[sebi0990]

Hey guys I have a quick question im trying to run 245/40/19 front and 275/35/19 rear tires on my g42 m240i and I wanted to know what the ideal wheel width sizes are for those tires?

[Jayphil]

Depends what you mean by ideal. Usually 245 are measured by manufacturers on a 8.5” wheel and 275 on a 9.5” wheel. So the tire measurement is based on that and this would be a neutral figment

That said if you like more protection or stretched look better you can play with the width:

245/40 Michelin PS4 are good for 8” to 9”
275/35 Michelin PS4 are good for 9” to 11”


Then comes the figment to the car. Is it dropped, what offset the wheel will have, camber etc. Consider that 245/40 up front on dropped car can be tight since it is taller vs factory.


You can consider 245/35 and 285/30 as well but then proper offset in the back will be important.

In both instance those tire size will not help the understeer characteristics of the car.

[sebi0990]

Originally Posted by Jayphil

Depends what you mean by ideal. Usually 245 are measured by manufacturers on a 8.5” wheel and 275 on a 9.5” wheel. So the tire measurement is based on that and this would be a neutral figment

That said if you like more protection or stretched look better you can play with the width:

245/40 Michelin PS4 are good for 8” to 9”
275/35 Michelin PS4 are good for 9” to 11”


Then comes the figment to the car. Is it dropped, what offset the wheel will have, camber etc. Consider that 245/40 up front on dropped car can be tight since it is taller vs factory.


You can consider 245/35 and 285/30 as well but then proper offset in the back will be important.

In both instance those tire size will not help the understeer characteristics of the car.

Thanks for the reply! The things you brought up are exactly the issues I’m trying to figure out. I definitely want a staggered setup because I’ve always liked the look of a wider rear but I dont want to deal with too much understeer. I also plan on lowering my car, so I want tires thick enough to get good traction since I’m RWD, but I don’t want any rubbing issues that’s why I’m waiting to get wheels and tires before lowering.

That being said, I’m completely lost on what offsets to get because I want the tires to sit out enough and not have that tucked-in look. Any advice on what offsets would work best depending on the tire size? also if you have any other alternatives to staggered setups that work good with what id like id love to hear it.

[Jayphil]

Originally Posted by sebi0990

Thanks for the reply! The things you brought up are exactly the issues I’m trying to figure out. I definitely want a staggered setup because I’ve always liked the look of a wider rear but I dont want to deal with too much understeer. I also plan on lowering my car, so I want tires thick enough to get good traction since I’m RWD, but I don’t want any rubbing issues that’s why I’m waiting to get wheels and tires before lowering.

That being said, I’m completely lost on what offsets to get because I want the tires to sit out enough and not have that tucked-in look. Any advice on what offsets would work best depending on the tire size? also if you have any other alternatives to staggered setups that work good with what id like id love to hear it.

First since you are rear wheel drive you can play more with tire sizes. Something like 255/35 Front and 265/35 rear could give good handling characteristics but does 265 wide enough for you?

#1 Select the tire size you want to run
#2 Select wheel width matching tire size on look you want.
#3 define the perfect offset based on wheel width.

I would say 255/35 or 245/40 up front is safe but need good offset for dropped car.

In the rear there is more room 275 or even 285 could fit with proper wheel offset.

Some would go wider but will requires camber plates or some modification for proper figment on dropped cars.


On my side I am running stock ZTK PS4 on aftermarket wheels the same size as stock ZTK wheels. I may try to fit 285/30 in the rear when I will be due. Not overly concerned about understeer since I do not track my car. I was running 245/35R20 front and 285/30R20 on my F10 535i xdrive and it served me well.

[sebi0990]

Originally Posted by Jayphil

First since you are rear wheel drive you can play more with tire sizes. Something like 255/35 Front and 265/35 rear could give good handling characteristics but does 265 wide enough for you?

#1 Select the tire size you want to run
#2 Select wheel width matching tire size on look you want.
#3 define the perfect offset based on wheel width.

I would say 255/35 or 245/40 up front is safe but need good offset for dropped car.

In the rear there is more room 275 or even 285 could fit with proper wheel offset.

Some would go wider but will requires camber plates or some modification for proper figment on dropped cars.


On my side I am running stock ZTK PS4 on aftermarket wheels the same size as stock ZTK wheels. I may try to fit 285/30 in the rear when I will be due. Not overly concerned about understeer since I do not track my car. I was running 245/35R20 front and 285/30R20 on my F10 535i xdrive and it served me well.

Okay so im 100 percent sure im gonna be going with 245 front and 275 rear. how would you go about defining the perfect offset with these tire sizes in mind? And also is there any benefit to going to a lower side wall like 35 or 30 for me? Should i be considering maybe a 245/35/19 275/30/19 or maybe even 245/35 275/35, im not really sure what to do regarding sidewall.

[Jayphil]

Originally Posted by sebi0990

Okay so im 100 percent sure im gonna be going with 245 front and 275 rear. how would you go about defining the perfect offset with these tire sizes in mind? And also is there any benefit to going to a lower side wall like 35 or 30 for me? Should i be considering maybe a 245/35/19 275/30/19 or maybe even 245/35 275/35, im not really sure what to do regarding sidewall.

You should look for
245/35 and 275/30 or
245/40 and 275/35 if you want more protection and a close size match.

Again the wheel offset will depend on the wheel size you chose.

Front 8.5” would be perfect stock ZTK are 8.5 with ET25. Most put 10-13 mm spacer so ideal offset is between ET12-ET15. You will not find these offset without going custom.. so find something close and plan on spacers.

For the rear let assume you go with 9.5”. Stock ZTK are 9.5 ET35. Most add 12-15mm spacers so ideal offset for 9.5” wheel would be ET20-ET23.

On 10” around ET26-ET30.

Highier offset is more conservative and lower is more agressive.

Do not take these numbers for granted, make your own calculation depend on the look you are looking for. Easier to reduce the offet by adding spacer later. If you buy to agressive wheel it it difficult to fix where a spacer is an easy fix.

[sebi0990]

Originally Posted by Jayphil

You should look for
245/35 and 275/30 or
245/40 and 275/35 if you want more protection and a close size match.

Again the wheel offset will depend on the wheel size you chose.

Front 8.5” would be perfect stock ZTK are 8.5 with ET25. Most put 10-13 mm spacer so ideal offset is between ET12-ET15. You will not find these offset without going custom.. so find something close and plan on spacers.

For the rear let assume you go with 9.5”. Stock ZTK are 9.5 ET35. Most add 12-15mm spacers so ideal offset for 9.5” wheel would be ET20-ET23.

On 10” around ET26-ET30.

Highier offset is more conservative and lower is more agressive.

Do not take these numbers for granted, make your own calculation depend on the look you are looking for. Easier to reduce the offet by adding spacer later. If you buy to agressive wheel it it difficult to fix where a spacer is an easy fix.

Okay bet thank you so much for all the help.