I know that you should have matching tires on front and rear to use 4 wheel drive without hurting the differential/gears. Does this mean that that they have to be the same brand and tread desing or just the exact same size. I hive a F150 and need to replace the front tires but not sure if I can just get same size or must replace all with matching size and design. Thanks . Love yous guys David B. Syracuse NY
Same tire size all around is needed. Tread design on the same axle is a must. However, your owner’s manual should address this and its advice should rule your actions.
If this is a true 4wd, the tires one each axle should match, but not required for all 4. If you have AWD or “full time” 4wd, then you do need matching tires (diameter) all around.
It means same size, same brand, same model, same amount of wear.
There is no standard as to what dimensions tire manufacturers have to make their tires. There can be considerable difference between tires. Put another way, there is a reason why in official industry documents, they refer to “size designation”.
Same brand? Because there isn’t a sizing standard, you can’t be sure that a particular tire maker is using the same dimensional target as the next brand.
Same model? Even within the same manufacturer, there could be differences in how the tires are dimensioned.
Same state of wear? Yes, small differences in wear cause different rolling diameters.
So if you want to absolutely sure to avoid any risk of a very expensive drivetrain failure, you should match all 4 tires as closely as possible. The more the difference, the greater the risk!
It is best to get the same brand, style, tread design, and size tires on all 4 wheels. Not just for differentials, but also for balanced handling and braking.
I’d shop several stores and pay a bit more if you find a store that can match same brand, style, tread design, and size tires. Even if the tires aren’t “in-stock” they can be obtained from a wholesaler in a day or two.
You have been given very good advice so far, but I want to add another bit of information for your benefit:
Needing to replace just the front tires tells me that you have not been rotating the tires, and/or your truck is in serious need of alignment and/or front-end repair.
If you had rotated your tires every 5k or 7.5k, the wear on them would be even enough so that you would not be in a situation of having two tires that are much more worn than the others. While some people debate the economics of tire rotation per se, on a 4WD or AWD vehicle, it is really just plain bad economics to skip tire rotation.
If you will simply start rotating your tires (and/or seeing what type of attention your front end needs), you will no longer be in a situation of having tires with a different amount of tread wear from one axle to the other.
Agree on AWD, not 4WD. You are only going to use a true 4WD when you are on a very low friction surface. If you use 4WD on a high friction surface, you will ruin the transfer case in very short order no matter how well your tires are matched.
AWD is engaged full time. It has some type of differential in the transfer case, a true 4WD does not have a differential in the transfer case. The differential is usually some type of limited slip, it can tolerate intermittent differences in tire speeds for cornering and such, but it can/will suffer damage from a constant difference in rotational speed between the front and rear tires.
For those that still insist on tire rotation, I would suggest that the rotation should be based on tread depth, not miles. Get a tread depth gauge or a machinist pocket ruler and rotate the tires when the tread depth between the front and rear tires is 1/16" (2/32" on tread depth gauge). This give ample time to detect a tire wear problem from a alignment issue.
Alignment is the key to tire life, more than anything else. The difference between “in spec” and “right on” can mean a 2:1 or greater difference in tire life. The right on from the factory is for the average driver in average conditions. Your tires will tell if your vehicle should be adjusted a little off from the factory specs, or if it is even close enough to the factory specs for your driving style.