It all depends on the width (thickness), the size of the teeth (depth) and the materials used to build the gears. But given the similar size of the tranny (because the tranny has to fit within a certain space), it makes sense that the 5 speed would have at least thicker gears, all else being the same.

 

Bingo....
Unless they gears are made out of different materials completely, the smaller the gears, the lesser threshold to high power.

 

I am not sure about the 05 evo's, but I have an article from 03' & the only diffenrces between the 5 & 6 speed, is that the 5th gear in the 6speed is basically a gap gear. 1st-4th are the same ratio's between the 2 trannies.

Kinda sucks IMO.

 

\ the 6 spd's gear ratios are just lot more tighter than 5 speed hence shifting faster...

I heard it's a lot more criper but who cares, I don't like 6 spd, too much shifting make it loose power...

 

1-3 are almost identical, 4-6 are a lot closer and 6 gives the EVO MR a higher top speed ....

 

On paper, the ratios are not that different. The top speed for each gear are:

5-Speed: 1st - 40, 2nd - 60, 3rd - 83, 4th - 113, 5th - 162

6-Speed: 1st - 40, 2nd - 59, 3rd - 80, 4th - 105, 5th - 133, 6th - 166

So on the street, I don't think you'd notice a huge difference since gears 1-3 are pretty much the same. As for better cruising rpms, not really.

5-Speed turns 2600 rpms at 60 mph and 80 mph is ~3400-3500 rpms.

6-Speed turns ~2500-2600 rpms at 60 mph and 80 mph is ~3300-3400 rpms.

I used the gear ratio calculator on f-body.org. The only real benefit of the 6-speed would be on the track where it would keep you in the power band after 4th gear.

I personally am far more interested in the durability aspect.

 

My MR 6-speed shifts more smoother and precise compared to my '03 5-speed and the MR 6-speed has a lower final drive ratio.

 

Why do almost all of the super high performance (Porsche, Ferrari, Viper, Lamboghni, etc.) cars have six speeds if they are so weak? And some of them have been using 6 speeds for years.

Anybody have any PERSONAL knowledge of 6 speed failures? I guess I should always be nervous about Mitsu parts.

 

Generally speaking, the more gears within a certain sized tranny casing, the weaker the overall sum of parts is. You gotta think, they had to make SOMETHING smaller to fit that extra gear in there. Thats one reason a 2 speed powerglide is so damn strong. I cant comment on anything about the 6 speed yet because I have yet to drive one, or see any pictures or info on the internal parts.

 

Under low RPM normal driving this seems true. I will verify once my car breaks in . I'm curious how the car speed shift, powershift and etc.

 

Definately 5 speed over 6

 

Here is my opinion... I have spent at least a good 3-4 hours behind the wheel of my dad's MR and then gotten back into my 5 speed for my daily driver and I think both transmissions are wonderful. The MR is a really really nice transmission. It is geared perfectly and it seemingly shifts smoothly all the time, unlike my 5 spd, which sometimes is a little difficult before the car is fully warmed up. If I had to make a pick between the two, I would honestly have to go for the 6 spd. The gearing is just right and it is definitely a step up from the 5 spd. Hope this helps.

 

I personally like the 6spd a lot. I was initially put off by the feel at the dealer (kinda clunky and notchy) dry shifting and cold. After about 5-10 min and the trans gets up to temp it shifts as smooth as silk. The only car I've driven that I thought had a better shift feel was an 2001 M5 w/ a short throw shifter (no shift cables, directly bolted to the trans). On my MR, even after 2200mi, it still is a bit clunky for the first couple of miles, but this is fairly normal, and also serves as a reminder (for me anyway) not to push the car until everything is up to temperature

 

Most of 6-speeds are nothing but a marketing gimmicks primarily designed for fuel economy on a highway. Rare exceptions are some high revving cars that make top output within some certain rpm band like S2000 - you upshift at 9300 and are back to 6800, still in vtec zone.
After drinving an S2000 I don't care about smooth shifts on EVO anymore since nobody can't touch Honda's 6-speed anyway. Put some heavy-a$$ knob and voila!
But I would not mind retrofitting '05 teflon coated shift cables Anybody knows a p/n for those?

 

2005 EVO 5-spd here

The only thing I noticed is if I floor it I get to shift smoothly, but if I drive like a granny and shift @3000rpm it feels alittle bit harsh? 1st -> 2nd the first 10~20mins then it feels smooth. (could be because of the break-in period?) 531miles on the odometer.

I dunno about the 6-spd on the MR, but I know that it does it's job very well on my Supra when it comes to 100mph+