Max optimal tread width to rim width chart?

chimchimm5 · 01-12-2007, 05:56 PM

Is there a chart or guideline as to what the optimal tread width to rim width is?

What I'm getting at is if the tread is narrower than the rim, then the sidewall would camber in from the rim edge (bead) and says you could have gone bigger (for more traction). If the tread is wider than the rim, then the sidewall will have to bulge out over the rim like a beer gut and the deformation reduces the effectiveness of the extra tire area.

So there must a window of balance between diminishing returns. On the stock 06 17" wheel, it's 215mm vs 7". 215 millimeter = 8.464 inch so the stock tire is wider than the rim. Is this why 225 is already pushing it on the stock rim?

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DrD · 01-12-2007, 09:38 PM

People run 225s on the 16x6.5 rims which come one the 02-05 cars without too much fuss - why do you think 225 is pushing it on the 06/07 rims? Shouldn't be a problem at all.

As far as workable rim widths for a tire, on the tire rack site if you look at the spec table for a given tire, they show you the recommended rim width for each size.

BIGSKYWRX · 01-12-2007, 11:27 PM

There is a "general" rule of thumb to use a rim width that is 90% of the tread width (not section width).

For a 225/50/16 tire- tread width varies but is usually in the 8.3" ish range= 90% is 7.47" or 7.5"

Just a general rule of thumb

01-12-2007, 05:56 PM	#1
chimchimm5 Scooby Guru Member#: 88501 Join Date: Jun 2005 Chapter/Region: BAIC Location: NorCal Vehicle: 2006 WRX Wagon CGM	Max optimal tread width to rim width chart? Is there a chart or guideline as to what the optimal tread width to rim width is? What I'm getting at is if the tread is narrower than the rim, then the sidewall would camber in from the rim edge (bead) and says you could have gone bigger (for more traction). If the tread is wider than the rim, then the sidewall will have to bulge out over the rim like a beer gut and the deformation reduces the effectiveness of the extra tire area. So there must a window of balance between diminishing returns. On the stock 06 17" wheel, it's 215mm vs 7". 215 millimeter = 8.464 inch so the stock tire is wider than the rim. Is this why 225 is already pushing it on the stock rim? * Registered users of the site do not see these ads.

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01-12-2007, 09:38 PM	#2
DrD Scooby Guru Member#: 22412 Join Date: Aug 2002 Chapter/Region: SWIC Location: Albuquerque, NM Vehicle: 2012 Legacy 2.5GT Ice Silver Metallic	People run 225s on the 16x6.5 rims which come one the 02-05 cars without too much fuss - why do you think 225 is pushing it on the 06/07 rims? Shouldn't be a problem at all. As far as workable rim widths for a tire, on the tire rack site if you look at the spec table for a given tire, they show you the recommended rim width for each size.

01-12-2007, 11:27 PM	#3
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	There is a "general" rule of thumb to use a rim width that is 90% of the tread width (not section width). For a 225/50/16 tire- tread width varies but is usually in the 8.3" ish range= 90% is 7.47" or 7.5" Just a general rule of thumb