MOT Tester Crashes Lamborghini

[Birdster]

Sorry for the Daily Mail link

http://www.dailymail.co.uk/news/article-2233278/Un...

Do they have to take these cars out then to test?

[Output Flange]

Birdster said:

Do they have to take these cars out then to test?

No.

article said:

'With the Lamborghini being a four-wheel drive, it has to be road tested to test the efficiency of the brakes. You can’t put it through the rolling road brake-tester here because it would damage it.'

Really?

[Chicane-UK]

Well - unless the garage didn't have proper brake test rollers, or the Lambo was too low to get on them... in which case he may have had to take it out and use a decelerometer for the brake test...

[E30M3SE]

Output Flange said:

Birdster said:

Do they have to take these cars out then to test?

No.

Actually, yes, to test the brakes.

Anything with a LSD or 4X4 systems should not be tested using the brake test rollers.

[hornetrider]

No more than 25-30mph eh?

[Podie]

Not sure what's rarer... an LP640 or a bobby on the beat!

[Robatr0n]

E30M3SE said:

Output Flange said:

Birdster said:

Do they have to take these cars out then to test?

No.

Actually, yes, to test the brakes.

Anything with a LSD or 4X4 systems should not be tested using the brake test rollers.

Pretty much this.

[jbi]

If the brake tester only tests one set of wheels at a time... I can see why a 4x4 car would not work on it

[Podie]

hornetrider said:

No more than 25-30mph eh?

Looks superficial, so probably.

[Manicminer]

DM Article said:

'With the Lamborghini being a four-wheel drive, it has to be road tested to test the efficiency of the brakes. You can’t put it through the rolling road brake-tester here because it would damage it.'

Are there any set rules for this on road brake testing? All done by feel, hands off the wheel style?

[hornetrider]

Podie said:

hornetrider said:

No more than 25-30mph eh?

Looks superficial, so probably.

You'll note that it's the rear of the car that is smashed up. From doing a brake test. At 30mph.

Do you want me to draw a picture?!

[Output Flange]

E30M3SE said:

Actually, yes, to test the brakes.

Anything with a LSD or 4X4 systems should not be tested using the brake test rollers.

Then someone needs to tell every MOT tester I've ever used that bit of news.

[14-7]

How do you test the efficiency of the brakes on the road then? Surely you have to have a machine to check brake balance not just a mechanic saying, "it feels ok".

[Podie]

hornetrider said:

Podie said:

hornetrider said:

No more than 25-30mph eh?

Looks superficial, so probably.

You'll note that it's the rear of the car that is smashed up. From doing a brake test. At 30mph.

Do you want me to draw a picture?!

Thought I'd put a on the end!

[jon-]

14-7 said:

How do you test the efficiency of the brakes on the road then? Surely you have to have a machine to check brake balance not just a mechanic saying, "it feels ok".

Decelerometer for retardation, feel for balance.

[rhinochopig]

jon- said:

14-7 said:

How do you test the efficiency of the brakes on the road then? Surely you have to have a machine to check brake balance not just a mechanic saying, "it feels ok".

Decelerometer for retardation, feel for balance.

Well the Tester certainly scored highly for retardation.

[E30M3SE]

Output Flange said:

E30M3SE said:

Actually, yes, to test the brakes.

Anything with a LSD or 4X4 systems should not be tested using the brake test rollers.

Then someone needs to tell every MOT tester I've ever used that bit of news.

It's not Breaking News,

http://www.ukmot.com/3-7.asp

[mrmr96]

Output Flange said:

E30M3SE said:

Actually, yes, to test the brakes.

Anything with a LSD or 4X4 systems should not be tested using the brake test rollers.

Then someone needs to tell every MOT tester I've ever used that bit of news.

What makes you doubt it?

Most MOT stations have a rolling brake test machine where you put only one axle on at a time. On 2WD cars it's no problem since spinning either the front or rear wheels has no effect on the other end of the car.

On a 4WD car spinning one set of wheels will spin the other, as they are linked by the centre diff. Unless the centre diff is fully open, i.e. not a limited slip diff of somekind. If it was fully open then putting the car in neutral would allow one set of wheels to rotate independently of the other. (It would make the gearbox spin instead.)

You can also get around it by spinning one wheel of an axle forward, and the other wheel of that axle backward. Then the centre diff won't move at all. But this can be bad for the diff on the axle you're spinning.

Something like the Lambo, and indeed most performance 4WD cars, will have limited slip diffs (front, centre and rear). And as such it will cause damage to spin two out of the 4 wheels. The MOT station could roll them on a 4WD brake tester (with 4 rollers) but most stations don't have them. As such a 'moving brake test' is usually employed instead and is an acceptable alternative to using the brake testing machine.

Just seems this MOT tester crashed while he was out in the car. But there was a valid reason for being there.

[jjones]

http://www.tapley.org.uk/braketestmeter.html

as brake testing a single axle on an AWD with LSD is bad

[14-7]

jon- said:

Decelerometer for retardation, feel for balance.

Well you learn something everyday!