I am replacing my stock 235/70/16 tires with 265/75/16. Should I also replace my spare? Or would it be ok to drive a few miles with my old spare if needed ? Also how much will this tire change effect my gas mileage and over all performance?

Thanks in advance
The Judge

99
4x4
5.4
XLT

 

With a 5.4L it won't be a HUGE loss in power, but still noticable. I'd reccommend getting a similar sized spare. You might be ok running on that, but its always best to have a spare the same size as your tires, especially if you have a LS.

 

Yes, you should replace your spare tire also. You will also need to have the dealer adjust the speedometer.

You will definately notice a loss in power and a loss of mpg. You will also lose some towing capacity. Make sure your real axle is at least 3.55 or 3.73.

 

Thanks for the quick response. I don’t know why Ford put the small stock tires on my truck. It seems that my truck is over powered for the small tires. I just want to fill out the wheel wells and make the truck look nice. I don’t want to sacrifice too much power or gas mileage. Maybe I should go for a 245/75/16 instead. It might be middle ground between looks and power. What do you guys think?

Thanks again

The Judge

 

One more thought, my current ratio is 3.73

The Judge

 

In my opinion the 255 is the perfect tire. It looks good in the wheel well and is a good balance of power and mpg.

I used to drive a 99 just like yours, only with the 265/75/17 tires. I now have a 3.55 rear axle with the 265/75/17 tires, and same rim. One thing I have noticed is that the 3.73 axle is a better match for the 265 wheels. Also, the 265 does look better in the wheel wells on a 4x4 because of the extra lift.

The 235s were standard tires back in 99. The 3.73 was available at no charge, and increased your towing capacity. The 255 and 265 tires were an option that you paid extra for, at about $275 - $300. I don't remember, my 265s were part of the Off Road package.

 

If you really want to fill out the wheel well go with a285/75/16 with the 3:73 ratio your power and MPG loss is not going to be that great. I have a 1997 4x4 with 3:55 LS and am running the 285's i would like to do a gear swap however the cost is a bit much for me due to haveing to do both axles.If you are that concerned with gas milage maybe you should stick with what you got considering trucks don' tget good gas mileage period that isnt why we buy them. At least I don't . Don't take it wrong. I bought a truck for towing andm useing in the great outdorrs gas mileage does concern me especially now that gas prices are rising again hwoever it's a truck and that's one of the things you deal when owning a truck. Your MPG loss is not going to be so much that it breaks your pocket book you may lose 1-5 MPG at the most and that also depends on your driveing style.

Richard D.

https://www.f150online.com/galleries....cfm?gnum=2479

 

I have 35s but still retained the stock spare! I don't see the purpose of buying another expensive tire for no reason just to sit under the bed and rot away. However I do keep another 3 ton hydrualic bottle jack in my truck. If I ever blow out one of my rear tires, I have two jacks so that I could sway a 35 from the front to the back and put the spare up front. Thus I won't screw up my limited slip rear. The little tire will do its job on the front until I can get the truck home and repair the 35" tire.

kev

 

Thing is kev, you can go to a tire store and get a used tire that will work for a spare that should be close to the size you have for not much money. We're talkin $5-10 here for a tire that will work just fine for a spare. I did this for my F150, but the big reason was that my spare was a 235/70/16 and I'm running 35s.......thats just TOO big a difference.

 

I have a 17" rim as a spare, that is hard to find a tire 35" for a 17" rim. I had enough trouble finding a set of brand new ones let alone a used one.

My stock tire size is around 31.6". 35/31.6 is about the same ratio that other car manufactures use for those little tiny doughnut tires that come with the cars. But if you are to do a ton of offroading, then yes pick up another similar size tire. When I 4x4, I am hardly ever 1/4 mile away from the nearest road, thus I would make it out with the tiny spare if I had to.

Did your 35" spare fit nicely under the truck? Did it hit the trailor hitch? When I purchase my next set of tires, I will definetly keep the best one I have now and mount it on the spare rim but for now, the little one works.

kev

 

just to give you an idea of visual differences in size try ...

http://www.miata.net/garage/tirecalc.html

p.s. i would only drive a Ford found the miata site by mistake!

 

That doesn't explain why you are a Junior member here and a Senior member on the Miata site.

 

must be someone else .... wouldn't lie to ya'l

 

Ok but, that still doesn't 'splain why your hair has that 'wind blown' look and when you arrive your face looks like you've been cramped up.

 

KEV you can pick a 16" steel wheel up for about 20.00 and a used 35" tire to match your others for about 10-15 like Powestroke said at a tire shop . I actually traded in my stock 17" wheel for the steel 16" wheel at Americas Tire and then had them put one of my old 285/75/16 on it when I purchased a new set of tires so i have a spare the same size as the tires i run .If you are running a 35 and plan on putting a 265/70/17 in the event you get a flat that is to much of a size differance especially on the front which is what your steering is controlled by ,you may have a hard time driving the truck.I recently bought some new wheels and have 2 Centerline 16x8 wheels for sale for anyone who would like to have a full size spare with the same wheel and tire size you may be running. I am keeping one of the Centerline's myself for my spare and getting rid of the black wheel i have been useing.Anyway just a thought you might want to consider.

Richard D.