It's been awhile since I posted on here, but I am looking at buying a set of GXP rims and was wondering if there is going to be any changes as far as speedometer reading, or anything like that? Also I should be able to just put the rims on and not change anything else, right?

Thanks,
John

_________________
John
2003 SSEI - Nighthawk
Performance: Boat Roller Mount, Intense FWI, Moog Polyurethane End Links, 180* tstat, silicone vacuum lines
Appearance: "Supercharged" 3rd Brake Overlay, LED Interior Lights, RallyArmor Splash Guards, Red Calipers, HID retrofit, black GXP rims
Audio: Nothing... yet!

The internet is a wonderful thing full of tons of useless and a small fraction of useful information. I did this in <5 minutes after reading this post to get your answer.

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

Your stock tire size is 235/55/17. A GXP's tire size is 235/50/18

Diameter;
yours: 27.2"
GXP: 27.3"

Width;
yours: 9.25"
GXP: 9.25"

Sidewall;
yours: 5.09"
GXP: 4.63"

Circumference;
yours: 85.3"
GXP: 85.6"

Revs per Mile;
yours: 742.5
GXP: 740.4

So at 60MPH, your stock reading would be 60mph, with the GXP setup, it would be 60.2mph.

If you want to change tire sizes, that's a whole different ball of wax, but going stock size to stock size, it'll bolt on and you won't notice a difference.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

Ok thanks! Didn't even know that they had something like that... the wheels I'm looking at have 225 40r18s on them, so I'm not sure if thats good or bad...

_________________
John
2003 SSEI - Nighthawk
Performance: Boat Roller Mount, Intense FWI, Moog Polyurethane End Links, 180* tstat, silicone vacuum lines
Appearance: "Supercharged" 3rd Brake Overlay, LED Interior Lights, RallyArmor Splash Guards, Red Calipers, HID retrofit, black GXP rims
Audio: Nothing... yet!

That's odd, why would they go smaller/narrower tire like that? That thing would have to look like it's on bicycle tires... LOL!

Anyway, that makes a considerable difference, something like an 8% difference. I'd almost re-tire those wheels because of it.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

I'll check when I go to look at the tires, it could have been a typo or something...

_________________
John
2003 SSEI - Nighthawk
Performance: Boat Roller Mount, Intense FWI, Moog Polyurethane End Links, 180* tstat, silicone vacuum lines
Appearance: "Supercharged" 3rd Brake Overlay, LED Interior Lights, RallyArmor Splash Guards, Red Calipers, HID retrofit, black GXP rims
Audio: Nothing... yet!

Probably came off a Grand Am or something with a smaller OE tire size. Those tires won't work on your Bonne...

_________________
Bye Bye:

RIP sandrock

That depends on your definition of work... they will fit and roll / drive just fine, however they would look goofy and there would be a big funny looking gap between the tire and fender.

_________________
Ryan

2003 Bonneville SSEi - The Black Mirror SOLD!
2002 Bonneville SE - The Mutt Complete 2004 SLE interior, drivetrain, and body harness swap, ECC swap, HUD swap, black GXP wheels, GXP headlights and tinted tails - SOLD
2003 BMW 540i M Sport, 2001 BMW X5 4.4i, 2010 GMC Acadia, 2017 Grand Design Imagine 3150BH
1982 Cutlass Supreme - The fun one

That and the speedometer would be like 15 MPH off...

_________________
Bye Bye:

RIP sandrock

The guy did have them on a grand am wanted $700 for the complete set... I would buy them but I dont want to have to spend another $600-700 on a set of tires... guess I'll just have to keep looking.

_________________
John
2003 SSEI - Nighthawk
Performance: Boat Roller Mount, Intense FWI, Moog Polyurethane End Links, 180* tstat, silicone vacuum lines
Appearance: "Supercharged" 3rd Brake Overlay, LED Interior Lights, RallyArmor Splash Guards, Red Calipers, HID retrofit, black GXP rims
Audio: Nothing... yet!