Emergency Wheel for E53 with 20" style 87

Overboost · #1 01-21-2018, 08:51 PM

I browsed around the forums looking for the correct emergency wheel tire for my X5 running 20" style 87. I see a 19" emergency spare, is that the only option?

Currently have the full size 18" spare and although it may get me home but wouldn't want to put the diff through all that...

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PropellerHead · #2 01-21-2018, 09:43 PM

Quote:

Originally Posted by Overboost

I browsed around the forums looking for the correct emergency wheel tire for my X5 running 20" style 87. I see a 19" emergency spare, is that the only option?

Currently have the full size 18" spare and although it may get me home but wouldn't want to put the diff through all that...

My bet is that your tire height is similar for the two, so unless you're 3000 miles out and don't find a tire, I wouldn't worry.

The 4.8's have a little 18" donutty thing. I had a full size in my 3.0 so before I sold it, I swapped the two, spare tire lift straps and all.

But this December, I finally changed over to a 19" from an E70 so it would clear the big brakes.

Overboost · #3 01-21-2018, 09:55 PM

Quote:

Originally Posted by PropellerHead

My bet is that your tire height is similar for the two, so unless you're 3000 miles out and don't find a tire, I wouldn't worry.

The 4.8's have a little 18" donutty thing. I had a full size in my 3.0 so before I sold it, I swapped the two, spare tire lift straps and all.

But this December, I finally changed over to a 19" from an E70 so it would clear the big brakes.

I am not opposed to the donutty thing if that is the right way to do it (it is for emergency only) but maybe a spare front 9,5x20 style 87 with a 275x40x20 would be the way to go? Do you know if anyone has ever tried to fit one in the tub?

Is the 19" emergency using a run flat the largest and the proper wheel for the X5 with 20" OEM spec wheels? I can't find any info on a 20" emergency wheel.

Doesn't the E70 have a larger wheel hub size needing a hub centric ring?

Fifty150hs · #4 01-21-2018, 10:24 PM

Quote:

Originally Posted by Overboost

I browsed around the forums looking for the correct emergency wheel tire for my X5 running 20" style 87. I see a 19" emergency spare, is that the only option?

Currently have the full size 18" spare and although it may get me home but wouldn't want to put the diff through all that...

You can run a 17" with the correct tire. The overall tire diameter is essentially the same so it won't throw codes. You're not going to leave it on long anyway and the 17 actually fits the spare tire well.

oldskewel · #5 01-21-2018, 10:28 PM

I have a 3.0i, with 19" wheels - 285/45R19 107V rear; 255/50R19 103V front; 235/65R17 spare

I once calculated the rolling diameters of these and found that they are extremely close, which makes sense since BMW designed it that way.

To keep your differential and transfer case happy, you just need the rolling diameter (radius, circumference, etc.) close enough.

Quick calculations on your tire size vs. my 17" spare shows them 1.3% apart (your 20 is actually the smaller of the two. My 19's are even closer than that.

radiuses calculated here in inches:
17/2 + 235*0.65/25.4 = 14.51
19/2 + 285*0.45/25.4 = 14.55
20/2 + 275*0.40/25.4 = 14.33

So if a 17" spare will clear your brakes, it should not cause problems with the diff and TC.

Overboost · #6 01-21-2018, 10:54 PM

Quote:

Originally Posted by oldskewel

I have a 3.0i, with 19" wheels - 285/45R19 107V rear; 255/50R19 103V front; 235/65R17 spare

I once calculated the rolling diameters of these and found that they are extremely close, which makes sense since BMW designed it that way.

To keep your differential and transfer case happy, you just need the rolling diameter (radius, circumference, etc.) close enough.

Quick calculations on your tire size vs. my 17" spare shows them 1.3% apart (your 20 is actually the smaller of the two. My 19's are even closer than that.

radiuses calculated here in inches:
17/2 + 235*0.65/25.4 = 14.51
19/2 + 285*0.45/25.4 = 14.55
20/2 + 275*0.40/25.4 = 14.33

So if a 17" spare will clear your brakes, it should not cause problems with the diff and TC.

Great info, thanks!
So I guess my 18" 255x55x18 should be close enough?

18/2 + 255*0.55/25.4 = 14.52
20/2 + 275*0.40/25.4 = 14.33
20/2 + 315*0.35/25.4 = 14.34

bmw540san · #7 01-21-2018, 10:58 PM

Have you checked real oem? They should have a list.

Overboost · #8 01-21-2018, 11:07 PM

The largest emergency wheel I found for the E53 was 19". There are a couple on fleaBay for $250 + shipping but I am guessing from this thread I may not need to do anything and I am obsessing over nothing?

Qsilver7 · #9 01-21-2018, 11:25 PM

If you look at the tire pressure chart on your driver's door door/jamb...or in the owners manual...BMW gives multiple tire size recommendations.

ALL of the tire sizes listed in the owners manual and door jamb are within allowable rolling diameter/circumference specifications and can be used.

But as mentioned above...the spare tire well will only fit either the 17" (possibly the 18", too) tire/wheel combo. The 19" & 20" wheel/tire combo will stick up to far to allow the cargo floor to fit properly in place.

My 06 came with 18" 153 wheel style...but the spare is a 17" wheel/tire combo. BMW started putting the smaller spare back around the early 2000s (to save money). The first time I heard of it was for the 2003 e39 model year. There were guys/gals that had ordered the 540i M-sport which was supposed to come with five 18" Style 37 MPars...but some started getting letters from BMW that they would only get four 18" MPars, and the spare would be a lesser 17" wheel/tire.

Again, all of the tire sizes listed in the pages from the owners manual below have the same rolling diameter/circumference and can be mounted without causing issues. In fact, the standard spare tire/wheel for the 18"/19"/20" set-ups is the 17" spare tire/wheel...unless you have the compact 19" emergency spare tire: