Reply
 
Thread Tools Display Modes
 
Old 10-02-2010, 07:11 PM   #1
Junior Member
 
ScotFree's Avatar
 
Join Date: Apr 2010
Location: Las Vegas, NV
Posts: 27
Ground Clearance: How much is Enough?

Hello all,
Newbie has searched here but can't find anything on point so I'll start this in hopes of some experienced opinion.

Currently comparing 3 4x4 Conversion shops for my 08 E350 EB. All will lift the van 4" ABOVE the axle centerline, plus 17" replacement wheels/tires. That raises the center of gravity 4" to a vehicle that some safety groups already consider dangerously top-heavy.

Tire height is the only component that raises Clearace, right? By Clearance, I mean distance from ground to bottom of Diff on the level. Factory is 8.2." with 29" tires/wheels. 33" tires will increase Clearance to about 10". So, if folks with experience could assure me that 9" Clearance is enough, then I could go with 31" tires and keep the C of G and entry/exit height an inch lower. Plus the 33s will require the front fenders to be cut out + flares, which I would rather not do.

My usage:
60%-Highway with occaisional snow.
30%-maintained County Roads with some pot-holes & miles of Washboard.
10%-5mi jogs to secluded campsites on Forest Service/BLM trails with some steep hills often littered with chunk rocks the size of 1-2 gal. jugs. Most of these can be negotiated, but some lie in ambush in vegetation between the tracks. (Sneaky Rocks!)
Also, I have not seen mention of a Skid Plate for the Diff? Any input will be appreciated.
__________________

__________________
'08 E350 SD EB Cargo 6.0
Bought New 5/2010
Quad Van 4x4
Rudimentary DIY Camper
ScotFree is offline   Reply With Quote
Old 10-02-2010, 09:24 PM   #2
Senior Member
 
yvrr's Avatar
 
Join Date: Oct 2007
Location: Newark, CA
Posts: 795
Re: Ground Clearance: How much is Enough?

The "trick" to negotiating off-road rocks is not to worry about clearance under the differential but clearance under the nerf bars, i.e., directly in line with the front tires. When you encounter rocks, drive directly for them and get your front tire onto them. That way, you are not trying to clear them with the differentials but need only enough body clearance in line with the front doors. After the front tire drops down, do the same thing with the rear tire. No problem....

If the road is too narrow to drive over the rock with your tires, have a spotter position you so that the rock is between the tire and the differential (closer to the tire where there is more ground clearance).

Likewise for rock steps...have the spotter position you so that both front (and then rear) tires drop off the steps at the same time...the differentials will clear without a problem.

The only time I thought we had a problem was coming off some steps that were on an angle. That meant that it was impossible for both tires to come down at the same time. From my angle in the driver's seat, I was sure that the steps were too high. But my wife was spotting me (which would have made her responsible if we got hung up <g>) and kept motioning me to come ahead slowly. She gave me a signal that the first front tire was about to drop down about 8" and when it dropped down, gave me a signal that the differential still have 3-4" of clearance! No sweat! And our van was only 2-1/2 weeks old at the time! That trail (Eye of the Whale) was rated as a 6 (out of 10) in Massey/Wilson's Utah book.
__________________

__________________
Jack
'01 Ford EB50p Quigley 4WD
yvrr is offline   Reply With Quote
Old 10-03-2010, 03:48 PM   #3
Senior Member
 
geoffff's Avatar
 
Join Date: Apr 2007
Location: Seattle, WA
Posts: 933
Re: Ground Clearance: How much is Enough?

I've never had any clearance problems with my Sportsmobile 4x4, even with the "smaller" LT285/75R16 tires, in the kind of travels I like to do -- mostly Massey/Wilson adventuring like yvrr suggests. It's extremely rare that I contact rocks with the bottom of my van (though I have hit my nerf bars a few times fooling around). I haven't taken the van up the Eye of the Whale trail yet, but I once did so with my Jeep Grand Cherokee and that has less than 9" clearance. For the kind of use you describe -- especially if you're thinking about wheel placement -- you should have no trouble with the a van lifted the minimal 4".

-- Geoff
__________________
2004 Ford, SMB 4x4, RB-50
http://octopup.org/sportsmobile
geoffff is offline   Reply With Quote
Old 10-03-2010, 06:24 PM   #4
Senior Member
 
Join Date: Dec 2009
Posts: 582
Ground Clearance: How much is Enough?

Two thoughts to consider:

1. Don't know about all conversions, but SMB and Quadvan conversions both increase axle width. This helps mitigate increased hight of the CG. Mine is an SMB and is significantly more stable post conversion.

2. In my not-so-humble opinion, diff skids are not the way to go (this from a guy with nearly everything protected underneath both SMB and Jeep). Heavy duty covers are the way to go. I had multiple problems with leaking diffs on my Jeep. Switched to Dynatrac covers and haven't had a leak since. So, I added the Dynatrac cover to the rear diff of my van as well.

Hope that helps.
__________________
Current: 2014 15 Passenger V8
Former: 2009 SMB 4x4 6.0
TwoVans is offline   Reply With Quote
Old 10-03-2010, 07:15 PM   #5
Junior Member
 
ScotFree's Avatar
 
Join Date: Apr 2010
Location: Las Vegas, NV
Posts: 27
Re: Ground Clearance: How much is Enough?

jessenej, I hadn't heard of a Diff Cover, good tip, I'll look into it.
And Geoff's comment about his Jeep is a help, because he gave his Diff Height. It seems to me we have to specify Diff Clearance as the standard of reference, then we can compare experiece regardless of whose build we have or how much lift, or what size tires. Thanks, hope to get some more input, but I am leaning toward the 31" tires and 9" Diff Clearance. I just hope they don't look like little donuts in my 4" body lift.
__________________
'08 E350 SD EB Cargo 6.0
Bought New 5/2010
Quad Van 4x4
Rudimentary DIY Camper
ScotFree is offline   Reply With Quote
Old 10-03-2010, 07:17 PM   #6
Junior Member
 
ScotFree's Avatar
 
Join Date: Apr 2010
Location: Las Vegas, NV
Posts: 27
Re: Ground Clearance: How much is Enough?

P.S.
If anyone has a picture of 31" tires in 4" lift, I would love to see it. Thanks again.
__________________
'08 E350 SD EB Cargo 6.0
Bought New 5/2010
Quad Van 4x4
Rudimentary DIY Camper
ScotFree is offline   Reply With Quote
Old 10-04-2010, 08:51 AM   #7
Senior Member
 
jage's Avatar
 
Join Date: Apr 2007
Location: Franktown, CO
Posts: 7,599
Re: Ground Clearance: How much is Enough?

I don't rock bash that much, and never in the van. I don't see a need for insane diff cover protection, because if a rock is too big I just turn around and go another way. If you're going to build for things the van will never see, you might as well look into Rockwells...
__________________
and then
everything changed
jage is offline   Reply With Quote
Old 10-04-2010, 11:24 AM   #8
Senior Member
 
geoffff's Avatar
 
Join Date: Apr 2007
Location: Seattle, WA
Posts: 933
Re: Ground Clearance: How much is Enough?

Quote:
Originally Posted by ScotFree
If anyone has a picture of 31" tires in 4" lift, I would love to see it. Thanks again.
Well, my 285/75R16 tires are just about 33", and they even look a bit small on my van, I'd say. But they seem to work for me.



Compare to twolost's van with 35"s:



-- Geoff
__________________
2004 Ford, SMB 4x4, RB-50
http://octopup.org/sportsmobile
geoffff is offline   Reply With Quote
Old 10-04-2010, 01:41 PM   #9
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 9,832
Garage
Re: Ground Clearance: How much is Enough?

I have a standard SMB conversion and take it in some places I probably shouldn't. I'm running 285's on 16" rims. I get zero rubbing on trails so I'll probably stick to that size. I do like the looks of the taller tires though but haven't had problems with how my van is set up. Plenty of pics in my album.


I agree with the previous posts and when it gets too rough, go back. Tire placement is important but if you have to there are ways around, such as stacking rocks to get you out of a situation. BTW being able to pull the disconnects on the sway bar helps such as in this picture.
Attached Thumbnails
DSC02184.JPG  
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 10-04-2010, 10:12 PM   #10
Senior Member
 
UJOINT's Avatar
 
Join Date: Feb 2009
Location: AVL NC
Posts: 969
Re: Ground Clearance: How much is Enough?

Don't just consider ground clearance to the diffs. Quite a few conversions use radius arms that hang down low and can easily be damaged.

I also agree with the above posts. If you need more clearance, maybe you shouldn't be there! Of course I said this before I caved in my rocker panel on a rock.....
__________________

__________________
Chris Steuber
02 E350 7.3 (V4)
05 E350 V10 (V7)
17 Focus RS,90 SHO,49 Willy CJ2A
ujointoffroad.com
UJOINT is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Sportsmobile Registry

Queen bee

Deaner

AWOL

Twoxentrix
Add your Sportsmobile
Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 03:47 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×