What can i expect out of my 7.17 gears?

Hunter44

Hunter44

Well-Known Member
Joined
Feb 26, 2014
Location
Lexington
How significant of a difference will I see between 5.71(current setup) and 7.17 when I get my truck back on the road with 49s and a 4banger? Right now 5th is useless buy 4th pulls very good
 
I somehow doubt that few, if anyone, is running that kind of combination to comment. Tons, 49s, and a 4-cylinder? To just use some math, that gear ratio is 25% deeper than what you had, so your engine will turn 25% more RPM at any speed given the same tire size. However, I am guessing you are also going up in tire size, so the math needs to be adjusted back down for that. And if you go to larger tires that means they weigh more and take more energy to spin, plus your new axles are a bit heavier than what came out, so that also makes the truck less peppy.

To give you some sort of relative comparison, I went from 4.63s with 32" tires to 6.15 with 37" tires. Straight math said I needed about a 5.80 ratio to be "even". But I went to a significantly heavier wheel and tire combination (I think I added 60# per corner) and I put a 60/14 combo with portal boxes under the truck. I increased the weight almost a TON (yes, 2000#) and so the truck feels winded anyway and gets terrible fuel mileage. I will also note that I swapped out the transmission to one with shorter ratios in all gears except 4th to get more RPM out of the engine (about 10%). Again, she still drives slow. And I have a V6 with ~170Hp/200lb-ft at the crank.
 
JC could chime in. I believe his old crawler rig was a wrangler with a 2.5L/granny transmission/7.17 gears. Don't think he had 49s though.
 
JC ran 42s... Believe he loved it lol
 
Poor resale value. That's something that's very vehicle specific and I'd say 99.9% of those wanting to buy one tons look for 4.56-5.38 gear range.
 
@JC, you should chime in.
 
it was his grampas truck so no resale worries, should do fine i bet you will get 5th back for sure!!
 
it was his grampas truck so no resale worries, should do fine i bet you will get 5th back for sure!!
 
I'm actually downsizing to 46s, the Goodyear mvt which weigh around 210 compared to 285, and when I get more money I'm going back to 44 tsl or boggers.
 
OnlyOneDR said:
I somehow doubt that few, if anyone, is running that kind of combination to comment. Tons, 49s, and a 4-cylinder? To just use some math, that gear ratio is 25% deeper than what you had, so your engine will turn 25% more RPM at any speed given the same tire size. However, I am guessing you are also going up in tire size, so the math needs to be adjusted back down for that. And if you go to larger tires that means they weigh more and take more energy to spin, plus your new axles are a bit heavier than what came out, so that also makes the truck less peppy.

To give you some sort of relative comparison, I went from 4.63s with 32" tires to 6.15 with 37" tires. Straight math said I needed about a 5.80 ratio to be "even". But I went to a significantly heavier wheel and tire combination (I think I added 60# per corner) and I put a 60/14 combo with portal boxes under the truck. I increased the weight almost a TON (yes, 2000#) and so the truck feels winded anyway and gets terrible fuel mileage. I will also note that I swapped out the transmission to one with shorter ratios in all gears except 4th to get more RPM out of the engine (about 10%). Again, she still drives slow. And I have a V6 with ~170Hp/200lb-ft at the crank.
Click to expand...

That's a Lot better, than what I started to say, "A Slow, High Revving, Whiny Gear Truck"!:D
 
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