Tire Size
Changing from 265's to 305's will upset your truck's speedometer and odometer electronic calibration, and may also affect shift points if you have an AT. You might want to consider having a dealer recalibrate your speedo/odo.
crewzer
Anyone else found a good replacement? I have had "radial pull" on the last set of Steeltex ATs and I'm not giving Firestone any more of my money.
Scott.
It’s worth keeping the load range designations in perspective. The “E” range for any given tire just means it can be safely inflated to 80 psi, and the manufacturer certifies its load capacity at that pressure. Similarly, a “D” range designation is for load capacity @ 65 psi, and a “C” range is for load capacity @ 50 psi. A tire’s actual load capacity is based on a combination of size and the “load range” designation.
For example, a 235/85R16E is rated at 3,024 lbs @ 80 psi. The 265/75R16E, a larger tire of essentially the same rolling radius and the same “load range”, is rated at 3415 lbs @ 80 psi. The 265/75R16D, a lightly larger tire but with a lower “D” range rating, is rated at 3300 lbs @ 65 psi.
The point here is my suggestion that you determine your load requirements (separately weight the front and rear axles of your loaded truck), add a safety factor, and purchase the correct size and load range to meet your requirements and/or preferences. In addition to the “E” tires, you may find a broad range of styles, prices and availability in the “D” range that are suited to your GVWR.
I have a 2001 F-350 Crew Cab with the factory Deluxe Alloy Wheels. I have been told that the Factory wheel for 2001 is an 8" x 16" is that true???
Can you put a 315/75R16 tire on that wheel??
What is the negative inpact of oputting a tire that is larger than the size capacity of the rim??
for example if the factory rim is in fact a 7" x 16 then what is the negative impact of using the 315/75R16 or a 305/70R16??
What is the ture size difference between these two sizes for example???
I would be very appreciative of any assistance you can provide.
Please E-Mail me at IDKwhy(No Email Addresses In Posts!), if you can shed any light on this for me
Thanx - IDK
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2) BFGoodrich recommends a wheel width of 8 to 10 inches for the 315/75R16.
3) The negative impact of putting a tire on a rim that’s too narrow is that the tire beads are “pinched” by the rim, causing it the tread to curl from side-to-side. Reducing air pressure will flatten the tire, but may subject the tire to excessive heat build up and reduce your fuel economy. Many reputable tire shops won't mount tires on improperly sided rims.
4) The 265/75R16 has a nominal diameter of 30.7 inches (654 revs per mile). The 315/75 is 34.7 inches, or 599 revs per mile. The lowest recalibration setting for the SD speedometer/odometer is either 600 or 601 revs per mile.
The tire manufacturers post a lot of information on their web sites. www.bfgoodrichtires.com and www.dunloptire.com are two good places to visit.
Ford Trucks for Ford Truck Enthusiasts
My question is: how does the static height of a 265/75R/16 compare with a 235/85R/16? All the specs. that I have seen show that the two are similar but I am concerned that the difference may interfere with the auto's calibrations. I like the look of the wider tire but I wonder if it is worth the headaches?
You can have your dealer perform SSM 11789 & 11790. Besure to find your Revs/mile from the tire manufacturer. This is the critical variable for the reprogramming.
BFGoodrich's site doesn't provide static radius data. Their AT TA-KO in 235/85R16 on a 6.5" rim is 654 revs/mile. The 265/75R16 on a 7.5" rim is also 654 revs/mile. Both tires are nominally 31.8" in overall diameter.
I doubt the AT would notice a 1% or 2% variation. I have Dunlop Radia Rover 285/75R16D tires (658 revs/mile) on my truck, and my speedo and odo are low by 3%. I've not noticed any trans performance issues.
I have them mounted on the stock Y2K XLT 16 X 7 aluminum rims. They're not too noisy for a mild AT tread design, but they were difficult to balance (but we did eventually manage). I have ~12,000 miles on them and they seem to be wearing well and evenly -- I expect to get 50K miles from them.
The AT's are MUCH more comfortable than the stock Generals. I haven't noticed any particular difference in dry weather performance, but they are significantly better in rain. They seem to be OK in snow and light-duty off-roading but I doubt they can compare to real modern snow tires. I usually carry about 400 lbs of sand over the back axle in winter.
Although the 285's are much wider than the stock 235's, they're also a larger diameter. I haven't noticed any difference in mileage. Another size to consider in the AT model is the 255/85R16.
The cost - $65.00 Each. They were on their "clearance rack" for 3 Months. They wanted them out the Door.
SM







