Rim size and offset.

[focus1974]

What is the effect of the ride ? if you put on Rims specs different from OEM?

I found my Merc w212 uses 17inch rim spec with 8jx 17 , offset ET48, and pcd 5x112.

But I went and itchy backside changed at a tyre shop ... to the newer rims form a C class.. which is lgihter and smaller car

So the Rims spec is 17inch spec with 7x17 , offset ET48 and pcd5x112.


SO will the rim width off by 1inch ... affect the quality of the ride?


and worse ... i just found out
a 7x17 .. should not be using 245/45 17inch tyre... max supposed to be only 225/45.


https://www.tyresizecalculator.com/charts/tire-width-for-a-wheel-rim-size-chart

so.. any suggestion how to improve the ride?
Should I change the Rims ...or will changing the tyre to the correct width be good enough?

 

[myviowner]

Itch rear really caused you more problem. Change back stock rims and tire profile.... lolz

 

[mp4005 help]

Suspension and tyres are the key to a quality ride. Air suspensions are great.

rims offset and width affects the alignment. Little effect on quality but likely to change some handling characteristics which affects tyre wear and tear as well.

You need to send the car for alignment in order to ensure that the tyres are all aligned properly and touching the ground equally as per the original specs .. you can adjust the alignment to give you better handling based on your needs. but people do it for racing only. Most will align to factory specifications.

 

[focus1974]

Suspension and tyres are the key to a quality ride. Air suspensions are great.

rims offset and width affects the alignment. Little effect on quality but likely to change some handling characteristics which affects tyre wear and tear as well.

You need to send the car for alignment in order to ensure that the tyres are all aligned properly and touching the ground equally as per the original specs .. you can adjust the alignment to give you better handling based on your needs. but people do it for racing only. Most will align to factory specifications.

Thanks for the advice.

Definitely did the alignment and balancing helps a lot.

But now more concern about the safety issues.. as the offset and pcd are all to factory spec
7inch width rim can support max of 225 tyres, but i got a 245/45ZR17 tyres on which is the factory default.
https://www.tyresizecalculator.com/charts/tire-width-for-a-wheel-rim-size-chart
They say mounting wider tyres outside of min/max values is not recommended.

Anyway, the car is all good .. just a little harsh on the road.. can feel every bump.. I lowereed the pressure to 240kpa instead of 260kpa stated on the car specs and it helped smooth the bumps.

Now just have to wait for 1 yr ..when tyres are due for change and I will changed out the tyres and rims together to 18inch!
and i will make sure of the spec and offset.

 

[focus1974]

So those who want to change rim.. go tyre shop must check the spec hor..

example..
Brand : Mercedes
Size : 18" x 7.5 ET48
PCD : 5 x 112
Condition : Excellent
Quantity : 04

You must go and see from the mercedes configuraiton website whether they allowed this spec on your Mercedes.

C class and E class got vastly different specs.

The example can fit a C class, but E class specs demands 18" x 8.5 ...
1 inch is 2cm difference.. in car on road is like quite a lot

 

[superman]

Better to change back to 8J Rim, otherwise change tyre to 205/55R17 (+0.8%) or 215/50R17 (-0.8%)

 

[Flexamoria]

What is the effect of the ride ? if you put on Rims specs different from OEM?

I found my Merc w212 uses 17inch rim spec with 8jx 17 , offset ET48, and pcd 5x112.

But I went and itchy backside changed at a tyre shop ... to the newer rims form a C class.. which is lgihter and smaller car

So the Rims spec is 17inch spec with 7x17 , offset ET48 and pcd5x112.


SO will the rim width off by 1inch ... affect the quality of the ride?


and worse ... i just found out
a 7x17 .. should not be using 245/45 17inch tyre... max supposed to be only 225/45.


https://www.tyresizecalculator.com/charts/tire-width-for-a-wheel-rim-size-chart

so.. any suggestion how to improve the ride?
Should I change the Rims ...or will changing the tyre to the correct width be good enough?

Nothing wrong with the rims, but very wrong with the tyres

Too wide for 7 “ rims width, might be unstable doing cornering due to flex .245 tyres goes well with 8” or 8.5” rims

 

[focus1974]

thanks guys for the input.

I think most probably change rims is better. Go back to 8J x 17 ... for bigger cars.

Reason why i changed rims was 10yr old car had a 16inch rims, so i tot changed the rims to newer 17inch ORIGINAL rims and tyre shops got lots of mercedes trade in their new 17inch rims to upgrade to 18inch rims.

haiz...

 

[focus1974]

This guy explains it perfectly in layman... Very good. for those considering upgrading stock rims

 

[focus1974]

Ok.. just an update.. for guys who changed rim..


Remember to check your official car specs and see what rims spec your model (different model same brand also has different spec) supports.

Best to stick to it.

I just changed back my rim width to 17x8 instead of 17x7...

The difference is night and day...
it is back to the new car feel... very stable.. no wobbly.. no vibration.. no rocking or bouncy or jerky ...

very satisfied! Shiok!