BMW 135i needs street, slalom tires

John Mahler

SPECIAL TO THE STAR

Q: The tires on my BMW 135i are finished so I am looking for replacements. I want a tire that can run on the street and on autocross courses. The wheels are 7.5-inch front and 8.5-inch rear and OE tires are Bridgestone RE050A runflats P215/40R18 front and P235/35R18 rear.

The car suffers from excessive understeer at the limit. My goal is to have the highest performing summer tire for street driving and occasional lapping days, and to move the car's balance more towards neutral.

Tire selection in the OE sizes are rather limited, as is the ability to fiddle sizes without affecting diameters. The car has an rpm-based tire warning system, which can presumably accommodate some mismatch in diameters (you reset it after setting pressures). I am tempted by a square setup of P225/40R18 all round.

Obviously, I don't care about maintaining the runflat capability.

The tires that come to mind are: Bridgestone RE-11, Dunlop Direzza Sport Z1, Hankook Ventus R-S2, and Kumho Ecsta XS.

A: There is a new tire just introduced that has escaped your search. The Yokohama Advan Neova A08. It is an improvement on the Neova A07, a tire I have used extensively on the street and track. In independent testing, the new Neova shows improvements in all categories over the old tire.

It is easy to drive, warms up quickly and has tonnes of grip. I found the wear rate excellent. One set lasted a whole season of road and track use, and still had some tread left after a total of 12,000 km on a Porsche Turbo.

The Dunlop Direzza Sport Z1 Star Spec is the stickiest thing Dunlop makes now. The Star Spec label indicates it is fast-to-warm autocross version. It grips very quickly, as shown by its chain of major autocross victories in the U.S.

The Kumho Ecsta is a non-starter because of its poor wet performance. The Hankook Ventus R-S2 is a virtual copy of the last Yokohama Neova, with just a few extra shoulder grooves added. As such, it is a great last generation tire. Its best feature is its low price.

The Bridgestone RE-11 is a big hunk of rubber with grooving for every angle of water attack. Water can be channelled out circumferentially or laterally. This tire is a further improvement on the RE-01R, which was the grippiest tire Bridgestone has made for the street in quite some time. Tire Rack in the U.S. places it at number 1 in its grip rankings overall.

However, based on my past experience with the Yokohama Neova and how many extreme heat cycles it could stand, I'd be inclined to rank it my number 1. I suspect it also has a slightly lower void ratio (grooved area vs. solid tread) and that aids in dry grip and wear. However, in very wet road conditions the Bridgestone will have the edge. And in your size, the Yoko weighs 10.4 kg compared to 11.8 kg for the Bridgestone.

So overall my choices would be Yokohama, Bridgestone, Dunlop, Hankook, Kumho. If we factor in price as a prime consideration the list reads: Dunlop, Hankook, Yokohama, Bridgestone.

The speed rating between W and Y are not going to make a difference on your BMW 135i.

TIRE STORAGE WANTED

Many readers are asking where they can store their tires for off-season. The Tire Guy would like to help. . If you operate a tire storage facility or service, please email me at the address below. . I'd like to compile a list of services. Please include your fees for storage and/or changeover charges.

Email tire questions to John Mahler at thetireguy_1 @ hotmail.com. Please

include vehicle's make, model and year, tire brand and size, as well as your name, address and phone number.

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