Want to change 4 high to 1.1:1
10-13-2009, 08:32 AM
#21
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your use of the term "correctly" is subjective. Your opinion that 4.88 is too high (numerically low) of a gear for 33" tires is noted.
I cannot afford just to buy new 5.29 gears and hope that you are not just perpetuating De facto standard advice. I am very weary of your advice, tc because of your eagerness to insult me. My main use of the vehicle is transportation on surface streets and freeways.
I can easily afford to take a chance on the 4.56 and 4.88 gears because I can get them used from a junkyard
I cannot afford just to buy new 5.29 gears and hope that you are not just perpetuating De facto standard advice. I am very weary of your advice, tc because of your eagerness to insult me. My main use of the vehicle is transportation on surface streets and freeways.
I can easily afford to take a chance on the 4.56 and 4.88 gears because I can get them used from a junkyard
Right now I have 4.88's with 35's. Starts are sketchy and I can use 5 gear, not enough power to maintain unless it's on flat ground. I'm going to 5.29's or 5.71's and 38's or 40's.
10-13-2009, 08:36 AM
#22
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I wouldn't get 4.56's if i was you, i don't see them making any real difference with 35's. Personally i run 35's with 4.88's. With 4.88's you will have very good acceleration in 1st - 3rd gears (you'll notice a huge difference starting off in 1st) but top speed isn't great, you won't be winning any races. I do have to shift between 4th an 5th but that doesn't bug me, an there is one long steep grade around here where i have to shift into 3rd, but thats still doin like 50mph. Still i can cruise at 70 if i want, but i usaully keep it at 60-65 just to save gas. I wouldn't run 5.29's because i prefer to get my low gearing in the transfer case and keep my axle gearing as close to stock as possible.
10-13-2009, 02:24 PM
#23
I'd say give the 4.88s a try. I have recently finished with a build up that includes 35s and 5.29s. "Everyone" said that is the magic combo but now that I have it, I think it is too much. Driving around town it always seems whiny. Compared to my GPS my speedo runs about 5mph slow (i.e. speedo 50mph and actual speed 45mph). After the fact, I found these calculators:
http://www.4x4offroads.com/gear-ratio-chart.html
According to the first one I should gear to 4.94 based on current 35 inch tires and 235/75/15 from the factory. That is a lot closer to 4.88 than 5.29. Looking at some of the other calculators on that page it appears I could go to a 37-38 inch tire on my set up. Still thinking about that.
All that said, I just got back from a longish highway trip in the truck and there was still quite a bit of shifting to 4th and 3rd on the long steep uphill grades. Fortunately for me, it is mostly a weekend warrior and I don't have to drive it all day every day.
Give the 4.88s a try if you want to. Then report back to us with some real world results. Could be interesting. Good luck.
http://www.4x4offroads.com/gear-ratio-chart.html
According to the first one I should gear to 4.94 based on current 35 inch tires and 235/75/15 from the factory. That is a lot closer to 4.88 than 5.29. Looking at some of the other calculators on that page it appears I could go to a 37-38 inch tire on my set up. Still thinking about that.
All that said, I just got back from a longish highway trip in the truck and there was still quite a bit of shifting to 4th and 3rd on the long steep uphill grades. Fortunately for me, it is mostly a weekend warrior and I don't have to drive it all day every day.
Give the 4.88s a try if you want to. Then report back to us with some real world results. Could be interesting. Good luck.
Ex.
Stock Toyota 65mph x 4.10 x 336 / 29 = 3087
Altered Toyota 65mph x 4.88 x 336 / 35 = 3045
Or 65mph x 5.29 x 336 / 35 = 3300
So which is closer to stock as designed by the Toyota engineers? It has nothing to do with V8 or I4 or V6 or any of that. Now those examples I have given are based on the equation in the link I posted earlier. From what I can gather that is the figure for 4th gear in a 5 speed transmission. I base that on info found in this link from Randy's Ring and Pinion.
http://www.ringpinion.com/Calc_RPM.aspx
The above results coincide exactly with the 4th gear results in the calculator found there. Unfortunately the 5th gear #s will be off because Randy's assumes a 0.80 5th gear and (at least for me with a W56 the figure is actually 0.85) Also note that the Randy's site shows recommended RPMs for a 4 cylinder engine in the 2200-3200 rpm range so...
To the OP, it looks like you got the info you needed from 4crawler in a concise and straightforward manner. The rest of it is just opinions, mine included, and you will have to sift through them and decide which you agree with and why. If you decide to buck the trend of the majority, good for you, but expect a certain amount of backlash for doing so. Again, good luck and let us know what you do and how it works out for you.
10-13-2009, 10:51 PM
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Ok, so I crunched some numbers today and had an epiphany after I noticed similarities between my truck and what "theAuthority" had said about his on post #21 . I am going to risk exposing myself as a DB but will do so in hopes of helping someone else.
I am now very confident that I have 4.88 gears in my truck. I was assuming my gears were stock since the truck is undergeared but now I suspect that the person (kid) I bought the truck from upgraded from 33" to 35" without changing the drivetrain.
I will be looking to swap my tires for some 33s asap and will likely get some 31 or 32" tires for towing and 4.7 gears in the transfer case for wheeling.
Id like to thank everyone who posted in the thread, you helped me realize what I think is the best options for my truck
I am now very confident that I have 4.88 gears in my truck. I was assuming my gears were stock since the truck is undergeared but now I suspect that the person (kid) I bought the truck from upgraded from 33" to 35" without changing the drivetrain.
I will be looking to swap my tires for some 33s asap and will likely get some 31 or 32" tires for towing and 4.7 gears in the transfer case for wheeling.
Id like to thank everyone who posted in the thread, you helped me realize what I think is the best options for my truck
10-14-2009, 12:00 AM
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i used this equation knowing that my truck odo read about 16% different (less) than the odo on my gps
.84x=4.10
x = what gears I have in my truck
.84 = 100%-16%
4.10 is the stock gears that my truck odo is calibrated to
solve for x
x=4.10/.84
x=4.880952....
YAY math class!
.84x=4.10
x = what gears I have in my truck
.84 = 100%-16%
4.10 is the stock gears that my truck odo is calibrated to
solve for x
x=4.10/.84
x=4.880952....
YAY math class!
Last edited by YotaBob; 10-14-2009 at 12:07 AM. Reason: add math
10-14-2009, 12:07 AM
#27
Jack it up and count the rotations to be sure. One full rotation of the tire will equal your gear ratio in turns of the drive line (4.88 turns). If you are locked it's easy. If you are open, leave one rear tire on the ground and do the same, but rotate the tire two full turns. Good luck.
Chock your tires and put the tranny in neutral with the parking brake off.
Chock your tires and put the tranny in neutral with the parking brake off.
10-14-2009, 04:21 AM
#29
Did Toyota engineers design for this 100hp engine to have 35's on it? No the did not you have the extra rotational weight, and extra width of the tire all causing drag on the drivetrain......
I'd also like to know how you have 4.88's?, jack it up and rotate and see how many rotations it takes.
I'd also like to know how you have 4.88's?, jack it up and rotate and see how many rotations it takes.
10-14-2009, 05:28 AM
#30
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i used this equation knowing that my truck odo read about 16% different (less) than the odo on my gps
.84x=4.10
x = what gears I have in my truck
.84 = 100%-16%
4.10 is the stock gears that my truck odo is calibrated to
solve for x
x=4.10/.84
x=4.880952....
YAY math class!
.84x=4.10
x = what gears I have in my truck
.84 = 100%-16%
4.10 is the stock gears that my truck odo is calibrated to
solve for x
x=4.10/.84
x=4.880952....
YAY math class!
If you're too lazy to jack up your truck, you can record your RPM's at 60mph (on your GPS) in 4th gear (we will assume your tach is reading correctly). Using this number you can calculate your axle ratio since you know (approximately) your tire diameter, you can calculate the number of tire rotations per minute at 60mph, and the 4th gear ratio is 1:1. For example, if your tires are exactly 35" in diameter, and you have 4.88's, you should be around 2812 rpm at 60mph in 4th. If you have 4.56's, 2628rpm. If you have 4.10's, 2363rpm. For reference, 5.29's would be 3048rpm.
Last edited by mastacox; 10-14-2009 at 05:47 AM.
10-14-2009, 06:47 AM
#31
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I didn't use the speedo. I used the odometer difference after a full tank (over 230 miles). I am confident my math is correct but I am not lazy, I will jack up my rig today
10-14-2009, 09:41 AM
#32
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The only way to get an accurate measurement is my method which assumes the tachometer and GPS are accurate (probably a good assumption), or jacking up the vehicle and measuring the ratio directly. Keep in mind that you'll want to spin the wheel several times and watch how many times the driveshaft rotates, the higher the number of times you spin the wheel the more acurate your measurment will be (around 10 times is probably best, where the driveshaft should rotate around 41-48 times depending on your gear ratio).
Last edited by mastacox; 10-14-2009 at 09:47 AM.
10-14-2009, 10:49 AM
#34
Yep, speedo and odo can read differently, odo is most "accurate" in that is is 100% gear driven off the cable and simply counts revolutions. Of course it can be off with gearing/tire size mismatches, since it in effect counts drive shaft revolutions and not tire revs. The speedo is more prone to being off as it relies on a spinning magnet and a spring (in a mechanical speedo) to register a speed. On my '85 with 4.88 gears, I find the odometer is within 1% error with 33" tires but the speedo is off, have to drive nearly 70 on the speedo to go 65 MPH. But with 35s, the speedo is almost dead on and the odo is off (due to the larger tire diameter).
10-14-2009, 10:57 AM
#35
Yep, speedo and odo can read differently, odo is most "accurate" in that is is 100% gear driven off the cable and simply counts revolutions. Of course it can be off with gearing/tire size mismatches, since it in effect counts drive shaft revolutions and not tire revs. The speedo is more prone to being off as it relies on a spinning magnet and a spring (in a mechanical speedo) to register a speed. On my '85 with 4.88 gears, I find the odometer is within 1% error with 33" tires but the speedo is off, have to drive nearly 70 on the speedo to go 65 miles per hour. But with 35s, the speedo is almost dead on and the odo is off (due to the larger tire diameter).
10-14-2009, 02:43 PM
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OK, now I am officially confused. I rotated the tire twice and the driveshaft moved just over 4 times. Is this odd that I can drive around even on the steepest hills in Seattle in first gear with the truck undergeared so much. Albeit its not fun to do but i can do it
10-14-2009, 02:45 PM
#37
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Keep in mind, were both tires spinning, or was one stationary? That will throw a factor of 2 in your result. So say you spin the tire twice and the driveshaft spins 4 times, if both tires were spinnning together the d-shaft would have spun 8 times.
Last edited by mastacox; 10-14-2009 at 02:49 PM.
