[cd33]

*reposting from incorrect thread*

Hi all, just flipped my i8 for a 2019 850i with pretty low miles (~11k), love the tech and performance of this car!

Question on wheels/aesthetic. I really like the look of a full wheel well. Not much gap. I see a number of pics posted here with that look. I'm wondering if that is just the model? M8? And/or newer gran coupe?

Just kind of feel like my rear wheel looks small for the car. Car is 245/35r20 front, 275/30r20 rear. Seems like this is standard when I look at this year/model on tire rack etc.

I received feedback that many are running 35 in the rear. If so what is the full spec? Can I go 275/35r20 rear and not impact car performance or programming etc, odometer? I'm not up on all of the impacts.

Full car pic is what I think is ideal, I saw this posted to a different thread by the owner.

Thanks!!

[cd33]

Local tire shop is recommending going to 245/40/20 front and 275/35/20 rear to keep diameters in sync.

[Resjudicata]

Originally Posted by cd33

Local tire shop is recommending going to 245/40/20 front and 275/35/20 rear to keep diameters in sync.

That's what I'm thinking about doing to mine. But I haven't done it yet.

[cd33]

Originally Posted by Resjudicata

That's what I'm thinking about doing to mine. But I haven't done it yet.

I'm giving it a shot today. Will post an update. Took it to local bmw dealer. They noted the standard response that on the surface it won't impact warranty but they can't guarantee an inspector/adjuster wouldn't try to blame some issue on it. I guess thats a fight for another day

[FBMWWINS]

With that setup the FRONT wheelwell will be filled out by extra 12 mm. You will also have a slight negative scrub radius (about -4 mm) and there will most likely be a slight variance in the speedometer readings.
As for the REAR, the same appllies for speedometer readings, whereas the wheelwell will be filled out by extra 14 mm and the negative scrub radius will be about -5 mm.
I would always follow the last word of a professional tire shop in terms of being recommended or not. Look forward to pictures once it's all said and done.

[cd33]

Originally Posted by FBMWWINS

With that setup the FRONT wheelwell will be filled out by extra 12 mm. You will also have a slight negative scrub radius (about -4 mm) and there will most likely be a slight variance in the speedometer readings.
As for the REAR, the same appllies for speedometer readings, whereas the wheelwell will be filled out by extra 14 mm and the negative scrub radius will be about -5 mm.
I would always follow the last word of a professional tire shop in terms of being recommended or not. Look forward to pictures once it's all said and done.

Will post some pics soon. Quick question if you happen to know, does this impact recommended psi levels?

[Edtex]

For those who desire their wheel wells to appear "filled" it is common practice to use wheel spacers. Lowering the car using lowering springs also improves the appearance. I would personally go this route rather than experimenting with tire sizes other than oem.

[FBMWWINS]

Originally Posted by cd33

Will post some pics soon. Quick question if you happen to know, does this impact recommended psi levels?

I don't know the formulas for calculating the variance. Your professional tire shop should at least know the new adjusted PSI level to consider when inflating them. "Generally" speaking tires with taller sidewalls (higher aspect ratio) require lower pressure than those with shorter sidewalls. However you may read contrasting views on this as other variables come into play and for that reason especially I would always ask my tire shop who mounts the wheels and should know.

[Resjudicata]

Originally Posted by cd33

Will post some pics soon. Quick question if you happen to know, does this impact recommended psi levels?

I would over fill the tires slightly if you want to "fill up" the wheels. Stay in the 40 psi ranges, under 50 max.

I forget what stock is or the tire recommended but keep it well under 50 psi.

[cd33]

Originally Posted by Resjudicata

I would over fill the tires slightly if you want to "fill up" the wheels. Stay in the 40 psi ranges, under 50 max.

I forget what stock is or the tire recommended but keep it well under 50 psi.

That's good info. Inner door reads 39psi for stock. This calculator has it as 34/33 psi for new setup.

https://tiresize.com/pressure-calculator/

Here's a few pics I tried to compare before and after. And a few full body after shots. I think it's noticeable and looks better. My wife rolled her eyes at me ha!

[BeeMdblU]

looks much better, should've came like that factory setup

[Resjudicata]

Originally Posted by cd33

That's good info. Inner door reads 39psi for stock. This calculator has it as 34/33 psi for new setup.

https://tiresize.com/pressure-calculator/

Here's a few pics I tried to compare before and after. And a few full body after shots. I think it's noticeable and looks better. My wife rolled her eyes at me ha!

I like it a lot better! Thanks for the pictures; I'm definitely going to do the same to mine.

I think the convertible says 32 front 38 rear; but I'll check it again.

In any event, if the calculations say 34&33; then I would keep it there, or do a max of 36/35. No more than 2-3 psi cold because they heat up quick and easily can have 5-10 psi on the track or a hot day.

[FBMWWINS]

Originally Posted by cd33

That's good info. Inner door reads 39psi for stock. This calculator has it as 34/33 psi for new setup.

https://tiresize.com/pressure-calculator/

Here's a few pics I tried to compare before and after. And a few full body after shots. I think it's noticeable and looks better. My wife rolled her eyes at me ha!

Looks definitely better with the slight "extra filling" and most of all you have to like it and enjoy it. Yes there are calculators for determining what the appropriate pressure should be. However, you should also "test" the ride yourself and adjust accordingly. For example on most, if not all BMWs I have owned, the recommended specs were too low and the car/s felt spongy and over-ondulating it! This is why, including my M850i I always inflate higher than the recommended pressure. I usually have 3.0 bars all round (front+rear).

Here you can get a good schema too for the M850i:

https://tirepressure.com/bmw-m850i-x...20and%20safety.

[snowbimmer]

Originally Posted by cd33

That's good info. Inner door reads 39psi for stock. This calculator has it as 34/33 psi for new setup.

https://tiresize.com/pressure-calculator/

Here's a few pics I tried to compare before and after. And a few full body after shots. I think it's noticeable and looks better. My wife rolled her eyes at me ha!

Goddam that's a nice looking car!!

[Bogdan Rad]

Hello , can you tell me please if you have some problems or some error after this time ? Thanks