[DeTomaso] Fwd: RE: Wheel offset (ET)

Thu Aug 2 12:10:04 EDT 2012

IMHO --- If the only wheel change made is backspacing, you also change ET, which affects handling. Thus you may need to change something in the alignment to get handling where you want it.

Bud #3400

--- On Wed, 8/1/12, Julian Kift <julian_kift at hotmail.com> wrote:

From: Julian Kift <julian_kift at hotmail.com>
Subject: Re: [DeTomaso] Fwd: RE: Wheel offset (ET)
To: michael at michaelshortt.com, "De Tomaso List" <detomaso at realbig.com>
Date: Wednesday, August 1, 2012, 11:11 PM

Maybe I am missing something, I'm not questioning that if you change tire diameter and ride height etc. you'll need a realignment. The original statement implied that simply by altering backspacing alone in either direction a realignment is warranted, but I can't see anything has changed in that scenario. However, if you are saying that changing backspacing requires different alignment settings, that I can understand.

Julian

> Date: Wed, 1 Aug 2012 19:29:26 -0400
> From: michaelsavga at gmail.com
> To: detomaso at realbig.com
> Subject: [DeTomaso] Fwd: RE:  Wheel offset (ET)
> 
> If the ride height changes ( as with most tire upgrades) the springs go up
> and down and this causes new/different pull on the steering knuckle which
> affects toe, not to mention camber since the wheel hub / steering knuckle
> will be higher / lower in relation to the body since it moves in an arc.
> IMHO
> 
> Michael
> 
> On Aug 1, 2012 7:09 PM, "Julian Kift" <julian_kift at hotmail.com> wrote:
> >
> > You are moving the tire in or out in a horizontal plane, so your not
> changing toe, caster or camber, what aspect are you going to re-align?
> >
> > Julian
> >
> > ________________________________
> > Date: Wed, 1 Aug 2012 18:58:40 -0400
> > Subject: Re: [DeTomaso] Wheel offset (ET)
> > From: michaelsavga at gmail.com
> > To: shawkins777 at comcast.net
> > CC: julian_kift at hotmail.com; detomaso at realbig.com; guson at home.se
> >
> > Absolutely true, plus any real difference in either direction really
> necessitates a four wheel alignment.
> > Michael
> > On Aug 1, 2012 5:55 PM, <shawkins777 at comcast.net> wrote:
> >>
> >> You have to be careful though because you can affect the way the car
> handles.
> >>
> >> Steve
> >>
> >>
> >> ________________________________
> >>
> >>
> >> From: "michael at michaelshortt.com" <michaelsavga at gmail.com>
> >> To: "Julian Kift" <julian_kift at hotmail.com>
> >> Cc: guson at home.se, "De Tomaso List" <detomaso at realbig.com>
> >> Sent: Wednesday, August 1, 2012 4:43:04 PM
> >> Subject: Re: [DeTomaso] Wheel offset (ET)
> >>
> >> The problem is that there are too many number flying around.
> >>
> >> The only number that matters for 90% of most applications is backspacing,
> >> how it differs from stock.
> >>
> >> If the backspacing is a larger number, the wheel rides inboard more, if
> it
> >> is a small number, the wheel sticks out more.
> >>
> >> If the wheels are wider or smaller, you just have to do the math.
> >>
> >> let's say a car is OEM with an 8" wheel with 4" of backspacing,
> >>
> >> you want to buy a 10" wheel with 6" of backspacing
> >>
> >> Your wheel is 2" inches wider, and rides inboard 2" more, therefore, your
> >> exterior appearance should not look any different.
> >>
> >> If on the other hand, you want to use a 12" wheel with 3" of backspace,
> >> then the wheel will stick out past the
> >>
> >> OEM outer most point by 1" for the backspacing plus another 4" for the
> >> wider wheel for a total of 5",
> >>
> >> you are now driving a skateboard or have plans to install flares.
> >>
> >> Michael
> >>
> >>
> >>
> >> On Wed, Aug 1, 2012 at 5:34 PM, Julian Kift <julian_kift at hotmail.com>
> wrote:
> >>
> >> >  In my experience backspacing depends entirely on the wheel
> manufacturer
> >> > you are talking to and worth clarifying with them up front. Kodiak and
> most
> >> > others I have dealt with here in the US use the tire bead i.e. inner
> rim lip
> >> >
> >> > Kodiak has a worksheet on their website, which may or may not help you.
> >> > http://www.kodiakracingwheels.com/ordering.html
> >> >
> >> > Whose wheels do you have? I think there was a very quick jump to the
> >> > conclusion the part #'s represent the offset, which may or may not be
> the
> >> > case, but some substantiation is likely warranted.
> >> >
> >> > Julian
> >> >
> >> >  > From: guson at home.se
> >> > > To: michael at michaelshortt.com
> >> > > Date: Wed, 1 Aug 2012 12:44:30 -0700
> >> > > CC: detomaso at realbig.com
> >> > > Subject: Re: [DeTomaso] Wheel offset (ET)
> >> > >
> >> > > When calculating ET the reference is the middle of the tire which in
> >> > > turn is determined by the inner edges of the rim. You can assume that
> >> > > the outside of the edge is 1/2" further out on each side of the rim
> but
> >> > > especially on aluminum rims this measurement can differ from side to
> >> > > side on the rim. My calculations were assuming that your reference
> was
> >> > > the same for BS and rim width. If they weren't my calculations are
> off.
> >> > >
> >> > > Rim width is always inside the lip. Backspacing is measured outside
> the
> >> > > lip like Michael says.
> >> > >
> >> > > Tomas
> >> > >
> >> > > <-----Ursprungligt Meddelande----->
> >> > > From: michael at michaelshortt.com [michael at michaelshortt.com]
> >> > > Sent: 1/8/2012 7:51:57 PM
> >> > > To: Bjoern Flesland
> >> > > Cc: Tomas Gunnarsson,POCA Detomasolist Realbig
> >> > > Subject: Re: [DeTomaso] Wheel offset (ET)
> >> > >
> >> > > I do not think they use the lip, I think they use the outside edge,
> as
> >> > > in the part that touches the ground when it lays flat.
> >> > >
> >> > > Michael Shortt
> >> > >
> >> > > On Wed, Aug 1, 2012 at 1:43 PM, Bjoern Flesland <bflesland at gmail.com>
> >> > > wrote:
> >> > > > But stampings does not match quite up with the calculations that
> Tomas
> >> > > did.
> >> > > >
> >> > > > So I am confused!
> >> > > > Can it be measured in different ways?
> >> > > > Cheers Bjoern
> >> > > >
> >> > > > Sent from my iPhone
> >> > > >
> >> > > >
> >> > > > Den 1. aug. 2012 kl. 20:08 skrev "michael at michaelshortt.com"
> >> > > <michaelsavga at gmail.com>:
> >> > > >
> >> > > >> Yes, I think that is exactly what that means.
> >> > > >>
> >> > > >> Michael Shortt
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >> On Wed, Aug 1, 2012 at 1:06 PM, Bjoern Flesland <
> bflesland at gmail.com>
> >> > > wrote:
> >> > > >>> Thanks for helping out.
> >> > > >>> They are stamped the following:
> >> > > >>>
> >> > > >>> Front
> >> > > >>> 28 85 8 LA3
> >> > > >>> 8.5JX18H2E64
> >> > > >>>
> >> > > >>> Rear
> >> > > >>> 28 13 8 LA
> >> > > >>> 13JX18H2E39
> >> > > >>>
> >> > > >>> Could that indicate ET of 64 and 39 mm?
> >> > > >>>
> >> > > >>> Cheers Bjoern
> >> > > >>> Sent from my iPhone
> >> > > >>>
> >> > > >>>
> >> > > >>> Den 1. aug. 2012 kl. 19:36 skrev "Tomas Gunnarsson" <
> guson at home.se>:
> >> > > >>>
> >> > > >>> If you have used the same edges as reference for all measurements
> >> > > the narrow
> >> > > >>> rim has ET70 and the wide rim ET51.
> >> > > >>>
> >> > > >>> Tomas
> >> > > >>>
> >> > > >>> <-----Ursprungligt Meddelande----->
> >> > > >>> From: Bjoern Flesland [bflesland at gmail.com]
> >> > > >>> Sent: 1/8/2012 6:22:47 PM
> >> > > >>> To: POCA Detomasolist Realbig
> >> > > >>> Subject: [DeTomaso] Wheel offset (ET)
> >> > > >>>
> >> > > >>> I am trying to determine the offset (ET) of two wheels and need
> some
> >> > > advise:
> >> > > >>>
> >> > > >>> One wheel measure 184 mm from the mounting face/flange to the
> inner
> >> > > rim
> >> > > >>> edge.
> >> > > >>> Wheel width is 228 mm.
> >> > > >>>
> >> > > >>> The other measure 216 mm from the mounting face/flange to the
> inner
> >> > > rim
> >> > > >>> edge.
> >> > > >>> Wheel width is 330 mm.
> >> > > >>>
> >> > > >>> Appreciate your help. Thanks!
> >> > > >>> Cheers Bjoern
> >> > > >>>
> >> > > >>> _______________________________________________
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> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >> --
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >> Michael L. Shortt
> >> > > >> Savannah, Georgia
> >> > > >> www.michaelshortt.com <http://www.michaelshortt.com/>
> >> > > >> michael at michaelshortt.com
> >> > > >> 912-232-9390
> >> > > >>
> >> > > >>
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> >> > >
> >> > >
> >> > > --
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > > Michael L. Shortt
> >> > > Savannah, Georgia
> >> > > www.michaelshortt.com <http://www.michaelshortt.com/>
> >> > > michael at michaelshortt.com
> >> > > 912-232-9390
> >> > >
> >> > >
> >> > > This email is protected by the Electronic Communications Privacy
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> >>
> >>
> >>
> >> --
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Michael L. Shortt
> >> Savannah, Georgia
> >> www.michaelshortt.com
> >> michael at michaelshortt.com
> >> 912-232-9390
> >>
> >>
> >> This email is protected by the Electronic Communications Privacy
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> you
> >> have received this message in error, then delete it.  Thank you
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