SLK R171 - questions about auto / paddle shifting & sensors
Discussion
I'm thinking of buying an R171 SLK 350 to replace my old TVR. It would be a 2009-2011 model, partly because I prefer the body style and also because of the length of my garage. And it will almost certainly be an automatic because manual ones never seem to come onto the market.
From what I can see in photos of cars for sale, only some of the R171s have "flappy paddles" on the steering column ; but all of them seem to have sideways-pointing arrows at the Drive position of the gear lever.
Were the paddles an option when ordering, or is there some other rhyme or reason which cars have them? If there are paddles, does that mean the driver can manually change gear with either the paddles or the lever ; or does the presence of paddles disable the lever changes?
And finally, are the paddles and parking sensors retro-fittable by main dealers, if the car I buy doesn't have them?
Thanks for any help. I apologise if these appear silly or ignorant questions, but I've never owned a Benz, an automatic, or indeed any car newer than 1989 ...
From what I can see in photos of cars for sale, only some of the R171s have "flappy paddles" on the steering column ; but all of them seem to have sideways-pointing arrows at the Drive position of the gear lever.
Were the paddles an option when ordering, or is there some other rhyme or reason which cars have them? If there are paddles, does that mean the driver can manually change gear with either the paddles or the lever ; or does the presence of paddles disable the lever changes?
And finally, are the paddles and parking sensors retro-fittable by main dealers, if the car I buy doesn't have them?
Thanks for any help. I apologise if these appear silly or ignorant questions, but I've never owned a Benz, an automatic, or indeed any car newer than 1989 ...
Edited by frontfloater on Friday 18th March 16:40
Pretty certain the paddles wouldnt be retrofit but I havent seen an auto without them either. You can manually shift by using the paddles or side to side on the lever.
Bear in mind that the pre 2009 paddles are much smaller more like buttons on the wheel. You can always tell the post 2009 as the buttons in the centre console are gunmetal not silver and then the paddles are black and much bigger.
For parking sensors they have a tone and display front and rear FWIW I would go for retrofit non oem if what you buy doesn't have them. Most cars seem to have the rears only some have the front.
The post 2009 is worth seeking out as the 350 is +300bhp so reasonably brisk - a peach of an engine...
As said - watch out for rust, especially rear subframe and faulty seat heaters. Check the gearbox has had a fluid change.
Bear in mind that the pre 2009 paddles are much smaller more like buttons on the wheel. You can always tell the post 2009 as the buttons in the centre console are gunmetal not silver and then the paddles are black and much bigger.
For parking sensors they have a tone and display front and rear FWIW I would go for retrofit non oem if what you buy doesn't have them. Most cars seem to have the rears only some have the front.
The post 2009 is worth seeking out as the 350 is +300bhp so reasonably brisk - a peach of an engine...
As said - watch out for rust, especially rear subframe and faulty seat heaters. Check the gearbox has had a fluid change.
Edited by psychoR1 on Friday 4th March 21:54
psychoR1 said:
Pretty certain the paddles wouldnt be retrofit but I havent seen an auto without them either. You can manually shift by using the paddles or side to side on the lever.
Bear in mind that the pre 2009 paddles are much smaller more like buttons on the wheel. You can always tell the post 2009 as the buttons in the centre console are gunmetal not silver and then the paddles are black and much bigger.
For parking sensors they have a tone and display front and rear FWIW I would go for retrofit non oem if what you buy doesn't have them. Most cars seem to have the rears only some have the front.
The post 2009 is worth seeking out as the 350 is +300bhp so reasonably brisk - a peach of an engine...
As said - watch out for rust, especially rear subframe and faulty seat heaters. Check the gearbox has had a fluid change.
I have 2009 SLK350 with no paddles. The gearshift + and - when in D works if you want to change down without engaging kickdown or up without throttling off. But I rarely use it. The transmission is 7 speed so I let it do its thing mostly. Bear in mind that the pre 2009 paddles are much smaller more like buttons on the wheel. You can always tell the post 2009 as the buttons in the centre console are gunmetal not silver and then the paddles are black and much bigger.
For parking sensors they have a tone and display front and rear FWIW I would go for retrofit non oem if what you buy doesn't have them. Most cars seem to have the rears only some have the front.
The post 2009 is worth seeking out as the 350 is +300bhp so reasonably brisk - a peach of an engine...
As said - watch out for rust, especially rear subframe and faulty seat heaters. Check the gearbox has had a fluid change.
Edited by psychoR1 on Friday 4th March 21:54
Agree with your watch-out points.
Neck scarf is a nice option, I have it, but not essential. Parktronic is very good; I've had other cars with parking sensors that are like switches, or just hopeless, the Merc ones I like.I have a 2003 SLK 320, with the 5-speed auto. It can be manually shifted by knocking the stick left or right, to go up or down.
This can be surprisingly engaging once you learn how long a typical shift takes and what the approximate RPM change is per shift. So, if you're changing down from 4th to 3rd or 3rd to 2nd and you're in a 'spirited' mood, you can blip the throttle on the down changes to help rev match and get a smooth and quicker gear change.
You can also pre-set the gear 'hold'. This is useful if you're on a road you know and that you want to keep the gearbox from not going higher than that gear. For example, if you're at a junction / roundabout waiting to pull out but you know that the 'correct' gear for best driveability is say 3rd for the next complex of bends ahead. What you can do is to select '3rd' on the selector, when you pull away you will be in 1st, then 2nd but the gearbox will then 'hold' 3rd for you, as you previously selected this intentionally. This is useful if you do not want the gearbox to change up when you do not want it to!
With regards to paddles, I'm not sure this really provides any real benefits. My other car is a 2017 S213 E220d AMG Line (family wagon). Yes it has the 9g gearbox and in Sport + the gear changes are pretty quick but I've never really 'gelled' with the paddles. As such, that car is stuck in E mode most of the time unless pulling out of a tricky junction in which case I'll select S+. Also with the paddles, they are wheel mounted - this means they spin round with the wheel, obviously. With the stick s
t - it's always a constant for your left hand.
Good luck with your search - SLKs are underrated cars, IMHO.
This can be surprisingly engaging once you learn how long a typical shift takes and what the approximate RPM change is per shift. So, if you're changing down from 4th to 3rd or 3rd to 2nd and you're in a 'spirited' mood, you can blip the throttle on the down changes to help rev match and get a smooth and quicker gear change.
You can also pre-set the gear 'hold'. This is useful if you're on a road you know and that you want to keep the gearbox from not going higher than that gear. For example, if you're at a junction / roundabout waiting to pull out but you know that the 'correct' gear for best driveability is say 3rd for the next complex of bends ahead. What you can do is to select '3rd' on the selector, when you pull away you will be in 1st, then 2nd but the gearbox will then 'hold' 3rd for you, as you previously selected this intentionally. This is useful if you do not want the gearbox to change up when you do not want it to!
With regards to paddles, I'm not sure this really provides any real benefits. My other car is a 2017 S213 E220d AMG Line (family wagon). Yes it has the 9g gearbox and in Sport + the gear changes are pretty quick but I've never really 'gelled' with the paddles. As such, that car is stuck in E mode most of the time unless pulling out of a tricky junction in which case I'll select S+. Also with the paddles, they are wheel mounted - this means they spin round with the wheel, obviously. With the stick s
t - it's always a constant for your left hand.Good luck with your search - SLKs are underrated cars, IMHO.
Thanks Ian. That kind of downshift is mostly what I had in mind. In a manual car on country roads, I always change down from 4 to 3 while slowing before a bend, so as to accelerate better out of the bend. My concern with buying an auto is that the lack of throttle input at this point would cause the auto box to think it's time to shift UP, for economy. So a means of manually downshifting is important for me, both to retain control in similar situations and - I think - to feel like I'm still properly driving, not merely steering.
You say "What you can do is to select '3rd' on the selector...," to lock in that gear. How does that work?
There seem to be lots of buttons on the front of the steering-wheels of all the cars I have seen online. If there are no paddles, do some of those buttons serve the same function?
You say "What you can do is to select '3rd' on the selector...," to lock in that gear. How does that work?
There seem to be lots of buttons on the front of the steering-wheels of all the cars I have seen online. If there are no paddles, do some of those buttons serve the same function?
frontfloater - I had the same reservations about the auto-box and how it would interact with me with regards to DOWN shifts. As said, you can knock the lever to change up or down. Now, these changes are no way as quick as a modern PDK / DCT box as they work in completely different ways.
My only wish on the 5 speed box is that there was a smaller ratio gap between 3rd and 4th. I've not driven the 7g gearbox so I can't comment on the ratio stack.
With regards to 'pre-selecting', it doesn't actually select the gear, it's more of a future request. So, a typical example for me is this:
1. Driving in auto mode, come to a junction and stop and wait to pull out.
2. If I know the road ahead is going to be twisty / bendy (read 'fun'), I'll knock the gear lever to show '2nd gear'.
3. When I pull away, the gearbox will be 1st.
4. Pull away at WOT, keep WOT and the gearbox will shift to 2nd, as normal at 6,000 rpm.
5. Then as you moderate the throttle position to negotiate the bends, the gearbox will KEEP the car in 2nd, rather than changing to 3rd, just when you don't want it too. If you keep it at 6,000 rpm then it will change but it won't change when you reduce the throttle position.
6. If you think you'll want 3rd rather than 2nd for the twisties then you can select this instead.
Does the above make sense? I find it particularly useful on roads I know well where the optimum gear is known in advance.
A caveat is to make sure the gearbox has been properly serviced or just get is serviced once you collect the car. I bought my SLK 320 at 83k miles, I had all the fluids changed and the gear changes were considerably smoother with the 'manual' option being more direct and predictable.
I also found that after an engine only re-map the gear changes came quicker, probably due to the modest increase in torque of c.25NM.
My only wish on the 5 speed box is that there was a smaller ratio gap between 3rd and 4th. I've not driven the 7g gearbox so I can't comment on the ratio stack.
With regards to 'pre-selecting', it doesn't actually select the gear, it's more of a future request. So, a typical example for me is this:
1. Driving in auto mode, come to a junction and stop and wait to pull out.
2. If I know the road ahead is going to be twisty / bendy (read 'fun'), I'll knock the gear lever to show '2nd gear'.
3. When I pull away, the gearbox will be 1st.
4. Pull away at WOT, keep WOT and the gearbox will shift to 2nd, as normal at 6,000 rpm.
5. Then as you moderate the throttle position to negotiate the bends, the gearbox will KEEP the car in 2nd, rather than changing to 3rd, just when you don't want it too. If you keep it at 6,000 rpm then it will change but it won't change when you reduce the throttle position.
6. If you think you'll want 3rd rather than 2nd for the twisties then you can select this instead.
Does the above make sense? I find it particularly useful on roads I know well where the optimum gear is known in advance.
A caveat is to make sure the gearbox has been properly serviced or just get is serviced once you collect the car. I bought my SLK 320 at 83k miles, I had all the fluids changed and the gear changes were considerably smoother with the 'manual' option being more direct and predictable.
I also found that after an engine only re-map the gear changes came quicker, probably due to the modest increase in torque of c.25NM.
Paddles can be retrofitted but it requires changing the steering wheel and some software reprogramming.
I recommend that you join the website slkworld.com. See the following post for all you need to know about how to fit paddles.
https://www.slkworld.com/threads/retro-fit-gear-sh...
I recommend that you join the website slkworld.com. See the following post for all you need to know about how to fit paddles.
https://www.slkworld.com/threads/retro-fit-gear-sh...
Ian-27xza said:
frontfloater - I had the same reservations about the auto-box and how it would interact with me with regards to DOWN shifts. As said, you can knock the lever to change up or down. Now, these changes are no way as quick as a modern PDK / DCT box as they work in completely different ways.
My only wish on the 5 speed box is that there was a smaller ratio gap between 3rd and 4th. I've not driven the 7g gearbox so I can't comment on the ratio stack.
With regards to 'pre-selecting', it doesn't actually select the gear, it's more of a future request. So, a typical example for me is this:
1. Driving in auto mode, come to a junction and stop and wait to pull out.
2. If I know the road ahead is going to be twisty / bendy (read 'fun'), I'll knock the gear lever to show '2nd gear'.
3. When I pull away, the gearbox will be 1st.
4. Pull away at WOT, keep WOT and the gearbox will shift to 2nd, as normal at 6,000 rpm.
5. Then as you moderate the throttle position to negotiate the bends, the gearbox will KEEP the car in 2nd, rather than changing to 3rd, just when you don't want it too. If you keep it at 6,000 rpm then it will change but it won't change when you reduce the throttle position.
6. If you think you'll want 3rd rather than 2nd for the twisties then you can select this instead.
Does the above make sense? I find it particularly useful on roads I know well where the optimum gear is known in advance.
A caveat is to make sure the gearbox has been properly serviced or just get is serviced once you collect the car. I bought my SLK 320 at 83k miles, I had all the fluids changed and the gear changes were considerably smoother with the 'manual' option being more direct and predictable.
I also found that after an engine only re-map the gear changes came quicker, probably due to the modest increase in torque of c.25NM.
I had a 350 r171 and the car was great, fitted with the same 7 speed gearbox as in the 172 you are contemplating buying, but I never understood how to work the gearbox properly until I experimented more with the r171 55 I now have. This also has same gearbox.My only wish on the 5 speed box is that there was a smaller ratio gap between 3rd and 4th. I've not driven the 7g gearbox so I can't comment on the ratio stack.
With regards to 'pre-selecting', it doesn't actually select the gear, it's more of a future request. So, a typical example for me is this:
1. Driving in auto mode, come to a junction and stop and wait to pull out.
2. If I know the road ahead is going to be twisty / bendy (read 'fun'), I'll knock the gear lever to show '2nd gear'.
3. When I pull away, the gearbox will be 1st.
4. Pull away at WOT, keep WOT and the gearbox will shift to 2nd, as normal at 6,000 rpm.
5. Then as you moderate the throttle position to negotiate the bends, the gearbox will KEEP the car in 2nd, rather than changing to 3rd, just when you don't want it too. If you keep it at 6,000 rpm then it will change but it won't change when you reduce the throttle position.
6. If you think you'll want 3rd rather than 2nd for the twisties then you can select this instead.
Does the above make sense? I find it particularly useful on roads I know well where the optimum gear is known in advance.
A caveat is to make sure the gearbox has been properly serviced or just get is serviced once you collect the car. I bought my SLK 320 at 83k miles, I had all the fluids changed and the gear changes were considerably smoother with the 'manual' option being more direct and predictable.
I also found that after an engine only re-map the gear changes came quicker, probably due to the modest increase in torque of c.25NM.
There is 'M' for manual which I now never use, but think this was where I was going wrong with the 350 - I couldn't get it to change up whilst full throttle in manual...user error I'm sure!
However, as explained above, I leave it in 'C' (Comfort) or 'S' (Sport) so it is fully automatic...however if you change down (and select 4th) via flap it will stay in 4th (for example) and display '4' in instrument cluster, unless you come to a 'T' junction (as explained above). Pull away and it will go through gears from 1st automatically until it 'gets' to 4th, then will hold onto that gear unless you reach maximum rpm, then will go into 5th. Of course as you approach the 'T' junction you could select 3rd and 2nd, but it will always 'hang on' to the gear you last selected when accelerating again.
Sounds complicated but it isn't. I like hearing the engine change sound, even on light throttle settings, while it stays in 4th. If I was cruising along at 50mph without selecting a gear (in Auto) it defaults to 7th gear, whereas this way you can keep it in 4th or 3rd etc, makes overtaking sharper as no need to select a lower gear, or engine braking down hill etc.
Most importantly is to know how to go back into 'Auto' mode for 'normal' driving...using the 50mph and in 4th example, simply click up on flap to reach 7th gear, and the display reads 'D' for Drive where it previously read '4'. It only takes a second to select this.
Car now is fully auto, which is really smooth and seamless even by modern car standards.
The 350 is a great car, engine sounds lovely.
I never ever use the gear lever to change gear though, prefer the paddles. Only use the lever to select 'drive' etc and away we go.
Basically I never select 'M' (manual) on the button in front of the stick (the 'M' actually displays on instrument cluster) and if I want to change gear manually via flaps I can do that and just quickly click up to 7th gear to go back to fully auto.
By all means experiment with Manual but I am happy with a mixture of both.
Finally, my 55 has the larger metal flaps and they are much better than the little switches on the 350 I had.
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