Why do Z4s fair worse than 3 series for MOTs?

[Magicarcher]

I've been looking for a 3 series estate for my wife. One of the things i always do is look at the MOT history to see the sort of things a car fails on. It became apparent that the 3 series appears to suffer far fewer failure than a Z4 for equivalent age/mileage.

I decided to do a quick check. I went on autotrader and looked for cars between 10-12 years old with between 80k and 100k mileage. Looked for Z4s first then 3 series estates, petrol manuals. I looked into the MOT history for the top ten cars displaying registrations (sorted by price). Not an exhaustive comparison but gives an idea.

The Z4s performance:

Average failures = 3.6
Modal failures = 4
Highest number of failures = 6
Lowest number of failures = 1

The 3 series performance:

Average failures = 2.2
Modal failures = 2
Highest number of failures = 4
Lowest number of failures = 0

Would anyone like to speculate why the Z4 fairs so much worse than 3 series?

[1972nail]

Broken springs......

[Anmarube]

Broken springs......

Hit the nail on the head their I reckon.

[Zoomer]

Could it be because zeds were built in the states?

[LordOxygen]

Zeds are probably driven a bit harder as people think they're proper sports cars (which they're not - they're fast GT cars). So stuff will wear quicker.

[buzyg]

Your sample data is too small for any meaningful results. So you may or may not be correct.

It's good that you set a few meaning full parameters. However, I can't help thinking the cars are chalk and cheese, so what is the point of trying to compare them?

Your data is not allowing for type of use. Type of driver etc etc etc.......

Questions that might be more relevant.

Which zed4's fair best?

Do the preface lift cars fair better than the post face lift cars?

Is the steering system in the ///M more or less likely to fail than the one in the other E85/86 models?

Is the Zed4 more likely to fail an MoT than a similar Boxster?

[G600]

Broken springs......

I wouldn't be surprised, mines failed twice on a broken rear spring!

[ph001]

They break just as often, if not more on the E46 M3!

[Mr Tidy]

Strange really, seeing as most of the E85/E86 architecture is the same as the E46.

But does the OPs sample include E9* 3 Series models as well?

[dhobbs]

It could also be due to people buying the roadster for a summer and not looking after it. Then selling it on.

They do get a hard life, but they also stand up to it too.

[Z4M-2006]

It would be interesting to see what they are failing on


3 series snap springs just as often as Z4's and any other bmw ..

I notice that brake pipes seem a common issue and crap handbrake performance, again though that seems right across the board with BMW

Badly worn tyres and condensated lights seem to be a failure point on the Zeds we see

[kis]

I'd also add that rear tyres being illegal would attribute greatly to failures like the springs. Due to the camber they'll wear on the inside (becoming illegal) but if you're only looking at the wheel face on it'll seem like theres plenty of tred.

[Chris1981]

Well this thread fills me with confidence.... Z4 is in for MOT at 4pm!!

Fingers crossed I won't be adding to the failure statistics

[pvr]

Well this thread fills me with confidence.... Z4 is in for MOT at 4pm!!

Fingers crossed I won't be adding to the failure statistics

You should be ok, you will get a 3 series loaner if yours fails

[Chris1981]

z4 went through with just 2 advisorys both for front brakes which is an easy fix!

My old e46 went straight through too so I'd say that well maintained examples of either are fine for many years!