Educate me on spare tires!

[Abbie]

Hello everyone!

So i just swapped my run-flats with conventional tires R18 tires and getting ready to pull the trigger on a spare/space saver and realize that no one has addressed the following question.

does the spare tire/wheel need to be of the same diameter?

So... to be specific, if my car has 225/45R18 tires on it, do i need to consider a "17 spare or "18 spare?

Thanks everyone for weighing in!

[kiloTHREE]

The tire should be roughly the same diameter, minimum wheel size has to be 17 on a 35i and 16 on a 28i.

[Abbie]

Originally Posted by kiloTHREE

The tire should be roughly the same diameter, minimum wheel size has to be 17 on a 35i and 16 on a 28i.

Thank you! So driving on a "17 spare while the 3 others are "18 should be ok for a short distance?

[LevinBR]

I would definitely try to look for the same diameter spare. Mismatching wheel/tire diameters is generally not a good idea with an AWD car.

[woodman411]

Abbie didn't mention if she has an xDrive or sDrive. If she has an xDrive, this thread is worth a read, scary thought if tires are mismatched: http://www.bimmerfest.com/forums/sho...d.php?t=761193

[vstolpner]

Abbie, don't forget you have the option to get a can of slime and a compressor. They're cheaper, lighter, and take up less room than a spare.

[kiloTHREE]

Originally Posted by LevinBR

I would definitely try to look for the same diameter spare. Mismatching wheel/tire diameters is generally not a good idea with an AWD car.

Wheel diameter has zero bearing, all you need to be concerned about is overall tire diameter.

[themishmosh]

I keep slime, a plugging kit, a compressor, and a spacesaver kit in my trunk. I just want to have options.

[kry226]

Originally Posted by kiloTHREE

Wheel diameter has zero bearing, all you need to be concerned about is overall tire diameter.

This is true, but I have yet to see one wheel/tire combo the same overall diameter as a differently sized wheel/tire combo. Or at least close enough to where I felt comfortable running it. Even with the 225/45-18 and 225/50-17, there's just too much difference for my taste, especially in an AWD situation.

The OCD in me ensures my spare is the exact same dimensions as the other four tires. Actually, I do a five tire rotation most of the time anyway, so my "spare" is an exact copy of the other four.

[Abbie]

First, i'd like to thank everyone for responding. You guys really rock!

Second, i want to thank you for truly educating me on this. I had no idea that a difference in wheel/tire combo would have such a HUGE (read with a trump voice) impact on my little car

Third, for the sealant solution (where i am leaning), is Slime a better alternative than the conticomfort kit offered by continental?

[kiloTHREE]

Originally Posted by Abbie

Third, for the sealant solution (where i am leaning), is Slime a better alternative than the conticomfort kit offered by continental?

I would avoid slime and get a good plug kit.
If you go the slime route, and you have to use it, tip your tire guy well. It sucks ass having to patch or remove a tire from a rim when someone puts that crap in there.

[Abbie]

A quick thank you to everyone who weighed in and responded.

I ended up going the route of buying a tire plug kit, some slime, and a hydraulic jack.

will attempt to plug the tire myself, but if all else fails, will have to rely on slime!

[vstolpner]

I'm not sure about this so better if someone with some knowledge chimes in. But I would think the reaming part of the tire plug process would make the whole too big to be fixed by slime... So it might be one or other. But of course it is best to have options available to you when you're stuck at the side of the road.

[LevinBR]

Originally Posted by Abbie

Hello everyone!

So i just swapped my run-flats with conventional tires R18 tires and getting ready to pull the trigger on a spare/space saver and realize that no one has addressed the following question.

does the spare tire/wheel need to be of the same diameter?

So... to be specific, if my car has 225/45R18 tires on it, do i need to consider a "17 spare or "18 spare?

Thanks everyone for weighing in!

Abbie, how does the ride feel with conventional tires? Is it smoother than it was with run-flats?