Help picking a new studded winter tire and inflation pressure

[phooka]

This is a South Central Alaska (Homer) FJ60, daily driver. Snow covered roads in winter with 6-18" accumulations per storm. Down at sea level freezing rain, and ice covered surfaces is common. Temps are mostly 35 - 0 degF with occasional dips negative. Studs are legal Oct 1 - May 1 (often spring cut off is extended).

The Nokian Hakka's LT235/75/R15 I got from the PO have aged out. Plenty of tread for another season but 10 years old according to DOT stamp. I am not too saggy on a stock suspension and measuring I see plenty of space for a 31.

Nokian isn't making a studded tire in 235/75R15 or 31x10.50R15 anymore. The rims I'll be using are 15x7 so fine for mounting a 265 or 10.5 width.

So after looking around I am considering the following:

Hankook i*Pike RW11 31X10.50R15C1 109Q B

Cooper Discoverer M+S 31X10.50R15LT 109Q load C (availability unconfirmed)

Cooper Discoverer M+S 265/75R-15 112S

Hankook i*Pike RW11 LT235/75R15C1 104Q B

The LT Cooper lists a tread depth of 19 while the Euro Metric lists a depth of 15. The Hankooks in both sizes list a depth of 16.5.

I have i*pikes on a Subaru Legacy and like them, they are pretty much the standard snow tire around here for Subarus. The 31x10.5 tread profile looks more like the Nokian Hakka I'll be replacing.

The LT235/75 is in the running as about the only stay skinny option I have found.

The load ratings look fine to me for any of these options, but please point out any issues. The local tire guys were zero help in checking against the OEM H78-15 specs on the door plate. The door plate info follows if anyone has actual load inflation tables handy. I checked these against a Toyo document "Guidelines for the Application of Load and Inflation Tables" that reproduced what looked to be 2006 TRA tables.

Front GAWR: 3065 LBS with H78-15 (B) Tires, 15x6-JJ Rims, at 32 psi

Rear GAWR: 3220 LBS with H78-15 (B) Tires, 15x6-JJ Rims, at 32 psi

Thanks for any input

 

[gaijin]

This is a South Central Alaska (Homer) FJ60, daily driver. Snow covered roads in winter with 6-18" accumulations per storm. Down at sea level freezing rain, and ice covered surfaces is common. Temps are mostly 35 - 0 degF with occasional dips negative. Studs are legal Oct 1 - May 1 (often spring cut off is extended).

The Nokian Hakka's LT235/75/R15 I got from the PO have aged out. Plenty of tread for another season but 10 years old according to DOT stamp. I am not too saggy on a stock suspension and measuring I see plenty of space for a 31.

Nokian isn't making a studded tire in 235/75R15 or 31x10.50R15 anymore. The rims I'll be using are 15x7 so fine for mounting a 265 or 10.5 width.

So after looking around I am considering the following:

Hankook i*Pike RW11 31X10.50R15C1 109Q B 35psi Front/Rear

Cooper Discoverer M+S 31X10.50R15LT 109Q load C (availability unconfirmed) 35psi Front/Rear

Cooper Discoverer M+S 265/75R-15 112S 26psi Front/Rear

Hankook i*Pike RW11 LT235/75R15C1 104Q B 41psi Front/Rear

The LT Cooper lists a tread depth of 19 while the Euro Metric lists a depth of 15. The Hankooks in both sizes list a depth of 16.5.

I have i*pikes on a Subaru Legacy and like them, they are pretty much the standard snow tire around here for Subarus. The 31x10.5 tread profile looks more like the Nokian Hakka I'll be replacing.

The LT235/75 is in the running as about the only stay skinny option I have found.

The load ratings look fine to me for any of these options, but please point out any issues. The local tire guys were zero help in checking against the OEM H78-15 specs on the door plate. The door plate info follows if anyone has actual load inflation tables handy. I checked these against a Toyo document "Guidelines for the Application of Load and Inflation Tables" that reproduced what looked to be 2006 TRA tables.

Front GAWR: 3065 LBS with H78-15 (B) Tires, 15x6-JJ Rims, at 32 psi

Rear GAWR: 3220 LBS with H78-15 (B) Tires, 15x6-JJ Rims, at 32 psi

Thanks for any input

Here's the answer I posted in another thread:

**********

Hey Mark - I did not forget about you!

Here's what I found:

With an LT tire, the larger GAWR of your vehicle (in this case 3,220 pounds for the Rear) should not exceed about 94% of the Load Limit of the tires being used.

The General Grabber AT2's size LT235/75R15 are a Load Range C tire with a maximum Load Limit of 1,985lbs@50psi. When inflated to 41psi, they have a Load Limit of 1,709lbs which meets the Load Limit criterion. So if you go with these tires, I'd recommend 41psi Front and Rear.

The General Grabber AT2's size 225/75R15 are NOT an LT tire and do not have sufficient Load Limit to safely use on your vehicle. A non-LT tire's Load Limit must be 10% higher than an LT tire. In your case, this means it must have a Load Limit of 1,880lbs, but the tire is only rated for a Max Load of 1,874lbs @ 44psi. It's pretty close, but I would not recommend it as you would be right at the limit (or a little below).

At 41psi, in my opinion the Load Range C LT235/75R15 tires should not be a harsh ride.

Sorry it took so long, but if you have any further questions, just post 'em up!



**********

You can find my answer in context as post #32 in this thread: https://forum.ih8mud.com/tire-wheel-tech/700858-air-pressure-31-t.html

Info is derived from 2012 TRA charts.

I have indicated recommended Tire Pressures for all the tires in your post in yellow.

Any further questions, just post 'em up.

 

[phooka]

gaijin,

Thanks. The tables in the Toyo guide match for both cases you quoted.

I think I'd go up to 42 psi for an LT235/75R15 for a GAWR/load ratio of 92.6% instead of the 94.2% at 41 psi. Tire gauge accuracy and all.

For completeness on an 10/84 build date FJ60 I calculate the following inflation pressures to meet the 3220 lbs Rear axel GAWR.

31x10.5R15C @ 34 psi (GAWR is 93% of 1731 lbs single tire load)
265/75R-15 @ 26 psi (GAWR is 93.4 of derated 1896 lbs single tire load)
LT235/75R15 @ 42 psi (GAWR is 92.6% 1709 lbs single tire load)

So there's the inflation pressures worked out.

Anyone have experience with the Coopers and Hankooks?

Anyone with thoughts on the if extra tread depth of the 31x10.5R15 Discoverer M+S will change snow/ice performance?

 

[Topmounter]

I'm looking into snows for my hundy and am considering Hankook RW11 i-Pikes (265/75R16) or the Blizzaks in the same size (my AT's are 285/75R16). The price is right on the Hankooks and I can't seem to find anyone saying bad things about them. I haven't quite decided whether I'll add studs or not.

 

[phooka]

Went with the Hankook's

I went with the iPikes and studded them. They are a scaled up version of the ones I have on a Subaru Legacy. Love them on the Subie and the tread looks plenty aggressive in person. Haven't seen any winter precipitation yet, go figure, so no real experience yet.

The Cooper's were going to be a special order in 31x10.5R15 and that was going to add 12 days to the 10 days of barge time from Washington. Gotta love AK shipping times.

 

[084runnerltd]

I would just park at "The Salty Dawg" and wait til summer...then go Halibut fishing