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Calypso-E34

One rear wheel spins more than the other

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I have noticed lately that if I accelerate hard from standstill on a wet surface, the near side rear wheel slips / spins while the offside one does not.  Both tyres are the same, have about 5mm tread remaining, with no oil or grease evident.  Coil springs seem ok (both replaced within the last 2 years) and the car handles as it always has.  Car is an F10 6 cylinder 525d 3.0.

 

Any ideas?

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Just now, duncan-uk said:

Drive slower ;)

 

I was wondering who would be first with that one!!

 

I'm not a fast driver - I like a wee blast now and again, but usually just cruise around.  It's only lately I have noticed this slip happening.

 

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I would suspect that all things being equal its weight bias left to right. You say near side so passenger. The cars designed to be LHD but as it becomes RHD i don't believe the weight is as evenly spread out, add in the driver and on a common surface the lighter load wheel gives up first.

 

Or possibly the difference in friction through the diff to each wheel so on a common surface the same wheel will give up each time but i suspect the former.

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Would you expect any torque reaction from the car in relation to the direction of rotation of the engine & drive shaft?

 

Every action has an equal an opposite reaction apparently :wink: 

 

Just my $0.02

 

Regards,

 

Mick

 

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1 hour ago, TerryTibbs said:

It’s got an open diff, a limited slip diff would light both tyres up

 

I'd prefer not to light the tyres up at all!  I prefer good grip! 

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54 minutes ago, Ordnator said:

Would you expect any torque reaction from the car in relation to the direction of rotation of the engine & drive shaft?

 

Every action has an equal an opposite reaction apparently :wink: 

 

 

^This

 

If it was a rigid rear axle I would say it's the torque reaction from the differential/prop shaft in a left right movement across the car but it's independant rear suspension so the effect of that should be less. 

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^

Agreed, the effect will be mitigated but not eliminated.  The torque effect could cause the right side to squat down producing additional force on that rear wheel and the left side to lift up thereby reducing down force on that rear wheel.  The explosive nature of the application of this torque could account for the left side slipping first.

 

My assumption here is that the engine and drive line are rotating clockwise (viewed from the rear), please shoot my theory down if my assumption is incorrect.

 

This is the effect that I suspect to be a contributory factor to the root cause of M20 & M30 engines snapping number 6 cylinder lower rear exhaust studs.  That and there not being a rotating joint on the exhaust system, driving with diving boots on and the engine / gearbox / differential mounts wearing and allowing move rotational movement of the engine / drive line.

 

Did I mention that I have now had an E21 323i (M20), E28 520i (M20), E24 635i (M30) and an E28 525e (M20) present with this failure.

 

Regards,

 

Mick

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The diff is now controlled by the brakes, it’s open. The ecu now controls things for you. If you want more control, fit a proper diff.

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If you had a difference of power delivery to each wheel, the arse would slew out. Is this happening ?

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4 minutes ago, roofer said:

If you had a difference of power delivery to each wheel, the arse would slew out. Is this happening ?

 

Not really - but maybe the extra power is being spun off?  The ASC steps in to calm it down 

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35 minutes ago, Calypso-E34 said:

 

Not really - but maybe the extra power is being spun off?  The ASC steps in to calm it down 


The rear brakes control spin. I couldn’t work out why my rear pads used to wear out equal to the fronts in my old 335d. Until a BM tech asked about my driving style. Then it made sense.

 

If you have different wheel speed delivery, the arse will hang out.

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If you have the Teves 60 DSC, it will allow 2mph or 5% tolerance between the wheels before it kicks in. Maybe you have a lazy speed sensor on that wheel? The yaw rate sensor can also play funny tricks

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19 hours ago, roofer said:


The rear brakes control spin. I couldn’t work out why my rear pads used to wear out equal to the fronts in my old 335d. Until a BM tech asked about my driving style. Then it made sense.

 

Surprised they lasted as long as the fronts ;)

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4 hours ago, duncan-uk said:

 

Surprised they lasted as long as the fronts ;)

When i were a lad, used to be 2 fronts to a set of rears. :?

 

Got the ‘performance’ brakes on the touring, pad price is eye watering :evil:

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