Ground clearance questions

[Brad Walters]

Hi guys,

Was hoping you all could provide some answers (very knowledgeable folks on here, I have found)

1) How exactly is ground clearance on our vehicle measured? Ford lists 7.6" but I'm wondering where they got that number? I installed a Truxxx 3" spacer lift kit, and I'm getting 10.5" to the muffler, which seems to be the lowest point, but is that accurate?

2) With regards to the 3" Truxxx kit, if I go from 245/60s currently on it to 255/70s, will that improve my clearance? A 245/60 is 29.1" diameter while a 255/70 is 32.1".

Thanks guys

 

[peterk9]

While it will give you some more clearance, going from 245/60R18 to 255/70/18 is not a very good idea. The general rule is that you should not exceed the OEM maximum diameter size by more than 3%. The difference here is 8%. Tire size calculator: compare tires online
The extra weight will also put more strain on the suspension parts as well as the brakes. It will negatively affect some of the electronic systems like ABS and Traction Control, not to mention your speedometer.

Peter

 

[J_C]

^ 3% seems very conservative. Even Ford themselves went with a 4% difference for 2nd gen Explorers equipped with either 235/75R15 or 255/70R16, and lots of people have upgraded those to larger tires.

 

[peterk9]

If those were factory installed tires then they were OEM and the difference would be 0% since the vehicle and components were designed for them. Also, those generations did not have all the electronic computer systems the 5th and 6th gens. do.

Peter