GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Tire size (Looking for recommendation)
Tire size [message #124181] Mon, 02 May 2011 08:19 Go to next message
Jon payne is currently offline  Jon payne   United States
Messages: 495
Registered: May 2008
Karma: 1
Senior Member
All,

My local Discount Tire store has 16" steel wheels that "should" fit the GMC. The ones they have match the specs listed on one of the previous posts here. The tire I chose, based on recommendations here and by Discount Tire are the BF Goodrich commercial T/A. Tire size recommended by DT is 235 85 R16. This seems to be a good size. Any thoughts? Any other tire size suggestions?

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: [GMCnet] Tire size [message #124185 is a reply to message #124181] Mon, 02 May 2011 08:27 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
Messages: 4442
Registered: January 2004
Karma: 13
Senior Member
The 225 / 75 16" closely match the original tire diameter. The 235 /
85 will make your speedometer off more and give less clearance in the
wheel wells.

Emery Stora

On May 2, 2011, at 7:19 AM, Jon Payne <embrep@sbcglobal.net> wrote:

>
>
> All,
>
> My local Discount Tire store has 16" steel wheels that "should" fit
> the GMC. The ones they have match the specs listed on one of the
> previous posts here. The tire I chose, based on recommendations
> here and by Discount Tire are the BF Goodrich commercial T/A. Tire
> size recommended by DT is 235 85 R16. This seems to be a good
> size. Any thoughts? Any other tire size suggestions?
>
> Jon
> --
> Jon Payne
> 76 Palm Beach
> Westfield,IN
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] Tire size [message #124188 is a reply to message #124181] Mon, 02 May 2011 08:54 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
John,

Those tires are too big. Stick with 225-75R16's.

Ken H.


On Mon, May 2, 2011 at 9:19 AM, Jon Payne <embrep@sbcglobal.net> wrote:

>
> ... Tire size recommended by DT is 235 85 R16. This seems to be a good
> size. Any thoughts? Any other tire size suggestions?...
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Tire size [message #124192 is a reply to message #124188] Mon, 02 May 2011 09:11 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
John,

Perhaps I should have added this emphasis: Stick Miller's coach came with
those large tires. One of them managed to wear a hole in a new air bag.
Why risk it?

Ken H.


On Mon, May 2, 2011 at 9:54 AM, Ken Henderson <hend4800@bellsouth.net>wrote:

> John,
>
> Those tires are too big. Stick with 225-75R16's.
>
> Ken H.
>
>
> On Mon, May 2, 2011 at 9:19 AM, Jon Payne <embrep@sbcglobal.net> wrote:
>
>>
>> ... Tire size recommended by DT is 235 85 R16. This seems to be a good
>> size. Any thoughts? Any other tire size suggestions?...
>>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: Tire size [message #124196 is a reply to message #124181] Mon, 02 May 2011 09:29 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
Jon Payne wrote on Mon, 02 May 2011 09:19

All,

My local Discount Tire store has 16" steel wheels that "should" fit the GMC. The ones they have match the specs listed on one of the previous posts here. The tire I chose, based on recommendations here and by Discount Tire are the BF Goodrich commercial T/A. Tire size recommended by DT is 235 85 R16. This seems to be a good size. Any thoughts? Any other tire size suggestions?

Jon

Jon,

Could I beg a favor??

When you get the wheel(s).
Please post the manufacturer and part (model) number.
I have had some problems in this area.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Tire size [message #124198 is a reply to message #124181] Mon, 02 May 2011 09:33 Go to previous messageGo to next message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
Senior Member
I run 245-75-16's on my coach, which is close in diameter to the 235-85's you have chosen. "IMO" the coach looks better with the 245's. The down side is that it does effect your speedometer calibration. It also effects your final drive ratio. I have a 3.21FD and with these tires, I calculate something around a 3.03 actual FD ratio, also then changing the original 3.08 to something around a 2.90 which might not be what you want if you plan to tow or run the mountains. If you plan to run a steeper FD like the 3.50, 3.70 or 4.10 now available, you need to consider the minor canceling effect that the larger tire has on FD ratio. It brings the tires closer to the "T" skirts in the rear so you have to be careful about letting the suspension deflate to the ground or risk damage to the skirts. I have to take the skirts off when I put the coach up on ramps.

IMO if you are going to that tire diameter, you might consider the 245-75's instead of the 235-85's. The difference in aspect ratio of the 245's gives you a little wider tire, and a little more of a frontal patch on the road. On the other hand, the 235's might give you a little better traction in snow or wet weather with the extra ppsi and narrower frontal patch.

Nothing wrong with running the 225-75-16's...lots of people running them without the downers that I just outlined.


Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Re: [GMCnet] Tire size [message #124200 is a reply to message #124185] Mon, 02 May 2011 09:41 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
Messages: 4442
Registered: January 2004
Karma: 13
Senior Member
Forgot to say that the larger tire will also reduce your effective final drive ratio. If you use the 235 tire it will change from 3.07 to 2.89 ratio.

Emery Stora
77 Kingsley
Santa Fe, NM

On May 2, 2011, at 7:27 AM, Emery Stora wrote:

> The 225 / 75 16" closely match the original tire diameter. The 235 /
> 85 will make your speedometer off more and give less clearance in the
> wheel wells.
>
> Emery Stora
>
> On May 2, 2011, at 7:19 AM, Jon Payne <embrep@sbcglobal.net> wrote:
>
>>
>>
>> All,
>>
>> My local Discount Tire store has 16" steel wheels that "should" fit
>> the GMC. The ones they have match the specs listed on one of the
>> previous posts here. The tire I chose, based on recommendations
>> here and by Discount Tire are the BF Goodrich commercial T/A. Tire
>> size recommended by DT is 235 85 R16. This seems to be a good
>> size. Any thoughts? Any other tire size suggestions?
>>
>> Jon
>> --
>> Jon Payne
>> 76 Palm Beach
>> Westfield,IN
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Emery Stora
77 Kingsley
Santa Fe, NM


_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: Tire size [message #124201 is a reply to message #124181] Mon, 02 May 2011 09:45 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
Senior Member
Jon, just what Larry said. I run same and love them but I have a much lower final drive.
Dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: [GMCnet] Tire size [message #124208 is a reply to message #124198] Mon, 02 May 2011 10:22 Go to previous messageGo to next message
Ray Erspamer is currently offline  Ray Erspamer   United States
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
Senior Member
We have the 245/75R16 tires, when I first purchased my coach, I checked the
speed with our GPS and when the speedo said 65, we were actually doing about 58
mph. I purchased the adapter to correct it, now when speedo says 65 I'm
actually doing 75 !!! We have the 3:46 final drive per my PO's records, which
adapter should I get that would make the speedo read correctly? I would have
to take the adapter off and check the model number or gear ratio to tell what I
have now.

Ray


Ray & Lisa Erspamer
78 Royale "Great Lakes Eagle"
Center Kitchen TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/




________________________________
From: Larry <weidnerl@wwt.net>
To: gmclist@temp.gmcnet.org
Sent: Mon, May 2, 2011 9:33:11 AM
Subject: Re: [GMCnet] Tire size



I run 245-75-16's on my coach, which is close in diameter to the 235-85's you
have chosen. "IMO" the coach looks better with the 245's. The down side is that
it does effect your speedometer calibration. It also effects your final drive
ratio. I have a 3.21FD and with these tires, I calculate something around a 3.03
actual FD ratio, also then changing the original 3.08 to something around a 2.90
which might not be what you want if you plan to tow or run the mountains. If you
plan to run a steeper FD like the 3.50, 3.70 or 4.10 now available, you need to
consider the minor canceling effect that the larger tire has on FD ratio. It
brings the tires closer to the "T" skirts in the rear so you have to be careful
about letting the suspension deflate to the ground or risk damage to the
skirts. I have to take the skirts off when I put the coach up on ramps.

IMO if you are going to that tire diameter, you might consider the 245-75's
instead of the 235-85's. The difference in aspect ratio of the 245's gives you
a little wider tire, and a little more of a frontal patch on the road. On the
other hand, the 235's might give you a little better traction in snow or wet
weather with the extra ppsi and narrower frontal patch.

Nothing wrong with running the 225-75-16's...lots of people running them without
the downers that I just outlined.
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ray Erspamer 78 GMC Royale Center Kitchen 403, 3.70 Final Drive Holley Sniper Quadrajet EFI System, Holley Hyperspark Ignition System 414-484-9431
Re: [GMCnet] Tire size [message #124209 is a reply to message #124201] Mon, 02 May 2011 10:23 Go to previous messageGo to next message
Ray Erspamer is currently offline  Ray Erspamer   United States
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
Senior Member
what final drive do you have Dan ??

Ray


Ray & Lisa Erspamer
78 Royale "Great Lakes Eagle"
Center Kitchen TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/




________________________________
From: Dan Gregg <gregg_dan@hotmail.com>
To: gmclist@temp.gmcnet.org
Sent: Mon, May 2, 2011 9:45:14 AM
Subject: Re: [GMCnet] Tire size



Jon, just what Larry said. I run same and love them but I have a much lower
final drive.
Dan
--
Dan & Teri Gregg

http://danandteri.blogspot.com/




_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ray Erspamer 78 GMC Royale Center Kitchen 403, 3.70 Final Drive Holley Sniper Quadrajet EFI System, Holley Hyperspark Ignition System 414-484-9431
Re: [GMCnet] Tire size [message #124225 is a reply to message #124209] Mon, 02 May 2011 12:46 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
Messages: 495
Registered: May 2008
Karma: 1
Senior Member
Guys thanks for your input! I think based on the inputs given I will go with the 225-75R16's. And for sure I am planning on posting the wheel manufacturer, specs and pricing. If they have the 225's in stock then I will be getting the wheels/tires installed tomorrow. If not certainly by end of the week.

Thanks again for everyone's input!

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: [GMCnet] Tire size [message #124229 is a reply to message #124225] Mon, 02 May 2011 12:59 Go to previous messageGo to next message
k2gkk is currently offline  k2gkk   United States
Messages: 4452
Registered: November 2009
Karma: -8
Senior Member

If your local store does not have them in stock, I'll bet
that they can get them delivered from the nearest Discount
Tire warehouse or a nearby store within 24-48 hours.

When I had the Discount Tire in New Braunfels, TX put a set
on mine, they only had four in stock, but the last two were
delivered from somewhere by the time they had the first four
installed!

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ex-Palm Beach, 76 ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~



> To: gmclist@temp.gmcnet.org
> From: embrep@sbcglobal.net
> Date: Mon, 2 May 2011 12:46:15 -0500
> Subject: Re: [GMCnet] Tire size
>
>
>
> Guys thanks for your input! I think based on the inputs given I will go with the 225-75R16's. And for sure I am planning on posting the wheel manufacturer, specs and pricing. If they have the 225's in stock then I will be getting the wheels/tires installed tomorrow. If not certainly by end of the week.
>
> Thanks again for everyone's input!
>
> Jon
> --
> Jon Payne
> 76 Palm Beach
> Westfield,IN
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] Tire size [message #124235 is a reply to message #124225] Mon, 02 May 2011 13:23 Go to previous messageGo to next message
cbwoodsr is currently offline  cbwoodsr   United States
Messages: 1063
Registered: February 2004
Karma: 0
Senior Member
and please let us know after the installation what size your front calipers are ..
70mm or 80mm
and if they clear ok.


CBWood
77 Kingslay
MWC OK
ONLINE PARTS PROGRAM
www.GMCMHParts.com

Re: [GMCnet] Tire size [message #124242 is a reply to message #124235] Mon, 02 May 2011 14:02 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
Messages: 495
Registered: May 2008
Karma: 1
Senior Member
My calipers are the original. So I imagine they are the 70mm?

Also, called Discount Tire and they have the 225 75Rs in stock so I should have them installed on Wednesday. I'll keep you all posted.

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: [GMCnet] Tire size [message #124246 is a reply to message #124242] Mon, 02 May 2011 15:15 Go to previous messageGo to next message
cbwoodsr is currently offline  cbwoodsr   United States
Messages: 1063
Registered: February 2004
Karma: 0
Senior Member
You might have them try one wheel on the front to see if it fits before mounting tires/etc...
Backs should be no problem

FWIW


CBWood
77 Kingslay
MWC OK
ONLINE PARTS PROGRAM
www.GMCMHParts.com

Re: Tire size [message #124372 is a reply to message #124181] Tue, 03 May 2011 11:25 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
Messages: 495
Registered: May 2008
Karma: 1
Senior Member
Discount Tire Called this morning and the wheels are in. I'm scheduled on Thursday afternoon for the install. Question is what to do with the 16.5 wheels? I will retain one wheel assembly for a spare but will end up having to get rid of six of the 16.5 wheels. I'm going to ask DT if they have any interest in them but I'm not very hopeful.

My problem is I really don't have a place to keep them with out getting yelled at by the misses. I know people here on the net have sold and even given them away. Anybody interested in some free wheels? I will post the wheels in the "Swap Meet" along with my Alcoa look-a-like chrome hub caps. I have a total of 10 of those, four have never been installed and the other six have been on less than a year. Thinking $10/pc for those.

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: Tire size [message #124373 is a reply to message #124181] Tue, 03 May 2011 11:40 Go to previous messageGo to next message
larry.whisler is currently offline  larry.whisler   United States
Messages: 356
Registered: August 2005
Karma: 8
Senior Member
Jon,

I am running the Goodrich 235/85s.

if you want to see what they look like on the coach, I am just west of Cicero.

larry whisler
Re: Tire size [message #124374 is a reply to message #124372] Tue, 03 May 2011 11:43 Go to previous message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
Senior Member
Jon Payne wrote on Tue, 03 May 2011 11:25

Discount Tire Called this morning and the wheels are in. I'm scheduled on Thursday afternoon for the install. Question is what to do with the 16.5 wheels? I will retain one wheel assembly for a spare but will end up having to get rid of six of the 16.5 wheels. I'm going to ask DT if they have any interest in them but I'm not very hopeful.

My problem is I really don't have a place to keep them with out getting yelled at by the misses. I know people here on the net have sold and even given them away. Anybody interested in some free wheels? I will post the wheels in the "Swap Meet" along with my Alcoa look-a-like chrome hub caps. I have a total of 10 of those, four have never been installed and the other six have been on less than a year. Thinking $10/pc for those.

Jon


If you do your own mechanical work, you may want to keep 2 of them for use in aligning the rear. For aligning the rear, I put the bare rim on backwards. This allowed me to run a long streight edge over the two rims, and measure from the frame to check for "0" toe-in. Camber is another issue, but toe can be checked doing this. JFWIW


Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Previous Topic: Priorities
Next Topic: [GMCnet] BODY AND WHEEL FLARE KIT
Goto Forum:
  


Current Time: Sun Nov 17 16:03:17 CST 2024

Total time taken to generate the page: 0.01381 seconds