tire size question
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tire size question
In the market for tires for my recently purchased 91 F250 LD 4wd. The door jamb sticker calls for 7.5 16's. In looking around on the net and going to my local independent tire guy that I have been doing business with for years , LT215/85r16 seems to be the replacement size. Here's the monkey wrench , The PO put the nicer factory Ford aluminum rims on the truck and the tire size is LT265/75r16. My question is , does this throw my speedo off or not , and what do you guys think I should go with size-wise with new tires ?? Most of my driving is back and forth to work , with occasional runs to get hay for my horses . I do live out in the country and we don't see a plow often , plus I work rotating shifts{ never fails to snow heavy when I am on midnights} , so I need decent snow tread , but don't want to go too aggressive either.
Any brand preference also would be appreciated !
Thanks !!
Any brand preference also would be appreciated !
Thanks !!
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
If you got those tire sizes correct then your speedo will be off but more importantly the odometer will be off quite a bit so fuel milage calculations will be too. If you can get your hands on a GPS you can see just how much it is off, and if you want to correct it I believe on that truck you have to change a gear on the speedo drive cable at the transmission.. depends if your truck has the old style mechanical odometer or the newer digital version. If it's newer the PSOM has to be reprogrammed, but that's also a fairly simple DIY thing. HOW TO RECALIBRATE THE SPEEDOMETER ON 92-96 FORD F-SERIES AND BRONCO .: Articles
As for the size and type tires you get, check the axle code on the drivers door pillar first to determine the gear ratio. https://www.ford-trucks.com/article/...de_Chart_.html If it's 3.55 then you can use a smaller tire but if it's 4.10 you may want to go with a larger tire to keep fuel milage reasonable. All terrain tires work pretty good in the winter on these trucks as long as they are a narrow profile, wide tires on an unloaded pickup is a real handfull on snow covered roads.
As for the size and type tires you get, check the axle code on the drivers door pillar first to determine the gear ratio. https://www.ford-trucks.com/article/...de_Chart_.html If it's 3.55 then you can use a smaller tire but if it's 4.10 you may want to go with a larger tire to keep fuel milage reasonable. All terrain tires work pretty good in the winter on these trucks as long as they are a narrow profile, wide tires on an unloaded pickup is a real handfull on snow covered roads.
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Thanks Paul. Gears are 3.55's and speedo is cable drive. Think my best option would be to go with something closer to stock in size , just wondering if the later model factory aluminum rims on the truck will accept the stock size ????
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Sounds Great ! I did some checking around and the existing tires should make my speedo off by 2.67 mph but all in all it's not off by that much. I really appreciate all the help from everyone. Going to go with the stock replacement size , just have to decide what brand and tread pattern now.
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Learned something new today !
In talking to my local tire guy today , I learned something new. I you have been following my posts , I am looking for new tires , and discovered in my search the PO had installed tires that were the incorrect size , resulting in my speedo being off by aprx 5%. 60 mph is really 63 mph , and the odometer will be off too. Anyway , to make a long story short , my tire guy told me if I want to have the correct diameter { LT215 85 16} but want a wider tire than that , there is a formula to keep everything in order. He called it plus fitment.
Each time you increase width by 10 { the first number} you must decrease the aspect ratio number by 5{ the second number}in order to keep tire diameter to original spec. The truck has LT 265 75 16's on it now and if I wanted the same width on new tires I should actually have LT265/60's installed to give me the wider look but yet have the correct diameter to keep speedo/odometer happy. Not that I will go that wide again , but this really helped me get my head around this tire size stuff.
Each time you increase width by 10 { the first number} you must decrease the aspect ratio number by 5{ the second number}in order to keep tire diameter to original spec. The truck has LT 265 75 16's on it now and if I wanted the same width on new tires I should actually have LT265/60's installed to give me the wider look but yet have the correct diameter to keep speedo/odometer happy. Not that I will go that wide again , but this really helped me get my head around this tire size stuff.
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Joined: Nov 2002
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From: Mathews Virginia
my 1996 F-250 4X4 has the ford factory alloy wheels and it came with 235/75/16's on it from Ford when I got it it had 265/75/16 cooper discover's on it and when I put tires on it I put 285/75/16 pro comp all terrains on it Ilike the look of the 285's and have no rubbing problems the only downside is I am goona change the gearsa to 4:10's ! Now my truck is the heavy duty version I myself would not go back down to a 215 I would use a 235 or a 265 but this is my opinion!!
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From: Iowa
With 265/75s the speedo will be off, but only slightly. I wouldn't even worry about it unless you REALLY need to document actual miles traveled.
Personally, I'm going to put 285/75s on my F250 when the time comes
Personally, I'm going to put 285/75s on my F250 when the time comes
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fatdaddy
Brakes, Steering, Suspension, Tires, & Wheels
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Feb 11, 2002 04:21 PM
