Camprunner
New member
I was wondering all you guys who went from a tire size of 265/65/17 to a 265/70/17 were there any i'll effects like slow stearing, bad ride, effects on the track-control, and or ABS ?
Effects on tire size change?
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wolfgang
New member
According to the Miata Tire Calculator - When speedo now reads 60 MPH you are actually doing 62 MPH. Revs are now 638 revs/mile vice 660 rev/mile - so oher than tire weight (and speedo/odo error) wouldn't you get better gas mileage? I can see lower 0-60 MPG. The 70 series is 1" taller (diameter) and 3" more circumferance than the 65 series.
ObeseFieldMouse
New member
yea, rpms are lower, but thats not all that controls fuel mileage. you have to factor in where your foot is in the pedal. rpms only determine how fast a certain amount of fuel is delivered. the skinny pedal determines the volume of fuel delivered. lower rpms, but more skinny pedal = worse fuel mileage.
when you go to a larger than stock tire size, the radius of you tire changes. just for arguments sake say you had a 30" tire. thats a 15" radius. if you put a 34" tire on it you now have a 17" radius. thats 2" more torque the road, being stationary, has on you tire. what that means for you torque available to the wheels is take your torque and multiply it by 15/17. for the v8, which has 320lb/ft, it now has only 282lb/ft available.
increasing you tire size by one inch will take about 10lb/ft.
when you go to a larger than stock tire size, the radius of you tire changes. just for arguments sake say you had a 30" tire. thats a 15" radius. if you put a 34" tire on it you now have a 17" radius. thats 2" more torque the road, being stationary, has on you tire. what that means for you torque available to the wheels is take your torque and multiply it by 15/17. for the v8, which has 320lb/ft, it now has only 282lb/ft available.
increasing you tire size by one inch will take about 10lb/ft.
pipspeak said:
Just not thrilled with them off road and in snow . I always run BFG AT's and I thought I would try these since everyone loved them. they are a good road & wet weather tire though and ride nice. Just want something a little more aggressive/stronger load rating for my style.
Not a bad tire , more of an all season than an all terrain.
Camprunner
New member
Falls said:
Falls ...... right now im sticking with my Mastercraft Courser A/T-2 tires in 265/65/17 I just took them off and put my stock "D-Flops" back on so I can get another winter out of the M-crafts.
I was thinking today that if I were to buy tires today I think I would buy the new General Grabber A/T-2 tires. "DEEP" tread depth in size 265/70/17 and the price is great from the tire rack.
If I do decide to go to a 265/70/17 that is? .......... Im not a big fan of wide tires for the winter I still think it's better to go to a 245/70/17 size in a snow or a real good A/T tire and to be honest the 245/70/17 is real close to a 265/65/17 size Just a little taller and less wide. (better for snow but not as good for mud)
Falls ..... The BFG's are great but Im not sure about the ride quality ........ That stiff sidewall does not like to give much on the road. You may want to ck out the "Gen-A/T-2" I think it will ride better.
Camprunner
New member
Before I bought my Mastercrafts I was going to go with the Toyo"s but the local Toyo stealer that sells them wanted $ 35.00 more per tire then what I bought.
Kmvreter
New member
ObeseFieldMouse said:
I understand the effect on revs/mile and speedo error.
I'm not understanding the "skinny pedal" and torque logic. Can you explain it differently? Correct me if I'm wrong but I think you are saying that it takes more torque to move the larger diameter tire (that makes sense.) Isn't that only an issue on acceleration, during which you are also trying to move a proportionally much larger mass (the truck)? What about contact patch size, rolling resistance, and inertia at a steady speed? To many variables here to make it simple.
ObeseFieldMouse
New member
youre right that it takes more torque to move a larger diameter tire, but that isnt only during acceleration. the best way to describe it is an exercise bike. the bigger the front tire the harder it is to get it moving. if you put the little load thing on to emulate a hill, and have a small tire it takes a lot less effort to get it going and keep it going as it would the same load on a larger tire.
the larger the contact patch, the more rolling resistance.
as for inertia...on a bicycle if you are going 30mph in a low gear it takes less push to keep you at the same speed than it would if you were in the tallest gear possible...
did that clear it up any?
the larger the contact patch, the more rolling resistance.
as for inertia...on a bicycle if you are going 30mph in a low gear it takes less push to keep you at the same speed than it would if you were in the tallest gear possible...
did that clear it up any?
