How many gears

[Boza]

Hey guys I saw an ad for the new jeep Cherokee and it says they have a 9spd auto. I have driven cars with 6spd autos and thought geez they change gears a bit much but can't even fathom a 9spd box.
How far can they go with this before we get road ranger gear boxes in our cars and start splitting gears so we end up with 18spd's in our cars I'm all for fuel economy and technological advancements but how far will this go do you reckon?

[Franco Cozzo]

Probably means they can run a really short diff ratio that they have a massive amount of gears to swap between.

I guess people were probably saying the same thing about going from 5sp to 6sp manuals back in the day? TWO overdrives?!

[Cashie]

Some of the high end makers have said that 8 or 9 speed is probably the limit. I think Mercedes recently stated 8 was the sweet spot in a media review.

[XR Martin]

Originally Posted by Cashie

Some of the high end makers have said that 8 or 9 speed is probably the limit. I think Mercedes recently stated 8 was the sweet spot in a media review.

Porsche said years ago that 17" wheels was the sweet spot for ride and handling...

[Cashie]

Originally Posted by XR6 Martin

Porsche said years ago that 17" wheels was the sweet spot for ride and handling...

And in most applications they probably still are.

But I do get your point though.

[Stefan]

Originally Posted by XR6 Martin

Porsche said years ago that 17" wheels was the sweet spot for ride and handling...

I think this still true, probablty explains why new cars handle great and have a crap ride and suffer from horrible road noise.

[BradEL]

Originally Posted by Stefan

I think this still true, probablty explains why new cars handle great and have a crap ride and suffer from horrible road noise.

Yeah your right with that, all the high end cars these days have huge wheels, 19,20,21". Even the "luxury" cars such as Mercedes and Audi. They compensate for the worse ride quality with sophisticated suspension systems etc. But really all of this mainly seeme to be for appearances sake and just leads to more costs for the owners.
Same sort of thing happens in the transmissions, car makers add in all this stuff to try and appeal to buyers like paddle operated shifters, hill start assist etc. Adding more gears is just another thing to tell potential customers, even though everyone knows that the average driver won't notice if they have a 6 or 7 speed, especially with an auto.

[Franco Cozzo]

Surely the case of the thing would be limited in size to fit in a trans tunnel, so wouldn't all the components have to be smaller/thinner? Might not be able to hold up against as much torque as your usual 6sp would?

[bbbero]

I think Ford and GM are working on ajoint project for a 10spd Auto!

[Nova 8]

As mankind continues to develop stronger and lighter component materials coupled with seamless gear changes from auto boxes I see no reason to limit the amount of gears in a car just because people feel uncomfortable with change. I would rather a15 speed auto which changed quickly and smoothly then an older clunky 4 speed auto that takes an age to gear down.

I remember the first 6spd manual I drove years back, I thought it was too many gears and felt like I was constantly changing up and down, now it is the opposite, 5 just isn't enough.

[Bent8]

I think 8/9-speeds would work well with less powerful cars (under 300hp) to help keep the revs high for better acceleration and improved economy when cruising.

On the other hand, a 7-speed box in a 500+ hp car is all you really need eg. Aventador - 370kph / Veyron - 430kph.

[jimmyxr6t04]

The Jeep actually has an 8sp auto. Not sure why the adverts are saying 9? I noticed it say 9 speed too, and then i thought i was hearing things... Glad someone else heard 9 speed!

[wranger]

Grand Cherokee has an 8spd, Cherokee has a 9spd.

[mik]

I have driven plenty of 18 speed autos in trucks, and while a a bit less smooth than car autos for obvious reasons, they do the job very well, and with the close ratios engine braking is very nice, even though technically they where really auto shifted manual gearboxes and still had a clutch pedal for starting off , I cpuld see 8 or 9 speed autos in cars being ok, the trade off will probably be weight and more moving parts, how many gears do you really need to move 1 or 2 tons of car or suv?

[CyberWasp]

Isn't the 8 Speed the same gear box that they had the option of putting in the FH Falcon but aren't going to do?

[Bossxr8]

Ford and GM are doing a joint venture 10 speed that will be in Mustang within a couple of years.

These multi speed autos can skip gears up and down so they are not continually shifting through every gear on the way up/down, so they don't necessarily shift more often than say a 6 speed would.

[GASWAGON]

I still think its overkill these new 8-10 speed boxes.....Whats wrong with the ZF 6 Speeder?

[Wretched]

Originally Posted by EF_6

I still think its overkill these new 8-10 speed boxes.....Whats wrong with the ZF 6 Speeder?

What was wrong with the BTR 4 speed?
What was wrong with a crank handle?
Wood spoked wheels? hell even the horse and cart?

It's called advancement, I think the advantages have been clearly outlined in this thread.

[castellan]

Originally Posted by EF_6

I still think its overkill these new 8-10 speed boxes.....Whats wrong with the ZF 6 Speeder?

The holden and ford 6 sp autos are rubbish as they need 7 sp as 2ed to 3rd is way to far apart for much better perfomance. they fall into a hole in overtaking from around 100 110 km/h up to 140 say just gutless ! but the 6sp manual is fine as the ratios are great.

You could do away with the v8 if you had a 7 sp auto.
8 gears would be better as in hilly drives gets on my goat jumping back to 5th and then at time 4th, so i would say it yould not be as noticable with 8

I thought 6sp autos would be good untill i drove them, but i can't stand them as even the old 3sp and 4sp was a better auto for overtaking on the highway as 2ed would have you up to about 130 km/h in a good power range and i will say the most important performance you want is in the 100 to 140km/h range for good performance overtaking times.

The only good auto i have ever driven was a C4 Tbar auto with just a std 351 V8, loved that combernation and it had a 3.00 diff ratio and i could not point out one thing wrong with it as it was magic to drive. 'XB magic'

[madmelon]

Originally Posted by castellan

The holden and ford 6 sp autos are rubbish as they need 7 sp as 2ed to 3rd is way to far apart for much better perfomance. they fall into a hole in overtaking from around 100 110 km/h up to 140 say just gutless ! but the 6sp manual is fine as the ratios are great.

You could do away with the v8 if you had a 7 sp auto.
8 gears would be better as in hilly drives gets on my goat jumping back to 5th and then at time 4th, so i would say it yould not be as noticable with 8

I thought 6sp autos would be good untill i drove them, but i can't stand them as even the old 3sp and 4sp was a better auto for overtaking on the highway as 2ed would have you up to about 130 km/h in a good power range and i will say the most important performance you want is in the 100 to 140km/h range for good performance overtaking times.

The only good auto i have ever driven was a C4 Tbar auto with just a std 351 V8, loved that combernation and it had a 3.00 diff ratio and i could not point out one thing wrong with it as it was magic to drive. 'XB magic'

Not sure what you've been smoking but I drive a BF XR6 with the ZF 6 speed as a daily and going back to the 4 speed in my mums BFIII wagon is terrible. It's gutless in 1st in comparison, because 1st runs to almost 90km/h, in order to get the revs as low as possible in 4th gear. This might have worked on the EL and AU cars but performance really suffers in the B series onwards cars due the the massive weight increase. The shift quality is also pretty crap when compared to the ZF.

[castellan]

Originally Posted by madmelon

Not sure what you've been smoking but I drive a BF XR6 with the ZF 6 speed as a daily and going back to the 4 speed in my mums BFIII wagon is terrible. It's gutless in 1st in comparison, because 1st runs to almost 90km/h, in order to get the revs as low as possible in 4th gear. This might have worked on the EL and AU cars but performance really suffers in the B series onwards cars due the the massive weight increase. The shift quality is also pretty crap when compared to the ZF.

I agree with you, not the smoking and i have never smoked.
I was on about overtaking times at 100 km/h
The auto 6 speed box is great in 1st gear for taking off and yep the shifts are better.

[DFB FGXR6]

Reviews of the 9 Speed auto in the new Cherokee complain that it tends to 'hunt' for the right gear, especially with the base 2.4lt engine.

[Crazy Dazz]

Trucks have always used massive gearboxes because traditionally you're trying to move a massively under-powered load, so you'd have a diesel biased to low-end torque and just keep changing gears to stay in the sweet spot.

The only gripe I have about my current 5spd manuals, is that top gear isn't tall enough for super economical cruising at freeway+ speeds. I otherwise like them, so I think both could benefit from a 6th gear, but also just spreading the ratios would probably work.

[danzvtil]

This is ONLY driven by reducing fuel consumption, not for fun. Global consumption standards continue to tighten.

[chopstar87]

My 300c is fitted with an 8speed auto.... i am a big fan of it.

Very smooth, left in auto, you cant even feel gear changes, is very smooth and is never going hunting for gears, just picks the right one and then goes, has no problem going from 8th straight to 2nd or 3rd when passing someone on the highway. holds gears itself when going up hills without been prompted, so it wont be sluggish at all or jumping up and down gears..

very good for highway Economy, my V6 (210kw - 3.6 V6), sits on 1350rpms at 105kms on the highway, maybe 1400rpm at 110kms. (plus my car will drops to a 3cyclinders as well when cruising) - or if cruising at 60, it will be about 1100rpms in 6th, or if you make it go to 7th, it will sit on 900rpm (but doesn't like that RPM, as its makes the engine lug about at a bit and will shift up pretty quickly to 6th)

When doing spirited driving, and you going in to manual mode via Paddle shifters on the steering wheel, its ratios are similar to a 6 speed, the 7th & 8th only come in to play when cruising on the highway.

[SensationFG8]

Did you do an aftermarket gearbox swap or is that an option to get the 8spd? I thought the 300C's had a 5 speed box!

[cheap]

There is some parallels to bicycles

Remember the 3 speed hub
Then 10 speed (2 x 5)
Then 12 speed (2 x 6)
Then 16 speed (2 x 8)
Then 20 speed (2 x 10)
Now it is at least 22 speed (2 x 11)

Remember the 2 speed Fordomatic
Then 3 speed
Then 4 speed
Then 5 speed
Then 6 speed
Now 7 speed and 8 speed and more

Each to their own, but sometimes too many gears is just too many gears

But don't despair, in the not too distant future there will be CVT (Constant Velocity Transmission) which will render all the geared transmissions obsolete, it is happening in bicycles

[Ben73]

Originally Posted by cheap

There is some parallels to bicycles

Remember the 3 speed hub
Then 10 speed (2 x 5)
Then 12 speed (2 x 6)
Then 16 speed (2 x 8)
Then 20 speed (2 x 10)
Now it is at least 22 speed (2 x 11)

Remember the 2 speed Fordomatic
Then 3 speed
Then 4 speed
Then 5 speed
Then 6 speed
Now 7 speed and 8 speed and more

Each to their own, but sometimes too many gears is just too many gears

But don't despair, in the not too distant future there will be CVT (Constant Velocity Transmission) which will render all the geared transmissions obsolete, it is happening in bicycles

Bike gears are ridiculous. I have about 18 gears on my bike and probably use 5 of them.

As for CVT, I am not a fan and I used to own one. Never again, unless it was majorly improved.

[Ben73]

I drove an 8sp Grand Cherokee early in the year. It was only a 20 minute drive, but I didn't notice the gear changes in a negative way.
The 3L Turbo diesel was surprisingly powerful, I was more focused on that.

[chopstar87]

My 300c is a V6 petrol, which comes with the 8speed as standard, only the SRT and Diesel models have the 5speed. but i am sure with the update in the states later in the year, the 5 speed will be killed off, as its the last models with in the group (dodge, jeep etc) that has the 5speed.

the 300 and 300c V6 (petrol) have an 8speed, but only have Drive (auto) and Low

My Luxury and now the 300s, have drive plus a sports mode to choose from, plus the paddle shifters, where you can control the gears in either drive or sports modes