I am looking into regearing my FJ. I have 35" Toyo's with a Gibson exhaust, a TRD CAI & JBA headers. I also just had installed a TRD supercharger. My OffRoading is an occasional beach run. With that said I know that All Pro offers a 456 gear package. And also Ringpinion.biz offers a 488 package. AllPro is more money, but that is not the issue. The issue is I know that 488's will give a quicker exceleration but at highway speeds will my RPM'S be way to high. Also if ever I decide to sell the truck and want to put the stock tires back on, with 488 gears will the truck be driveable at highway speeds. I don't want it to sound like I am driving 60 in second gear.
If your not re-gearing for rock crawling, then your probably re-gearing to compensate for larger tires. The gear ratio, is often chosen to keep the engine in the same rpm band at the same speed as before. So, if the gears are chosen correctly (and they are available), you should be at about the same rpm at the same speed as before (with a corrected speedometer). In a perfect world that is.
So 4.13:1 gears should cause you to run the same rpms with the 35's as with the 32's. But I don't know of any that are available.
DEWFPO
__________________ 2007 FJ, 5AT, Sun Fusion Yellow, CQ, UP, GY, RB, 2Q, EL, VS.
"Wanted - young, skinny, wiry fellows, not over 18. Must be expert riders willing to risk death daily. Orphans preferred"
Original newspaper add placed by William Hepburn Russell, founder of the The Pony Express
If your not re-gearing for rock crawling, then your probably re-gearing to compensate for larger tires. The gear ratio, is often chosen to keep the engine in the same rpm band at the same speed as before. So, if the gears are chosen correctly (and they are available), you should be at about the same rpm at the same speed as before (with a corrected speedometer). In a perfect world that is.
So 4.13:1 gears should cause you to run the same rpms with the 35's as with the 32's. But I don't know of any that are available.
DEWFPO
Yea,
This is intriguing to me. If my calculations are correct (and often they are not), you would need a 38.6" tire to maintain the stock effective ratio with a 4.56 gears (the smallest aftermarket ratio available that I'm aware of). I haven't looked into it but someone has to be machining 4.10 gears for these rigs. If they're not, they should be....
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4.88 with a 35" tire is a perfect combo. Your RPM's are plenty reasonable at highway speed, and your performance will be excellent. We HAVE EXPERIENCE with gearing and 4.88 with a 35" tire and an overdriven top gear (wether at or mt) equates to decent RPM. We hear this on any newer vehicle. People are afraid to change gear ratio at first, fearing lost highway driveability. This is just not the case. In a couple years 4.88 will be the norm for 33s & 35s. This happens any time a vehicle comes out. On a forum you get the guys that say they run 35's with stock gears and get 20 mpg, etc, etc. You gotta remember we are basing this off real experience of hundreds if not thousands of vehicles over several years time, while the average forum guy is basing it off of his own single truck with no basis of comparison. Take it from sbechtold, he's got 4.88 and likes it. I do agree, 4.88 with stock tires is too low.
I run 4.88's with 35s and I like it. I would not want to run a 32" tire (stock size) on my FJC with the 4.88s.
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if you are just doing highway driving and you are supercharged, 4.56's would be plenty. if you are into crawling, look at the best pinion gear set to get you down the highway, then get the most gearing at the t-case.
With all due respect to your experience ringpinion.biz. The stock tires are 31.6" in diameter. I can't see how going to a 33" tire would make going from the stock 3.73's to 4.88's a normal event.....? The tires increase in size by only 4.4%, the gear ratio would increase by 30.8%. If you're just trying to correct for larger tires, that just doest't make any sense to me, at all.
DEWFPO
__________________ 2007 FJ, 5AT, Sun Fusion Yellow, CQ, UP, GY, RB, 2Q, EL, VS.
"Wanted - young, skinny, wiry fellows, not over 18. Must be expert riders willing to risk death daily. Orphans preferred"
Original newspaper add placed by William Hepburn Russell, founder of the The Pony Express
So, does the size of the tire alone warrant regearing? A 33 inch tire comes in different weights. So, for instance if you go with a 33x10.50 in comparison to a 33x12.50 the 10.50 is going to be less weight. Does the overall height change the revolutions of the tire which would cause a gearing issue or does the weight cause this issue? I guess it could be combined.
To me it seems that if your overall weight increases by 3-4lbs per tire over stock then regearing isn't really needed.
For instance a 255/85/16 tire: weight 53lbs Rim width 7in rpm's 625 33.3
265/75/16 tire: weight 51lbs Rim width 7.5 rpm's 652 31.9
Net difference 1.4 and 8lb increase
Seems to me your decreasing your rpm's by the increase in tire height then a increase in weight. So, the rpm's run lower with only a increase in weight of 8lbs. To me this combination would seem to give the advantage of clearance and no real reduction in torque or gas mileage.
However, if you go with a 35 then your total weight of each tire is 64lbs. So, your total weight increase is 52lbs. and rpm's drop to 598. 31.9 stock and 34.8 =2.9 difference. In this case it seems that rpm's decrease more because of the additional weight rather then height.
With my reasoning it seems that with the 33 inch option there would be no real disadvantage. Actually, with the added height, less rpm's and a increase of only 8lbs to me it would seem more advantageous.
So what am I missing?
__________________ SKINUM= Redskins fan not a taxidermist.
2007 FJ, 5AT, Sun Fusion Yellow, CQ, UP, GY, RB, 2Q, EL, VS.
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