Spare Tire Question
Thread Starter
|
Senior User
Joined: Sep 2004
Posts: 447
Likes: 0
From: Colorado
Spare Tire Question
Hey guys just wondering about something and hoping you can help me.
I currently have 325/60R18s on my 09 F150 FX4 with a 2.5" LK. As of right now I have the stock 275/70R17 as a spare. I know that sounds weird to go to 18s from a 17 but the aftermarket 18s came off my old 2004 F150 that came stock with 18s.
Anyway my question is if I needed to use that spare would it work as far as my Trac Control and crap like that? Would it cause my roll stability and trac control to kick on even going in a straight line? Would it tear up a bunch of stuff?
Last question should I get a new spare that has an 18" rim and if so how small of a tire could I get away with as I do not want to carry around a 5th 325/60.
Thanks.
I currently have 325/60R18s on my 09 F150 FX4 with a 2.5" LK. As of right now I have the stock 275/70R17 as a spare. I know that sounds weird to go to 18s from a 17 but the aftermarket 18s came off my old 2004 F150 that came stock with 18s.
Anyway my question is if I needed to use that spare would it work as far as my Trac Control and crap like that? Would it cause my roll stability and trac control to kick on even going in a straight line? Would it tear up a bunch of stuff?
Last question should I get a new spare that has an 18" rim and if so how small of a tire could I get away with as I do not want to carry around a 5th 325/60.
Thanks.
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
325/60R18 = 33.354" diameter 605 revs/mile (unloaded)
275/70R17 = 32.157" diameter, 627 revs/mile (unloaded)
9.65% difference.
This is just a guess, but I'd say you're going to have issues.
A 295/70R17 = 33.26" diameter 606 revs/mile (unloaded) should work for a spare.
275/70R17 = 32.157" diameter, 627 revs/mile (unloaded)
9.65% difference.
This is just a guess, but I'd say you're going to have issues.
A 295/70R17 = 33.26" diameter 606 revs/mile (unloaded) should work for a spare.
Thread Starter
|
Senior User
Joined: Sep 2004
Posts: 447
Likes: 0
From: Colorado
Yeah I agree. It just hit me this morning on my way to work that my spare is basically a doughnut compared to the tires I run on it. At least if I go with your suggestion I wouldn't have to buy another wheel just a bigger tire.
Do you think that 295 would still fit under the truck where the spare is now?
Do you think that 295 would still fit under the truck where the spare is now?
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
Well, the 295 is only 1.1" larger (diameter). You could crawl underneath and see if there's a 1/2" space all the way around.
Or you could go find a cheap used 295 (junkyard), get it mounted, and try it out.
Or you could go find a cheap used 295 (junkyard), get it mounted, and try it out.
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
Thread Starter
|
Senior User
Joined: Sep 2004
Posts: 447
Likes: 0
From: Colorado
Trending Topics
Thread Starter
|
Senior User
Joined: Sep 2004
Posts: 447
Likes: 0
From: Colorado
OK I did some quick checking real fast on the Nitto website, not saying I'll buy the Nitto as a spare just using the site as research.
This is what I found according to their specs.
Currently on truck:
325/60R18 = 32.99 x 12.83 Rev/Mile 630
Possible spare sizes
295/70R17 = 33.19 x 12.13 Rev/Mile 626
285/70R17 = 32.72 x 11.46 Rev/Mile 635
Based on that data would the 285 work? I ask as I have a feeling the 285 size would be cheaper than the 295.
Again thanks for the help guys.
This is what I found according to their specs.
Currently on truck:
325/60R18 = 32.99 x 12.83 Rev/Mile 630
Possible spare sizes
295/70R17 = 33.19 x 12.13 Rev/Mile 626
285/70R17 = 32.72 x 11.46 Rev/Mile 635
Based on that data would the 285 work? I ask as I have a feeling the 285 size would be cheaper than the 295.
Again thanks for the help guys.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
Currently on truck:
325/60R18 = 32.99 x 12.83 Rev/Mile 630
325/60R18 = 33.354" diameter 605 revs/mile (unloaded)
Possible spares:
275/70R17 = 32.157" diameter, 627 revs/mile (unloaded)
285/70R17 = 32.72 x 11.46 Rev/Mile 635
295/70R17 = 33.19 x 12.13 Rev/Mile 626
The values from Nitto's site must include some squish/loading in the diameter calculation (or their tires do not follow the metric sizing 'perfectly').
Regardless, as long as it's temporary, I doubt the 5 revs/mile difference would cause any issues.
325/60R18 = 32.99 x 12.83 Rev/Mile 630
325/60R18 = 33.354" diameter 605 revs/mile (unloaded)
Possible spares:
275/70R17 = 32.157" diameter, 627 revs/mile (unloaded)
285/70R17 = 32.72 x 11.46 Rev/Mile 635
295/70R17 = 33.19 x 12.13 Rev/Mile 626
The values from Nitto's site must include some squish/loading in the diameter calculation (or their tires do not follow the metric sizing 'perfectly').
Regardless, as long as it's temporary, I doubt the 5 revs/mile difference would cause any issues.
Posting Guru
Joined: Feb 2005
Posts: 2,295
Likes: 2
Unless you have an exact match, you'll need to only mount the spare on a front wheel. If you have a flat on the rear, move a front tire back and mount the spare up front. That will save your rear end from chattering/binding due to unequal tires.
Resident smarta$$
Joined: Aug 2006
Posts: 4,929
Likes: 9
From: Oaks,PA
And burning up. Agreed with moving the spare to the front, more work but you wouldn't puke the rear. I wouldn't take the chance, unless you get the bigger and let a little air out of it so its the same height, that could possibly work, no?
Posting Guru
Joined: Feb 2005
Posts: 2,295
Likes: 2
It could, if you want to carry tools to measure down to a few hundredths of an inch to make sure!
Move the spare to the front, don't engage 4WD, and drive it easy (keep in mind you'll still have ABS challenges due to unequal front wheel speeds) to a tire shop. Or carry a matching spare...
Move the spare to the front, don't engage 4WD, and drive it easy (keep in mind you'll still have ABS challenges due to unequal front wheel speeds) to a tire shop. Or carry a matching spare...
Thread
Thread Starter
Forum
Replies
Last Post
BlackHogDown
1999 - 2003 7.3L Power Stroke Diesel
17
Apr 6, 2016 12:29 PM
