enough! November 07, 2019, 08:27 AM
220-9erThe door pressures are a blend of ride quality, handling and other factors.
I run mine above the door sticker numbers, sometimes at the maximum load rating numbers shown on the tire sidewall.
Underinflation is a much bigger concern than over. Under causes the tires to flex more each rotation which leads to higher tire temps and much worse wear. Also the vehicle will have a sloppy and less precise feel.
The only time it might be ok for a short time is in extreme snowy or icy conditions at lower speeds to get better traction.
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November 07, 2019, 08:47 AM
tsmccullThanks for the comments. I’ll just leave them as-is. I usually put four 70lb bags of sand in the back of the bed for a little more rear traction once we start getting snow on the roads and that tends to smooth out the ride a bit anyway.
November 07, 2019, 09:03 AM
roberthThe tire installers don't read door panels, they read the tire and pump them up to max PSI.
I always adjust pressure after getting new tires or getting tires rotated.
November 07, 2019, 09:16 AM
tsmccullquote:
Originally posted by roberth:
The tire installers don't read door panels, they read the tire and pump them up to max PSI.
Yours may do that, but I'm pretty sure that's not what my service guy did. Max tire pressure on the sidewall is 44 psi and THAT would have made for a noticeably harsh ride!
November 07, 2019, 09:33 AM
NavyGuyThe door info is not always the best as vehicle weights can vary and tire characteristics change with wear. The chalk line method is a good way to determine proper pressure but it is a PITA. In the summer I like to run on the high side, and in winter right at the recommended pressure. I don't do much off-roading but the few times I drove on a beach, I aired down to 20 PSI and was amazed at the increased traction.
Men fight for liberty and win it with hard knocks. Their children, brought up easy, let it slip away again, poor fools. And their grandchildren are once more slaves.
-D.H. Lawrence November 07, 2019, 09:42 AM
IronbuttI usually try to keep my tire pressure within a couple pounds of the door recommendation. Both our vehicles have the tire pressure sensor on the display, and while not completely accurate, it allows me to keep on top of it.
Plus, tire pressures will vary with big temperature changes in the weather, so you should at least check your tire pressure at change of seasons.
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November 07, 2019, 09:48 AM
egregoreIt is very likely that the installer(s) didn't read, or fully read, the door sticker, but it won't hurt anything. Frankly, most people don't even know they
have a door sticker with tire pressures on it. You are actually an exception.
November 07, 2019, 10:01 AM
Oz_Shadow35 is pretty much the default tire pressure at tire stores.
Unless you are towing, monitor the wear and feel. They’re gonna drop as it gets colder.
November 07, 2019, 12:09 PM
Krazeehorsequote:
Originally posted by roberth:
The tire installers don't read door panels, they read the tire and pump them up to max PSI.
I always adjust pressure after getting new tires or getting tires rotated.
Not in my shop.
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November 07, 2019, 01:41 PM
John SteedIt often depends on the individual employee, how much of a hurry they are in, etc. I always check mine after they have done whatever.
In your case, I would leave the fronts at 35 and pump the rears up to 40.
... stirred anti-clockwise. November 07, 2019, 02:12 PM
rburgI'm kind of surprised tire changers can read. It very easily is the lowest of low skilled jobs. I would think most are considering a break or a smoke, not your tires. I will grant you they aren't all idiots, but its safe to go with that assumption.
Interesting the poster above aired his tires "down" to 20. When I go rock crawling, that's the pressure I go up to when I get back to the road to drive to the camp or motel. In places like Moab, and on some of the more interesting trails a pressure of 6 isn't unheard of. We used to joke about needing a vacuum pump. For mild or moderate trails 12 or 14 are good compromises. You boys haven't lived until you need low pressure. You can usually tell who the experienced drivers are by the bulge in their sidewalls. Yes, everyone has an on board air system of some type. Not to go back up to 30, but to go from the aforementioned 6 up to 14. I know, y'all drive street cars to the shopping center.
Unhappy ammo seeker
November 07, 2019, 02:20 PM
Krazeehorsequote:
Originally posted by rburg:
I'm kind of surprised tire changers can read. It very easily is the lowest of low skilled jobs. I would think most are considering a break or a smoke, not your tires. I will grant you they aren't all idiots, but its safe to go with that assumption.
Interesting the poster above aired his tires "down" to 20. When I go rock crawling, that's the pressure I go up to when I get back to the road to drive to the camp or motel. In places like Moab, and on some of the more interesting trails a pressure of 6 isn't unheard of. We used to joke about needing a vacuum pump. For mild or moderate trails 12 or 14 are good compromises. You boys haven't lived until you need low pressure. You can usually tell who the experienced drivers are by the bulge in their sidewalls. Yes, everyone has an on board air system of some type. Not to go back up to 30, but to go from the aforementioned 6 up to 14. I know, y'all drive street cars to the shopping center.
I have a bachelors degree and graduated with honors FWIW. Talk about painting with a broad and condescending brush.
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Be careful what you tolerate. You are teaching people how to treat you.
November 07, 2019, 02:35 PM
trapper189quote:
Originally posted by John Steed:
It often depends on the individual employee, how much of a hurry they are in, etc. I always check mine after they have done whatever.
In your case, I would leave the fronts at 35 and pump the rears up to 40.
At 35, his rears are probably overinflated.
Door sticker on my truck calls for 65 front, 80 rear. That's great with a load, but way overinflated empty. Empty, front weighs 4,900 and the rear weighs 3,300. Loaded with the 5th wheel hooked up it's 5,100 front and 6,300 back. At 80, the tires are rated for 7,280. There's no good reason to have 80 in them when it's not loaded, so I run 60 in the rears unloaded.
November 07, 2019, 02:47 PM
YellowJacketquote:
Originally posted by rburg:
I'm kind of surprised tire changers can read. It very easily is the lowest of low skilled jobs. I would think most are considering a break or a smoke, not your tires. I will grant you they aren't all idiots, but its safe to go with that assumption.
Interesting the poster above aired his tires "down" to 20. When I go rock crawling, that's the pressure I go up to when I get back to the road to drive to the camp or motel. In places like Moab, and on some of the more interesting trails a pressure of 6 isn't unheard of. We used to joke about needing a vacuum pump. For mild or moderate trails 12 or 14 are good compromises. You boys haven't lived until you need low pressure. You can usually tell who the experienced drivers are by the bulge in their sidewalls. Yes, everyone has an on board air system of some type. Not to go back up to 30, but to go from the aforementioned 6 up to 14. I know, y'all drive street cars to the shopping center.
before this post I wasn't sure who the coolest poster on sigforum was...
I'm gonna vote for the funniest frog with the loudest croak on the highest log. November 07, 2019, 03:22 PM
ffips- Door stickers are manufacturer's recommendations and are specific to the type tire
- By type of tire, I refer to pmetric (P) or light truck (LT)
- Each type of tire has different inflation requirements based on load
- Many switch from pmetric to LT and then UNDERINFLATE based on the door sticker
- Underinflated LT tires have LESS load capacity than pmetric tires
As an earlier poster mentioned, underinflation increases tire temps and that is bad.
In my opinion, often times LT tires are sought after for the higher ply counts, but then underinflated which likely makes them weaker than a comparable pmetric tire properly inflated.
Not always about being a "guru," sometimes it's about taking the time to understand differences.
November 07, 2019, 04:34 PM
VoshterkoffIt depends on the tire, vehicle, load, and conditions. Easiest method is to contact the tire manufacturer for their recommendation. For example, the BFGoodrich website would recommend a tire pressure for an entered vehicle and selected tire. I went to a 10 ply AT on my old truck and there was a large difference.
November 07, 2019, 04:40 PM
chellim1quote:
before this post I wasn't sure who the coolest poster on sigforum was...
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