6 speed vs. 5 speed

I have seen some cars offered with a 5 or 6 spd manual transmission. I'm just wondering what is the advantage of one over the other. Is the 6 spd. have two overdrives? What is closed ratio? Thanks.

I believe it is CLOSE ratio, meaning the gears are relatively close together.
6 speed is generally a better transmission because it has nice low gears (123) pretty standard 4th and 5th, and 6th is an overdrive gear.
my T56 has a .62 6th gear, which helps me get great mileage on the freeway.

they are usually more expensive however.

The exact gearing varies car to car, and sometimes even within cars (early Corvette C5 6-speeds are different than later C5 6-speeds). it depends more what the exact gear ratios are more than anything else. Usually the benefit is you can get closer ratios and still have a useable overdrive for highway driving.

most 6 speed trans have 2 overdrives. 5th and 6th are often overdrives. I prefer a 5 speed for lighter weight.

the differnce in weight is like 10-20 lbs.

this isn't an easy question...
in a car that has both available, like a miata, the final drive isn't much different...
it's just that they push the rest of the gears closer together...
it's all about the gearing though. you can have a great 5 speed, and not need the 6th gear...
the 6th gear in most cars on the street, like the mustang/viper/vette/f-body cars is an overdrive only, and used to keep your freeway mileage respectable...
in other cars, such as the miata, the gearing of the "overdrive" in the 5 and 6 speed is the same, but the rest are closer...
2 different schools of thought...
1. you add an overdrive to a 5 speed (i know that's oversimplified, but that's kind what it is with the tremec in those cars)
2. you keep the top gear the same, and push the rest closer... (again, oversimplified, but for all intensive purposes)

this is why you can't compare my 5 speed prelude to a 6 speed supra, and say that the supra is better/worse b/c of the # of gears...

did you just say that the differance is only 10-20 pounds. It seems like you are saying that is not alought of weight. Well, that is a lotta lotta lotta weight. JGTC guys take grams off of cars, taking 10-20 pounds off is more helpfull than you think. I am stripping my whole entire car, no iterior AC no rear seats no speakers or anything.

that's great.
Most people here don't have race cars where 10-20 pounds would make a difference.
And for the record, the performance gain could outweigh the weight disadvantage, depending on the transmission.

that's great.
Most people here don't have race cars where 10-20 pounds would make a difference.

exactly.
you could counteract 10lbs. by taking your SPARE TIRE OUT when you're racing.
oh wait... that's still a weight loss...
we drive street cars. not track-only vehicles...

Fromt he cars i have driven with a 6 speed, Tibaron(cant ever speel right), Corvet, Lambos, Ferrari's.

The Tib had a close gearbox. Beaning you would have to shift sooner from first to second than you would in a 5 speed box. A 6 speed usualy allows somewhat better acceleration, and retains teh top speed as well. I had the same experance with the other cars as well.

Thats just what i have experanced tho.

Transmission weights:

T5 5 speed - 75 lbs
T56 6-speed - 115-129 lbs (depending on gear ratio)
Tremec TR 3450/3550/ 5 speed - 113 lb

So converting from a T5 to a T56 will increase the weight 40-55lbs which you would notice, but converting from a Tremec TR to a T56 will not have any noticable weight increase.

Why not use a 5 speed and remove the spare :iceslolan . I mean, most people dont like doing this, but i dont care, I like spartan, I am completely removing everythign from my supra. The interior will only consist of driver and pass seat, no rear seats, no carpet, no plastic interior, no insulation, no radio or anything.

The shorter gearing of a 6th gear will easily beat the added weight over a 5 speed!!! I have an s2000 that comes with 6 speed 4.1 final gear & put 4.77 in it & i lost .5 seconds on my 1/4 mile.

Well...think about the 02-04 Sentra Spec-V's and the RSX Type-S. Both come in 6 speed and both at a race (driver depending), i've seen the spec-v take out a RSX Type-S stock against stock, but its the driver...

Yes well that proves nothing. The type s has no torque, obviously the more torque the less gears & the longer the gears are. And I bet if they made the 5 gears shorter it would be faster.

Gas mileage is great in 6th gear! :)

did you just say that the differance is only 10-20 pounds. It seems like you are saying that is not alought of weight. Well, that is a lotta lotta lotta weight. JGTC guys take grams off of cars, taking 10-20 pounds off is more helpfull than you think. I am stripping my whole entire car, no iterior AC no rear seats no speakers or anything.

For racing, a 6 speed transmission with closer gear ratios for highly tuned engined with a narrow powerband will be faster because it allows more time spent at peak power, which more than makes up for the added weight. If you're trying to remove weight, there are a lot of better places that are more effective to remove weight from than the savings of a 5-speed over a 6-speed. As an extreme example of this, take the Jaguar F1 team. They run a 6-speed sequential gearbox, but use a special lightweight green paint because most green paints are too heavy.

The only time I can see the weight benefits of a 5 speed vs a 6-speed to be beneficial is in a low power car (think under 100 HP) with a flat torque curve and wide powerband, which is not exactly the prime group of cars that someone who would be considering going from a 6-speed to a 5-speed to save 20 pounds would have.

I don't see anyone directly answering the question. If it’s a quicker ET time in a quarter mile that your after, you may wont to just swap out you're gears in the rear end. It is best to be at the top of your final climbing gear at the highest power out pot. Some cars red line is after the peek power curve and you can run slower times if you ride out your gears. I would find out were your torque curve is at before making any big decisions. A lot of newer cars with bigger engines need the extra gears to meet CAFE standards to be sold in the US, it is not always for performance.

I'm trying to refurbish a 69' Camaro SS Z28. I've done some research on them and it looks like they only come in a 4-speed manual transmission. I know that there are conversion kits for 5 and 6 speed, is it worth the money to convert the 4 into a 5 or 6 speed??