Changing tyre size past the recommend merc tyre size.

[Saeedk1995]

Hi all,

I’ve got a 2019 Mercedes e400d 4matic saloon with 20 inch alloys. The tyres fitted are following the guidelines from merc which is 245/35/20 and 275/30/20. I feel like the tyre profile is a bit too low/thin and the tyres seem to be stretched due to the alloys being 20inch AMG replicas 8.5j and 9.5j, front and back respectively. I want to change my tyres to 245/40/20 and 275/35/20. Is this possible or will it mess my car up?

Any advice would be much appreciated and hopefully helpful to others too.

 

[markjay]

Did the wheels come with the car from the factory when new, or are they an aftermarket option? If original, then are these also the original tyres sizes?

 

[SpikyMikey]

Hi all,

I’ve got a 2019 Mercedes e400d 4matic saloon with 20 inch alloys. The tyres fitted are following the guidelines from merc which is 245/35/20 and 275/30/20. I feel like the tyre profile is a bit too low/thin and the tyres seem to be stretched due to the alloys being 20inch AMG replicas 8.5j and 9.5j, front and back respectively. I want to change my tyres to 245/40/20 and 275/35/20. Is this possible or will it mess my car up?

Any advice would be much appreciated and hopefully helpful to others too.

Have a look here for a general idea of the effect of your proposed changes :
Alloy Wheel & Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

 

[BTB 500]

Hi all,

I’ve got a 2019 Mercedes e400d 4matic saloon with 20 inch alloys. The tyres fitted are following the guidelines from merc which is 245/35/20 and 275/30/20. I feel like the tyre profile is a bit too low/thin and the tyres seem to be stretched due to the alloys being 20inch AMG replicas 8.5j and 9.5j, front and back respectively. I want to change my tyres to 245/40/20 and 275/35/20. Is this possible or will it mess my car up?

Any advice would be much appreciated and hopefully helpful to others too.

Your current tyres are the sizes approved by Mercedes and AMG for 8J/9J rims. There are Brabus options for 8.5J/9.5J listed below that you could perhaps consider:

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

As mentioned by @SpikyMikey using a tyre/rim combo that isn't an approved one will affect the speedometer and milometer accuracy if the overall diameter (rolling radius) is different to stock setups.

 

[Saeedk1995]

Did the wheels come with the car from the factory when new, or are they an aftermarket option? If original, then are these also the original tyres sizes?

These are after market.

 

[Saeedk1995]

Your current tyres are the sizes approved by Mercedes and AMG for 8J/9J rims. There are Brabus options for 8.5J/9.5J listed below that you could perhaps consider:

View attachment 158163

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

As mentioned by @SpikyMikey using a tyre/rim combo that isn't an approved one will affect the speedometer and milometer accuracy if the overall diameter (rolling radius) is different to stock setups.

Thank you. So I have 8.5j and 9.5j. Basically if I want to change from the approved Mercedes alloys to the brabus setup I’d have to change all 4 tyres on my current alloy?

This won’t affect the 4matic system would it?

 

[Saeedk1995]

Your current tyres are the sizes approved by Mercedes and AMG for 8J/9J rims. There are Brabus options for 8.5J/9.5J listed below that you could perhaps consider:

View attachment 158163

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

As mentioned by @SpikyMikey using a tyre/rim combo that isn't an approved one will affect the speedometer and milometer accuracy if the overall diameter (rolling radius) is different to stock setups.

Your current tyres are the sizes approved by Mercedes and AMG for 8J/9J rims. There are Brabus options for 8.5J/9.5J listed below that you could perhaps consider:

View attachment 158163

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

As mentioned by @SpikyMikey using a tyre/rim combo that isn't an approved one will affect the speedometer and milometer accuracy if the overall diameter (rolling radius) is different to stock setups.

The current tyre on my rears are 9.5j alloy with 275/30/20 tyre and they look stretched, If I follow the first highlighted option which Is 255/35/20 for 9.5j then wouldn’t that cause the tyre to be even more stretched since the tyre width is shorter for that same alloy size?

 

[Saeedk1995]

Your current tyres are the sizes approved by Mercedes and AMG for 8J/9J rims. There are Brabus options for 8.5J/9.5J listed below that you could perhaps consider:

View attachment 158163

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

As mentioned by @SpikyMikey using a tyre/rim combo that isn't an approved one will affect the speedometer and milometer accuracy if the overall diameter (rolling radius) is different to stock setups.

My front alloy is et 38 with 10mm spacer (was needed for clearance to the brake caliper)

Back alloy is et45 with 5mm spacer.

 

[BTB 500]

The current tyre on my rears are 9.5j alloy with 275/30/20 tyre and they look stretched, If I follow the first highlighted option which Is 255/35/20 for 9.5j then wouldn’t that cause the tyre to be even more stretched since the tyre width is shorter for that same alloy size?

The first Brabus setup gives 255/35 tyres front & rear despite 1" difference in rim width ... that doesn't sound right. The second one (with 285/30 at the rear) makes more sense.

The offsets given there are ET40 at the front and ET45 at the back - that's virtually the same as your rims, so I'm surprised you needed spacers

Did you buy the car as it is currently?

 

[OneForTheRoad]

245/35/20 + 275/30/20. Are correct for your car , on 8.5 and 9.5 j rims.

 

[Saeedk1995]

The first Brabus setup gives 255/35 tyres front & rear despite 1" difference in rim width ... that doesn't sound right. The second one (with 285/30 at the rear) makes more sense.

The offsets given there are ET40 at the front and ET45 at the back - that's virtually the same as your rims, so I'm surprised you needed spacers

Did you buy the car as it is currently?

The rear was fine I didn’t need spacers I just put them in since the front looked wider than the back. The front I first got a 5mm offset put in and there was barely a hairline gap so the garage increased it to 10mm. Since mine is e400d 4matic the front calipers are the bigger merc calipers by default.

Yes but I’ve added the replica amg alloys that’s the only thing I’ve changed.

 

[Saeedk1995]

245/35/20 + 275/30/20. Are correct for your car , on 8.5 and 9.5 j rims.

Yes, ill get a picture of the wheels, you’ll see the tyre is stretched and doesn’t sit flush with the face of the alloy, since it is stretched the rim protection doesn’t protect the rim, also at the bottom it looks really thin and disproportionate for the car, i’m worried about it being more prone to cracking as well.

 

[Saeedk1995]

245/35/20 + 275/30/20. Are correct for your car , on 8.5 and 9.5 j rims.

I’m also get tyre skipping occurring during full lock, I think maybe the tyres being stretched is a potential cause of this

 

[OneForTheRoad]

I’m also get tyre skipping occurring during full lock, I think maybe the tyres being stretched is a potential cause of this

Feature of 4 matic I'm afraid . If I were you I'd buy the correct wheels in a 19 inch and all season tyres like crossclimates .

 

[Saeedk1995]

Feature of 4 matic I'm afraid . If I were you I'd buy the correct wheels in a 19 inch and all season tyres like crossclimates .

I had the 19 inches before with no issues, I got the amg 20’s because I like the look of them.

 

[Mercsrbest]

I use
Willtheyfit.com
It shows speedo error
Increase it height and width
Compared to existing set up.
For handling you cannot improve on Mercedes sizes,
For looks …. Your mind is your own!

 

[Saeedk1995]

I use
Willtheyfit.com
It shows speedo error
Increase it height and width
Compared to existing set up.
For handling you cannot improve on Mercedes sizes,
For looks …. Your mind is your own!

Thank you. For the front there will be -1.02% error and the rear there is -0.88% error if I follow the brabus 255/35/20 and 285/30/20 guideline. Is this reasonable?