Topic Options
Rate This Topic
#151214 - 04/21/07 12:05 PM Tire Sizes on Stock Wheels
Beazy301 Offline
Junior Member
Registered: 04/21/07
Posts: 4
Loc: Fort Washington, MD
I'm new to this forum and I have a 2004 grand prix with the stock 16*6.5 wheels. Does anyone know what is the widest tire I can put on the stock wheel?
Top
#151215 - 04/23/07 12:21 PM Re: Tire Sizes on Stock Wheels
ILikeMyGP Offline
Member
Registered: 08/03/05
Posts: 54
Loc: Michigan
remember that changing the width of the tires will change the height as well. also don't forget that with wider tires tend to lead to a small wall thickness and that means the rims are bent easier.

well you can go with 55s or maybe even 50s,but i wouldn't go much wider. the main thing is if you really want wider tires you will want to go with after market rims as well

the other thing to remember is will they rub in turns. i haven't don't any real sizing up and its been a while sense i last did tire work so i can't give you exact sizes that would work
Top
#151216 - 04/26/07 05:51 PM Re: Tire Sizes on Stock Wheels
Beazy301 Offline
Junior Member
Registered: 04/21/07
Posts: 4
Loc: Fort Washington, MD
Preciate the info... Just trying to set up something that will make my grand prix handle like a champ as well as hook up for the quarter mile... Any suggestions would be greatly appreciated.
Top
#151217 - 04/27/07 08:46 PM Re: Tire Sizes on Stock Wheels
Chew Offline
Member
Registered: 05/01/02
Posts: 311
Loc: Washington, DC
Quick primer on tire tech.

225-60-16
225 = width in mm
60 = % ratio of tire sidewall height to width
16 = rim hieght.

I know ILikeMyGP is trying to give you some advice but he's getting his numbers crossed.

225mm = approx 8.8" wide (Yep squeezing 8.8" onto a 6.5" rim = not a good idea and one reason for the boatlike ride and slow reaction from steering inputs).

Most car manufacturers run 205 width tires on a 6.5" rim, so GM going with 225 on a 6.5" wide rim was partly cost cutting and partly to save unsprung weight on the wheel BUT each tire manufacturer has specific minimums of their own, in terms of what size tire for what size rim. Check your specific tire brand for theirs - it's the only way to avoid any legal disclaimers if you get into an accident resulting from tire bead rolling off the rim under hard cornering.

The widest tire I have seen used on stock rim - which I don't recommend - is 245-50-16

245mm wide (= 9.65" approx)
50% of 245mm at the sidewall
and of course still 16" in height.

Bottom line - if you want to run a wider tire, get a wider wheel. OEM stock is already pushing the limits.

FWIW.
_________________________
Regards,

Chew

2007 Sly Silver Pontiac Solstice GXP
Top
#151218 - 05/05/07 06:15 PM Re: Tire Sizes on Stock Wheels
Beazy301 Offline
Junior Member
Registered: 04/21/07
Posts: 4
Loc: Fort Washington, MD
Thanks man. For the advice and the lesson. Prolly leave it just like they are until I can upgrade the rims. Also when I press the brake pedal I hear a grinding sound and when just driving you can hear a slight screech. I have fairly new ceramic pads. Could it be my rotors. If not then what could it be.
Top
#151219 - 05/11/07 02:32 AM Re: Tire Sizes on Stock Wheels
ILikeMyGP Offline
Member
Registered: 08/03/05
Posts: 54
Loc: Michigan
first off, chew...no i'm not confused, but i did word things wrong, so sorry bout that..i worked in a tire shop for a few years so i do know a thing or two about tires, more then most people.

at any rate, the rotor thing...if there was a prob with the rotors then i think you would have noticed with the brake job, or informed if you had someone else do them. you can try to clean the area out a bit to make sure there isn't any dirt that is rubbing, but that sound generally is more of a grind then a screech.
Top