Spare Tire

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slgriner1979

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My rig is a 2018 F150. It has a four inch lift with 35 inch tires. My spare is still the factory original. We are planning a more remote trips where a flat could be possible. Any suggestions for replacing the spare, or not? Will a 35 fit under the tuck? Am I OK with the factory tire in a pinch (probably 33 inches)?

Thanks!
 

MOAK

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Many things to consider, but a rule of thumb is to have all tires the same size, for a multitude of reasons. Personally I deplore mounting a spare underneath a vehicle for a lot of reasons, access being the primary and because for a lot of people since it’s out of sight, it’s out of mind, until you need it. Then find out it has about 10lbs of air and it is dry rotted. If you are truly remote and you cut a sidewall, which cannot be repaired in the field, you might be a day or two away from the nearest tire shop, then wait for shippping, at least 24 hours. Meanwhile your driving around on a poopy old wrong sized spare tire, that will wreak havoc on steering, and unless you have open differentials will wreak havoc on your driveline. Well, these are a couple of reasons, there are many more that I’m sure others will chime in on. Good luck! Say, where are you headed?
 

Alanymarce

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Many things to consider, but a rule of thumb is to have all tires the same size, for a multitude of reasons. Personally I deplore mounting a spare underneath a vehicle for a lot of reasons, access being the primary and because for a lot of people since it’s out of sight, it’s out of mind, until you need it. Then find out it has about 10lbs of air and it is dry rotted. If you are truly remote and you cut a sidewall, which cannot be repaired in the field, you might be a day or two away from the nearest tire shop, then wait for shippping, at least 24 hours. Meanwhile your driving around on a poopy old wrong sized spare tire, that will wreak havoc on steering, and unless you have open differentials will wreak havoc on your driveline. Well, these are a couple of reasons, there are many more that I’m sure others will chime in on. Good luck! Say, where are you headed?
Perfectly stated!
 

bgenlvtex

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I wouldn't carry the weight without the benefit of being able to use it with impunity. A little googling should answer your "Will it fit?" question, if getting underneath and having a look doesn't answer the question. If you're still uncertain take one off the truck and see if it fits. I personally have no big issue with under bed stowage, and definitely prefer it to "in the bed in the damn way 24/7".. Some aftermarket wheels (and some oem alloy wheels) won't stow under the truck because of design limitations at the center bore.

You definitely won't be able to use 4wd with a mismatched tire for any period of time, it will likely damage the transfer case in short order.
 
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MidOH

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Kenda makes the Mt2 in a 35x10.5" pizza cutter that should fit on your spare wheel.

No idea if it'll fit in the stock location. Make a 35" circle from cardboard. 35 will fit the Superduties stock location.
 

rtexpeditions

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Then find out it has about 10lbs of air and it is dry rotted.
One of the reasons I include the spare (in my case 2 spares) in tyre rotation.
Alternatively when I replace tyres, it is the least worn of the old set. Of course, it must be the same size and tread pattern.
 
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John Tasco

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I have a 2020 Ford F-150 XLT and recently got new tires. I went up one size from stock and bought a fifth for a spare. Since I was getting new wheels as well, I had them mount the full size spare on an old rim and it easily fit under the truck. While I’m not sure a 35 will fit, when I crawled under the truck to check the install I thought I could have easily gone one more size larger. FYI, I carry a Dewalt Impact wrench and upgraded to a 1 ton bottle neck jack. I don’t like to use an impact wrench but I got this one because with my luck, I’ll get a flat along side a busy highway, in a torrential rain storm, gusting hurricane winds, and at midnight. So, I want to get that flat off and spare installed as quick as possible.
 

hrichard

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As others have said, a 35 for sure fits under a superduty, I'm not sure on the f150. I would take one of mine off the vehicle and crank it up under there to see if it fits. I wouldnt run a smaller spare for any length of time on that truck, it will cause all kinds of drivability issues, could cause abs/traction control not to work, will definitely wreck any kind of true locker over the course of a few miles, and could cause the electronic 4wd not to engage due to the abs/traction control system not being able to make up for the difference in tire size
 

Jonathon

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From experience I would recommend moving it from underneath to the bed. As for size you will want a full size spare. The reasons for not wanting it under the truck is it can be punctured there much easer than in other locations (I have had this happen multiple times in company vehicles). As for full size spare you can cause damage to transmission, Transfer case, and diffs when you tires are differant sizes. I prefer match brand and model of tire as well.
 
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