Go Back   Ford Truck Enthusiasts Forums > Bronco > 1978 - 1996 Big Bronco
Sign in using an external account
Register Forgot Password?


1978 - 1996 Big Bronco SPONSORED BY:

Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!





 
Reply
 
LinkBack Thread Tools Search this Thread
  #1 (permalink)  
Old 12-13-2007, 01:28 PM
jbondi jbondi is offline
Senior User
 
Join Date: Mar 2004
Location: Norristown, PA
Posts: 146
jbondi is starting off with a positive reputation.
Tire size equivalent

I currently have 31x10.5x15 BFG Long Trails on my Bronco. I was told that 235/75/15 is the equivalent size. Something is telling me that is the stock size. Anybody know?? From what I've heard, 31x10.5x15 is a hard size to find?? Is that true??

Joe
__________________
Joe
1994 Bronco XLT (302)
Gibson Shorty Headers, Bassani catback
Alpine AM/FM cd player
MB Quart door speakers
Kenwood rear speakers
Reply With Quote
  #2 (permalink)  
Old 12-13-2007, 02:05 PM
s1120's Avatar
s1120 s1120 is offline
Senior User
 
Join Date: May 2003
Posts: 281
s1120 is starting off with a positive reputation.
Closest size to a 31 10.5x15 is a 265 75r15
31 10.5's are a VERY common size!!!
__________________
Paul B

95 Bronco, e40d,5.0HO shortblock, early 351 heads, ported w/1.94/1.60 valves, Crane 2030 cam, shorty headers, homemade Ypipe, and flowmaster cat back[for now]
Reply With Quote
  #3 (permalink)  
Old 12-13-2007, 02:14 PM
jbondi jbondi is offline
Senior User
 
Join Date: Mar 2004
Location: Norristown, PA
Posts: 146
jbondi is starting off with a positive reputation.
Quote:
Originally Posted by s1120
Closest size to a 31 10.5x15 is a 265 75r15
31 10.5's are a VERY common size!!!
That's what I thought!!! Do you think there is any price difference between the 31's and the 265/75/15's??
__________________
Joe
1994 Bronco XLT (302)
Gibson Shorty Headers, Bassani catback
Alpine AM/FM cd player
MB Quart door speakers
Kenwood rear speakers
Reply With Quote
  #4 (permalink)  
Old 12-13-2007, 03:05 PM
aurgathor aurgathor is offline
Postmaster
 
Join Date: Aug 2004
Location: Bothell, WA
Posts: 2,886
aurgathor is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by s1120
Closest size to a 31 10.5x15 is a 265 75r15
31 10.5's are a VERY common size!!!
And 265/75R15 is a very rare size. I don't think there should be much, if any difference in price for equivalent tires, except you have a lot more choice with 31x10.50.

Last edited by aurgathor; 12-13-2007 at 03:09 PM.
Reply With Quote
  #5 (permalink)  
Old 12-14-2007, 07:48 AM
s1120's Avatar
s1120 s1120 is offline
Senior User
 
Join Date: May 2003
Posts: 281
s1120 is starting off with a positive reputation.
Quote:
Originally Posted by jbondi
That's what I thought!!! Do you think there is any price difference between the 31's and the 265/75/15's??

Frankly the price diff will be more in style, and brand. Hard to say.
__________________
Paul B

95 Bronco, e40d,5.0HO shortblock, early 351 heads, ported w/1.94/1.60 valves, Crane 2030 cam, shorty headers, homemade Ypipe, and flowmaster cat back[for now]
Reply With Quote
  #6 (permalink)  
Old 12-14-2007, 09:32 PM
shift1313's Avatar
shift1313 shift1313 is offline
Elder User
 
Join Date: Apr 2005
Posts: 726
shift1313 is starting off with a positive reputation.
long trails are good tires. i ran a set of 30x9.5 on my bronco for like 6 years, then i got another year on them on my f150.

ive heard that 15" tires are going to start coming up in price but i dont believe it. honestly once you go over 235/75x15 the price difference is probably pretty small. I think i got some 235s for like $50 a piece for my truck. I got some bfgs 30" for $70 a piece on a deal. if you look at tire prices your looking at $110 atleast if your getting anything larger then 30".


just so you know with tire sizes, 235 is the width of the tread, 75 is the aspect ratio of sidewall to width of tire and then 15 is obviously the rim size. so 235mm wide, 75% of the width for the sidewall is 176.25mm so 6.9" sidewall. 15" rim plus 6.9" plus 6.9" is roughly 28.8" tire.
When you get 31x10.50x15 its 31" tall tire, 10.5" wide tread 15" rim. now a 31" tire isnt exactly 31", a bfg 31" tire might measure 31.5" and a mastercraft 31" tire might measure 30.5".

30x9.50s are about the biggest you can run on stock rims without rubbing the radius arms. 31x10.50s rub the radius arms on stock rims. 32x11.50s clear with offset rims with no rubbing issues. 33x12.50s fit okay on pre 87. dont know about87+ yet as i havent tried them on my truck.
Reply With Quote
  #7 (permalink)  
Old 12-16-2007, 11:25 AM
benshere benshere is offline
Elder User
 
Join Date: Oct 2005
Location: Longwood, Fl
Posts: 982
benshere is starting off with a positive reputation.
31x10:50x15

I think the OEM on my 93 was a 265---will have to look at the spare, it is a goodyear RTS. I have run 31's and now have 32X1150X15's on stock rims. If they do rub, it isnt much. Guess I need to looksee if I have polished radius arms. Very satisfied with the 32's (was also with the 31's).

I did a post (somewhere!) where I measured "rollout" of the 32's with PSI'S from 50 to 10 PSI and can say that my figures show very little difference in rollout (= circumference), maybe ~2-3 %. Also been my experience that a 31 and 32 may be a full inch short on actual height as computed by circumference. To be clear, thats MY tires (bridgestone APT) on stock rims on my bronco. I am not saying all tires do the same
Reply With Quote
  #8 (permalink)  
Old 12-16-2007, 12:13 PM
shift1313's Avatar
shift1313 shift1313 is offline
Elder User
 
Join Date: Apr 2005
Posts: 726
shift1313 is starting off with a positive reputation.
i know with my 89 anything over 9.5" wide rubbed the radius arm with full turn to the stops, im sure rim options were different though
Reply With Quote
  #9 (permalink)  
Old 12-16-2007, 04:24 PM
AbandonedBronco's Avatar
AbandonedBronco AbandonedBronco is offline
Moderator
 
Join Date: Dec 2007
Location: Boise, Idaho
Posts: 4,815
AbandonedBronco has a great reputation on FTE.AbandonedBronco has a great reputation on FTE.AbandonedBronco has a great reputation on FTE.AbandonedBronco has a great reputation on FTE.AbandonedBronco has a great reputation on FTE.
The main difference between a 265 75R15 and a 31x10.5 15 is the intention of what it's for.

265 75R15 mathematically is a 30.65"x10.45" 15 tire, almost exactly the same. However, tires that are measured in the 265 75R15 method are designed for road use, pavement, and highway. As a general rule, only tires measured in the 31x10.5 method are truck tires and have tread patterns designed more for off-roading, dirt, gravel, and other trucky things of that nature.

There's almost no difference in size between the two, except that the 31x10.5 method has a lot less lenient rules on it and sometimes they are much smaller. For example, when I take a tape measure to my 30 x 9.5" tires, they measure out to 28x8.5" tires. My speedometer is off as well as other things. Next time I go get truck tires, I'm bringing a tape measure with me. I'd recommend everyone else do the same.

Last edited by AbandonedBronco; 12-16-2007 at 04:30 PM.
Reply With Quote
  #10 (permalink)  
Old 12-16-2007, 06:06 PM
benshere benshere is offline
Elder User
 
Join Date: Oct 2005
Location: Longwood, Fl
Posts: 982
benshere is starting off with a positive reputation.
225x60x16

Abandonedbronco--
I have been looking at the difference between quoted and actual sizes for years now and have no real good explanation as to why the difference. Even on spec'd rims, there still is a difference. My "guess" is that mfg's target the size they want to build then hit slightly undersize. Not that it really matters a whole lot, as long as the Consumer is aware. Most of the time (on tires I have purchased) even the mfg's rev/per/mile figures are off---which directly relates to the circumference.

Car spec'd tires seem to be the same, maybe not as far off. My 03 Gran Marq, oem 225X60X16 Michelin to 235X60X16 BFG traction TA's back to 225X60X16 michelin's were all off by approx 1" on height. Again, not a problem as long as the buyer beware!
Reply With Quote
  #11 (permalink)  
Old 12-16-2007, 06:34 PM
Twistin's Avatar
Twistin Twistin is offline
Junior User
 
Join Date: Nov 2007
Location: Upstate NY
Posts: 84
Twistin is starting off with a positive reputation.
Try walmart, they have 4 differnt 265's 2 of them are at $100.00 ea. PeP boys as well has both the 31's and 265's Any one knowing where i can get my hands on a Futura Adventuer H/T 265 75 R15 please let me know, I have 4 new ones but need a spair and PeP boys said that tire is discontinued. Thanks!
Keep Em' Twistin'! Bob B.

Bronco Stables: 89 thru 96 / XLT / Eddie B / BR II
http://www.supermotors.net/vehicles/registry/15608



Quote:
Originally Posted by jbondi
I currently have 31x10.5x15 BFG Long Trails on my Bronco. I was told that 235/75/15 is the equivalent size. Something is telling me that is the stock size. Anybody know?? From what I've heard, 31x10.5x15 is a hard size to find?? Is that true??

Joe

Last edited by Twistin; 12-16-2007 at 06:35 PM. Reason: link isnt right
Reply With Quote
  #12 (permalink)  
Old 12-16-2007, 06:52 PM
aurgathor aurgathor is offline
Postmaster
 
Join Date: Aug 2004
Location: Bothell, WA
Posts: 2,886
aurgathor is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by AbandonedBronco
The main difference between a 265 75R15 and a 31x10.5 15 is the intention of what it's for.

265 75R15 mathematically is a 30.65"x10.45" 15 tire, almost exactly the same. However, tires that are measured in the 265 75R15 method are designed for road use, pavement, and highway. As a general rule, only tires measured in the 31x10.5 method are truck tires and have tread patterns designed more for off-roading, dirt, gravel, and other trucky things of that nature.
For the standard sizing, what differentiates is actually the P vs. LT. Ps usually have 4 treads while C rated LTs and floatation sizes have 5 or 6 treads.
Reply With Quote
  #13 (permalink)  
Old 12-16-2007, 08:15 PM
shift1313's Avatar
shift1313 shift1313 is offline
Elder User
 
Join Date: Apr 2005
Posts: 726
shift1313 is starting off with a positive reputation.
if you buy tires from walmart be very weary of them mounting them. i havent heard good things about their service dept. I bought a set of tires for my truck there and mounted them by hand with tire irons and used a bubble balancer rather then let them touch my truck. I know first hand of someone who had their oil changed there and within a mile all the oil had drained out and the engine locked up.

tires are cheap though
Reply With Quote
  #14 (permalink)  
Old 12-16-2007, 08:59 PM
Twistin's Avatar
Twistin Twistin is offline
Junior User
 
Join Date: Nov 2007
Location: Upstate NY
Posts: 84
Twistin is starting off with a positive reputation.
Sorry wasn't thinkin about that, I own my own tire machine, Coats 1010. Once mounted I take em to goodyear for spin balancing.
Keep Em' Twistin'! Bob B.

Bronco Stables: 89 thru 96 / XLT / Eddie B / BR II
http://www.supermotors.net/vehicles/registry/15608


Quote:
Originally Posted by shift1313
if you buy tires from walmart be very weary of them mounting them. i havent heard good things about their service dept. I bought a set of tires for my truck there and mounted them by hand with tire irons and used a bubble balancer rather then let them touch my truck. I know first hand of someone who had their oil changed there and within a mile all the oil had drained out and the engine locked up.

tires are cheap though
Reply With Quote
Old 12-16-2007, 08:59 PM
Reply

Go Back   Ford Truck Enthusiasts Forums > Bronco > 1978 - 1996 Big Bronco

Tags
105, 15, 235, 2357515, 31, 315, 31x105, 31x1050, 75, equivalent, f150, ford, measure, size, tire, tires

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump



All times are GMT -5. The time now is 05:46 AM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.5.2 ©2010, Crawlability, Inc.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup