Months ago, I lit into our long-term 2008 BMW 135i for having an insipid personality. But I didn't go to work yesterday. I took the day off and drove up to Willow Springs for an Evosport driving school on Big Willow. And there I buddied up with our 1 Series like never before.
Undoubtedly you've heard or know that Big Willow is a fast but not very technical track. Its turns don't require much actual turning, so if you have some idea about what you're doing, torque is pretty much all you need. The 135i has plenty of that. There doesn't seem to be a weak spot anywhere in its twin-turbo inline-6's powerband. As a track car, the 1 is incredibly user-friendly. It felt very quick, too, at full throttle down any straightaway.
Although I've criticized the 135i for not having good enough steering feel, the truth is that I knew exactly when the tires were gripping and when they weren't -- all that really matters on a track.
The One also has very strong brakes (13.3-inch front discs with 6-piston calipers, 12.8-inch rear discs with 2-piston calipers) and excellent pedal feel. It was very easy to skim off speed in preparation for Turn 1 at the end of the front straightaway. The brakes lasted well, too, and seemed none the worse for wear by the end of the day. But I can't say the same about the tires.
We knew going into it that this would be the last track day for the 135i's original equipment Bridgestone Potenza RE050A run-flat tires, size 215/40R18 85Y in front and P245/35R18 88Y in back. But when I went to refuel at lunchtime (after putting over 100 miles on the car during the morning session), I took one look at the left front tire and thought I might be done for the day.
In the morning, I'd set the tires (when warm) to 40 psi, which is 4 over the 36-psi cold spec. Either that wasn't enough for the fronts, or the camber settings weren't ideal for track use. Or, I wasn't doing enough to counteract the 135i's understeer. Probably all three.
Fortunately, most of the turns on Big Willow are right-handers, so the right front tire wasn't nearly as worn. A couple of the instructors and I did a left-right swap -- which is OK per Bridgestone for asymetrical, but non-directional tires. In the afternoon session, I tried to be less fussy at the steering wheel and rely on the throttle to correct my line -- obviously something I should be doing anyway. That got me another 125 miles at the track and another 90 all the way home to Santa Monica.
We'll be replacing all four tires very soon. Since the 135i is still in its first 12 months in our fleet, it's going to be another set of RE050A RFTs. You're welcome to try to talk us into something more interesting, though.
On Monday, I'll post a few more thoughts on my track day with our BMW 135i coupe. Until then, you can reacquaint yourself with the 135i's track outing at Spring Mountain Motorsports Ranch when it went up against our E46 M3 and a 335i.
Erin Riches, Senior Editor @ 16,234 miles
srlracing says:
05:50 PM, 01/16/09
The big track will do that to your car. Going off is even more painful. I recommend Falken Ziex ZE-912. I've been running them on all my performance street cars including a Miata and a Mercedes with a Chevy in it.
subytrojan says:
07:03 PM, 01/16/09
Nice post, Erin!
I'm glad the brakes held up well. If the 1er was tracked more, the brake caliper pistons could possible crack.
http://forums.bimmerforums.com/forum/showthread.php?p=14599231
pookgai says:
07:11 PM, 01/16/09
BMW has always been know for their great brake performance, this is one of the reasons that they produce so much brake dust.
subytrojan says:
07:32 PM, 01/16/09
D'oh! I meant "possibly crack" above.
I miss you, Edit function. :tear:
BMW brakes, pookgai?
The E82 135i has Brembo brakes. As far as I know, most Bimmers have in-house (as far as I know) sliding caliper brakes.
Does anyone know what the factory camber settings are for the 135i? I'm guessing the manual probably has them. More negative camber probably would've helped (for Turns 8 and 9).
bimmer13 says:
08:56 PM, 01/16/09
Can the RFT's. The cars handling and the ride improves greatly with non-RFT's and a mobility kit.
ddoouugg says:
11:09 PM, 01/16/09
That's nice to take a day off to go to the track and have your company pay for your tires! I wish i could dot that for school.
huyracing says:
11:41 PM, 01/16/09
Yeah, forget runflats... i believe one of the complaints was ride quality, so fix it!
That tire wear is simply due to not having enough negative camber. Of course, it is a street car, so the alignment is optimized for maximizing tire wear.
Just follow my suggestions for the M3. I wasn't wrong in suggesting the ADVAN's. Falken RT615's if you're cheap. If you're cheaper than that, its not worth my time.
slickersdrip says:
08:12 AM, 01/17/09
I agree with Huy, I have 615's on my car. They wear out really quickly but the stickiness is never ending.
adood84 says:
08:58 AM, 01/17/09
From what I've read, you are better off with Normal tires and the mobility kit from BMW, should be a much better ride
dragonflight says:
01:13 PM, 01/17/09
I'd like to hear how this car performs with non-runflats (probably my first course of action if I bought one). Does it lower the noise? Improve the ride? Grip? And will it strand an IL editor even when equipped with a mobility kit? Those are all the questions we could explore if you guys would be willing to try it :)
tenfifteen says:
06:50 AM, 01/18/09
But it doesn't have heated seats, so clearly a Mazda 3 is superior! ;)
MS3lvr92 says:
12:54 PM, 01/18/09
Keep the Bridgestones they're the only front and rear matching max performance summer tires you can get for it.
m_thrizzle says:
05:57 PM, 01/18/09
See the last two M3 posts for my tire suggestions.
1ToBeOn2Wheels says:
11:22 PM, 01/18/09
Please, please ditch the RFTs and get something more performance oriented! I have the stock RFTs on my 135i and I'd like to know how much difference a good set would actually make!
arm51 says:
12:44 PM, 01/19/09
Please, do not get another set of RFTs. They are truly horrible tires!
cocarguydj says:
08:23 AM, 01/20/09
Perhaps you guys should try a set of Toyo Proxes T1Rs for this car. I haven't personally run them on anything, but several of Toyo's other tires have been quite impressive to me over the years. They are non-RFTs and come in both of the required sizes to have a complete matching set of new shoes.
http://www.toyo.com/docs/tires/tires.asp?lpid=18966&name=Proxes%20T1R™&category=sport
stingray454 says:
12:07 PM, 01/20/09
Those tires look exactly like the rear tires of my '02 Z06 looked after about 100 miles at Pocono Raceway north course this past summer. I did the same thing to keep me going through the last sessions - did the left-right swap. Worked great, and got me home 200 miles too. It was scary though driving on tires like that. I think they got too hot from being worn so much to start with, causing the delamination of the tread from the carcass - apparently the tread grooves on street tires also help cool the tire. Mine were almost at the wear bars before I started the track day.
I miss the Big Track at Willow - I've done two full days there. Still my favorite, but I no longer live on the west coast. It's not the most technical, but there are a few tricky turns there, and for high horsepower cars its a ton of fun.