Buying new rims/tires: does the spare size matter?

[RampantAndroid]

Hi all,

I've got a Audi A4 Quattro with the 19" summer tires on it. They're sized at 255/35ZR19. The spare size seems to be 125/70R19.

I'm looking to buy some winter tires and rims to match. It looks like the Michelin Pilot Alpin PA4s are a good set, but what size do I want to get? Do I need to be concerned with the size of my spare here? Will the spare always be a different outer diameter than the main tires? Do my winter tires need to be R19s, or can I buy an R18?

Thanks!

 

[JulesMaximus]

Only if you get a flat.

Going down to an 18" tire your only major concern would be brake clearance. Being an AWD car I'm sure the donut is matched to the diameter of the wheels the car came with so just make sure your 18s are the same outer diameter and you should be fine.

BTW-You know that donuts are only for emergency use only and should be used just to get you a garage right?

 

[someone16]

Check an audi forum and see what people use for winter tires. You can also call tirerack.com or discounttiredirect.com and I'm sure they will have recommendations.

Usually you downsize because its cheaper + more choices available. You can also go with more narrow tires so its easier to go through snow.

 

[herm0016]

your wheels are 18 or 19 inches.

Check the outside diameter, and match that as closely as possible when choosing tire size. this will ensure that your speedo and your AWD system work properly.

you can do this with smaller wheels and tires with a higher sidewall ratio.

on my truck (also AWD) I have 265-65-18 summer wheels and tires, and 265-70-17 winter wheels and tires. very close in outside dia.

As for winter tires, the best i have used are the blizzak dmv1, but I'm not sure they are available in car sizes.

 

[DaTT]

Check an audi forum and see what people use for winter tires. You can also call tirerack.com or discounttiredirect.com and I'm sure they will have recommendations.

Usually you downsize because its cheaper + more choices available. You can also go with more narrow tires so its easier to go through snow.

Definitely agree with the narrower tires for snow. I go from a 285 in the summer to a 215 in the winter

 

[DaTT]

Also, when looking for tires, look yours up first and get the rolling diam. Then match it with whatever you want to buy. As stated above, check to see with some Audi forums if a 18" rim will fit.

 

[Jimzz]

Only if you get a flat.

Going down to an 18" tire your only major concern would be brake clearance. Being an AWD car I'm sure the donut is matched to the diameter of the wheels the car came with so just make sure your 18s are the same outer diameter and you should be fine.

BTW-You know that donuts are only for emergency use only and should be used just to get you a garage right?

What!!! You mean I can't take a long trip on the highway at full speed? Balderdash!!!


I saw 4-5 cars on my last highway trip doing 60+ with spare tires on. 1 was in heavy rain.

 

[cbrsurfr]

Only if you get a flat.

Going down to an 18" tire your only major concern would be brake clearance. Being an AWD car I'm sure the donut is matched to the diameter of the wheels the car came with so just make sure your 18s are the same outer diameter and you should be fine.

BTW-You know that donuts are only for emergency use only and should be used just to get you a garage right?

Brake clearance on an A4 will not be a problem with 18". Just get the right offset. Audi forums will have info and tirerack will also list wheels that are compatible.

 

[EagleKeeper]

Donuts are not intended for highway speeds and should not be used for long distances.

However, some people do not care about their safety or that of others.

It is to much of an inconvenience to stop and get the flat repaired after work or they destroyed the primary tire and do not have the $75-$400 to replace the tire.

 

[RampantAndroid]

I know the donut is for emergency use only - I've never driven on one, simply used it when rotating tires myself in years past.

Does the tire list the outer diameter on the sidewall, or do I need to measure it on my own?

I've seen reports on Audi forums of the A4 taking 17" rims.

I'm thinking of the Michelin Alpin PA4s or the Ice-X Xi3s (but can't decide because the Xi3 will work better on ice but will suffer mushy steering and wear faster. The PA4s will be sportier and wear better but will not be as good on ice.) The size will likely be 245/40R18 - I'm a little limited on the outer diameter aren't I? What happens if the outer diameter is different than the spare and I need to use the spare?

 

[herm0016]

I know the donut is for emergency use only - I've never driven on one, simply used it when rotating tires myself in years past.

Does the tire list the outer diameter on the sidewall, or do I need to measure it on my own?

I've seen reports on Audi forums of the A4 taking 17" rims.

I'm thinking of the Michelin Alpin PA4s or the Ice-X Xi3s (but can't decide because the Xi3 will work better on ice but will suffer mushy steering and wear faster. The PA4s will be sportier and wear better but will not be as good on ice.) The size will likely be 245/40R18 - I'm a little limited on the outer diameter aren't I? What happens if the outer diameter is different than the spare and I need to use the spare?

http://tire-size-conversion.com/tire-size-calculator/

just stick with close to the stock tire dia. and dont worry about the spare, its the factory unit, and you are not changing from factory specs.

 

[DeviousTrap]

Your spare is fine, what maters is circumference/revs. I'd step down to 17s in the same size as the base model A4. Your spare is actually better matched circumference-wise to the base tires than your sport package ones.

225 / 50 / R17
Circumference 81.2
780.3, revs / mile

Your spare:
81.3 / 779.4

Your regular 19s:

81.7 / 775.3