Ground clearance and tire size, old vs new trucks

[bd100]

Random thoughts comparing two vehicles:

Sometimes someone points out that in the "good old days" people did lots of offroading with 30-31" tires and it was fine. Now you seem to need 33" or better.

I did some measurements. My gen2 late 90s Ram 1500 has 10 inches clearance under the skid plate and transmission brace, no lift, stock sized 30.5" tires. And the back axle is leaf springs with nothing except the diff sticking down below the axle tube. The frame is tall and the body is above the frame. The only thing sticking below the frame is a brace for the single transfer case skid plate. The fuel tank is up high. Under the front axle there are the control arms like the JT, but the center is higher were breakover occurs.

The new JT Sport w/o lift has around 9" ground clearance in the middle under the transfer case. I added better skid plates with thick bracing and now it's 8". This truck has stock size 31.7" tires, no lift. I would need a two inch lift to equal the clearance of the old truck stock, or one inch if w/o the new skid plates. Lots of stuff sticks down below that frame. The fuel tank is right there. The back axle is a disaster with stuff sticking far below the axle. Etc.

All in the name of a comfortable ride, I guess. But part of why 30 inch tires used to be fine is that the trucks were different back then.

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[702Gladiator]

You just compared a full size truck to a mid size. Try comparing a ram to ram or gladiator to Dakota. Something along those lines.

tire size is different I’d say. Back then bigger tires just weren’t as readlly available too. Larger tires roll over obstacles better than smaller ones. As the tires get bigger the trails get harder. I’d say that goes hand in hand I guess.

Just my 2 cents.

 

[bd100]

Well the Dakota of the same year, also 4x4, shows about the same ground clearance as the Ram. But the funny thing is they list around 8" while modern Jeeps claim 9-11", but the old truck has better clearance in the middle than the new Jeep.

Slightly complicating things is that my truck has a 175lb cap on the bed.

 

[redriderjf87]

There is something to be said for older simpler trucks.

I don't think it's necessarily a tire size thing, it's just packaging trade-offs for a newer smaller truck that has more "stuff" to put somewhere, along with more restrictions on where stuff can be put.

You could lift/level the Jeep without changing tires. You just have to essentially lift more to make up for the frame and low hanging bits not being up as high (if that is in fact the case, I am presuming).

 

[Artsifrtsi]

The new JT Sport w/o lift has around 9" ground clearance in the middle under the transfer case. I added better skid plates with thick bracing and now it's 8". This truck has stock size 31.7" tires, no lift. I would need a two inch lift to equal the clearance of the old truck stock, or one inch if w/o the new skid plates. Lots of stuff sticks down below that frame. The fuel tank is right there. The back axle is a disaster with stuff sticking far below the axle. Etc.

So, you are saying that the belly of your truck sits down lower than your axles? I have the Rubicon suspension in mine, and am riding on 35's... pretty sure I have over 18 inches at the frame, my rock rails are over my knees. Center of axle with the 35's is around 17 inches, with the differential at 10-12?.

The dimensions you are saying, would be lower than my stock '05 TJ The front bumper on the TJ is over my knees, skid is about 12 inches... Here's a pic comparing the two...

 

[DailyMoparGuy]

I think I know what OP is talking about because I’ve wondered the same thing…it’s the reason I tend to like old Tundras and Rams so much…older trucks just sit nicer from factory in my opinion.

For example, a 2005 Tundra has 12.3” of ground clearance with 30.6” tires. However the 2023 Tundra only has 9.3” of ground clearance with 32.6” tires. I always assumed came down to either new packaging methods for manufacturing or optimizing fuel mileage. Not sure though ??‍

 

[bd100]

The dimensions you are saying, would be lower than my stock '05 TJ The front bumper on the TJ is over my knees, skid is about 12 inches... Here's a pic comparing the two...

Have you measured the actual clearance you have below the skid plate in the center of the vehicle? From the photo that doesn't look like 12 inches.

Part of the point is the older truck has more measured clearance below the skid plate, using smaller tires, than the new truck using larger tires. And there is a difference between the "ground clearance" printed spec and the actual measurement I get from skid plate to ground.

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