Whatís the diff ?


Weíre falling more in love with Bluey, thereís just one small thing

EAR-DRIVE performance cars under $50K with a standard limited-slip diff? Thereís a few of íem. Toyota 86 GTS, Mazda MX-5, XR6 Turbo, SS Commodore. Can name a few front-drivers as well. So it does strike one as unusual the $63K BMW M135i doesnít come with a standard limited slip differential. In Australia, a highpower rear-driver with an open diff is just not cricket.

But the M135i gets away with it surprisingly well. Driven in an aggressive manner yet displaying some semblance of restraint, traction is strong. Punch it and itíll light up an inside wheel before the electronics clamp down, but you rarely find yourself cursing that there isnít a bundle of happy cogs at the end of the tailshaft. Thereís still fun to be had.

In its half-off ESP setting, Dynamic Traction Control, and in Sport Plus, the M135i can also play a little on the throttle, though youíll have to already be heavily loaded up mid-corner, and itís more a brief wriggle necessitating a steering input than anything close to a big smoky slide.

Those, though, are possible on the track. BMW engineers have tried their best to simulate an LSD, using the chassis electronics, with the DCT switched all the way off. It works surprisingly well. Yet itís no match for the reliable locking feel of a proper R LSD, such that on the road, its slight lack of consistency might be a tad more frightening than fun.

Itís not difficult to understand why BMW hasnít offered the LSD as standard; as a figure, $62,900 is mighty nice-sounding. Surely only a small percentage of customers would care, and even fewer notice, that a proper differential is not included.

To some extent, for drivers the kind whoíd never visit a track, it doesnít need an LSD. Straight-line punch is strong from the rear 245s and there is still some playfulness available. Itís hardly single-spinner city.

But based on MOTORís experience with the M235i fitted with the optional limited-slip differential, the $4300 is money well spent Ė especially for a MOTOR reader.

Iíd certainly spend it, and itís telling that this month I found myself looking up finance options for $70K. I have to be careful I donít start gushing here.

Having now driven it on the freeway at length, on track, around town and in anger up some decent roads, I can say honestly Iíd own an M135i. Its faults are few and easy to overlook. And when you do that, thereís a mega car to be found.

But first, those faults. I donít know about you but the looks Iím on the fence about. The new one is probably an improvement on the old Ďrodentí face, but perhaps itís now swung too hard in a conservative direction. Iíd have to crack the knuckles and do some aftermarket-assisted restyling myself, I think.

It would also take you a very long time to get fully used to the variable steering in the urban environment. Itís darty, hyperactive and takes a long time to adjust to if youíve come out of anything conventional. But the bigger issue Ė and perhaps my main gripe with the car Ė is the brakes. Around town, theyíre initially a little grabby and the pedal assistance is calibrated such that itís basically impossible to brake to a smooth stop,. The aroundtown pedal feel needs more work.

But, truly, these are minor complaints. And I certainly wouldnít not buy the car because of it.

The steering and brakes, in a performance context, are mega. So is the rest of the car, in fact. The M135i surely has one of the best interiors in a car less than $65K. It rides uncommonly well for a performance car. The 240kW, 450Nm single-turbo 3.0-litre N55 straight-six has a very satisfying amount of grunt (to the tune of 0-100km/h in 4.84sec). The eight-speed tranny does one of the best twin-clutch impersonations Iíve ever felt from a torque converter auto.

Perhaps most impressive of all, the chassis: the M135iís limits are not too low, not too high. And up to, and at them, the car never feels flustered and is always honest. Confidence is central to having fun driving fast, and the M135i pumps you full of it.

Itís so fun and friendly, and so sorted in its drivetrain, steering and chassis, I can truly think of little that might offer major improvement.

Well, there is one thing. Ė DC

From our experience with an LSD-equipped M235i, the $4300 is money well spent

MONTH three


Itís so easy and friendly to drive fast. Big on confidence, this little blue thing.

Loving it


Jury still out on styling for me

MOMENT favourite

Hearing exhaust from the outside at start-up.

Surprisingly burbly.