Truck tire question re replacing

[beowulf]

deleted:

Thanks for responding guys. Very sorry for the delete, but I was not sure of the info I provided - I started to doubt my info after I posted - and as the truck was in the woods in the dark, I wanted to go back and check this morning.

I did not want to waste anyone's time possibly providing information that was based on incorrect info, so deleted it last night and planned to check info this morning and repost. It seems however, you guys are too quick for me and were already providing info. I went out this morning and verified the size, changed the tire, and plan to get four new tires. While I thought the treads were pretty good on the working four, when I looked at the treads on the spare they were so much better that I decided I should get four new ones.

Anyway, the existing tires are 235-75-17s. I found some in this size late last night on Internet - though not a lot of brand choices and only a very few choices overall -spent an hour poking around last night. I found 235-70-17 at Costco and a much better deal re cost and a brand I like.

So my question, I know that if I was going to replace only one tire I need the size to be the same, but now that I will be replacing four tires, can I go with a 235-70-17 with the existing wheels? (tho the spare would be 235-75-17 - I guess that would be okay in a pinch). I have not checked re tires at Costco or elsewhere re the recommended 352-80-17s as ning advises. I will be checking more sellers this morning, tho I think I have pretty exhausted the search re area tire dealers - some require you to call them tho, and could not do that late last night - I will start my calling now.

So, I will be getting four new tires today and prefer the more common size of 235-70-17s - doable? Suggestions?
Again, sorry for the delete.

 

[ning]

What tire size numbers mean:
235/75 R 17
235 = width of tire tread, in mm.
75 = aspect ratio - the "height" of the tire (from the wheel to the outside of the tire), divided by the width.
R = radial
17 = size of the rim, in inches.

A lower aspect ratio (70) with the other values the same will be a smaller diameter tire (not by a lot, but some). Definitely don't mix different size tires.

Smaller tires will effectively increase your axle ratio (engine turning moves truck less), and lower the truck.
Larger tires effectively decrease your axle ratio (engine turning moves truck more), and raise the truck.
Either change will make your speedometer & odometer inaccurate, though this can be adjusted (used to be by changing a little gear; these days probably by changing something in the computer).

Depending on your setup, larger tires may improve your mileage; smaller tires will probably not.
I'd check out 235/80r17 if I were you.

 

[newbury]

deleted

What?

What tire size numbers mean:
235/75 R 17
235 = width of tire tread, in mm.
75 = aspect ratio - the "height" of the tire (from the wheel to the outside of the tire), divided by the width.
R = radial
17 = size of the rim, in inches.

A lower aspect ratio (70) with the other values the same will be a smaller diameter tire (not by a lot, but some). Definitely don't mix different size tires.

Smaller tires will effectively increase your axle ratio (engine turning moves truck less), and lower the truck.
Larger tires effectively decrease your axle ratio (engine turning moves truck more), and raise the truck.
Either change will make your speedometer & odometer inaccurate, though this can be adjusted (used to be by changing a little gear; these days probably by changing something in the computer).

Depending on your setup, larger tires may improve your mileage; smaller tires will probably not.
I'd check out 235/80r17 if I were you.

A couple of notes on this -
I've read several places that putting bigger tires on leads to premature front end part failure.
Larger tires without correcting the odometer decreases the mileage. Thus with a 10% difference if your warranty is based on mileage it will last 10% longer

 

[topbuilder]

"Nothing is permanent."

Even a question it seems.

 

[beowulf]

Update: I am finding a few tires - and being told that my 235-75-17 is a bit of an "odd ball" size and can be found but would have to be ordered. I have been told a 235-70-17 would be a good choice (more common and easier to find in the future) given my usage, miles per year, etc. and would fit the wheels I have and would lower the truck very slightly, and speedometer would change but not likely typically noticeable.

Looking at Consumer Reports, and reviews, so will try to find the 235-70-17 tires in the area (while continuing to ask about the 235-75-17s), in the tires I want, and at best price.

 

[LD1]

Why are you stuck on 235s?

What is limiting you from going a little wider? 245's 255's 265's etc.

Lot of tire choices. You could probably find 5-6 metric sizes that are all within an inch or two of what you have in both width and height. And I have yet to see a truck that wasn't a little flexible in sizing when changing all 4.

Also looks like you have some fat-finger issues too:laughing:

What kind of tire are you looking for? Mud? All terrain? What are you considering thus far?

 

[beowulf]

Why are you stuck on 235s?

What is limiting you from going a little wider? 245's 255's 265's etc.

Lot of tire choices. You could probably find 5-6 metric sizes that are all within an inch or two of what you have in both width and height. And I have yet to see a truck that wasn't a little flexible in sizing when changing all 4.

Also looks like you have some fat-finger issues too:laughing:

What kind of tire are you looking for? Mud? All terrain? What are you considering thus far?

Thanks for the input.. . and went back to edit my fat finger errors - thanks also for pointing that out (lol).

Anyway, I think I will go with the 235-75-17s as I see that I can order those in a Consumer Reports recommended tire.

The truck is used in Central Calif foothills - not a lot of weather issues - some rain at times. Almost all highway miles as we live about an hour from the town we go to for project supplies, hay or whatever. I drive it maybe once a week, sometimes once every two weeks depending on what I am working on. Unless we really need a pick up, we take our other car to town. I do go to So Cal 2-3 times a year to help daughter with repairs, projects, etc and then need the truck. I guess I put less than 7500 miles a year on it.

The tire I will likely order is the Michelin Defender LTX M/S based on reviews, ability to order it from Costco, and size to be what I have (235/75/17). I looked at the 245 and 255 widths. . . not too much more money (and the increased cost not really an issue), but for some reason less mileage on the warranty for the wider widths (70 k vs 60k vs 50k). They did not show the 265 in a 17.

I guess I will be pulling the trigger today and order as I may need the truck in a week or so.

Again, thanks for the input. I am thinking about your suggestion.

 

[LD1]

I know 265/70-17 is a popular size cause thats what I have

And they are the same diameter (+/- an irrelevant hair) as the stock size on my truck which was a 235/80-17, which is also a popular tire.

The Michelin LTX you mention....I like that tire alot. Specifically the tread design as it does real well in the snow. But I didnt want to pay Michelin prices. But still wanted a quality and American tire. Which is why I arrived at the Mastercraft courser HXT. Real similar tire (tread), quality and American made, and alot less $$$.

 

[John Fitzgerald]

My 2010 F150 has the same size, P235/75/R17 (from factory). I have been told by tire shops they are an odd size. They recommend AT245/70/R17 as replacements. Many more tires are made in the latter size. Also, if your truck is a 4x4, your new tires should be very close to the spare size, or using the spare will damage the drivetrain. The 245/70/R17 is very close in diameter to the originals. I would like to find another aluminum rim like the factory rim and buy 5 new tires so I can work the spare into the normal 6k mile normal rotation.

 

[beowulf]

My 2010 F150 has the same size, P235/75/R17 (from factory). I have been told by tire shops they are an odd size. They recommend AT245/70/R17 as replacements.

That is the same thing I am being told re that size. I could certainly live with the size but have some concern finding a replacement if have a blow out somewhere far from home - I want to be able to buy a tire that matches. I found the 245/70/R17 tires in the Michelin Defender so may order those. I don't have a 4x4, and I don't think I would have major issues if my spare would remain a 235/75/R17 as it would be only a temporary use.

 

[John Fitzgerald]

That is the same thing I am being told re that size. I could certainly live with the size but have some concern finding a replacement if have a blow out somewhere far from home - I want to be able to buy a tire that matches. I found the 245/70/R17 tires in the Michelin Defender so may order those. I don't have a 4x4, and I don't think I would have major issues if my spare would remain a 235/75/R17 as it would be only a temporary use.

As I said: The 245/70/R17 is very close in diameter to the originals. I was thinking of getting a matching rim for the spare and rotate that one in every 6k miles or so, but the Tire Pressure Monitoring System makes that impractical. Even if a sensor was in the spare, the system can only remember 4 tires, so every rotation would require a trip to an authorized dealer, or the TPMS light would be on, and the vehicle performance might possibly be reduced by the TPMS.

 

[Egon]

I'm of the impression the narrow tire's give better service and are easier on the front suspension - steering components. No data to support these thoughs other than seeing wide tires in mud or snow.

 

[Rock Crawler]

235-75-17s =

235mm divided by 25.4mm in an inch = 9.25" wide
75% aspect ratio, or the tire is 75% as high from bead to tread as it is wide. It is 9.25" wide.
9.25" wide times 0.75 aspect ratio is 6.94" bead to tread.
You have bead to tread 2 times, ground to wheel and then again top of wheel to top of tire... so 6.94" times 2, then add the rim bead diameter to get overall height.
6.94"+6.94"+17" = 30.88" tall
So it is a 30.88"x9.25"-17".

Now rinse and repeat for any metric size that you want to convert to inches... a dimension we Americans can understand!

Stock tire 30.88"x9.25"-17

235-70-17s is 29.95"x9.25"-17

245-75-17s is 31.47"x9.65"-17"

245-70-17s is 30.5"x9.65"-17" (Closest to factory)

 

[John Fitzgerald]

I am getting another OEM rim with TPMS monitor and go with 5 tire rotations on my F150 4x4. Probably get five AT 265/70/R17's. If the TPMS lights up, that's ok. We didn't have it with our last truck. I check my pressure often anyway, and can easily adjust at home.

 

[scdeerslayer]

As I said: The 245/70/R17 is very close in diameter to the originals. I was thinking of getting a matching rim for the spare and rotate that one in every 6k miles or so, but the Tire Pressure Monitoring System makes that impractical. Even if a sensor was in the spare, the system can only remember 4 tires, so every rotation would require a trip to an authorized dealer, or the TPMS light would be on, and the vehicle performance might possibly be reduced by the TPMS.

You can get a TPMS reset tool for not very much money, and any place that sells and/or rotates tires should also be able to reset them, so if you get other service done you could rotate your tires before going there and ask them to reset them for you. Not sure what kind of truck you're talking about but on mine you can reset them without the tool by adding or letting out air for so many seconds when you're in the reset mode, but I think they did away with that feature after the first few years.

I don't know how old your TPMS sensors are, but you may want to replace them when getting new tires, they only seem to last 8 or 9 years.

 

[John Fitzgerald]

You can get a TPMS reset tool for not very much money, and any place that sells and/or rotates tires should also be able to reset them, so if you get other service done you could rotate your tires before going there and ask them to reset them for you. Not sure what kind of truck you're talking about but on mine you can reset them without the tool by adding or letting out air for so many seconds when you're in the reset mode, but I think they did away with that feature after the first few years.

I don't know how old your TPMS sensors are, but you may want to replace them when getting new tires, they only seem to last 8 or 9 years.

2010 F150 4x4 extended cab 4.6 V8. I wish it didn't have TPMS. To me, it's a nuisance, because I check my tires often anyway, and have compressed air at home.

 

[IvanS]

John Fitzgerald: Why do you want to have 5 tires to deal with? Are you of the mindset that it will add to the total mileage you get from the tires? If you rotate every 5k and maintain alignment and appropriate air pressure you will get the maximum life out of the tires and they should all (4) be due for replacement at the same time. You need to do the math on this, but I think it's economically a disadvantage to have a 5 tire setup. Not to mention the hassle of retrieving and stowing a wheel/tire from the spare location at every rotation.

Also, unless the tire size difference is significant, driving with a spare of a different size for a limited time won't damage the drive train. A spare tires only mission in life is to get you to a tire shop to repair/replace the damaged tire, not to permanently replace the road tire. I run much larger tires than my spare, if I have a flat I'll call someone for assistance. No more often than I've had tire failures (knock on wood) I'm money ahead by not purchasing the 5th tire for a spare. The tires on my truck are $250 each, by not spending that money on a spare, I feel like that's my repair budget.

Increasing tire size can effect performance and mileage, it will impact the speedometer / odometer. Today there are aftermarket interfaces that you can install to calibrate the speed/odometer readings to be correct.

By the way, if the need arises to compare tire sizes, you can use this nice calculator at: Tire Size Calculator - Tire & Wheel Plus Sizing

 

[robertsa]

I'm of the impression the narrow tire's give better service and are easier on the front suspension - steering components. No data to support these thoughs other than seeing wide tires in mud or snow.

The width doesn't have any effect on front end parts unless you're talking about the doofuses that mess with the backspacing to make their wheels stick out past the fenders because they think it looks cool.

An advantage to a narrow tire is use in ice and snow; it places the weight of the vehicle on a smaller patch of land, making it bite.

 

[robertsa]

2010 F150 4x4 extended cab 4.6 V8. I wish it didn't have TPMS. To me, it's a nuisance, because I check my tires often anyway, and have compressed air at home.

TPMS is nice when you pick up a nail on a trip, causing a slow leak. You'll get the dash light that you've got a low tire before you start feeling the effects. On a slow leak, it can buy you enough time to get yourself somewhere safe.

If you get a different size tire that's close to the same diameter, don't bother with replacing your factory spare. The width doesn't matter.

 

[John Fitzgerald]

John Fitzgerald: Why do you want to have 5 tires to deal with?

I think it would be advantageous for the spare to always match perfectly, and be fairly new. I built a tool to allow me to get the spare down and up very quickly. It is carried in the truck tool box along with a real lug wrench and jack. Gravel roads around here occasionally have flint rocks, from creek gravel still used by some entities, which are like knives when broken. If I only buy four tires, at my next tire change, the spare would be about fourteen years old. I don't put a lot of miles on per year, maybe 5-6k. I don't need to buy high mileage tires, 50k tires would be plenty.