[rainman54]

I have the 20" W spokes on my i8 - Need to order new tires, currently on stock bridgestones that are nearly out.

Wanted to try Pirelli PZ4 but it seems the front 215 are on back order.

Can I just order 245 and put them on the front also? From previous threads it seems some people did go up to 245 and there is no rubbing issue on stock wheels. Just wanted to confirm.

So basically 245/40R20 99W XL on all 4 stock wheels.

[vance]

I have 245/40/20 Michelin Pilot sport 4s on all 4 stock wheels and it works great. No spacing issues or anything

[evanevery]

Originally Posted by vance

I have 245/40/20 Michelin Pilot sport 4s on all 4 stock wheels and it works great. No spacing issues or anything

Nice, thanks for that info!

[Coastali8]

Tire manufacturers recommended maximum width tire for a 7 1/2 inch rim is 235mm.
With 215-225mm being “ideal”.

[evanevery]

Originally Posted by Coastal i8

Tire manufacturers recommended maximum width tire for a 7 1/2 inch rim is 235mm.
With 215-225mm being “ideal”.

So, are the wheels 20x7.5 ? Do you know the offset?

[evanevery]

Originally Posted by atthelimit

Depends on how your car was spec'd.

There are different width and offsets that correlate with the various tire size setups. While I haven't had my wheels off the car yet to look at the casting marks on the back, my setup looks to be the middle setup in the graphic below, with 7.5" wide/ET40 front, and 8.5" wide/ET50 rear.

Tire size recommendations for wheel sizes are informed by a number of factors... but generally, more meat = more roll, unless you go down a bit in sidewall height (from a 45 to a 40 or 35). Sidewall stiffness certainly plays a big part... pay attention to load rating.

One of the drawbacks with larger spec tires is weight, and the slight increase in rolling diameter, where going too tall can impact final applied ratio.

However, the research I have been reading is that high-torque electrics play nice with "tall" tires. Think: dragster. Ever seen a top fueler with short little tires. Big radius good for big torque (never mind cornering).

The OEM Bridgestones on my i8 are quiet and sympathetic and have decently low rolling resistance. Not surprised that BMW spec'd them. Wheels and tires are set to be replaced soon. Have to improve braking first.

Thanks! I understand tire dynamics. (I have been working tire/wheel options on my M4 Track Car for a couple of years).

That chart doesn't appear to be correct. It says the OEM wheels/tires are HIGHLIGHTED. My OEM tires are 215 in the front and 245 in the rear so something is not right... Maybe my OEM wheels (MY 2019) match the specs in the second row...

[evanevery]

My fine friends at iND Distribution also gave me this link:

https://www.etkbmw.com/bmw/EN/search...i8/USA/36_2467

I was telling them that there appears to be a healthy market for an Off-The-Shelf set of wheels and tires optimized to improve performance, handling, and appearance of the i8.

I see a lot of people are hand-rolling their own solutions, but to have one pre-packaged and ready to go might be attractive to a lot of folks.

[evanevery]

Originally Posted by atthelimit

Would a distributor like IND tie up capital (or ask their suppliers to tie up capital) in wheel sets with mounted tires for a split market, where each side of the split has high variability?

By split market I mean those who want custom looks: larger diameter flush-fit with less tire gap and a custom finish. As opposed to those who want performance and subdued aesthetics: wider and different offsets to accommodate performance tires, and probably not larger wheel diameters than the oem 20". (This isn't to suggest that 21's or 22's and certain tires couldn't deliver better performance than stock.)

If it makes them money - why wouldn't they? They don't have to meet everyone's needs or desires. They just need to have something to offer that a meaningful portion of the community wants to buy.

Based on the continual questions about max tire size and fitment here in this forum, it appears a large portion of owners might benefit from someone who has already figured this out and has viable pre-configured options to offer. Nothing needs to be married/mounted until its sold. Think "Tire Rack".

In fact, they sold me a fitted set of Yoko Advan Neova's and BBS FI-R's for my M4.

Business "Tie up capitol" all the time. Its called inventory.