[urq] Diff Lock Question

Tue Jul 1 11:55:09 PDT 2014

No.  It is always 50/50 on an open diff.
(a diff can be made to be something other than 50/50, but it is always
constant when open.)
The Audi diff is 50/50.

If you lift a wheel and it spins freely and you still have a 50/50
split.
You are not producing much torque because there is little resistance on
the lifted wheel.
The same amount of torque that it takes to spin the free wheel is
transmitted to the wheel with traction.
It is just such a small amount that the car doesn't move.

The locked diff can have different split.
In that case if both wheels have the same traction it is 50/50.
Lift a wheel and 100% of the torque is to the wheel that is down.

Mike

> -------- Original Message --------
> Subject: Re: [urq] Diff Lock Question
> From: Stephen Kraus <ub3ratl4sf00 at gmail.com>
> Date: Tue, July 01, 2014 1:04 pm
> To: John Koenig <koenigj at comcast.net>
> Cc: Mike Sylvester <mike at urq20v.com>, "urq at audifans.com"
> <urq at audifans.com>
> 
> 
> The gearing of the differential allows for the power split to normally be
> 50/50 until a variable changes, at which point the power split will change
> to make up for slippage
> 
> 
> 
> On Tue, Jul 1, 2014 at 12:55 PM, John Koenig <koenigj at comcast.net> wrote:
> 
> > I'm a little confused. Since an open diff will allow one wheel to spin
> > freely while the other doesn't, how does that translate to a constant 50/50
> > torque split?
> >
> > ----- Original Message -----
> >
> > From: "Mike Sylvester" <mike at urq20v.com>
> > To: "David Schaible" <David.Schaible at jrspharma.com>, "Paul Ahvenainen" <
> > pahven at gmail.com>, urq at audifans.com
> > Sent: Tuesday, July 1, 2014 11:25:48 AM
> > Subject: Re: [urq] Diff Lock Question
> >
> > David,
> >
> > I would not recommend doing that.
> >
> > An open diff can have unequal rotation but has a 50/50 torque split all
> > the time.
> > A locked diff has locked rotation and can have a 100/0 torque split
> > which means one wheel will loose traction and be forced to do so in
> > tight corners.
> >
> > How did you turn around in a parking lot? I'm surprised you didn't
> > break something driving 10k miles that way.
> >
> > Mike
> >
> > > -------- Original Message --------
> > > Subject: Re: [urq] Diff Lock Question
> > > From: "Schaible, David" <David.Schaible at jrspharma.com>
> > > Date: Tue, July 01, 2014 9:30 am
> > > To: 'Paul Ahvenainen' <pahven at gmail.com>, "urq at audifans.com"
> > > <urq at audifans.com>
> > >
> > >
> > > Probably good advice thinking about $ and parts availability to repair,
> > however I don't know that I've heard of anyone in 15 years who has had any
> > issues with center or rear diffs. I broke the actuator arm on my 200q20v
> > rear diff in the lock position and drove it locked almost 10k miles before
> > I replaced the diff. You can feel it and it will scrub your tires down
> > faster but as far as it being dangerous.....I don't agree. Many people say
> > the old setup, mechanical diff in center and rear is more predictable than
> > the torsion.
> > >
> > > David Schaible
> > >
> > > JRS PHARMA LP | 2981 Route 22, Suite 1 | Patterson, NY 12563
> > > (P) 845.878.8343 | www.highfunctionalityexcipients.com |
> > www.jrspharma.com
> > >
> > > This e-mail and any attachments may contain confidential and privileged
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> > >
> > > -----Original Message-----
> > > From: urq [mailto:urq-bounces at audifans.com] On Behalf Of Paul Ahvenainen
> > > Sent: Monday, June 30, 2014 10:17 PM
> > > To: urq at audifans.com
> > > Subject: [urq] Diff Lock Question
> > >
> > > I had 2Bennett do some work on my 83 urq last week. It's very nice to
> > work with a team that understands these cars and actually keeps parts on
> > hand.
> > >
> > > Any way, when I picked up the car, they gave me some advice about the
> > differential locking mechanism. Basically, they said don't use it for
> > anything other than getting out of a ditch. They said it should only be
> > used at low speed, in a straight line, otherwise the handling will be
> > dangerous and the repairs will be expensive. According to the owners manual
> > the system is recommended for use for low traction conditions, like rain.
> > >
> > > I'm curious about experiences that other early urq owners have had. My
> > car has the single stage activation that locks both the center and rear
> > diff at the same time.
> > >
> > > Thanks. Paul
> > >
> > > Sent from my iPad
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