Larger tire problems????
07-19-2011, 07:10 PM
#1
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Larger tire problems????
OK don't worry I am not about to ask what size will fit, I have done plenty of research....
However, I have heard it said that there can be/are problems when you chance the overall diameter of your tire by more than 3% from factory. Does anyone know what these problems are, and for those of you who have larger tires have you noticed any problems. I have stock 20" rims on my 2010 FX4 with Pirelli's which are 31.9" diameter. I will be going to either 305/55R20 or 285/65R20 which would both be at or above 3% difference and I want to know what I am getting myself into before I'm there.
However, I have heard it said that there can be/are problems when you chance the overall diameter of your tire by more than 3% from factory. Does anyone know what these problems are, and for those of you who have larger tires have you noticed any problems. I have stock 20" rims on my 2010 FX4 with Pirelli's which are 31.9" diameter. I will be going to either 305/55R20 or 285/65R20 which would both be at or above 3% difference and I want to know what I am getting myself into before I'm there.
07-19-2011, 07:41 PM
#2
Master Gunner
If you don't change anything else but tire diameter, here are things to expect:
1) Speedometer will show you going SLOWER than you actually are. This will impact other systems that depend upon speed for their operations (e.g. Odometer)
2) Transmission may not shift at optimal speeds. It may tend to shift later than you would expect it to, to include downshifting later than it should.
3) Gas mileage may tend to get worse, especially with wider than factory tires.
At least these were the results I found on my 01 SCrew when I went from factory to 35" tall tires (and 6" lift, of course).
I will be getting 305/55R20's on my 09 soon...
1) Speedometer will show you going SLOWER than you actually are. This will impact other systems that depend upon speed for their operations (e.g. Odometer)
2) Transmission may not shift at optimal speeds. It may tend to shift later than you would expect it to, to include downshifting later than it should.
3) Gas mileage may tend to get worse, especially with wider than factory tires.
At least these were the results I found on my 01 SCrew when I went from factory to 35" tall tires (and 6" lift, of course).
I will be getting 305/55R20's on my 09 soon...
Last edited by Augster; 07-19-2011 at 07:45 PM.
07-20-2011, 12:39 AM
#3
'11 Lariat EcoBoost 4x4
If you don't change anything else but tire diameter, here are things to expect:
1) Speedometer will show you going SLOWER than you actually are. This will impact other systems that depend upon speed for their operations (e.g. Odometer)
2) Transmission may not shift at optimal speeds. It may tend to shift later than you would expect it to, to include downshifting later than it should.
3) Gas mileage may tend to get worse, especially with wider than factory tires.
At least these were the results I found on my 01 SCrew when I went from factory to 35" tall tires (and 6" lift, of course).
I will be getting 305/55R20's on my 09 soon...
1) Speedometer will show you going SLOWER than you actually are. This will impact other systems that depend upon speed for their operations (e.g. Odometer)
2) Transmission may not shift at optimal speeds. It may tend to shift later than you would expect it to, to include downshifting later than it should.
3) Gas mileage may tend to get worse, especially with wider than factory tires.
At least these were the results I found on my 01 SCrew when I went from factory to 35" tall tires (and 6" lift, of course).
I will be getting 305/55R20's on my 09 soon...
07-20-2011, 12:51 AM
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change the diff ratios and get it tuned.
I would also be concerned about the functions....ABS, stability and traction control. Also, our trucks have a very good braking system, but with those cool guy tires, I can guarantee that the tires will break traction while the brakes do what they are 'posed to do.
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07-20-2011, 01:05 AM
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i went from 235/75/r17 (30.9") to 305/55/r20 (33.2") about 7%. I have a tuner to account for the tire size so shift points are where they should be. however, the tuner i got doesn't fix the speedometer for 2009+ f150's (edge evolution cs) which sucks. i wish i got a SCT or something else.
The traction control does turn on a bit too easily while cornering over bumps.
gas mileage was affected but not my that much, maybe 1mpg on average
Either way, i am pretty happy with them and will not go back to stock.
The traction control does turn on a bit too easily while cornering over bumps.
gas mileage was affected but not my that much, maybe 1mpg on average
Either way, i am pretty happy with them and will not go back to stock.
Last edited by mikeylikesit75; 07-20-2011 at 01:55 AM.
07-20-2011, 01:17 AM
#9
'11 Lariat EcoBoost 4x4
07-20-2011, 05:48 AM
#10
FN SWT
