Want to change 4 high to 1.1:1
Oct 14, 2009 | 02:59 PM
#41
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From: Fort Worth, TX
... and hence the reason I said the odo was not a reliable way to go.
Last edited by mastacox; Oct 14, 2009 at 03:00 PM.
Oct 14, 2009 | 04:59 PM
#42
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Joined: Apr 2008
Posts: 25
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From: Shoreline, WA
Well I went out there with my little chicken scratch sheet and counted 20 turns of the wheel and 40 turns of the drive shaft. I'm assuming I missed one turn of the drive shaft and it seems pretty conclusive that I have 4.10 gears. At 60mph on flat ground my RPM was @ 2200RPM +/- 50RPM
...Well ....back to the old 4.88 vs 5.29 debate
Anyone in western WA got an extra 4.88 I can throw in there for a couple days?
...Well ....back to the old 4.88 vs 5.29 debate
Anyone in western WA got an extra 4.88 I can throw in there for a couple days?
Last edited by YotaBob; Oct 14, 2009 at 07:26 PM.
Oct 14, 2009 | 08:09 PM
#43
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From: Paso Robles CA
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).
Oct 14, 2009 | 08:15 PM
#44
Test it on a mile marked freeway, most interstates have mile (paddle) markers and record your odometer reading as you pass one and drive 10 miles and record the ending reading. If you get to the nearest 0.1 mile on the odo you'll have your odometer reading to within ~1%.
Oct 15, 2009 | 08:47 AM
#46
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Joined: Nov 2005
Posts: 8,875
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From: Longmont, CO
Yes, when somebody asks what is essentially the same question as has been answered a 100000000x, then I tend to assume they're not so bright.
But since this is the newbie section and I can't say "search ya newb", I'll sum it up for ya:
Toyota says 4.56 was the right gearing for 31's with a V6/MANUAL transmission so:
31 = 4.56
33 = 4.88
35 = 5.29
37+ = 5.71
For a V6/AUTOMATIC, they said 4.88 was right for 31's:
31 = 4.88
33 = 5.29
35 = 5.71
37+ = fuhgeddaboudit
Now, since that doesn't account for the extra weight/drag of the larger tires, or the power drop from going to a 4 cyl, I would say those are the MINIMUM, and you may want to step down (up numerically) one step from that, which will raise your RPM about 250 on the highway. You want to be at 3000 - 3500 RPM at your highway speed. That will result in the lowest throttle opening and the best gas mileage, while providing enough throttle response to not have to downshift on every roll in the road, and a low enough 1st gear to get good clutch life.
But since this is the newbie section and I can't say "search ya newb", I'll sum it up for ya:
Toyota says 4.56 was the right gearing for 31's with a V6/MANUAL transmission so:
31 = 4.56
33 = 4.88
35 = 5.29
37+ = 5.71
For a V6/AUTOMATIC, they said 4.88 was right for 31's:
31 = 4.88
33 = 5.29
35 = 5.71
37+ = fuhgeddaboudit
Now, since that doesn't account for the extra weight/drag of the larger tires, or the power drop from going to a 4 cyl, I would say those are the MINIMUM, and you may want to step down (up numerically) one step from that, which will raise your RPM about 250 on the highway. You want to be at 3000 - 3500 RPM at your highway speed. That will result in the lowest throttle opening and the best gas mileage, while providing enough throttle response to not have to downshift on every roll in the road, and a low enough 1st gear to get good clutch life.
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