Tire sidewall question... Who has the facts? - BMW 3-Series (E90 E92) Forum

Biimmer · 06-01-2010, 03:25 PM

So, I have been doing some tire research and I am seeing that a ton of people are going with a thinner sidewall for the rear tire setup ex: 235/35/19 front and 275/30/19 rear.

What is the reason for a thinner sidewall for the rear instead of maybe a thicker "rear" or perhaps a even sidewall setup?

Thanks for the help!

Tee212 · 06-01-2010, 03:33 PM

peformance aspects? hardly
most ppl choose this route due to clearance/speedo/looks

Biimmer · 06-01-2010, 03:50 PM

Still confused.. I have always thought that the "30" in a 275/30/19 tire would refer to the thickness of the sidewall. How does the width have any effect on the diameter/aspect ratio?

Thanks for the help I'm trying to learn

I335 · 06-01-2010, 03:53 PM

275 is the width of the tire
30 is the aspect ratio - 30% of the width
19 is the diameter

Tee212 · 06-01-2010, 03:56 PM

Quote:

Originally Posted by I335

275 is the width of the tire
30 is the aspect ratio - 30% of the width
19 is the diameter

3-2 =+1

Biimmer · 06-01-2010, 04:02 PM

So based on the width with a 235/35 and 275/30 the aspect ratio would be the same?
I want the sidewall thickness in the front to be equal to the rear. I wouldn't be a fan of the look when running a lower profile tire in the rear. ** if people are even doing that**

Thanks!

Biimmer · 06-01-2010, 04:07 PM

Quote:

Originally Posted by Tee212

3-2 =+1

Thanks, I didn't have a calculator handy.

kramerica72 · 06-01-2010, 04:20 PM

Quote:

Originally Posted by Biimmer

Still confused.. I have always thought that the "30" in a 275/30/19 tire would refer to the thickness of the sidewall. How does the width have any effect on the diameter/aspect ratio?

Thanks for the help I'm trying to learn

If you are talking about the distance from the rim edge to the tread, you'll want to refer to it as "sidewall height."

Sidewall "thickness" denotes something else completely--(i.e. RFT sidewalls are thicker so they won't collapse when punctured)

Biimmer · 06-01-2010, 04:55 PM

Quote:

Originally Posted by kramerica72

If you are talking about the distance from the rim edge to the tread, you'll want to refer to it as "sidewall height."

Sidewall "thickness" denotes something else completely--(i.e. RFT sidewalls are thicker so they won't collapse when punctured)

Thx, but you know what I'm refferimg to as my initial question was not about "Run Flats".

Biimmer · 06-01-2010, 05:14 PM

BTW Thanks to everyone who helped :-)

Orient330iNYC · 06-01-2010, 09:47 PM

275/30/19

275 is the width
30 is the aspect ratio, ratio of sidewall height to width.

so the sidewall height is 275 *0.30=82.5mm
235/35/19
235*0.35= 82.25mm

sidewall height almost exactly the same

Biimmer · 06-02-2010, 12:39 AM

Quote:

Originally Posted by Orient330iNYC

275/30/19

275 is the width
30 is the aspect ratio, ratio of sidewall height to width.

so the sidewall height is 275 *0.30=82.5mm
235/35/19
235*0.35= 82.25mm

sidewall height almost exactly the same

Thanks, I completely understand now

Hey, I guess you learn something new everyday!

**Gary@TireRack** · 06-02-2010, 12:13 PM

Tech Rat's first reply had a link explaining it all.

Biimmer · 06-02-2010, 09:33 PM

Quote:

Originally Posted by Gary@TireRack

Tech Rat's first reply had a link explaining it all.

Thanks Mr. TireRack.

06-01-2010, 03:25 PM	#1
Biimmer Enlisted Member Drives: 08 e92 335i Join Date: Jun 2010 Location: Phoenix, AZ Posts: 37 iTrader: (0)	Tire sidewall question... Who has the facts? So, I have been doing some tire research and I am seeing that a ton of people are going with a thinner sidewall for the rear tire setup ex: 235/35/19 front and 275/30/19 rear. What is the reason for a thinner sidewall for the rear instead of maybe a thicker "rear" or perhaps a even sidewall setup? Thanks for the help!
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06-01-2010, 09:47 PM	#11
Orient330iNYC Major Drives: 2013 335i M Sport Join Date: Apr 2007 Location: Wall St Posts: 1,336 iTrader: (2)	275/30/19 275 is the width 30 is the aspect ratio, ratio of sidewall height to width. so the sidewall height is 275 0.30=82.5mm 235/35/19 2350.35= 82.25mm sidewall height almost exactly the same __________________ Past: 2001 Orientblue E46 330i Past: 2004 S60R 6MT Past: 2007 E90 335i 6MT Past: 2010 335xi ZMP, BMW Performance Kit, BMW Performance Exhaust Present: 2013 335i 6MT ZMM/ZDH/ZTP/3AG/494/508

06-02-2010, 12:13 PM	#13
Gary@TireRack Moderator Drives: Formerly 1995 M3 Join Date: Oct 2006 Location: South Bend, IN, Tire Rack HQ Posts: 2,862 iTrader: (1)	Tech Rat's first reply had a link explaining it all. __________________ Gary Tire and Wheel Forum Moderator The Tire Rack, Sales Rep Gary@Tirerack.com http://www.tirerack.com/a.jsp?a=AH8&url=index.jsp 1-877-522-8473 ext 386 Refer to 'Gary/E90Post' as your previous contact when you order online. Credit E90post.com by ordering through the sig link.

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06-01-2010, 03:33 PM	#2
Tee212 Banned Drives: yes Join Date: Oct 2008 Location: Riverside Posts: 4,550 iTrader: (9) Garage List 2010 335 [4.83]	peformance aspects? hardly most ppl choose this route due to clearance/speedo/looks

06-01-2010, 03:50 PM	#3
Biimmer Enlisted Member Drives: 08 e92 335i Join Date: Jun 2010 Location: Phoenix, AZ Posts: 37 iTrader: (0)	Still confused.. I have always thought that the "30" in a 275/30/19 tire would refer to the thickness of the sidewall. How does the width have any effect on the diameter/aspect ratio? Thanks for the help I'm trying to learn

06-01-2010, 03:53 PM	#4
I335 Brigadier General Drives: '08 335i Coupe Join Date: Jan 2008 Location: New England Posts: 4,261 iTrader: (11)	275 is the width of the tire 30 is the aspect ratio - 30% of the width 19 is the diameter

06-01-2010, 04:02 PM	#6
Biimmer Enlisted Member Drives: 08 e92 335i Join Date: Jun 2010 Location: Phoenix, AZ Posts: 37 iTrader: (0)	So based on the width with a 235/35 and 275/30 the aspect ratio would be the same? I want the sidewall thickness in the front to be equal to the rear. I wouldn't be a fan of the look when running a lower profile tire in the rear. if people are even doing that Thanks!

06-01-2010, 05:14 PM	#10
Biimmer Enlisted Member Drives: 08 e92 335i Join Date: Jun 2010 Location: Phoenix, AZ Posts: 37 iTrader: (0)	BTW Thanks to everyone who helped :-)