Load range conversion?

[French_Toast]

Ok, So I need to get some new tires for my truck, since mine are starting to show considerable wear. I want to try and stay as close to stock size for now, so ive been keeping an eye out in the local classified adds for a good deal. I found a set of tires that are a decent price, but the "load range" rating on them is 109s. I've always just gone by the "E" ratings, (or other letters). My question is what does a tire with a load range of 109s compare to in the alphabetical rating, is it an E, D, ect. Thanks.

[bigcountrysg]

I do not know I have never heard of a tire having a load range 109. I know there are a couple tire guys on here. I am sure they can tell you.

[Eric]

109S is the speed rating. Load range is D or E (8 ply, 10 ply)

[bigcountrysg]

Originally Posted by whitelongbed

109S is the speed rating. Load range is D or E (8 ply, 10 ply)

That makes sense to me. But I never seen the mph on the tire. Just the letter like S,Z, and what ever the other code letters are.

[Eric]

I've worked for a tire distributor for almost 5 years and still don't know a whole lot about how the speed rating works I know for example that on a 205/40ZR 17, the "Z" means the tire is rated for 149+ m.p.h.

[dhanna6powerstroke]

Originally Posted by whitelongbed

109S is the speed rating. Load range is D or E (8 ply, 10 ply)

109S is not the speed rating. The "S" alone is the speed rating but the 109 is a load index. Different from the Load Range. Also, if you are looking at a "P" Metric size, it will not have a load range any higher that a "C" load range and usually is not printed on the tire. "C" = 6 ply, "D" = 8 ply, and "E" = 10 ply. Check this link. I think it will help you out.
Tire Tech Information - How to Read Speed Rating, Load Index & Service Descriptions

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Last edited by dhanna6powerstroke : 07-11-2008 at 08:20 PM.

[choctaw]

Are they P265/??/?? or are they LT265/??/??.
I think the LT's have load range ratings and the P rated have the load index assigned to them

[French_Toast]

Well after some searching on google, I came across this site Tire Info That has the information I was looking for. It turns out that "109s" is the "Load Index" Which has load rating, and speed rating all in one peice. The load rating of 109 is rated at 2271 pounds per tire(110 is 2337 per tire). the S is the speed rating which is 180 Kph. With "110" being a Load range E tire, I'm guessing it's safe to use a set of tires that are only rated for 66 lbs less then the ones on it now. I figured something was up, because I work in a warehouse at a tire store, and most of the tires i see coming in now, have this numerical rating on them instead of the Alphabetical rating. The website has alot of other good info on tires and how ratings are applied, so maybe it can be of good use to someone else too Thanks for the help


EDIT dhanna6powerstroke got the link first lol
And yes they are LT245/75/R16s