Bigger tires vs. gear?
The leverage of taller tires jacks with your overall ratio, effectively reducing it.. making getting it moving harder.. once its moving, it should help you... But...
Folks forget that rotations mass is x4.. five pounds of mass that rotates causes the equivalent of twenty pounds at the center of the rotation.. keeping that mass in motion takes energy.. for every pound extra you add to wheels and tires, you've effectively added four.. it adds up quick.
You can figure you're saving gas/energy by using larger tires on the highway, and the math concerning ratios will agree, but the math that everyone forgets, the weight, does not agree.. it will work you over..
4.56 @ 70mph for me is about 2200 rpm in fourth o/d with tc locked and 35".. iirc it was around 1800 w/ 3.92's with 33".. . its likely around 1600 w/33" and 3.55..
Folks forget that rotations mass is x4.. five pounds of mass that rotates causes the equivalent of twenty pounds at the center of the rotation.. keeping that mass in motion takes energy.. for every pound extra you add to wheels and tires, you've effectively added four.. it adds up quick.
You can figure you're saving gas/energy by using larger tires on the highway, and the math concerning ratios will agree, but the math that everyone forgets, the weight, does not agree.. it will work you over..
4.56 @ 70mph for me is about 2200 rpm in fourth o/d with tc locked and 35".. iirc it was around 1800 w/ 3.92's with 33".. . its likely around 1600 w/33" and 3.55..
Or they're in denial...
This is by far one of the best explainations of why big tires don't work with low numerical gears. Along with why your gas mileage doesn't improve much (if at all) when you "gear down". Well that and aerodynamics and hp/weight ratio
.Nicely done Drew!
My truck, at an uncorrected 65mph, tachs about 1700-1800 rpm. Thats with well worn 33 inch tires.
Record Breaker
Joined: Feb 2009
Posts: 1,133
Likes: 18
Y'know, a lot...or pretty much everybody, doesn't understand what happens when you increase the unsprung weight of tire/rims and how much more REAL effort it takes to get that mass of rubber and metal moving from a dead stop, or BACK to a dead stop!
Or they're in denial...
This is by far one of the best explainations of why big tires don't work with low numerical gears. Along with why your gas mileage doesn't improve much (if at all) when you "gear down". Well that and aerodynamics and hp/weight ratio.
Nicely done Drew!
My truck, at an uncorrected 65mph, tachs about 1700-1800 rpm. Thats with well worn 33 inch tires.
Or they're in denial...
This is by far one of the best explainations of why big tires don't work with low numerical gears. Along with why your gas mileage doesn't improve much (if at all) when you "gear down". Well that and aerodynamics and hp/weight ratio
.Nicely done Drew!
My truck, at an uncorrected 65mph, tachs about 1700-1800 rpm. Thats with well worn 33 inch tires.
Champion
Joined: Aug 2010
Posts: 2,697
Likes: 3
From: Cape Carteret NC
HA!!!! I'm a mountain biker, and scoffed at this concept until I had to choose between tires with perfect tread (maxxis mobsters 2.4) and great weight (conti verticals 2.2).. It was a 12 hour race, and I went with the heavier mobsters for grip.. I figured it out by lap three, and swapped them out by lap four.. the time i lost in corners and washes was easily recouped everywhere else..
the principle is the same no matter the application..
Record Breaker
Joined: Mar 2010
Posts: 1,169
Likes: 0
From: Texas
Ok with 35's and 3.55, my truck is at 1600 rpms at 70mph, but thats acording to my gps. My speedo is 10 mph off with 35's" tires.
So 60 mph on the factory gauge is 70mph on my garmin. You have to take all this into consideration when you change tires/gears.
As for mpg I get about 14-16 mpg average from a full tank.
So 60 mph on the factory gauge is 70mph on my garmin. You have to take all this into consideration when you change tires/gears.
As for mpg I get about 14-16 mpg average from a full tank.
Thread Starter
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Professional
Joined: Jul 2011
Posts: 138
Likes: 0
From: Livonia,MI
Ok with 35's and 3.55, my truck is at 1600 rpms at 70mph, but thats acording to my gps. My speedo is 10 mph off with 35's" tires.
So 60 mph on the factory gauge is 70mph on my garmin. You have to take all this into consideration when you change tires/gears.
As for mpg I get about 14-16 mpg average from a full tank.
So 60 mph on the factory gauge is 70mph on my garmin. You have to take all this into consideration when you change tires/gears.
As for mpg I get about 14-16 mpg average from a full tank.
