I practice law in Washington, DC, but I’m still an Ohio farm boy at heart. So, I recently ordered a new 2010 F-150 XLT Regular Cab (4x4) to replace my 2007 Cadillac STS. Given my profound lack of technical knowledge, however, I’m seeking your collective advice on tire selection. Among other options, I’m buying F-150 Platinum Edition 20” wheels. I measured the space between the tire wall and the inner arm of the left front tire of a 2010 F-150 Platinum Edition truck equipped with 20” Pirelli Scorpion ATRs and found 1” leeway. I did not examine the area between the tire and the inner fender for clearance with the wheel turned at full lock. With no intent to level or lift my truck, I need to understand minimum clearance requirements to avoid rubbing or other issues. Is 1” spacing necessary for the area described, or is a ½” gap sufficient to avoid all rubbing issues with the interior sidewall of the front tire? In order of preference, I would like to install the (#1) Nitto Terra Grappler 305/50/20, (#2) Nitto Terra Grappler LT285/55/20, or (#3) Nitto Terra Grappler 275/55/20. Below are the manufacturer specifications for the Pirelli Scorpions (standard of comparison) and the Nittos:

Scorpion ATR 275/55/20 = width 11.3”/overall diameter 31.9”.

#1 Nitto Terra Grappler 305/50/20 = 12.20” width/overall diameter 32.09”.

#2 Nitto Terra Grappler LT285/55/20 = 11.73” width/overall diameter 32.28”.

#3 Nitto Terra Grappler 275/55/20 = 11.10” width/overall diameter 31.80”


The Nitto 305/50/20 hypothetically takes up approximately ½” (half the overall increase in section width) of the 1” gap between sidewall and inner arm, leaving approximately ½” (the thickness of my index finger) leeway. The overall diameter increase appears to be fairly slight. Will my #1 tire selection work? The Nitto Terra Grappler LT285/55/20 may fit, but I heard that LT tires are heavier, consume more gas, and ride much rougher then the P-rated tire. The Nitto Terra Grappler 275/55/20 is simply my fall-back tire because it meets standard Ford specifications for the original equipment issued on the Platinum Edition. “Gtullous”, an F-150 Online Forum member, posted pictures of his 2009 F-150 Platinum Edition truck with Cooper Zeon LTZ 305/55/20s and he experienced absolutely no rubbing issues after 400 miles! Assuming that his wheels and inner wheel well area are identical to my 2010 Regular Cab XLT, I believe the Nitto Terra Grappler 305/50/20s will fit! But what do I know?

To Wandell & Company, I apologize for the length of this dissertation and thank you in advance for your collective wisdom in straightening out a confused lawyer.

 

wow a lawyer who knows how to prepare a good list of suggestions and does his homework in advance to come up with multiple scenarios of pertinent examples seeking input from the varied masses.
#1 welcome to the forum
#2 nice choice on the truck
#3 i lived in severn and odenton by ft. meade for 10 years and know those winters
#4 you got to be a defense lawyer lol.

people will chime in with their opinions and experiences. just wait they will be here.

 

papajohn:

Your speculation is uncanny! In fact, I do maintain a private criminal defense practice with prior experience as a former Special Assistant United States Attorney and Army JAG. I know my way around a courtroom and I imagine I can still help my Dad out on his Ohio farm, where he raises dairy beeves (Holsteins) and veal. Lord knows I miss Ohio! But I am clueless when it comes to the intricacies of Ford truck mechanics. That is why I've turned to this forum for guidance. Its amazing how much respect F150 Online has from my Ford service manager and various tire outlets. Any good lawyer knows when he must rely on experts; so too with tire selection. Wandell, PawPaw, and several others here offer an uncanny amount of insight into everything surrounding the F-150.

 

Welcome, good to see a member with the ability to convey your message/questions clearly ( though not quite concisely )!

Welcome to the forum, not only will you find tons of information on your new truck, you might be come across some interesting characters here too.

Do you have any intention of "modding" or upgrading your truck? Even if you don't, if you spend any time around here you'll find yourself slowly getting sucked in.

I'm not as up to speed on the 09+ models, but I think any of those tire selections should fit without issues. As for P vs LT tires, what's the primary use for your truck, daily driver, road trips, hauling/towing, offroading, etc?

- NCSU

 

NCSU:

Thanks for the welcome. Since when are lawyers concise?

I plan on adding the Truxedo LoPro soft tonneau cover, chrome exhaust tip, Platinum Edition 20" wheels, Nitto tires, and wheel lip covers. The truck will arrive from the factory with Ford SYNC, drivers package, XLT convenience package, SIRIUS radio, reverse sensing system, rear view camera, remote start, 4.6L V8, 3.73 limited slip, 6-speed automatic transmission, trailer tow package, and sliding rear window.

I will use the truck as my daily driver in the wilds of Northern Virginia and Washington, DC. I grew up with F-250 work trucks on the farm. I want this truck to look good - no hay bales, feed bags, farm equipment, etc.

One daughter just graduated from the University of Alabama and starts grad school in August. The other will be a sophomore at Ohio State this Fall. I no longer have to transport anyone, so I want a regular cab F-150 4x4 simply for my own selfish use. I love driving a truck! I've had BMWs, Jaguar S-types, a Porsche and a Cadillac STS, but I've also owned four trucks and a Hummer H2. Besides that, country music sounds better in an F-150.

I like the Nittos for their aggressive look and reviews indicate they are good performers on nearly every surface. The 305/50/20 adds a beefy look without sacrificing overall diameter inside the wheel well.

 

Without a leveling kit, I think the 305/50-20's or 285/55-20's will give you the look you want without any rubbing. As you have found in your research, a 305/55-20 may or may not touch the control arms at full steering lock. Now, this is very minor rubbing. In fact whether or not a 305/55-20 rubs varys from truck to truck and tire design to tire design.

 

i really like the tone of this thread, if only everybody expressed themselves this way more often!! welcome to the forum dave, before you know it well see you in the exhaust section of the thread, i dont think an exhaust tip will cut it on you new 4x4

 

Wandell:

As previously noted, with the Nitto Terra Grappler 305/50/20 I calculated an approximate 1/2" gap between the control arm and tire sidewall. Based on your assessment, I am confident that roughly 1/2" clearance is sufficient to avoid all rubbing issues in normal driving situations. With respect to overall diameter, I assume the 2/10" increase over the standard Pirelli Scorpion is statistically insignificant. Nor do I anticipate any problem with the Nitto Terra Grappler 305/50/20 protruding too far outside the front wheel well.

The Nitto Terra Grappler LT285/55/20 offers a conservative increase in section width and overall diameter, but I'm unsure whether the weight or rough ride of an LT tire outweighs anticipated size benefits.

In any event, Wandell, thank you for your very courteous and insightful response.

 

Fine Style 150:

I will likely be a mere observer on all technical issues, but certainly an admirer on matters of appearance. My expertise is limited to the courtroom, trust me.

F150 Online is a great forum. The tone remains generally moderate and forum veterans are exceptionally knowledgeable and prompt in their responses to lawyers who know........very little.

Thank you for welcoming me to the group!

 

Dave, I think the 305x50x20 which according to Nitto is an XL rated tire, kinda in between a P and a LT rated tire. It's rated at 50 psi max loaded and running them at 40-42 psi should give you the smooth ride you're looking for while still having the aggressive look's of an all terrain tire. Congrat's on getting the new truck also! Please don't sue me or any other's on here for any bad info you may get!

 

PawPaw:

Thanks for the advice.

I assume that tire size specifications for the Nitto Terra Grappler 305/50/20 are calculated at 50 psi. If one runs the tire at 40-42 psi, does increased tire softness also increase tire bulge, thus closing the gap between sidewall and control arm to a measurably significant degree? I am clueless. I know nothing of tire compression, tire rigidity, air pressure, or blue moons, for that matter.

By the way, I assume all the risk for acting on any advice issued in good faith by the members of this forum. I've followed the folks here long enough to see that everyone looks out for one another with the very best of intentions. Any rogue advice will be quickly spotted and corrected by vigilant forum members, I'm sure, so I'm not worried. If I buy the 305/50/20 Nitto Terra Grapplers and they rub, the onus is on me. No one forces anyone to act on information passed along on F150 Online.

 

According to Nitto's website, they recommend a 9.5" rim for the 305/50/20 Terra Grapplers (although they show 8.5" to 10.5" as acceptable). I believe that the Ford 20" rims are a little narrower. Tires perform best when fitted to the appropriate width rim...going with a too narrow rim bows the tread surface while too wide tends to cup it. So as a lawyer, you would understand why some tire dealers will not install "plus sizes" on stock rims. In the past, I've used wider tires than recommended on my vehicles and both tread wear and handling suffered as a consequence. Rubbing might be the least of your concerns.

 

GoingGoingGone:

Your observation appears to be both logical and sound. Just how bad is the wear and tear you describe if, for example, the Ford Platinum Edition 20" wheel is 8.5 versus 9.5 (measured rim per Nitto)?

My research shows that section width decreases by 2/10" for every 1/2" decrease in rim size. Accordingly, the Nitto Terra Grappler 305/50/20 tires, which has a 12.20" width on a measured rim of 9.5", should hypothetically have an 11.80" width when mounted on the Platinum Edition 20 x 8.5 rim. The outside sidewall of a narrower wheel will be tucked further inside the wheel well, whereas a wider wheel will push the sidewall out more. Additionally, a narrower rim pulls the beads closer together, curving the sidewalls. Increased curvature allows the sidewall to flex more readily over bumps and absorb more road shock during driving, thereby offering a softer ride. Every source I checked stressed the fact that rims must be within the approved range. Am I in over my head or what!

Any further thoughts on this subject?

Thanks again to everyone for your insights into the F-150!

 

THe OEM 20's are 8.5 inches wide so any of the tires you are considering will work fine.

 

Wandell:

You have me 100% convinced me that the Nitto Terra Grappler 305/50/20 will work on my truck! Because of my inexperience and overall lack of technical knowledge, however, I am really trying to learn something here.

Since width decreases by 2/10" for every 1/2" decrease in actual rim size (8.5") from the manufacturer's "measured rim" (9.5"), will the Nitto Terra Grappler 305/50/20 decrease from 12.20" to 11.80" on my truck? Also, will there be any change to the overall diameter from this configuration? Academic curiosity is killing this cat.....

Thanks, Wandell.