Accurate measurement of tread could be done from left side of left tire to left side of right tire OR right side of left side of right tire.
Mac in OKC, OK
Sent from my iPhone
G'day,
Thanks to all that commented, below you will find detailed research I did on
this before I asked the question.
Here's a link to Wikipedia's definition of track measurement.
https://en.wikipedia.org/wiki/Axle_track
As you can see the track is measured from center to center of the tire
width.
http://www.gmcmotorhome.com/faq/dimensions.html
As you can see the dimensions stated are:
Track
Front: 75.28 in.
Rear: 85.12 in.
The question is how were these measurements taken?
A) From the INSIDE of the tread to the INSIDE of the tread?
B) From the CENTER of the tread to the CENTER of the tread?
C) From the OUTSIDE of the tread to the OUTSIDE of the tread?
Here's a link to the Tire Racks notes on tread width:
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=194
Here's a link to the specs on specs on a LT 225/75-16R tire:
https://tiresize.com/tiresizes/225-75R16.htm
That's where I screwed up! The width of the tire is 8.9 inches NOT the tread
width!
Here's a link to the tires I have on The Blue Streak:
https://tiresize.com/tires/Nexen/Roadian-AT-Pro-RA8-225-75R16.htm
Unfortunately it does not provide the tread width only the width.
Bottom line: I'm heading down to my workshop and measure the Roadian AT
tires as installed on The Blue Streak.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
________________________________________
From: D C _Mac_ Macdonald [mailto:k2gkk]
Sent: Tuesday, May 30, 2017 2:44 AM
To: GMC Mail List; GMC Mueller, Rob
Subject: Re: [GMCnet] GMC Track Width
Rob, I believe you have miscalculated the rear tire width for the lift. You
have to add one full tire width to the track to get the total width. Adding
8.9 to the 75.28 DOES result in the 84.18 you came up with for the front,
but adding the 8.9 to the 85.12 would result in 94.02 inches for the rear
tire width which is just a bit inside the 96" total coach width claimed (and
allowed) when the coach was built.
These would be the absolute minimum to get the rear wheels totally on the
lift treads/tracks. Subtract the 8.9 inches from standard front track to
get the spacing between the insides of the lift treads/tracks so as ensure
that all wheels will completely fit onto the lift. Needless to say that the
lift treads/tracks should probably be an inch or so wider in each direction
to allow some leeway when driving the coach onto that lift. I suggest that
the tread/track widths be specified to be at least 4 inches wider than that
of the tires to make loading the vehicle much less critical.
Nice to have the vertical space to even be able to conceive of such a
capability!
Cheers!
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"
________________________________________
From: Gmclist on behalf of James Hupy
Sent: Monday, May 29, 2017 10:23
To: gmclist
Subject: Re: [GMCnet] GMC Track Width
Rob, back is wider than front. Due to combinations of front end spacers, 1
ton conversions, 16.5 vs 16 steelies, ALCOAs, and other alloy wheels. If
you go with rear width, add a couple inches, you should be good.
Jim Hupy
G'day,
On
GMCMotorhome.com I found the dimensions below:
Track
Front: 75.28 in.
Rear: 85.12 in.
According to convention track is measured in the center of the tire, which
would result in the following measurements at the outside of the treads for
a LT225/75-16R (8.9 in tread width):
Track
Front: 84.18 in.
Rear: 91.02 in.
I'm on crutches and can't drive due to having my right knee replaced three
weeks ago so it is very difficult for me to get to my workshop to check
these numbers, can anybody check them for me.
The reason I'm asking is I'm investigating buying a lift to raise the GMC so
I can park cars under it in my workshop.
Regards,
Rob M.
The Pedantic Mechanic
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