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      03-25-2019, 01:47 PM   #67
stressdoc
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So as to be clear on this, you mounted 245/40 on the stock front rims and they have clearance? Or have you put wheels from rear to check?
Thanks!
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      03-25-2019, 05:17 PM   #68
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Quote:
Originally Posted by stressdoc View Post
So as to be clear on this, you mounted 245/40 on the stock front rims and they have clearance? Or have you put wheels from rear to check?
Thanks!
245/40 on the front stock rims.
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      05-26-2019, 07:11 PM   #69
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245/40 19 Firehawk Indy 500 up front on Fast 8.5x19 flow formed wheels. 275/35 Firehawk Indy 500 on Fast 9.5x19 wheels. Weight 19.5 and 20.2 respectively. I choose this combination for a variety of reasons. Mostly I wanted to be able to drive to different tracks and after a weekend, be able to drive home and do this repeatedly. These are no Hoosier R7 for sure but they are working out well and the car is cornering comfortably at over 1G once warmed up. I ran in the rain this past weekend and just drove around the cars on stickies. I have seen friends aggressively tear up a set of RE71R on a hot weekend- better times but not by enough to justify it for me.
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      05-28-2019, 07:26 PM   #70
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I just got these AG 20's. Love the blue I wish I would have done this a couple years ago.

AG 20' rims with Verdestein Tires
285/35/20 tires back
245/40/20 tires front
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      05-29-2019, 05:04 AM   #71
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Quote:
Originally Posted by FastCar View Post
I just got these AG 20's. Love the blue I wish I would have done this a couple years ago.

AG 20' rims with Verdestein Tires
285/35/20 tires back
245/40/20 tires front
I got mine custom make 20x8 et 35
20x8 et 40
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      06-18-2019, 06:55 PM   #72
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I'm new to the i8 community and just had a set of Michelin Pilot Super Sport tires installed on my i8... 275/35-20 Rear and 245/40-20 front and they fit perfectly with no rubbing... Thanks to those that paved the road ahead of me... It's like a different car now that the BF Goodrich tires are gone...
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      06-21-2019, 11:56 PM   #73
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Update 6-21-19
The following is what I posted a while back on another thread.
Still no issues. Running 30 psi front and rear.
However... if your driving over 118 mph on W rated tires (fronts) or 136 mph on Y rated (rears) for long periods of time you may want to increase the pressure a pound or two.




———————————————————————————————————————————-




Just finished mounting new tires.
Wanted to make the tire size issues perfectly clear.

Put 245/40X20 Bridgestone Potenza S001 on the front.
Put 275/35X20 Bridgestone Potenza S001 on the rear.

Tire diameter and sidewall dimensions stay nearly the same as original equipment tires but width increases by slightly more than 1 inch front and rear.
Factory wheels, no spacers.

Absolutely no issues. Everything clears over rough roads and tight turns.
Probably still about 1/4 inch clearance in the tightest spots.

Although putting narrow tires on wide rims can have safety issues. Placing slightly wider tires on narrow rims the only real issue can be uneven tire wear. That can be mitigated with proper monitoring of tire pressure.

The car looks better.
In my opinion the original tires didn’t match the aggressive look of the car.

These tires give you slightly more protection from curbs for the wheels and fill the fender wells just a bit better.

The car feels just a tiny bit heavier with steering, and understeer disappears.

I feel it’s a improvement in looks and handling.

Last edited by Coastal i8; 06-22-2019 at 03:24 PM..
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      06-22-2019, 12:05 AM   #74
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I also posted this as a follow up to the previous post.


——————————————————————————————————————————-


I purchased the 245/40X20 and 275/35X20 from Tire Rack (not Tyre Rack)

They will email you and tell you that the tires are not standard sizes. Just respond “okay “you know.

Local tire shop mounted them up with no issues.
Factory wheels, no spacers.
Everything fits, no clearance issues.

Just for reference... many vehicle manufacturers have put wider than tire manufacturers recommend tires on narrow wheels as original equipment. Both BMW and Porsche have done this.

Because the wider tire has a higher load carrying capacity at a lower inflation pressure.
You can reduce front and rear tire pressure by around 3 psi to carry the same weight as the original equipment tire to coincide with what BMW decided to use. By reducing the inflation pressure a couple of psi that will also help compensate for a wider tire on a narrow wheel wanting to bulge in the center and give you a more even tire wear.

Original tires
Front 215/45X20 load index 95XL @32psi=1227 lbs
Rear 245/40X20 load index 99XL @32psi=1371 lbs


New tires
Front 245/40X20 load index 99XL @28psi= 1243 lbs
Rear 275/35X20 load index 102XL @29psi= 1388 lbs


I decided on running 30 psi in the front and 30 psi in the rear. (The tire pressure monitoring system is happy down to -25% or 24 psi.) Just as a starting point, and see how it feels and how the tires wear.

So far, so good.

Load index vs inflation pressure:
https://www.toyotires.com/media/2125...s_20170203.pdf

Tire size comparison chart:
https://tiresize.com/comparison/

Last edited by Coastal i8; 06-22-2019 at 09:48 AM..
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      06-26-2019, 08:06 AM   #75
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I decided to purchase a set of OEM turbine wheels and mount Continental ExtremeContact DWS06 all seasons on them for my 2015 i8. Front 245/40R20, rear 275/35R20. I bought a set of used OEM turbine wheels for these Continental tires, so I still have another set of stock rims on the W style rims. I daily drive the car and wanted to have more confidence in all weather conditions. I've already taken it on a 750 mile road trip through occasional thunderstorms and loved them. I have no issues with fit and even put chalk on the front control arms to detect if there was any rubbing, and there was not. I measured the actual sidewall width difference and it was only 5/8" wider than stock tires.

I'm running 33-35psi for decreased road noise but will feel the bumps more than before, in comfort mode. The only issue I found is: Everything was great for a few weeks, however, I'm now noticing flat spotting if I let it sit a day in my concrete floor garage. In the first 5 miles of driving I'm getting noticeable vibration in the rear tires (not steering wheel shake). However, my original OEM Potenza S001's would sometimes do this as well if I let the car sit for a day or two. Maybe it's normal? If I don't let the car sit for a day, this never occurs. EDIT TO ADD: This appears to be flat spotting and only occurs when the car sits for 2 days without driving.

The best thing I notice is that I can feel the road more with these tires than the OEM ones. The car no longer pushes in turns, and in fact, if I increase/decrease throttle in the turns, I can adjust how sharp the car turns if I keep the steering wheel in the same position. Very interesting!

Last edited by patsgarageonline; 07-03-2019 at 09:08 AM..
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      08-21-2019, 12:14 PM   #76
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Quote:
Originally Posted by PaddyMac View Post
I decided to purchase a set of OEM turbine wheels and mount Continental ExtremeContact DWS06 all seasons on them for my 2015 i8. Front 245/40R20, rear 275/35R20. I bought a set of used OEM turbine wheels for these Continental tires, so I still have another set of stock rims on the W style rims. I daily drive the car and wanted to have more confidence in all weather conditions. I've already taken it on a 750 mile road trip through occasional thunderstorms and loved them. I have no issues with fit and even put chalk on the front control arms to detect if there was any rubbing, and there was not. I measured the actual sidewall width difference and it was only 5/8" wider than stock tires.

I'm running 33-35psi for decreased road noise but will feel the bumps more than before, in comfort mode. The only issue I found is: Everything was great for a few weeks, however, I'm now noticing flat spotting if I let it sit a day in my concrete floor garage. In the first 5 miles of driving I'm getting noticeable vibration in the rear tires (not steering wheel shake). However, my original OEM Potenza S001's would sometimes do this as well if I let the car sit for a day or two. Maybe it's normal? If I don't let the car sit for a day, this never occurs. EDIT TO ADD: This appears to be flat spotting and only occurs when the car sits for 2 days without driving.

The best thing I notice is that I can feel the road more with these tires than the OEM ones. The car no longer pushes in turns, and in fact, if I increase/decrease throttle in the turns, I can adjust how sharp the car turns if I keep the steering wheel in the same position. Very interesting!


Any change you know if the W wheels the same size and can take the same tires in the same size? Also in MD with the W wheels on my I8 and would want to run DWS06s like I had on my 4 series before so I can daily this thing. Any issues since posting this with running those tires?
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      08-27-2019, 02:03 PM   #77
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Quote:
Originally Posted by shujaat View Post
Any change you know if the W wheels the same size and can take the same tires in the same size? Also in MD with the W wheels on my I8 and would want to run DWS06s like I had on my 4 series before so I can daily this thing. Any issues since posting this with running those tires?
Thanks for our chat on DM on Instagram. I haven't logged into bimmerpost in a while. For the rest of the group: The W and Turbine style wheels are the same size. And the only differences I've noticed with the DWS06 tires over the stock S001 tires is that they are a little noisier, and ride a little harder, but I feel the road so much better and the car no longer pushes in the turns. It performs better than the skinny S001 tires. I'm pretty happy so far.
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