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Opposite Side Offset Differential Locations in a Buggy....Why?

Sean

Sean

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This is regarding a front engine, 2 seat, 4 wheel steer portal chassis:

To me, matching the front & rear diff on one side of the car makes a lot of sense. Same axle shafts....diff has to clear the same obstacle. With either set up, the offset diff allows a small, axle mounted suck down winch.

What is the advantage of having the diffs on opposite sides of the car? Mostly I see passenger drop front and driver drop rear.

If they are both offset the same distance, just to opposite sides....it's still the same spares (which makes sense), but is the reasoning that the rear diff on the driver side will be easier to locate since it's directly behind your seat?

I'm leaning towards building with the diffs both on the passenger side (front Hero tcase is passenger drop, so that is fixed), but should I be considering putting the rear on the driver?
 
Because when you take a gm front Dana 60 and put it in the back the diff is on the drivers side. Do you think people are actually doing this on purpose or they are just doing it because that’s how it works out and they are too lazy to do it right?
 
benw said:
Because when you take a gm front Dana 60 and put it in the back the diff is on the drivers side. Do you think people are actually doing this on purpose or they are just doing it because that’s how it works out and they are too lazy to do it right?
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He mentioned small 4ws portal buggies, so yes scratch built on purpose.

My guess would be the way the drivetrain is layed out. Those moon buggies often stick the drivetrain in however it fits best. Offset to one side and at an angle seems common. So if the rear output is pointing towards the driver side, a driver rear diff probably makes the most sense.

Or maybe they just want exact matching housings?:confused:
 
You’re right I missed the portal thing. The angled drivetrain reason makes sense.
 
YotaAtieToo said:
He mentioned small 4ws portal buggies, so yes scratch built on purpose.

My guess would be the way the drivetrain is layed out. Those moon buggies often stick the drivetrain in however it fits best. Offset to one side and at an angle seems common. So if the rear output is pointing towards the driver side, a driver rear diff probably makes the most sense.

Or maybe they just want exact matching housings?:confused:
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Right, I get it more with the moon buggies (but I've always considered that classification a single seat, rear engine). These are traditional 2 seater, front engine....and I don't think the drivetrains are angled....but that is a good reason, if that's what's happening.
 
Sean said:
Right, I get it more with the moon buggies (but I've always considered that classification a single seat, rear engine). These are traditional 2 seater, front engine....and I don't think the drivetrains are angled....but that is a good reason, if that's what's happening.
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I can't think of a reason then.

woody Would probably know though.
 
Examples:

They don't seem to be the same cars since the first one has the new JHF portal boxes and the other one doesn't....but those could be swapped obviously along with the wheels/panels, etc.
 

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On comp rock crawlers they put the diffs close to the wheel to get it out of the way of rocks and so that it "lifts" when the tire goes over an obstacle to keep it out of the way. Also keeps the driveshaft close to the lower link for extra protection.

Nothing magical, it's just something some guys do to get an edge on the competition.
 
SLOWPOKE693 said:
On comp rock crawlers they put the diffs close to the wheel to get it out of the way of rocks and so that it "lifts" when the tire goes over an obstacle to keep it out of the way.

Nothing magical, it's just something some guys do to get an edge on the competition.
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Right....Tiny was built this way...but not at opposites sides of the car, IIRC. Putting the diff next to either wheel will help lift it out of the way....I'm just trying to figure out what advantage there is to having them at opposite sides.

Granted, a loaded Ford 9" third member is something like 95 lbs (obviously a Toyota 3rd is lighter). Putting them at opposing corners would balance them out somewhat....but putting them both (190 lbs) on the passenger side would help balance the weight of your average male driver.

Beats me. Guess I'd need to ask Jesse Haines as it appears he's designed a few that way.
 
SLOWPOKE693 said:
Are you sure the drivetrains in those cars are not angled?
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I absolutely am not sure. I know in the JHF Trail Buggy builds I've asked and those were all centered/straight drivetrains....that obviously doesn't mean these two examples of Jesse's aren't angled.
 
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belly is more concern in portal buggies. most hang it low to be low
 
Never noticed that on those pictured examples. My JHF 2 seat trail chassis portal buggy both diffs are offset to passenger side using the same dimensions for universal spares. My drivetrain is straight in the chassis but is offset to the passenger side 1" from center since the accessory drive on my engine hangs off drivers side more, allows rear driveshaft to have a little less offset, and allowed me to build a little bigger foot pocket for the drivers side pedal area.
 
SteerAndStuff said:
Never noticed that on those pictured examples. My JHF 2 seat trail chassis portal buggy both diffs are offset to passenger side using the same dimensions for universal spares. My drivetrain is straight in the chassis but is offset to the passenger side 1" from center since the accessory drive on my engine hangs off drivers side more, allows rear driveshaft to have a little less offset, and allowed me to build a little bigger foot pocket for the drivers side pedal area.
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And I'm wondering if Jesse didn't angle the drivetrain on those cars to give a little more footwell room for the driver.

I'm leaning your direction though...possibly shift the drivetrain an inch passenger (or so) for increased room for the driver and keep both diffs on the passenger side so that if you clear the front diff, the rear should generally follow along.
 
My pro mod has front driver drop and rear passenger drop. The pinion offset on the 9" puts the driveshafts further from center this way.

Makes more room for other stuff. In my case the fuel cell is next to the rear drive shaft, and the oil pan is next to the front drive shaft.

20170628_194330(1).jpg


I also offset the drivetrain about 2" passenger from center in my car, which worked out well.

I don't buy into the "diffs have to clear the same obstacles" thing - how often do you drive straight without turning where diff clearance is a concern?
 
Opiebennett said:
My pro mod has front driver drop and rear passenger drop. The pinion offset on the 9" puts the driveshafts further from center this way.

Makes more room for other stuff. In my case the fuel cell is next to the rear drive shaft, and the oil pan is next to the front drive shaft.

20170628_194330(1).jpg


I also offset the drivetrain about 2" passenger from center in my car, which worked out well.

I don't buy into the "diffs have to clear the same obstacles" thing - how often do you drive straight without turning where diff clearance is a concern?
Click to expand...

Some climbs where the crest at the top is a not a nice level shelf.
 
Opiebennett said:
My pro mod has front driver drop and rear passenger drop. The pinion offset on the 9" puts the driveshafts further from center this way.

Makes more room for other stuff. In my case the fuel cell is next to the rear drive shaft, and the oil pan is next to the front drive shaft.

20170628_194330(1).jpg


I also offset the drivetrain about 2" passenger from center in my car, which worked out well.

I don't buy into the "diffs have to clear the same obstacles" thing - how often do you drive straight without turning where diff clearance is a concern?
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Is this a 2 seater? Got any pics of the front? Thanks for the input.
 
My jeep has the front end driver side, rear end (slightly) passenger side. The engine/trans/case and both axles were carried over unaltered from my prior unlimited buggy.
It was on purpose (though mostly irrelevant now) in the buggy: the engine/trans/transfer are 3" right of center to keep a smaller (24" wide) belly, to weight balance the car with a driver only, and still be able to get a front driveshaft out. The rear pinion was centered on where the atlas output ended up.
Same reasons others have noted, packaging issue(s).
 
ScottRS said:
My jeep has the front end driver side, rear end (slightly) passenger side. The engine/trans/case and both axles were carried over unaltered from my prior unlimited buggy.
It was on purpose (though mostly irrelevant now) in the buggy: the engine/trans/transfer are 3" right of center to keep a smaller (24" wide) belly, to weight balance the car with a driver only, and still be able to get a front driveshaft out. The rear pinion was centered on where the atlas output ended up.
Same reasons others have noted, packaging issue(s).
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That's makes a ton of sense for a number of reasons.

Probably makes routing a front driveshaft much easier also.
 
I asked Mike Johnson this question regarding his new car. He said that the axles are identical and offset for the drivetrain angle/ packaging. The portals negate the advantage of having both diffs line up, like we used to see.
 
Wilson said:
I asked Mike Johnson this question regarding his new car. He said that the axles are identical and offset for the drivetrain angle/ packaging. The portals negate the advantage of having both diffs line up, like we used to see.
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That makes total sense.....thanks for the reply.
 
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