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Re: Quandry.. 14" or 15" Wheels for MGB

To: Andy Ramm <aramm@concentric.net>
Subject: Re: Quandry.. 14" or 15" Wheels for MGB
From: John Steczkowski <stecz@pswtech.com>
Date: Mon, 02 Mar 1998 20:20:56 -0600
Why use the same spec tire? Why not use a ower profile on the 15" rims to
maintain the ride height and gearing? Why not use a 195/60/15?  That will
improve turn-in do to the lower sidewall height, won't hurt acceleration (due
to taller gearing with taller tires), although it will increase ride harshness.



Andy Ramm wrote:

> OK, assume that either the 14" or 15" wheels will
> be of the same make/model (i.e. 72 spoke wires
> 5.5" wide) and the tires will be the same
> make/model, (i.e. both 185/60 series).
>
> I'm not sure I agree with your assessment of turn
> in.  I think the smaller diameter wheel/tire combo
> will exhibit faster turn-in, though it might not
> have as much grip once the car starts turning.
> Please correct me if I'm wrong, I may have the
> incorrect assumption.
>
> You did raise some good questions though, this is
> absolutely the kind of discussion I'm looking for.
>
> Rick Morrison wrote:
> >
> > On Fri, 27 Feb 1998 09:54:40 -0800 Andy Ramm <aramm@concentric.net>
> > writes:
> > >I'm weighing the plusses and minuses of 14" vs.
> > >15" wheels for my MGB.  I have some pros and cons
> > >but am wondering if any listers have some
> > >definitive answers based on experience.  Here
> > >goes:
> > >
> > >14" Advantages
> > >Lower cost for both rims and tires
> > >Look more appropriate in the wheel wells
> > >Lower unsprung weight
> >  Not neccessarily so. Too much depends on the particular wheel/tire
> > combo. Alloy wheels with low profile tires would probably LOWER the
> > unsprung weight, vs. Rosytles and 75 series tires.
> >
> > >Faster turn-in
> >  Only if you increase the overall diameter of the tire
> >
> > >Maintains proper scrub radius
> >  See above
> >
> > >Less prone to rub (?)
> >  Rubbing will be a function of wheel offset (if any), tire width and tire
> > diameter. All are variable.
> > >Less WW flex
> >  Assuming both are 60 spoke wheels. 15 " WW are availible in 72 spoke
> > designs. Less flex than 60 spoke wheels.
> >
> > >15" Advantages
> > >Higher overall gearing
> > >Slightly larger contact patch (a little more grip)
> > >Lower rotational speed in corners (also a little
> > >more grip)
> >  All the above assume that the particular tire is increased in diameter,
> > but has the same aspect ratio and nominal width.
> >   With the proper inflation (which will vary with the tire construction
> > and size) the total area of the contact patch on a given car will remain
> > the same. The Shape of the patch will change. for example, the contact
> > area shape on a standard 155 x 14 tire is long and narrow. With a modern
> > low profile tire, say a 185/60 x 14 the contact patch shape is short and
> > wide. But the total area of the tire contact patch is the same.
> >  Higher gearing and lower rotational speeds are purely a function of  the
> > over all diameter of the tire. Properly sized, the 15" tire can have the
> > same OD as the 14"
> >  Ie. a 155 x 14 tire has an overall diameter of about 23.53".  A 205/50
> > x15 tire has an OD of 23.07" almost 1/2" SMALLER.
> >  I think I just made a simple question complicated. But as in so much
> > else, there ain't not simple answers. Just more questions!
> >
> > Rick Morrison
> > 72 MGBGT
> > 74 Midget
> >
> > >Look cool inside wheel wells
> > >
> > >These are just suppositions.  Can anyone give me
> > >some useful feedback on the subject?
> > >
> > >Thanks,
> > >
> > >Andy
> > >
> > >--
> > >
> > >
> > >
> > >
> > >Andy Ramm
> > >A silver face in a tweed world.
> > >Remove obvious spam filter from email address when
> > >replying.
> > >"What we play is the blues, straight from the
> > >delta, and I believe we'll make it on that,"  B.B.
> > >King
> > >
> > >
> > >By US Code Title 47, Sec.227(a)(2)(B),
> > >Sec.227(b)(1)(C) and Sec.227(b)(3)(C), it is
> > >unlawful to send any unsolicited advertisement to
> > >this equipment.  A violation of the aforementioned
> > >Section is punishable by action to recover actual
> > >monetary loss, or $500, whichever is greater, for
> > >each violation.
> > >
> >
> > _____________________________________________________________________
> > You don't need to buy Internet access to use free Internet e-mail.
> > Get completely free e-mail from Juno at http://www.juno.com
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>
> --
>
> Andy Ramm
> A silver face in a tweed world.
> Remove obvious spam filter from email address when
> replying.
> "What we play is the blues, straight from the
> delta, and I believe we'll make it on that,"  B.B.
> King
>
> By US Code Title 47, Sec.227(a)(2)(B),
> Sec.227(b)(1)(C) and Sec.227(b)(3)(C), it is
> unlawful to send any unsolicited advertisement to
> this equipment.  A violation of the aforementioned
> Section is punishable by action to recover actual
> monetary loss, or $500, whichever is greater, for
> each violation.



--
John Steczkowski
Director, Business Systems Solutions, Central & West
PSW Technologies, Inc.
512-343-6666
stecz@pswtech.com
http://www.pswtech.com/~stecz
http://www.pswtech.com





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