[oaktonarcher]

can some one explan what the gear number ratios on tranny gears mean? i heard that the ones on the v6 autos are pretty weak, and so they corralate to the rearend gear ratios? thanks for the help

 

[97Stallion]

Well I would say they suck, but they're not as good as a 5-speed. Back to answering you question, I think it's best explained if you even ridden on a 10-speed bike. If you have then this will make sense. Have you even switched the gears on the bike so that you can pedal really fast but weren't moving? You had the chain connected to the 2 smallest gears. That would be like 5th gear in our cars. Now if you connected to the largest gear, you noticed you didn't have to pedal much in order to start moving. That would be like 1st gear. The ratio mean how much the gear has to turn in order to make one rotation in regards to its counterpart which is always 1. Take two gears and put them next to each other. One must be a constant size, so we'll say 1". Now 5th gears ratio is .73:1 which means that when 5th gear makes one rotation is counterpart is only went around 73"% of the way. Now 1st gears ratio is 3.35:1. So if you do the same scenrio, by time 1st gear made one rotation its counterpart went around 335%. Does that make sense to you. I tried to dummify it for you, no offense.

 

[oaktonarcher]

yea makes perfect sense. so its a little like rearend gears, the high the number on the gear the better the accerleration? and for gas milage you want a small 4th (in an auto)gear? thanks for your help

 

[97Stallion]

Well it's kinda like rear-end gears, but not exactly. You're read-end is kinda like a multipler. And you're right the higher the number the better the accel., but as you also know the gears in the tranny can only reach a certain RPM. So the reason when you car shifts to a lower gear and the RPMs go down is because the gear itself is actually smaller. If you ever watched a record go around or been on a merry-go-round, you will notice that the most inner part of the circle when spinning goes kinda slow, while the outer most part is going extremely fast, this works the same way as your tranny. So when you do shift, the tranny doesn't have to rotate so much and your rpm's go down. How about that, does that make sense.

 

[oaktonarcher]

yea that also makes good sense. now im trying to fig this out. so if im going lets say 60 mph at about 2k rpms and im in 4th and for what ever reason i decided to shift in to 3rd and my rpms went up to like 4k that means i shifted to a larger gear which has a lower to speed which is reflected by the higher rpms right? thanks for all your help 97stallion

 

[97Stallion]

yea that also makes good sense. now im trying to fig this out. so if im going lets say 60 mph at about 2k rpms and im in 4th and for what ever reason i decided to shift in to 3rd and my rpms went up to like 4k that means i shifted to a larger gear which has a lower to speed which is reflected by the higher rpms right? thanks for all your help 97stallion

Ya, i think so. What you wrote kinda didn't make sense. But if downshift, your RPMs go up because you the gear is larger. So since it's a larger gear it's radius will be larger and the outside edge spins faster reflecting in your RPMs. Your welcome for the help.

 

[oaktonarcher]

o sorry i ment top speed if that was what didnt make sense. thanks for all your help

 

[97Stallion]

No problem, and to answer your question about top speed. Actually you can achive the same speed in any gear it's just a matter of RPM's, so if you wanted to do 55 in first gear you could try, but i wouldn't recomend it because you'd be doing about 9000 rpms. Way past the point of engine failure.

 

[ttpancakes]

 

[SpectorV]

tranny gears start off 2.8-3.3 for first gear auto being around 2.8 and manual being 3.3~ and so forth till final drive is .67-.68

what are those compared to direct engine rpm input vs drive train turning being equal? or what, i know 4th in a manual is 1 to 1 or 1.00