Tire Pressure unloaded

[Firebird]

Any funny wear from running the fronts underinflated?

I’ve read posts from several folks that say anything less than 80 psi on the front of DRW’s with stock sizes produces uneven wear.

I never had any weird wear at all, but was running 255/80/17 Toyo AT III's

 

[AH64ID]

I never had any weird wear at all, but was running 255/80/17 Toyo AT III's

Ah, that explains the front pressure being so low.

Ok brand was the wrong term. What ply and rating and size. You can use a chart for sure or do the math on % of max load. I just do the caulk test and make sure the tire has even contact.

I did the math for years before having good access to the charts, it does work and won’t leave you underinflated.

 

[CdnHO]

Dealer is wrong, the 3500 only displays pressure no warnings. The 1500/2500 has monitoring with low pressure alert

NO WAY; the dealer can't be wrong.

 

[H3LZSN1P3R]

NO WAY; the dealer can't be wrong.

To be honest these days its more surprising when they are right!

 

[AH64ID]

To be honest these days its more surprising when they are right!

It’s pretty pitiful, isn’t it.

My most recent example was having to show the dealership how to route the wiring for the Y43 recall… after giving them 2 tries.

 

[2/7 Gunfighter]

I have a 2022 3500 SRW mega cab and have been running 37x12.50R18LT for the past 35k miles. I run them at 46psi front / 33psi rear unloaded (based on the chalk test) and 46psi front / 56psi rear when towing my toy hauler (per Nitto's recommendation when I reached out to them). My tires have started cupping and the outer most tread ring has worn down almost all the way while the inner most tread ring still has a ton of tread depth left. I think the cupping is just from me not rotating the tires frequently enough but I'm not sure why the outer tread has worn down so much faster than the inner tread.

I'm putting on new 37x12.50R18LT tires now and wanted to ensure this doesn't happen again so I just weighed my front and rear axels on a CAT scale.

Front axel: 5,320lbs
Divided by 2 = 2,660

Rear axel: 4,040
Divided by 2 = 2,020

But with those numbers, per the load inflation table, it's saying I should be running approximately 35psi front and 25psi rear. That's way too low. Am I looking at this wrong?

 

[Units]

I have a 2022 3500 SRW mega cab and have been running 37x12.50R18LT for the past 35k miles. I run them at 46psi front / 33psi rear unloaded (based on the chalk test) and 46psi front / 56psi rear when towing my toy hauler (per Nitto's recommendation when I reached out to them). My tires have started cupping and the outer most tread ring has worn down almost all the way while the inner most tread ring still has a ton of tread depth left. I think the cupping is just from me not rotating the tires frequently enough but I'm not sure why the outer tread has worn down so much faster than the inner tread.

I'm putting on new 37x12.50R18LT tires now and wanted to ensure this doesn't happen again so I just weighed my front and rear axels on a CAT scale.

Front axel: 5,320lbs
Divided by 2 = 2,660

Rear axel: 4,040
Divided by 2 = 2,020

But with those numbers, per the load inflation table, it's saying I should be running approximately 35psi front and 25psi rear. That's way too low. Am I looking at this wrong?

Do you have the front end alignment to Thuren specs? Ram for some reason sends the truck out with excess camber, it creates uneven wear on the outside edge of the front tire.

 

[Dinky503]

I have a 2022 3500 SRW mega cab and have been running 37x12.50R18LT for the past 35k miles. I run them at 46psi front / 33psi rear unloaded (based on the chalk test) and 46psi front / 56psi rear when towing my toy hauler (per Nitto's recommendation when I reached out to them). My tires have started cupping and the outer most tread ring has worn down almost all the way while the inner most tread ring still has a ton of tread depth left. I think the cupping is just from me not rotating the tires frequently enough but I'm not sure why the outer tread has worn down so much faster than the inner tread.

I'm putting on new 37x12.50R18LT tires now and wanted to ensure this doesn't happen again so I just weighed my front and rear axels on a CAT scale.

Front axel: 5,320lbs
Divided by 2 = 2,660

Rear axel: 4,040
Divided by 2 = 2,020

But with those numbers, per the load inflation table, it's saying I should be running approximately 35psi front and 25psi rear. That's way too low. Am I looking at this wrong?

37s will have a way different load spec then say 35s. It's a lot more tire for same weight, but that does seem pretty low pressure.

I used this calculator makes it super simple. If you feel like it is still not correct just do a chalk test to confirm.

Tire Pressure Calculator

Back by popular demand Since transitioning to the new website, we have not had our tire pressure calculator live on the site. Having had numerous people reach out asking for it back, we figured it was time. A little legal mumbo jumbo: As always - feel free to use this as a reference guide for...

ororacks.com

 

[2/7 Gunfighter]

Do you have the front end alignment to Thuren specs? Ram for some reason sends the truck out with excess camber, it creates uneven wear on the outside edge of the front tire.

I'm not sure what specs it's aligned to. I have the full Carli pintop 3.25 suspension/lift on it so I'm assuming it was aligned to whatever those specs are.

 

[2/7 Gunfighter]

37s will have a way different load spec then say 35s. It's a lot more tire for same weight, but that does seem pretty low pressure.

I used this calculator makes it super simple. If you feel like it is still not correct just do a chalk test to confirm.

Tire Pressure Calculator

Back by popular demand Since transitioning to the new website, we have not had our tire pressure calculator live on the site. Having had numerous people reach out asking for it back, we figured it was time. A little legal mumbo jumbo: As always - feel free to use this as a reference guide for...

ororacks.com

That calculator seems about right. It's telling me 46 front 35 rear which is almost exactly what I've been running at based on the chalk test.

 

[AH64ID]

The chalk test is only so-so, the load and inflation tables are far more accurate.

The charts put you at 40/25 and that’s what I’d run over a calculator that is clearly not using published load and inflation table data but rather the liner math that each psi supports an equal number of pounds, which isn’t true. It’s safe numbers, but not proper pressure as indicated.

As far as your alignment specs they are likely OEM if you didn’t specify other specs. The OEM specs use too much toe and will wear tires outer edges quickly.

Don’t be scared of 40/25 on an empty truck.

Is your RAW 7,200 when towing?

 

[Deleted member 47449]

Unloaded Ram 3500 4x4 Crew Cab Cummins SRW at 56F and 50R OEM sized Toyo C/T's set during morning below freezing temperatures. It makes a difference in the PSI when it warms up 35 to 40 Fahrenheit by the afternoon.

 

[2/7 Gunfighter]

The chalk test is only so-so, the load and inflation tables are far more accurate.

The charts put you at 40/25 and that’s what I’d run over a calculator that is clearly not using published load and inflation table data but rather the liner math that each psi supports an equal number of pounds, which isn’t true. It’s safe numbers, but not proper pressure as indicated.

As far as your alignment specs they are likely OEM if you didn’t specify other specs. The OEM specs use too much toe and will wear tires outer edges quickly.

Don’t be scared of 40/25 on an empty truck.

Is your RAW 7,200 when towing?

Thanks for the reply. Wow, 25 for the rear? I don’t think I’ve seen anyone else running that low. Is that normal?

And if you don’t mind me asking, how did you get those numbers? For example, 40 for the front. Based on the weight on my front axle which is 5320 (2660 per side), it looks like the closest psi on the inflation table would be 35 psi but I’m not using any type of formula, just going by what the table says.

As far as the weight when I’m towing, I haven’t even weighed this truck with my trailer attached because I just have a 26 foot bumper pull toy hauler and don’t have a toy in it so my truck is so overpowered for that trailer, I haven’t really worried about it.

 

[AH64ID]

Thanks for the reply. Wow, 25 for the rear? I don’t think I’ve seen anyone else running that low. Is that normal?

For 37’s at that weight, yes it’s normal.

I run 30-35 empty in the rear with my stock sized tires.

And if you don’t mind me asking, how did you get those numbers? For example, 40 for the front. Based on the weight on my front axle which is 5320 (2660 per side), it looks like the closest psi on the inflation table would be 35 psi but I’m not using any type of formula, just going by what the table says.

Just lookin at the charts. You could technically go 35 front, but you might not like the feel in corners so I said 40.

As far as the weight when I’m towing, I haven’t even weighed this truck with my trailer attached because I just have a 26 foot bumper pull toy hauler and don’t have a toy in it so my truck is so overpowered for that trailer, I haven’t really worried about it.

How did Nitto give you a pressure without a weight? Or is it just based on the axle ratings?

 

[H3LZSN1P3R]

Thanks for the reply. Wow, 25 for the rear? I don’t think I’ve seen anyone else running that low. Is that normal?

And if you don’t mind me asking, how did you get those numbers? For example, 40 for the front. Based on the weight on my front axle which is 5320 (2660 per side), it looks like the closest psi on the inflation table would be 35 psi but I’m not using any type of formula, just going by what the table says.

As far as the weight when I’m towing, I haven’t even weighed this truck with my trailer attached because I just have a 26 foot bumper pull toy hauler and don’t have a toy in it so my truck is so overpowered for that trailer, I haven’t really worried about it.

I know it seems low but thats not for such a large tire. I had a jeep on 40s and the unloaded pressure was around 12PSI IIRC

 

[2/7 Gunfighter]

For 37’s at that weight, yes it’s normal.

I run 30-35 empty in the rear with my stock sized tires.



Just lookin at the charts. You could technically go 35 front, but you might not like the feel in corners so I said 40.



How did Nitto give you a pressure without a weight? Or is it just based on the axle ratings?

Regarding your question of how Nitto gave me a pressure, this is what they told me.

"Calculation is based off your driverside door placard which recommends 65 psi for the front and 80 psi for the rear for the factory tires. We see how much weight your factory tires carry at the recommended inflation pressure on that placard and then we see at what inflation pressure the replacements carry that same amount of weight."

 

[2/7 Gunfighter]

The chalk test is only so-so, the load and inflation tables are far more accurate.

The charts put you at 40/25 and that’s what I’d run over a calculator that is clearly not using published load and inflation table data but rather the liner math that each psi supports an equal number of pounds, which isn’t true. It’s safe numbers, but not proper pressure as indicated.

As far as your alignment specs they are likely OEM if you didn’t specify other specs. The OEM specs use too much toe and will wear tires outer edges quickly.

Don’t be scared of 40/25 on an empty truck.

Is your RAW 7,200 when towing?

Well, I set my tires at 40 front / 25 rear and ran some errands around town and that is BY FAR the most comfortable ride I have had in this truck. I’m going to keep them at that pressure and keep an eye on them to ensure there’s no uneven wearing but otherwise that’s my new unloaded pressure. Thanks again for the advice.