tire rating question

josh1981

Petty Officer 3rd Class
Joined
Oct 22, 2009
Messages
75
Is it ok to have a stronger tire than is required? Meaning I only need a load range "C" tire (225/75/15) but can get a load range "D" for cheaper (I dont know why maybe supply and demand). Common sense tells me I will be fine and just have a stronger tire. I just wanted to ask and make sure that I am not overlooking something. Thanks
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,095
Re: tire rating question

Ayuh,... Heavier rated is just Fine,.... Under rated is Not...
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: tire rating question

The D-range tire will have a higher inflation pressure spec on the sidewall, but odds are your rim won't be rated that high. Inflate to the c rating and you'll be fine. Just keep track of it so you don't over-inflate the tires and blow a rim. Not only does it wreck your day, it could take your head off.

hope it helps
john
 

josh1981

Petty Officer 3rd Class
Joined
Oct 22, 2009
Messages
75
Re: tire rating question

The D-range tire will have a higher inflation pressure spec on the sidewall, but odds are your rim won't be rated that high. Inflate to the c rating and you'll be fine. Just keep track of it so you don't over-inflate the tires and blow a rim. Not only does it wreck your day, it could take your head off.

hope it helps
john

The d rating and the c rating both use a 15x6 rim. Is there a difference in rims? Will it be stamped on the rim anywhere? Thanks
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,204
Re: tire rating question

rims actually have PSI ratings? Seems strange, rims are usually a fairly decent chunk of metal, and as far as pressure, there might be a 20 to 30 difference in psi. Not that much in the grand scheme of things...

Anyway, one thing to consider. On a typical rough riding leaf spring trailer, your tires provide some cushioning. Running higher capacity tires at their rated PSI is going to make for a rougher ride.
 

Mark_VTfisherman

Lieutenant
Joined
Nov 29, 2008
Messages
1,489
Re: tire rating question

The d rating and the c rating both use a 15x6 rim. Is there a difference in rims? Will it be stamped on the rim anywhere? Thanks

Alloy and aluminum rims will probably be the only ones that show a load rating at a certain pressure. Steel rims have a max pounds rating. Steel rims won't show a max air PSI. Or I probably should say usually don't cuz someone somewhere will make one that does and someone will point that out :D

A "D" tire compared to a "C" tire has a 15# difference in max air pressure. If your rim doesn't have a margin or error or capacity ABOVE that little difference I would probably get new rims- ratings are generous enough to provide a margin of safety.
 
Last edited:

surge006

Petty Officer 2nd Class
Joined
Sep 25, 2009
Messages
100
Re: tire rating question

just a rougher ride on your truck
 

josh1981

Petty Officer 3rd Class
Joined
Oct 22, 2009
Messages
75
Re: tire rating question

Looks like i am going to go with a local dealer anyways instead of order the tires offline. So I will get the appropriete tire. Thanks for the input.
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Re: tire rating question

go with the heavier tires.... you don't have to inflate to max and they will handle better while towing
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: tire rating question

Alloy and aluminum rims will probably be the only ones that show a load rating at a certain pressure. Steel rims won't. Or I probably should say usually don't cuz someone somewhere will have one that does and point that out :D

A "D" tire compared to a "C" tire has a 15# difference in max air pressure. If your rim doesn't have a margin or error or capacity ABOVE that little difference I would probably get new rims- ratings are usually generous enough to provide a margin of safety.

No they aren't. I've blown them. Don't do it. Inflate to the pressure the rim is designed for, and no more.

15 psi increase in pressure is a ton or more of increased sidewall force on the bead of the rim.
 

Mark_VTfisherman

Lieutenant
Joined
Nov 29, 2008
Messages
1,489
Re: tire rating question

...I've blown them. Don't do it. Inflate to the pressure the rim is designed for, and no more...

Steel rim, or aluminum?

Show us a published max psi chart for rims... Tires have PSI ratings, other than some Aluminum and alloy rims, rims are rated max pounds of load. I am all for learning but I am unfamiliar with rim ratings of max tire psi. We are not talking about overpressuring or overloading tires here- just whether he can use a "D" tire instead of a "C".

Most of the probs with Aluminum rims (or alloy) are with the old cast rims from the sixties, or the older welded-rim steel wheels meant for tube tires. Machined aluminum or alloy wheels have the load and PSI data provided by the manufacturer.

Running the D tires at the C pressure doesn't raise any alarms for me as long as the load capacity is not exceeded.

I do get your point though- I do remember tire training during which we were warned about welded steel and cast alloy wheels and newer tires or low-profile tires which had greater PSI. and something about old cast-and-machined magnesium wheels getting brittle over time- like Halibrand mags. But I haven't heard that brought up in recent years.

My 2 cents, but I am not a lawyer either.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,241
Re: tire rating question

Looks like i am going to go with a local dealer anyways instead of order the tires offline. So I will get the appropriete tire. Thanks for the input.

Look the tires over carefully to be sure they are USA made. I have personally had issues with every Chinese, Taiwan, etc. tire I ever bought. Even some of the USA name brands actually import some sizes. You can still find US tires, or at least you could as recently as 2 years ago.
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Re: tire rating question

I recently noticed that the alum rims on my dually state "do not exceed 65 psi"..... I have been towing with it at 80 psi for years and will continue to do so but it does make me nervous airing them up now and I am keeping an eye open for some different rims
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,095
Re: tire rating question

Show us a published max psi chart for rims...

Ayuh,... Ditto for me too..... Your claim sounds bogus...
 

red85k100rs

Seaman
Joined
Sep 10, 2007
Messages
74
Re: tire rating question

I recently noticed that the alum rims on my dually state "do not exceed 65 psi"..... I have been towing with it at 80 psi for years and will continue to do so but it does make me nervous airing them up now and I am keeping an eye open for some different rims


never seen a wheel blow, but seen the aftermath of an air compressor tank blow... you wouldn't want to be standing near it, or even in the same room!!
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Re: tire rating question

there is a chance that it would be fatal if you were right next to it. Like I said I am in the market for different rims
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: tire rating question

Well, His claim may sound bogus, but I learned a long time ago that unless I know facts to the contrary, not to reject a statement out of hand. I, for one, will file that rim pressure statement away in my mind for future invesigation.
 
Top