@CapriRacer said the 235/75 tires will work. I think he’d know.
sgtrock21 said:
“Truck tire measurements make perfect sense for us. Passenger car tires used to be in inches ie 8.50 X 15. What is the conversion formula for the interim letter X number X inches ie G70 X 15? I’m sure some day the US and UK will join the rest of the world but then we would lose one of our confusing discussions.”
http://www.barrystiretech.com/tiresizing.html
Oh and a small quibble. The symbols “/”, " - ", and “X” aren’t interchangeable when it comes to tire sizing. They are used in particular ways - and the proper way to do the size sgtrock21 mentioned is “8.50-15”. Refer to the link for the details.
But that is a minor quibble.
We had the BF Goodrich Long Trail TA tires before on this vehicle. They lasted about half as many miles as the Michelin LTX/MS. The available size in LTX/MS2 is 235/75. Although this would probably be OK, I think we will play it safe and go with the Firestone Destination LE2.
Thanks to everyone for the input.
We had the BF Goodrich Long Trail TA tires before on this vehicle. They lasted about half as many miles as the Michelin LTX/MS.
Since Michelin owns BG Goodrich…that doesn’t surprise me.
the same mountainbike 8.50 inches tire width by 15 inches wheel diameter is exactly what I meant. Is this incorrect?
sgtrock21 said:
"the same mountainbike 8.50 inches tire width by 15 inches wheel diameter is exactly what I meant. Is this incorrect? "
I think what mountain bike was getting at is you need more information to determine the diameter of the tire, which would be important for gearing, speedometer, clearance, etc. Those numbers don’t tell you that. You have to look it up.
CapriRacer I think what mountain bike was getting at is the use of “X” or “BY” being technically incorrect as that is not how the size is displayed on the tire. My example of 8.50 15 was how tires were marked when I started driving in the late 1960s. If you were verbally stating the tire size as displayed on the tire it would be " eight fifty fifteen". Diameter was not normally displayed on passenger car tires. I suppose a tire shop in those days would have catalogs which listed diameter. Of course it’s easy enough to just use a tape measure and if you asked what the aspect ratio was you would get a blank stare.
I was only speaking to the meaning of “X” as it was being used, the fact that it isn’t a multiplier.
Capri corrected us in clarifying that it should be a “/”, but that too could be misinterpreted as a math symbol, and that wouldn’t be correct either.
Whether you use an “X” or a “/”, it ain’t a math symbol. It’s only a means of differentiating the section width from the aspect ratio. All of which, frankly, confuses the heck out of people. Which proves my initial point… the informational system to describe tires is the most screwed up system since, well, ever! Someone should write a book of how this system evolved. Only “car guys” understand it. To the average person, it’s all gobbledygook. It doesn’t need to be this way, but it is what it is.
They tried the letter system, but then you needed a conversion table. At least this system has all the information in it.
I can sympathize with Mountain bike, but there are problems no matter what system is used.
But to counter a bit, the average person doesn’t need to know much about tire sizing systems. Just like with oil filters, he needs to find the vehicle tire placard (or look up his vehicle using the on-line tools) and go from there.
If the average guy wants to know more, then he isn’t the average guy!
I was only speaking to the meaning of "X" as it was being used, the fact that it isn't a multiplier.
“X” is a valid symbol to use. It’s widely used in other industries. 2x4x8 - That’s a 2 by 4 that’s 8’ long. The X is a multi-use symbol. Tires the 30x8.5 means the tire stands 30" high and is 8.5" wide. That is a lot easier for people to understand then the aspect ratio. Try to explain that to your 85yo father-in-law that the 16" rims off of his sons mini-van would work on his mini-van. He was concerned with raising the height since he had a hard enough time getting into the van with the tires/rims he has. He wanted to get a set of winter tires. His current tires are 265/75-15. If he went to a 265/70-16 - the new height would be very very close. So I calculated the conversion for him…and then he understood.
30.64 x 10.43 30.60 x 10.43 - That he understood.
It is for general conversation, but Capri speaks “tire”, and in that language it’s supposed to be a “/”. I’m empathetic.
Capri, what you say is perhaps true, but I still wonder how sizing became a combination of three different measurement systems. And why so much of the other data is coded rather than stated. Why “H” instead of “113mph max”? Why code the date of mfg? Why confuse the public for nothing?
And yet, with all that mysterious coding, they don’t tell you what rim widths the tire will fit?
It is for general conversation, but Capri speaks "tire", and in that language it's supposed to be a "/". I'm empathetic.
But truck tires still use the X. So the “/” may be more common…but it’s NOT the only thing used. X is a very scientific way to show dimensions. H x W x D - That’s standard in almost everything you buy that you need to know the dimensions on…(Stereo Equipment, Appliances, Cabinets…the list is endless. Why do tires have to be special.
Letters are international. Avoids having to list two speeds km/h and mph.
Mike, I TOLD you it was confusing!
Texases, it still doesn’t answer the other questions. And is it really harder to CNC mill “210Km/hr, 130mph max” into the mold?
Besides, is the 215 in 215/45R17 international?
I tell ya guys, this stuff was created by little elves in a cave somewhere intent on creating a secret code.
height x width x diameter in inches or centimeters or cubits, what could be more easy?
Quick wes, without looking it up, what’s the maximum speed on a Q rated tire? In kilometers?
215 is international ( 215 mm ). I guess I don’t have a problem with the size. My problem is the hundreds of size/speed/load combinations. My old Sohio station could stock most tire sizes in the 70s with one rack around the walls. No way now.
what is a q rated tire? 
its around 70 mountainbike, because that s as fast as im gonna go, unless I m being chased by the Taliban…