Dear Bree,

Recently, I took my car in somewhere (not an RNR location) for new tires, and my boyfriend just noticed that I have three matching tires and one tire of a different size and brand.  He told me to take it back to the shop immediately, but do you know what a pain in the tush it is to make time for things like this?  I had to shift everything around just to fit in the first appointment!  So, here’s the question: Is it really a problem to have tires of two different sizes on the front of my car?

Lazy in Lakeland

 
Dear Lazy,

Long story short: Yes, it is a problem to have two tires of different sizes on the front (or back) of your car.  Having two different-sized tires on the same axle is generally not a good thing.  If the diameter of the two tires is close, then the rolling radius is about the same, so in the short term, you probably won’t have any damage, but long term, you run the risk of messing up your car’s differential.

The simplest explanation of differential is that it lets your wheels spin at different speeds.  This is important because when you turn your car, the wheel with less distance to go (the inside wheel) will roll more slowly than the wheel on the outside.  Likewise, the wheels in the back will travel more distance than the ones in the front, so they will turn more quickly than the front tires.  Differentials allow your wheels to do this.  If your wheels all traveled at the same speed (no differential) all the time, the wheels would have to be locked together and turning would be difficult and hard on your car (it would strain components in the axle).  This is why, when your tires (on the same axle) wear unevenly, you still need to buy two tires instead of just one.  So, differentials are important and you don’t want to go messing yours up because someone else made a mistake and you were too lazy to fix it, right?

Sometimes, people choose to put larger tires on the rear axle of their vehicle for handling reasons, cosmetic reasons, etc. Before you make a decision like this though, you should take a look at your vehicle’s manual and see what tire and wheel sizes are recommended.  Also, discuss this with a professional, someone in the know about tires, wheels, and how different sizes affect vehicles, and what changes may need to be made to accommodate larger wheels or tires.  You’ll find people in the know at your local RNR store and you shouldn’t hesitate to contact them before you make a decision like this.  For now, though, this is not your issue.  Your issue is having two differently sized tires (of different brands) on the same axle, and we just can’t recommend this.

Something else to think before you let laziness get the best of you.  What do you know about this off tire?  Are you familiar with the brand?  Is the quality better or worse than the tire you paid for?  Does it look different than the other tires in a noticeable way? In the end, this is not your mistake, it’s a mistake made by the store you paid to do work for you, and it’s their problem to fix.  Call and talk to them about scheduling and make sure you get a time that’s convenient for you to take your car in.  Don’t let a mistake like this lie, Ms. Lazy.  And the next time you need some new tires, come see us at RNR.  We can set you up on a payment schedule that works for you, if needed, and even better, get your tires put on correctly in a timely manner!:)  And we’ve got some perks if you buy a set of new tires with us, like FREE rotating and balancing as long as our tires are on your vehicle.  Hope this problem gets resolved fast!  Be safe!

Bree