New 2nd Generation Mercedes B Class

[7hm]

Hi, good to see another b class owner - mine purchase was back in 2013. Good to see that you had a good price due to the Coe. Btw, did u experience an oversteer - Somehow it takes sometime to move to a higher gear - whenever you do downslope . I dun like it but I was told this is b class cvt technology ....

 

B-Class CVT technology?

What nonsense is this? The second generation MFA-based B-class is using a 7G-DCT!

[M2a2r2k]

B-Class CVT technology?

What nonsense is this? The second generation MFA-based B-class is using a 7G-DCT!

Guess they are using w245 transmission to educate me earlier.

[therock]

Hi, good to see another b class owner - mine purchase was back in 2013. Good to see that you had a good price due to the Coe. Btw, did u experience an oversteer - Somehow it takes sometime to move to a higher gear - whenever you do downslope . I dun like it but I was told this is b class cvt technology ....

It's a 7 speed DCT :)

But it's still on a slow boat from Rastatt :)

[7hm]

For people who think the B-class is a chunky, oddly shaped box car...

 

Its drag coefficient is 0.26.

For reference, the Prius (not the latest one) is 0.25.

[therock]

Yeah and on the Blue Efficiency Model, I think it goes down to 0.24!

 

BTW

 

Since it uses a DCT gearbox, in start stop traffic with frequent gear changes, does it wear out some kind of clutch pad? 

 

So does one need to change anything - wear and thin of such a pad perhaps? 

[7hm]

Yeah and on the Blue Efficiency Model, I think it goes down to 0.24!

 

BTW

 

Since it uses a DCT gearbox, in start stop traffic with frequent gear changes, does it wear out some kind of clutch pad? 

 

So does one need to change anything - wear and thin of such a pad perhaps?

It will, but of course you have twice as many clutch pads. Admittedly MFA cars have less complaints about their 7G-DCT failing than Volkswagen group models but car reviewers also say Mercedes ought to go to a class hosted by Audi on how to make the damn things.

 

Just follow the usual recommendations for handling a DCT. Avoid excessive crawling, allow wider distances so the computer doesnt have to half-clutch as often, for example.

You might need to replace transmission fluid, but I doubt the clutches will wear out substantially faster than a manual if you drive like a manual. Heck, it might last longer since there's two clutches.

[therock]

Thanks bro

But don't Audi cars, such as the A3 use the exact same gearbox as the VW DSG dry clutch ones?

 

And the MFA DCT gearbox is a wet clutch if I am not wrong.. 

 

Cheers

[7hm]

Thanks bro

But don't Audi cars, such as the A3 use the exact same gearbox as the VW DSG dry clutch ones?

 

And the MFA DCT gearbox is a wet clutch if I am not wrong.. 

 

Cheers

Depends on the model, longitudinal Audis use a different transmission because of the different layout.

What the reviewer in that case I mentioned meant was probably the feel of the transmission while driving.

[Silverkris]

Depends on the model, longitudinal Audis use a different transmission because of the different layout.

What the reviewer in that case I mentioned meant was probably the feel of the transmission while driving.

 

Yes, Audi Dry Double Clutch Gear Boxes are very smooth and efficient, really just a tap and go business with no loss in transmission. Mercs on the other hand feels more like my friend driving when he's in a manual EVO (for the jerkiness, not the speed) when you want to drive fast. Leisure Driving? Mercs never disappoint you.

[DioPian]

It's a 7 speed DCT :)

But it's still on a slow boat from Rastatt :)

 

Congrats, Bro!

Nice car!  

[Heman75]

Can anyone enlighten me why the 7G tronic doesnt feel as smooth as those gear box found in A and b class. when the one in A and b class seems smoother . i thought 7G suppose to be better?

 

 

[Silverkris]

7G-tronic are conventional auto-gearboxes with 7 gears.

Simply put, you step on the gas, car starts from gear 1, disengages gear 1, engages gear 2, dis-engages, engages gear 3, ............

 

7G-DCT are double clutches gearboxes with 7 gears,

gear 1 is engaged by one clutch, 2nd clutch engages gear 2 on standby. Once gear 1 disengages, the 2nd clutch already takes over. the first clutch immediately goes to gear 3 on standby to take over once gear 2 disengages and so on ...........

[Heman75]

7G-tronic are conventional auto-gearboxes with 7 gears.

Simply put, you step on the gas, car starts from gear 1, disengages gear 1, engages gear 2, dis-engages, engages gear 3, ............

 

7G-DCT are double clutches gearboxes with 7 gears,

gear 1 is engaged by one clutch, 2nd clutch engages gear 2 on standby. Once gear 1 disengages, the 2nd clutch already takes over. the first clutch immediately goes to gear 3 on standby to take over once gear 2 disengages and so on ...........

oic.. so which is better? should be 7G tronics right else wont be 9G tronics now

[Silverkris]

oic.. so which is better? should be 7G tronics right else wont be 9G tronics now

 

Errrrrr. Hard to explain which is better, it really depends on the engine that is paired with it too. Engine and gear boxes must match.

 

Put it this way then:

 

7G-Tronic - Old Technology but quite reliable. Last time only luxury cars can get up to 7 gears, Toyotas that time uses 4 gears and Honda mostly 5 gears. But now all cars seems to have this gearbox.

 

7G-DCT - New Technology, the double clutches enables minimum loss of transmission power from engine to wheels. eg, when 7G-Tronic gears disengages from gear 1 to gear 2, at that point of time, when you step on the gas, the engine cannot transmit the power to your wheels at least until the next gear is engaged. The DCT gearboxes do not have such problems. This new gearbox technology works wonderfully for the car but it is complicated (expensive to repair).

 

9G-Tronics - As the name suggests, it uses old technology but with 9 gears instead. More gears means the car has more ratios to choose from during the drive, and I think it should be very economical and efficient though I can't think of any situations that requires a 9th gear, most probably travelling at above 200km/hr?

 

So far none of the car manufacturers can create a 9G-DCT that can combine the best of both worlds though Audi is launching (or if they still can) a 8G-DSG (equivalent to 8G-DCT) soon on their new models.

 

Hope the above can answer your questions.

[inlinesix]

Can anyone enlighten me why the 7G tronic doesnt feel as smooth as those gear box found in A and b class. when the one in A and b class seems smoother . i thought 7G suppose to be better?

 

How can conventional AT be less smooth than DCT?

[therock]

Yes, Audi Dry Double Clutch Gear Boxes are very smooth and efficient, really just a tap and go business with no loss in transmission. Mercs on the other hand feels more like my friend driving when he's in a manual EVO (for the jerkiness, not the speed) when you want to drive fast. Leisure Driving? Mercs never disappoint you.

I guess if they have the speed coupled with reliability, they will have the perfect gearbox.

And Audi car interiors are very well made. The tactile feel is superb.

[Heman75]

How can conventional AT be less smooth than DCT?

now i am confuse .. seems different school of thoughts. personal experience is 7G tronics not as smooth as DCT because i have both.

[Vratenza]

I had a 7g-tronic mated to a 3.5l v6.  

The 1st to 2nd gear clunks under certain acceleration situation. 

Put it in permanent sports mode seem to make it better. 

 

Beyond the 2nd gear the AT drives live a dream. 

 

now i am confuse .. seems different school of thoughts. personal experience is 7G tronics not as smooth as DCT because i have both.