Wrong tire size on recently acquired Suburban
December 13th, 2016, 3:19 PM
#11
Though I am a proponent of using the OEM sizes, there are many who increase their Tire size with no major problems. So other than the correctable Speedometer error, one will feel a decrease in power, breaking and an increased center of gravity, with a larger tire.
One thing that is often disregarded, is, that the width of the Tread, and the Width of the rim, should be the same.
From a performance point of view, keeping the sidewalls of the Tire vertical by having these two measurements the same will considerably enhance controllability, breaking stability, traction on ice or wet roads an mileage.
So, before you arbitrarily select a tire size, check the width of your rims, and allow that measurement to guide you.
Additionally, I recommend using Tire Pressure within 2 lbs of the MCIP.
The MCIP (Maximum Cold Inflation Pressure) for all Tires sold in the USA, is stamped on the sidewall of each tire.
One thing that is often disregarded, is, that the width of the Tread, and the Width of the rim, should be the same.
From a performance point of view, keeping the sidewalls of the Tire vertical by having these two measurements the same will considerably enhance controllability, breaking stability, traction on ice or wet roads an mileage.
So, before you arbitrarily select a tire size, check the width of your rims, and allow that measurement to guide you.
Additionally, I recommend using Tire Pressure within 2 lbs of the MCIP.
The MCIP (Maximum Cold Inflation Pressure) for all Tires sold in the USA, is stamped on the sidewall of each tire.
December 13th, 2016, 11:15 PM
#12
CF Beginner
Big tires look coool...but
The Burb can handle the tires, but changing from stock sizes can complicate things. More expensive tires, noisy aggressive treads, mismatched spare, speedometer/odometer error and reduced fuel mileage sometimes too. Can't see the whole truck in the pics you gave, but it may have been lifted to accommodate those tires...(?) If you go back to stock size now it might look kinda funny. And yes, the spare tire could do damage to the rear differential and the front if you have a 4x4. Different tire circumference is not to be taken lightly. I'd keep the tires if they're good (you said they are) and find a cheap spare wheel in 17" size. Try summitracing dot com for plain steel wheels.
December 18th, 2016, 8:13 AM
#14
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The Burb can handle the tires, but changing from stock sizes can complicate things. More expensive tires, noisy aggressive treads, mismatched spare, speedometer/odometer error and reduced fuel mileage sometimes too. Can't see the whole truck in the pics you gave, but it may have been lifted to accommodate those tires...(?) If you go back to stock size now it might look kinda funny. And yes, the spare tire could do damage to the rear differential and the front if you have a 4x4. Different tire circumference is not to be taken lightly. I'd keep the tires if they're good (you said they are) and find a cheap spare wheel in 17" size. Try summitracing dot com for plain steel wheels.
Unfortunately, I'm not keeping the truck for me, but passing it on as a charity donation next week. When I asked about a larger spare at the shop they told me it wouldn't fit in the well. I haven't had a chance to see if that's the fact or not yet.
Thanks.
December 18th, 2016, 8:21 AM
#15
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I would have to disagree with the statement I hightlighted. MCIP on my tires is 80 PSI. The stickers on my door (several posts above) say 50 front and 71 rear. Those are the numbers to go with. There's a big difference in ride and handling when the fronts are at 50 vs 80. I trust the vehicle manufacturer to specify tire inflation pressures.
In my case my door sticker says 80 PSi for the rear and that's the MCIP for these tires. (50 PSI in the front.)
Thanks
December 18th, 2016, 8:23 AM
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December 18th, 2016, 5:04 PM
#17
I honestly never "got" the whole lifted truck/big tire thing. I remember seeing huge numbers of boneheads out in Colorado with 6" lift blocks on the rear axles of their rigs.
Please tell me what I'm missing. Larger wheels/tires:
1) Cause more wear on your brakes - more angular momentum to arrest, and a larger moment arm, so the brakes have to work harder to stop the truck.
2) Cause more wear on your wheel bearings, especially if you have to use spacers to get clearance. Again, larger moment arm creates more stress.
3) Raise your center of gravity and make the vehicle less stable in an emergency maneuver, and more prone to rolling
4) Cause more wear and tear on the powertrain, having the same effect as regearing to a lower ratio, and forcing the transmission to transmit more torque
5) Probably increase your CV angles, causing them to fail prematurely
6) Reduce gas mileage - wider tires have more rolling resistance
7) Make it harder enter/exit the truck
All just to change the "look" of your truck? Really? What am I missing?
Sorry for the rant and thread derail.
Please tell me what I'm missing. Larger wheels/tires:
1) Cause more wear on your brakes - more angular momentum to arrest, and a larger moment arm, so the brakes have to work harder to stop the truck.
2) Cause more wear on your wheel bearings, especially if you have to use spacers to get clearance. Again, larger moment arm creates more stress.
3) Raise your center of gravity and make the vehicle less stable in an emergency maneuver, and more prone to rolling
4) Cause more wear and tear on the powertrain, having the same effect as regearing to a lower ratio, and forcing the transmission to transmit more torque
5) Probably increase your CV angles, causing them to fail prematurely
6) Reduce gas mileage - wider tires have more rolling resistance
7) Make it harder enter/exit the truck
All just to change the "look" of your truck? Really? What am I missing?
Sorry for the rant and thread derail.
December 19th, 2016, 2:56 PM
#18
Super Moderator
Great list ! 
Another thing that may be added is...
When larger tires are selected, one does not customarily consider that with additional "width" comes additional wet traction issues mainly related to increased Bow Wave. (that water being pushed ahead of the tires on wet surfaces) With sufficient speed, the BW can raise tires off the surface. causing loss of control.
Of course it's accepted that this can occur with OEM sizes as well, but, given the weight of the Vehicle hasn't changed, it would be expected that additional problems may be encountered with wider Tires.
Offset to this problem would be selecting a Tread Pattern which would dispel the wave, allowing speed and control to be maintained.
When selecting new Tires, considering this type Tread is not a bad idea, even if one is not increasing size, specially in regions where there is an abundance of rainfall.
Almost all the Name Brand Manufacturers have at least one choice of dedicated tread like this, though maintenance usually requires the "I" type rotation because these patterns are usually directional.
Another thing that may be added is...
When larger tires are selected, one does not customarily consider that with additional "width" comes additional wet traction issues mainly related to increased Bow Wave. (that water being pushed ahead of the tires on wet surfaces) With sufficient speed, the BW can raise tires off the surface. causing loss of control.
Of course it's accepted that this can occur with OEM sizes as well, but, given the weight of the Vehicle hasn't changed, it would be expected that additional problems may be encountered with wider Tires.
Offset to this problem would be selecting a Tread Pattern which would dispel the wave, allowing speed and control to be maintained.
When selecting new Tires, considering this type Tread is not a bad idea, even if one is not increasing size, specially in regions where there is an abundance of rainfall.
Almost all the Name Brand Manufacturers have at least one choice of dedicated tread like this, though maintenance usually requires the "I" type rotation because these patterns are usually directional.
Last edited by SWHouston; December 21st, 2016 at 3:31 PM. Reason: Wet Traction - Bow Wave
December 21st, 2016, 3:48 PM
#19
Super Moderator
Wet Traction - Bow Wave
I probably should clarify something at this point...
Wet and Dry Traction are basically the same.
The Traction entry in most statics for Tires is for Wet Traction, not Dry.
The determination of ability of Wet Traction, is done on Concrete, then Asphalt at about 40mph an relates to Stopping Distance only.
This has nothing to do with a Tire's ability to dispel Bow Wave.
The ability of a Tire to dispel the Bow Wave, lays entirely with it's Tread Pattern. A Tread Pattern which has Cleats which throw the water to the sides of the direct contact path of the Tire on the road, reduce the Wave.
Wet and Dry Traction are basically the same.
The Traction entry in most statics for Tires is for Wet Traction, not Dry.
The determination of ability of Wet Traction, is done on Concrete, then Asphalt at about 40mph an relates to Stopping Distance only.
This has nothing to do with a Tire's ability to dispel Bow Wave.
The ability of a Tire to dispel the Bow Wave, lays entirely with it's Tread Pattern. A Tread Pattern which has Cleats which throw the water to the sides of the direct contact path of the Tire on the road, reduce the Wave.
