Date: Sun, 17 Nov 2024 12:10:16 -0800
Reply-To: David McNeely <davmcneely40@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David McNeely <davmcneely40@GMAIL.COM>
Subject: Re: Tire size question
In-Reply-To: <E2A0F4FD-485B-4AB3-84D1-EB56607CC3F0@icloud.com>
Content-Type: text/plain; charset="UTF-8"
All the talk about tire size and mpg seems to ignore the fact that larger
tires cause an error in the odometer readout. The odometer is calibrated
to the factory tire size. The odometer does not read distance travelled,
but rotations of the wheel, and converts that to distance travelled.
On Sun, Nov 17, 2024 at 10:05 AM Jeff Palmer <w.jeff.palmer@icloud.com>
wrote:
> I have an 85 with a 2.1 Boston Bob motor and just “upgraded” to 16 inch
> wheels last year. I use the quotes because I don’t actually know if the
> ride quality is much better. Feels a bit wobbly compared to the multi ply
> continentals. I bought Nokians with a high load rating.
>
> I generally keep track of mileage when we go on family road trips. About
> 5000km return to Vancouver or 7000km to Quebec City. Next year Newfoundland
> but not in the van. I feel that is long enough to factor in variables like
> speed elevation change etc.
>
> I have noticed I get about 5% better mileage travelling east than west. I
> have always attributed that to prevailing winds. But the number one factor
> is speed. I would love to see a graph that compares speed and economy. The
> difference every 10km/h makes between 90 and 120 is huge. I haven’t noticed
> any significant difference between adding the 2.1 and the larger tires.
> Both of which were added because it seemed like parts/tires for the current
> setup was getting hard to find.
>
> Jeff in Winnipeg
> 85 Westfalia GL
> 19 Alltrack
> 13 Sportwagen (soon to be replaced with an ID.4)
> 90 Cabriolet (that’s a secret!)
> 69 Type 3 notchback
>
> Sent from my iPhone
>
> > On Nov 17, 2024, at 10:41 AM, Mike Miller <mwmiller6@att.net> wrote:
> >
> > Good start Eric!
> >
> > However, back when I actually got paid for working for a while a big
> part of my duties was designing and analyzing studies just like
> this...okay, kind of like this. So I have a few additional variables:
> > Wheels nuts, just think of what that weight does, being unsprung and
> all. To say nothing of wheel nut torque.Wind direction variability between
> runs.Headlight variables, think of how many different headlights are
> available and the immense difference in wind resistance, which must
> directly affect mpgNumber of spectators, and the individual differences in
> their enthusiasm for one or other participant.Magnetic declination of the
> moons of Jupiter
> > And so many, many more.
> > I think you need me to come supervise this trial. And then I'll need a
> second. And a reporting schema. The list goes on.
> > Can you tell that I worked for the government?
> > Mike
> > tee hee.
> >
> > On Sunday, November 17, 2024 at 07:17:30 AM PST, Eric Caron <
> ericcaron96@comcast.net> wrote:
> >
> > Hi Karl and others,
> >
> > We could search for differences in the vans for days. And
> state this is not a scientifically valid study. But, to save time. I
> agree with that.
> >
> > Still, Karl’s van is about the closest I’ll find to compare.
> >
> > My less then scientific thinking is that if I’m getting 15 mpg with
> smaller tires and Karl gets 16.5 or better with larger tires. Then maybe.
> >
> > If Karl ran tires smaller his MPG might go down some. If that is
> correct. Maybe increasing my tire diameter to match Karl’s might increase
> my Mpg some.
> >
> > I know we could talk about tire friction, type of roads near Karl and
> me, and temperature differences, type of gas we put in the tank, and how I
> weigh more then Karl.
> >
> > But, is it kind of possible that there really is something to the wheel
> diameter and MPG?
> >
> > Remember all the 1970 adds telling us to be sure our tires were
> inflated? Were they tricking me? OK they probably were.
> >
> > OK, the tire inflation might be about friction not diameter of tire,
> they didn’t say.
> >
> > I think the solution is that Karl should drive over here to VT and we do
> a drive side by side with the vans, then we switch wheels and do it again.
> Both at the same time of day, gas from the same station, and the vans
> matched for weight.
> >
> > No bra on either van, same mirrors, same wax on the body.
> >
> > We can do this!
> >
> > Karl, we can do it before West River Westies July 2025.
> >
> > And your van sounds nice. How did you ever end up with that engine? I
> only recently learned about those European versions of our water boxers.
> >
> > Eric
> >
> >
> >> On Nov 17, 2024, at 2:26 AM, Karl Mullendore <tdiguru@WESTYVENTURES.COM>
> wrote:
> >>
> >> Other factors are mine is a Multivan poptop, at 4300 feet, and a good
> running
> >> 112i with factory Digijet, totally stock except for the 4-hole
> injectors. You
> >> have a slightly larger engine at sea level running GW's whatever they
> threw
> >> together which may or may not achieve as good mileage ever.
> >> Karl
> >
>
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