[CharPatton]

Hi:

Would appreciate some advice regarding the best approach to obtaining compatible runflat snow tires for our new plug-in hybrid.

Option 1 would be to buy just 19***8221; snow tires to swap out the existing 19***8221; All Weather tires.

Option 2 would be to buy the snow tires and accompanying wheels/rims.

What do you experts think? A couple other points:
1. If wheels/rims AND tires, should we get steel wheels/rims? Are these OK with the BMW? Some folks say steel is better cuz cheaper and more durable to dings.
2. Where do the tire pressure monitoring devices fit into all this strategy? I***8217;ve heard that some shops won***8217;t put on tires without these now due to new laws. If so, does one have to buy an extra set of 4 tire pressure monitors? It***8217;s been a long time since I***8217;ve had a new car so I don***8217;t understand these.
3. I know nothing about tires, but would there be any reason to buy 18***8221; rims and 18***8221; snow tires for better durability if we are buying wheels/rims (instead of 19***8221; wheels/rims and 19***8221; tires)?

Any and all advice greatly appreciated! Thank you.

 

[smashmonkey]

Option 1 would be to buy just 19" snow tires to swap out the existing 19" All Weather tires.

Option 2 would be to buy the snow tires and accompanying wheels/rims.

What do you experts think? A couple other points:
1. If wheels/rims AND tires, should we get steel wheels/rims? Are these OK with the BMW? Some folks say steel is better cuz cheaper and more durable to dings.
2. Where do the tire pressure monitoring devices fit into all this strategy? I've heard that some shops won't put on tires without these now due to new laws. If so, does one have to buy an extra set of 4 tire pressure monitors? It's been a long time since I've had a new car so I don't understand these.
3. I know nothing about tires, but would there be any reason to buy 18" rims and 18" snow tires for better durability if we are buying wheels/rims (instead of 19" wheels/rims and 19" tires)?

I've been using winter tire sets for decades. I have a winter set on 20" wheels nearly identical to the summer set. Recommend going with Option 2 and buying a set of inexpensive wheels and mounting the winter tires and TPMS. Easy swap twice a year. Also have a full size emergency set of in case a damaged wheel needs to be replaced/repaired.

Option 1 is not ideal. Mounting and dismounting tires on wheels repeatedly can damage the bead. Also, have to repeatedly pay for mounting/dismounting and rebalancing twice a year. Also, TPMS can accidentally get damaged during mount/dismount.

In winter the wheels can get damaged by pot holes and hidden curbs and road salt. Get inexpensive ones. I doubt there are steel wheels in the X5's size. Steel is cheaper and more durable, but heavier. Cheapie alloy wheels can be more easily bent.

I bought wheels and winter tires w/ TPMS from Tirerack and they mounted and balanced everything no extra charge. If you use RFT TPMS are required, otherwise you may not realize the tire is flat and have an accident. I recommend TPMS for whatever tires.

For winter tires RFT are more expensive and heavier. Non RFT tires will give you more choice of tires and better ride and lighter unsprung weight. But the X5 40e has no storage for a spare, so you'd have to carry a can of fix a flat.

18" wheels will increase the amount of tire wall which can change the handling feel a little. But the big advantage will be more rubber to mitigate pot holes and curbs. It may also give you more tire choices.

When driving through snow/slush/ice a narrower tire tread will perform better because less surface area will cause the tire to dig in more. But on dry or wet cold asphalt a narrower tire may have less grip than a wider tire. A lot depends on how often the roads are snow/ice covered vs. cold and dry/wet.

 

[CharPatton]

Great detailed response

Thank you very much! Really appreciate your taking the time to share your expertise.