18x11 Track Rear Wheels - what tires?

[adc]

Originally Posted by CanAutM3

As I posted above, it is the 275/35-305/35 combo that keeps things the closest to stock. With a 275/40 in front, you are reversing the diameter stagger with a larger tire in front. The 315/30 is just too small IMO. For reference, tire diameters for 18" wheels:

255/40 PSS 26.0"
275/40 PSS 26.7"
275/35 NT01 25.6"
275/40 NT01 26.7"
305/35 NT01 26.4"
315/30 NT01 25.4"

Yes but I see it the other way around. 275/40 with 305/35 has a diameter stagger of 0.3" to the front, but 275/35 with 305/35 has 0.8" to the rear.

RRT in Dulles VA thought the 0.8" diameter stagger might cause issues with the DSC/ABS and rest of the alphabet soup.

What do you see as the negative with the 274/40?

For the record I haven't bought front tires yet but I'm about to in the next few days, so any bit of advice and info helps...

[CanAutM3]

Originally Posted by adc

Yes but I see it the other way around. 275/40 with 305/35 has a diameter stagger of 0.3" to the front, but 275/35 with 305/35 has 0.8" to the rear.

RRT in Dulles VA thought the 0.8" diameter stagger might cause issues with the DSC/ABS and rest of the alphabet soup.

What do you see as the negative with the 274/40?

For the record I haven't bought front tires yet but I'm about to in the next few days, so any bit of advice and info helps...

Look at it this way, the ABS/DSC are calibrated to work with 0.7" larger rear tires in stock form. Going with the 275/35-305/35 combo increases that by a small 0.1". However, the 275/40-305/35 combo has larger front by 0.3", essentialy shifting the stagger by a full 1" (10 times the error).

There is nothing "wrong" with the 275/40 per se. It will probably run fine with DSC off. However, you will very likely get much more useless DSC interventions with it. For instance, when running a square setup last year, even Euro MDM was crazy intrusive. Everything was fine with DSC off though. Also consider that the 275/40 is a bit more expensive, so you are spending more for a less optimal tire .

[adc]

Originally Posted by CanAutM3

Look at it this way, the ABS/DSC are calibrated to work with 0.7" larger rear tires in stock form. Going with the 275/35-305/35 combo increases that by a small 0.1". However, the 275/40-305/35 combo has larger front by 0.3", essentialy shifting the stagger by a full 1" (10 times the error).

There is nothing "wrong" with the 275/40 per se. It will probably run fine with DSC off. However, you will very likely get much more useless DSC interventions with it. For instance, when running a square setup last year, even Euro MDM was crazy intrusive. Everything was fine with DSC off though. Also consider that the 275/40 is a bit more expensive, so you are spending more for a less optimal tire .

That makes sense. I hadn't realized the stock setup has such a large stagger - wasn't the case before.

Thank you, you've just saved me some $50.

[BitchinManWheels]

Originally Posted by CanAutM3

Look at it this way, the ABS/DSC are calibrated to work with 0.7" larger rear tires in stock form. Going with the 275/35-305/35 combo increases that by a small 0.1". However, the 275/40-305/35 combo has larger front by 0.3", essentialy shifting the stagger by a full 1" (10 times the error).

There is nothing "wrong" with the 275/40 per se. It will probably run fine with DSC off. However, you will very likely get much more useless DSC interventions with it. For instance, when running a square setup last year, even Euro MDM was crazy intrusive. Everything was fine with DSC off though. Also consider that the 275/40 is a bit more expensive, so you are spending more for a less optimal tire .

With your 275-305/35 set up do you have any traction control problems? I have 275/35 NT-01 squares and the MDM is WAY too intrusive. I like having a back up when learning a new track or doing something a little different.

[CanAutM3]

Originally Posted by BitchinManWheels

With your 275-305/35 set up do you have any traction control problems? I have 275/35 NT-01 squares and the MDM is WAY too intrusive. I like having a back up when learning a new track or doing something a little different.

Agreed, with a square setup, MDM (even Euro-MDM) is way too intrusive.

I have not yet tried my 275-305 setup yet, first track day of the season is this coming Saturday

[tchiers]

I've done the 275-305 setup. When the R888s were fresh (see my gripe at the bottom of p3) it provided good balance. Euro-MDM with that setup was pretty reasonable. It did not like letting you rotate with trail braking and it wanted the wheel nearly straight before it let you have full power, but that's to be expected. The penalty for MDM vs DSC off was 1:57.4 -> 1:58.6. The ca can be driven quite fast with Euro-MDM, just not quite 10/10ths dancing on the knife's edge...

[lifebimmer]

What's the best street perfomance tires that can be mounted on the EC-7 18x11 and 18x10?

[FLOSS M]

I have run the 275-305/35/18 combo with R888, euro MDM - 6 track days so far. I find the car is very stable and balanced.

[Russell263]

Originally Posted by FLOSS M

I have run the 275-305/35/18 combo with R888, euro MDM - 6 track days so far. I find the car is very stable and balanced.

I will still be running a 305/35/18 Toyo R888 on the 18x11

here is a picture comparing the 305/35/18 to a 285/35/19 Re71r

[FLOSS M]

Originally Posted by russell2686

This is the set up I was planning on running also, but turns out you can not use a 275/35/18 front with the 18x10 if you have KW HAS. Looks like I will need to drop down to the 18x9.5 et22 with the 275/35/18

I will still be running a 305/35/18 Toyo R888 on the 18x11

here is a picture comparing the 305/35/18 to a 285/35/19 Re71r

I have the stock adaptive suspension. I was thinking about the KW HAS .... you answered that question for me.

thank you

[Russell263]

Originally Posted by FLOSS M

I have the stock adaptive suspension. I was thinking about the KW HAS .... you answered that question for me.

thank you

yeah I found out the hard way from assuming I wasn't the only one on HAS out of the ton of people running this set up. KW coilovers will also have issues

[FLOSS M]

Wow! Thankfully the tire didn't blow out

[Russell263]

Originally Posted by FLOSS M

Wow! Thankfully the tire didn't blow out

Luckily, That was just from backing out my driveway and heading out of the neighborhood, all of 1/8 mile on the tires...

Looks like there is no option with running a 275/35/18 Toyo R888 with KW HAS and an Apex wheel in the front. Even the 18x9.5 et22 looks like it will still rub considering it is wider than a NT555 which still requires a 3mm spacer from what I've seen.

[FLOSS M]

sucks for sure... good luck

Let me know if you are selling the rear R888's

[C-Mu]

This news is troubling. The Apex group buy ends in 6 days and I was ready to pull the trigger on a set of track wheels. I'm on a stock suspension for now but planning on going to go with the BMW HAS kit once it's released. I wonder if there will be the same rubbing issue with the BMW kit. Russell2686, how low did you set the ride height? Would raising it up a bit help?

[Russell263]

Originally Posted by C-Mu

This news is troubling. The Apex group buy ends in 6 days and I was ready to pull the trigger on a set of track wheels. I'm on a stock suspension for now but planning on going to go with the BMW HAS kit once it's released. I wonder if there will be the same rubbing issue with the BMW kit. Russell2686, how low did you set the ride height? Would raising it up a bit help?

From what I've seen on here, the BMW HAS kit will be identical to the KW HAS so will have the same problem

[Reach]

Originally Posted by russell2686

Luckily, That was just from backing out my driveway and heading out of the neighborhood, all of 1/8 mile on the tires...

Looks like there is no option with running a 275/35/18 Toyo R888 with KW HAS and an Apex wheel in the front. Even the 18x9.5 et22 looks like it will still rub considering it is wider than a NT555 which still requires a 3mm spacer from what I've seen.

How about running a 5 or 7 mm spacer? Should be all you need for clearance.

[Russell263]

Originally Posted by Reach

How about running a 5 or 7 mm spacer? Should be all you need for clearance.

It looks like it needs more than 5mm and the et25 sticks out pretty far already. Apex said 5mm would clear a regular KW coilover, but the HAS is most likely needs more than 5mm

Current plan is to just swap out the KW HAS for Swift Springs

[scottn2retro]

We're running Achilles slicks in 270x18 up front on 18x10.5 wheels and in the back on Apex EC-7 18x11" et44, we're running 300x18 Achilles slicks

[Russell263]

18x10 et 25 with 275/35/18 R888
18x11 et 44 with 305/25/18 R888
with swift Springs