With the front wheels turned, my daughter bumped the car next to her in a parking lot. There was no damage to the adjacent car. But, the suspect tire developed a slow leak. She thought she hit debris in the road and called AAA service. They found nothing wrong with the tread, but a bubble test showed that the bead of the tire is “broken”, like a seal, I imagine. The flat, suspect tire is off her car and replaced by a full-size spare. However, the two front tires don’t match.
They say not to drive this way - with mismatching tires. She needs the car tomorrow for a 60 mile commute round trip. Can she drive this way for 2-3 days at say up to 50mph max until we can get this solved? What if it were a donut spare? A donut would not match, and people drive on donuts.
Your thoughts and the whole story about mismatched tires on the same axle appreciated.
I’m not a tire expert, but I’ve heard that you have to be careful with front tires since they affect steering. I’ve heard that you shouldn’t have new tires on the back and old tires on the front. When you turn in that config, the grippy back tires will have a lot of push strength but the worn front tires may not have the matching grip strength to turn the car. The car may plow straighter than you might expect when you turn the wheel. As for mismatched front wheels, maybe one tire would grip more than the other and maybe affect steering. Or maybe cause the car to drift a bit while driving straight. Those things might be more of a factor when it’s wet. If it’s dry, it may not be as big of a deal. But as you know, people drive on spares/donuts all the time. So it’s probably something that has some risk, but may be mitigated if you’re careful and drive cautiously.
Yes, do this if it is a front wheel drive car. If it is an all wheel drive or rear wheel drive car then you might need to get four new tires, or possibly can find a single used tire that matches the other three.
I believe the problem is slightly different circumferences means the tires spin at different speeds, which is very stressful on the differential. If the different size tires are on the non-driven wheels, then spinning at slightly different speeds won’t matter.
I can’t say if 60 miles is enough to cause a very expensive problem, but it is probably safest to swap cars or something while hers gets fixed.
Yeah, I had a WAG that’d be the answer about donuts. I haven’t had one on the front end (driving wheels). On the rear for my CR-V, I never felt any real difference while maintaining 50mph max for 50 miles from home.
That thread is so passe. Now-a-days autos aren’t coming equipped with spare tires of any description but a sealer/inflator kit instead – useless if the tire’s been run flat before you noticed it. That’s what my '23 Bolt came with. Luckily there’s plenty of room in the bin behind the rear seat for a tire so I’m contemplating getting one.
Back in July I was in northern Nevada just west of Gerlach when I was flagged down by a woman in an Escalade. Turned out she was a tourist from Beijing in a rental who was touring the west. Her tire had ‘gone flat’ but she had no idea how to replace it – would I help? The tire actually was shredded, not just flat.
I took a quick peek under the bottom and did not notice a spare, so I was suspicious but looked in the back for where the tools or inflator might be. Two guys in a pickup stopped and one of us finally remembered, rental – it’s bound to have the manual still aboard. The compartment was above the left rear wheelwell and sure enough, an inflator kit – no tools. Useless with the tire ruined.
Luckily, being a rental, it was the company’s problem, we just had to get her within a phone service area. She was anxious to get to Cedarville, I think she had a room reservation there, so the pickup guys took her there. She was back in a tow truck after two hours so the Escalade went bye-bye towards Cedarville.
Now now, while that’s largely correct, some new vehicles come with ye olde donut. My wife’s brand new 2024 Rav4 Prime PHEV has a donut, and considering the crappy road conditions Colorado ends up with from out endless freeze/thaw cycles, it was a big plus.
That being said, my FiL’s new (1 year old now technically) extended cab pickup didn’t, which pissed him off to no end, so he bought a full size spare and chained it to the bed.
My (formerly my wife’s before we traded my ancient Subaru on the Prime) 2007 Rav4 has one of the rarest of rares - a dedicated full sized spare mount on the rear of the vehicle!
I’m still getting used to the top of it just appearing in my rear view mirror, but it’s shockingly comforting considering my earlier feelings on how bad some of my prior cars handled with a donut on the front end!
But -IF- you have the space and the $$$, nothings stopping you from getting a new/gently used full size spare and tossing it in the back just like my father-in-law.
You got me! But for the record, “on holidays” is the time he’d much prefer to be tossed in the back, to the extent that in years past he tried to arrange to head out to “help” my wife and I with some car-related or similar issues so he could escape.
ONE MORE Q: When “they” say two tires on the same axle should match, do they mean just tire size OR do they mean brand and everything down to the last detail such that even the tread pattern must match?
In theory, everything should match. In practice, two tires of the same size and similar tread are unlikely to cause you to crash.
But, I still wouldn’t do it.