How important is ground clearance for your fulltiming adventure?

[akrvbob]

They may be measuring different areas like the differential as the lowest point?
Bob

 

[Vagabound]

There's a bit of a ground clearance discussion going on over in the "Ford vs. Chevy" thread as well.  However, I'm posting this here because it seems a more appropriate place.

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Although different ways to describe vehicle people are nearly endless, I've noticed that there are two basic kinds in the world:

Type 1)  Point A to Point B.  Vehicles are tools that do a job, like any other tool.  Only interested in changes / additions / features if they are practical and you get easily noticeable, life-improving, bang-for-the-buck.

Type 2)  Passionate.  They somehow manage to care if the washer under the nut on the muffler clamp is the authentic 1973 washer from Mopar.  And will debate this with people ... without laughing.

It might be based on DNA.  

I am firmly Type 1.  

I say that to explain my motivation and approach to the thing I'm posting about below.  In short, I'm trying to find out, as a Type 1, if there is anything to care about in this ground clearance kerfuffle.

So, forgoing various computer tools, I used an old-fashioned method (drawing) to try to figure this out.  I drew a diagram of a long wheel base (LWB) and a short wheel base (SWB) Chevy Express van going over a bump.  Added measurements.  It's mostly to scale.  While professional draftspeoples and engineers might laugh, it was good enough to get the answer that I was after.

That answer:  Even in a case where the size / slope / steepness of the bump is unrealistically exaggerated -- yielding the maximum ground clearance increase for the SWB van -- the added clearance is about 5".  

However, and this is crucial, in that case, neither van can clear the bump anyway so it is nonsensical.  So, reducing the bump height and slope by maybe half of what's drawn -- the amount needed to make the example more realistic and get the SWB van to barely clear the bump -- the actual extra clearance is reduced to about 50% of the extra clearance mentioned above, or 2.5".

Yeah, just like with cheddar cheese, more is better when it comes to clearance.  However, I don't know about others, but that 2.5" number, which would probably be even less in real-word situations, is not enough to get me excited and fretting over wheelbase lengths of available vans for purchase.

If interested, my rocket fuel formula drawing is hopefully attached to this post.  Sorry about the poor quality.  If you see anything wrong with my drawing, please point it out.  The objective is learning.

Vagabound

 

[NeedAnEscape]

What you are describing is the breakover angle, which is essentially the angle from the bottom of the tire to the center of the body section between the wheels. The bottom of the van also is often higher than the rear diff which is the lowest point on most vans so the ground clearance measurement won't tell you how high the body is. Also, your drawing seems to show the vans having 20" tires, but a "1 ton" van typically has 245/75r16 tires, which are approx. 30.5 inches tall.

 

[Vagabound]

What you are describing is the breakover angle,
...
Also, your drawing seems to show the vans having 20" tires, but a "1 ton" van typically has 245/75r16 tires, which are approx. 30.5 inches tall.

Breakover Angle:  Thanks for the right term.

20" tires:  Yep, knew that.  I was shooting for 16".  The specs which I found online gave a range of 15-18" diameter.  Maybe they should have said "radius".  Or I misread it.  

I had to go with the closest size of coin I could find for a drawing template = 20".  Not sure about the 20" vs. 30" discrepancy, but now that you mention it, in the back of my mind, I was thinking, "You know, 16" sounds really small for a car tire."  Hmm.

Vagabound

 

[NeedAnEscape]

The wheel is typically 16", which is what the r16 at the end of the tire size I mentioned represents.

 

[Vagabound]

The wheel is typically 16", which is what the r16 at the end of the tire size I mentioned represents.

By the way, I think we were posting and editing at the same moment.  See my post above yours for some changes.

In any case, all things considered, if the actual wheel diameter should have been 30" in my drawing, how do you suppose that would change the results?  If more clearance, how much more?

Vagabound

 

[NeedAnEscape]

It will effect it, since that puts the bottom of the body at around 15" off the ground instead of around 10" off the ground. But, while the bottom of the body is even or slightly above the center of the wheels/tires, there is also stuff below the body below the center of the wheels/tires.

Edit:

that pic shows the stuff hanging down below the bottom of the body.

 

[NeedAnEscape]

If I had to guess, I'd say that stuff hangs down about 2" below the center of the wheel, so with 30.5" tires that makes it approx 13.25" off the ground. That gives the 135" WB van a 11.1 degree breakover angle, and the 155" WB van a 9.7 degree breakover angle.

 

[Vagabound]

If I had to guess, I'd say that stuff hangs down about 2" below the center of the wheel, so with 30.5" tires that makes it approx 13.25" off the ground. That gives the 135" WB van a 11.1 degree breakover angle, and the 155" WB van a 9.7 degree breakover angle.

So, what's that in ruler measurements, in terms of the difference in clearance between the two models?

 

[Bster13]

I appreciate the technical discussion (love the participation in this forum) as I learn something new every day. But is there a ground clearance or vehicle type (any old cargo van of various lengths, or "that RAV4 Hybrid will get er' done.") that you can put the "you'll be fine" stamp of approval on for most of the roads out West that you fulltimers travel on? My goal is to make it to most places a tribe would hang out at for a few days, not necessarily the most remote place in the lower 48 for solitude.

 

[highdesertranger]

boy you guy's are really getting into this. I love it. I am much simpler, put tallest tires on that are practical and run with it. highdesertranger

 

[ArtW]

Any fullsize van or pickup should do the trick, a RAV 4 actually has pretty good ground clearance too, if I recall correctly, though it'd be tight to sleep in
most cars like the Prius or even some minivans will have trouble, and FWD platforms tend to be more breakable and less modifiable than RWD platforms, although you can put larger diameter tires on any car, within limits, which would add ground clearance
Taking from HDR's point about more GC being better, UP TO A POINT, the real reason most SERIOUS offroaders I know give for putting a lift on a 4x4 is to get more tire on it, because more tire (larger circumference) is where true usable GC comes from
I've 'soft roaded' a 1969 Dodge Polara station wagom with chunky tires and 'po boy positraction' and driven past some mighty purty 4x4s in my time

 

[jimindenver]

I appreciate the technical discussion (love the participation in this forum) as I learn something new every day. But is there a ground clearance or vehicle type (any old cargo van of various lengths, or "that RAV4 Hybrid will get er' done.") that you can put the "you'll be fine" stamp of approval on for most of the roads out West that you fulltimers travel on? My goal is to make it to most places a tribe would hang out at for a few days, not necessarily the most remote place in the lower 48 for solitude.

There are vans that have been converted to 4x4 but they cost the bucks even used. I'd love one with a pop up top.

 

[highdesertranger]

could just do a cheap Jeep, http://oldiesmusicradio.com/cheapjeep.htm . highdesertranger

 

[Bster13]

.... and FWD platforms tend to be more breakable and less modifiable than RWD platforms

Interesting point there.  I read about folks putting in "locker" differentials in their RWD platforms, something I know little about, but I understand it gives better traction on less than ideal roads.  But when you mention FWD platforms tend to be more breakable.... a similar conversion came up about the Prius vs. RAV4 Hybrid.  FWD vs. AWD.  When you get a flat tire on a FWD car, you replace two tires on the single axle, but when you get a flat tire on a AWD car you replace 4 tires?  :huh:  $$$. Then to add further confusion and to contradict myself, I've read these modern AWD systems are electronically controlled and the AWD isn't always in play. It's mostly a 2WD system so maybe you'd only need to replaces 2 tires if you get a flat on an AWD car? #puzzled

 

[ArtW]

That's getting into territory I'm not familiar with, mostly I repair, not replace, flats, (regardless of what the guy at the tire shop says, I've driven 100s of miles on tires with multiple plugs in them, and never had a problem, I've gone from Austin to Coushatta and back on a tire with 7 plugs in it, running 90 all the way) and since i usually have RWD cars without posis or limited slip ('po boy positraction' is something else entirely, tricking an open diff int putting the power where you want it) i can replace 1 tire at a time if I blow one out

 

[Bster13]

I agree on plugging tires. I always have a plug kit and compressor with me and will plug away just like I used to plug my motorcycle tires with strong plugs and no problem, but I assume there will come a time when the tread separates and I'll have to replace it, so still curious as to the protocol with AWD as it may affect budgeting.

 

[RVTravel]

Current RAV4's are about 6.5" ground clearance. In the past they were 8", but that changed.

 

[ArtW]

so the older RAV has better ground clearance, and will be cheaper, win win! still seems cramped, though

Also, on a FWD car, there is no need to replace tires in pairs unless you have a limited slip differential (most FWD cars don't) NO car with open differentials requires replacing tires as 'sets' that I know of, just those with limited slips and lockers (which probably means all AWDs)
I'm quite sure the guy at the tire shop will disagree, he makes his living selling tires
That doesn't mean it's not a good idea, but unless you have an LSD, it's not necessary

 

[Bster13]

so the older RAV has better ground clearance, and will be cheaper, win win! still seems cramped, though

Also, on a FWD car, there is no need to replace tires in pairs unless you have a limited slip differential (most FWD cars don't) NO car with open differentials requires replacing tires as 'sets' that I know of, just those with limited slips and lockers (which probably means all AWDs)
I'm quite sure the guy at the tire shop will disagree, he makes his living selling tires
That doesn't mean it's not a good idea, but unless you have an LSD, it's not necessary

The newer RAV4 hybrid has genuine A/C and Heating, so that's what I was after with more ground clearance than the fulltiming Prius Folk mentioned on this forum.  But the AWD of the RAV4 would necessitate replacing all 4 tires vs. just 1 tire on a regular FWD vehicle. Doh!