275/40/19 instead of 255/40/19

Have an Ecoboost with PP and a 1" drop. For the time being until I get a completely new wheel/tire setup down the road I'd like to do a swap for the 255/40/19s currently on the PP with 19X9 45ET with just new tires that are 275/40/19. I don't think there will be any clearance issues but I wanted to make sure. Anything for me to worry about?

275 is kinda wide for a 9 inch wide rim .. i know i had 255/40s on my old challenger on the front and i had a weeee little bulge . mine where 255/40/20s on a 9 inch rim.. pic if that helps.. sorry thats the only one that will load right .. the rear is a 275/40 on a 10.5 inch rim . i should have went bigger but. ah well

My 2003 Cobra came stock with 275's on a 9 inch wide rim if that tells you anything.:shrug:

Most of the serious autox guys run 275/35/19 on stock GT PP wheels so you shouldn't have any issues.

okanizer3 said:

Have an Ecoboost with PP and a 1" drop. For the time being until I get a completely new wheel/tire setup down the road I'd like to do a swap for the 255/40/19s currently on the PP with 19X9 45ET with just new tires that are 275/40/19. I don't think there will be any clearance issues but I wanted to make sure. Anything for me to worry about?

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Something to consider is the diameter difference, the 275's will be taller by about 7 tenths of an inch. Speedo will be off by about +1.6 mph at 60.
Clearance shouldn't be a problem at all.

thanks everyone... I get different opinions about the 275 on a 9" the tire spec says ok (9"-11") but some say it will bulge, some say it will be fine... I am going to stick with the Pzeros as I like them ( I know most hate them) and from looking at a bunch of pics it seems they fit the 9" rim nicely for a 275... Was mainly worried about clearance issues with the 1" drop... The tire shop is giving me a decent deal, $215 per tire installed but said if it doesn't fit I am stuck with them... they will check strut clearance just to be safe but I didn't want to go through all the motions if there is no chance of fitting. I feel a little better now that many members are running a 275/40/19 on a 9" up front with no issues... I guess I'll find out tomorrow...

Is it tire bulge or rim protection...hmmm

In my experience the 275 on a 9" rim causes the tire to loose foot-print and grip; also tends to squirm a bit in roll-over. The better match is a 255 on a 9". I'd go so far to say that a 275 on a 9.5" is not optimal despite Ford's choice for the PP wheels. Check out the GT350 and R. The factory sizes look stretched over the wheels.

qtrracer said:

In my experience the 275 on a 9" rim causes the tire to loose foot-print and grip; also tends to squirm a bit in roll-over. The better match is a 255 on a 9". I'd go so far to say that a 275 on a 9.5" is not optimal despite Ford's choice for the PP wheels. Check out the GT350 and R. The factory sizes look stretched over the wheels.

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what's your choice for a optimal tire/wheel size?