Smaller Diameter Snow Tires - Problems?

tires
nissan
winter
xterra

#1

I just purchased a new Nissan Xterra Pro-4x and am planning on putting snow tires on the vehicle for the winter(I live in New Jersey but will be commuting to and driving in Quebec several times this winter). The stock tire size is 265/75/16 but it seems that the more popular SUV winter tires come in size 265/70/16. Would there be any problems if I put a size 265/70/16 on stock rims? I am particularly interested in getting the Bridgestone Blizzak DM-Z1 but the closest size they are available in is 265/70/16. Would handling or braking be affected by a smaller tire diameter? Are there any drawbacks to a smaller tire diameter than stock size?


#2

I believe the lower load rating for the narrower tire could be problematic. Check the owner’s manual, and the label inside the driver’s door.


#3

Smaller tires can adversely affect handling in addition to the load rating consideration already mentioned. I strongly recommend staying with the manufacturer’s recommended size.


#4

If we look at this like tire folk what we will come up with is: the tire in either 70 series or 75 series will be 265 millimeters across the width of the tire. the 75 means that the sidewall height is 75 percent of the tread width, the 70 of course means 70 percent of the tread width. So what we have with the 70 series tire is 5 percent less sidewall. With this in mind I believe there would be less sidewall flex resulting in firmer handling. Might actually throw your speedo off a mph or two but nothing significant. As far as load capacity I dont see that changing between a 70 or 75 series tire


#5

One issue with changing tire diameter, up or down, is that the change right away affects the speedometer and odometer. You will either be going faster or slower than the speedometer is reading (if you put smaller diameter tires on the car, you will be going slower than what the speedometer reads, and you will register more than a mile for each mile travelled - not good). It also is outside of what the car’s engineers intended, so unless there is an engineering problem, keep it the same if you can.


#6

The sidewall will be ? inch thinner. That will be good in snow. You will push towards the road a little better and get a little better traction. The Speedo will read 3.5% faster. Make sure the winter tyres are rated the the weight of your car.

If it were mine, I would consider it a upgrade, in ability to handle snow and ice.

#7

Should be no problem. If you have a GPS you can use it to check your speedometer reading. Since most speedo error is on the fast side, I don’t think the difference will be great, but a GPS check is a good idea if you like to push the mph as you cruise along. There are lots of cops on the Northway so be sure of your actual speed.


#8

“If we look at this like tire folk … As far as load capacity I dont see that changing between a 70 or 75 series tire.”

Well, I ARE a tire folk, and THE most important thing is load carrying capacity AND going down in aspect ratio (with no other changes) makes the load carrying capacity go down as well. In this case, almost 200# per tire.