225/75/15 VS 31x10.50r15
10-30-2009, 07:13 PM
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225/75/15 VS 31x10.50r15
this has been running around in my head for a while and could not find anything with the SEARCH button, anyway i was curious to see what your input is. what are the advantages/disadvantages with a 225/75/15(stock tire size)?? what are the advantages/disadvantages with a 31x10.50x15?? i know the obvious is smaller tire less top speed, easier acceleration, less ground clearance and the bigger tire would be more ground clearance(is it that significant?) and higher top speed but loss in power to the ground.
WHAT DO YOU THINK?
WHAT DO YOU THINK?
10-30-2009, 07:25 PM
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given same engine output and final drive ratios for both:
smaller tire means less rotating mass, consequently meaning less power required to turn it hence more torque to the ground and better ability to maintain speed and likely a higher top speed in any particular gear.
larger tire means greater rotating mass hence requires more torque to turn it and maintain speed thus lower top speed in any particular gear
additionally, the smaller tire presents a smaller frontal cross-section thus lower wind resistance than the larger tire, consequently less aerodynamic drag with the smaller tire versus the larger tire which also leads to a higher top speed in any particular gear with the smaller tire.
smaller tire means less rotating mass, consequently meaning less power required to turn it hence more torque to the ground and better ability to maintain speed and likely a higher top speed in any particular gear.
larger tire means greater rotating mass hence requires more torque to turn it and maintain speed thus lower top speed in any particular gear
additionally, the smaller tire presents a smaller frontal cross-section thus lower wind resistance than the larger tire, consequently less aerodynamic drag with the smaller tire versus the larger tire which also leads to a higher top speed in any particular gear with the smaller tire.
Last edited by abecedarian; 10-30-2009 at 07:26 PM.
10-30-2009, 07:29 PM
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You'll only get a higher top speed with a larger tire when compared to a smaller tire and using the same gear ratio(s) if the engine has sufficient power to overcome aerodynamic resistance.
Given the same gear ratios and sufficient power, the larger tire can result in higher speeds but the smaller tire will allow the vehicle to accelerate more quickly provided traction can be maintained during acceleration.
Given the same gear ratios and sufficient power, the larger tire can result in higher speeds but the smaller tire will allow the vehicle to accelerate more quickly provided traction can be maintained during acceleration.
10-30-2009, 08:30 PM
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10-30-2009, 08:33 PM
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just because the door jamb tag says 225/75's...doesn't mean he has 4.10 gears..the axle code is where its at
my '92 4runner says it came with stock 225/75 tires..but my gear code says otherwise...G254..which means 4.56's..which means HOT DANG im lucky..lmao
my '92 4runner says it came with stock 225/75 tires..but my gear code says otherwise...G254..which means 4.56's..which means HOT DANG im lucky..lmao
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10-30-2009, 08:38 PM
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that site said it was 28.3" tall, so its anywhere from 1-2" taller and about 1-1.5" wider. the smaller tire also seems to cost less but its harder to find aggressive off road tires. so next tire change ill try out the 225's unless anyone has any contradictions.
10-30-2009, 08:54 PM
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Both my '91 4x4's, my old truck with the 225/75/15 tire came with 4.56's, and my 4Runner with the 31's has 4.56's.
My 1st Toyota 4x4, an '84 with the 225/75/15 tire, came with 4.10's
My 1st Toyota 4x4, an '84 with the 225/75/15 tire, came with 4.10's
10-30-2009, 09:03 PM
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g294?:edit: found it....i have 4.10's 
but i did find some tires....http://www.cricripneus.com.br/images/produtos/12.jpg 
but i did find some tires....http://www.cricripneus.com.br/images/produtos/12.jpg
Last edited by Built2Grind; 10-30-2009 at 09:16 PM.
10-30-2009, 10:01 PM
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To the original poster:
The advantages and disadvantages lie in what you want to use the truck for. If its a daily driver that sees occasion easy trails, the smaller tires in an AT tire will give you slightly better mileage, quieter ride, better road manners and slightly better accelleration.
If you want to run tough trails without completely ruining the commutability (new word!) of your truck, put on some 31-10.50 MTs and get another inch or two of clearance, i've seen an inch or two make the difference between getting stuck and not on several occasions.
There was actual an article online i found once where a fella put on 31-10.50s, a locker and a winch on an otherwise stock toyota and followed a bunch of highly modded trucks all over MOAB, pretty cool article.
The advantages and disadvantages lie in what you want to use the truck for. If its a daily driver that sees occasion easy trails, the smaller tires in an AT tire will give you slightly better mileage, quieter ride, better road manners and slightly better accelleration.
If you want to run tough trails without completely ruining the commutability (new word!) of your truck, put on some 31-10.50 MTs and get another inch or two of clearance, i've seen an inch or two make the difference between getting stuck and not on several occasions.
There was actual an article online i found once where a fella put on 31-10.50s, a locker and a winch on an otherwise stock toyota and followed a bunch of highly modded trucks all over MOAB, pretty cool article.
10-31-2009, 05:56 AM
#14
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I have 2 almost identical 4runners.
Both are 3.0 auto's with 4.56 gears.
The 91 has 31" tires and will not hold O/D when pulling even a small trailer.
Sometimes it won't hold O/D going into a head wind.
The 90 has 235/15 tires and will hold O/D when pulling a 1500 lb trailer and always works into a headwind.
Fuel mileage sucks on both.
Both are 3.0 auto's with 4.56 gears.
The 91 has 31" tires and will not hold O/D when pulling even a small trailer.
Sometimes it won't hold O/D going into a head wind.
The 90 has 235/15 tires and will hold O/D when pulling a 1500 lb trailer and always works into a headwind.
Fuel mileage sucks on both.
Last edited by Marc; 10-31-2009 at 05:58 AM.
10-31-2009, 07:49 AM
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i definitely have problems pulling any kind of hill at freeway speeds, i think the cost and hassle of putting in gears is not worth it compared to the benefits of having the correct tire size, the difference in size is only about 2 inches so that means i only have 1 less inch in ground clearance. if i get a 2 inch lift(which i was planning on doing anyway) that puts me an inch above where i am now. less tire mass, smaller tire, means i can put less stress on steering components, be able to go faster than 50 on a steep grade, get better mileage, and less unsprung weight. with the bigger tire the obvious advantages i see are 1 more inch of ground clearance and a bigger footprint for more traction. i think im going to go back to the stock tire size, put in an aussie or a lock-right(i haven't decided yet) and get a 2 inch lift until i have problems with ground clearance.
10-31-2009, 09:47 AM
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You can get a nice set of Yokohama geolander a/t's or bfg a/t's in a 235/75/15 on http://www.tirerack.com/ for reasonable rates. That's what I plan on doing whenever the tires I have now wear out. I like the good performance on the street with option of taking it offroad if I need to.
Last edited by pruney81; 10-31-2009 at 09:50 AM.
10-31-2009, 11:00 AM
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You can get a nice set of Yokohama geolander a/t's or bfg a/t's in a 235/75/15 on http://www.tirerack.com/ for reasonable rates. That's what I plan on doing whenever the tires I have now wear out. I like the good performance on the street with option of taking it offroad if I need to.
Good call, i've had both tires and I think the bfg's have better mud performance, my 2 cents.
10-31-2009, 11:07 AM
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i have been searchin around and i found out that a set of 4.88 gears and 4 new 225/75/15's are about the same price....hmmm now i have no idea what to do. gears would be a pain to do on the front maybe not so much the back? but tires are easy. is 1 more inch of ground clearance really worth it?
11-01-2009, 11:04 AM
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i would like to have a pretty capable trail rig but still keep it as my dd. i was planning on a 2 inch lift, bj spacers up front and new leafs out back, aisin manual hubs, good skid plate, onboard air, twin stick, rear locker, rock sliders, etc.
