w211 (04) No cruise 60mph onwards

[merc85]

A friend of mine has a 2004 e-class e320 cdi, The cruise control has stopped working at speeds 60 + mph. But fine upto 60mph.

Any ideas on whats up??

 

[whitenemesis]

Have the tyres been swapped or changed?

 

[merc85]

Have the tyres been swapped or changed?

2x New tyres 300 miles ago both correct sizes

 

[GordonTarling]

2x New tyres 300 miles ago both correct sizes

That's the problem then. Differences between old and new tyre diameters causes rotational speed difference outside of CC limits above a certain speed (60mph in this case).

 

[merc85]

Why didnt it play up when the Old tyres were new then?

 

[Stratman]

Why didnt it play up when the Old tyres were new then?

Were all four tyres new at this point?

 

[merc85]

Were all four tyres new at this point?

Hi Stratman, yes they were.

 

[whitenemesis]

It's the speed differential between the axles that causes the CC to drop out

 

[merc85]

Many thanks peeps will let you know and keep this thread upto date

 

[BTB 500]

I would be double (or triple!) checking that the new tyres are the right size. It's not unusual to replace rears more often than the front ones (for example), and AFAIK this doesn't generally disable the CC. But fitting a different size with a significant change in rolling radius often does.

 

[Kevlaar]

So this means that anyone who modifies a w211 and changes the wheels without perfectly matching the factory rolling radius will mess up their cruise control?

Surely this logic is flawed even when considering standard wheels. This would mean that either the CC works when you have brand new full tread, or when it has reduced by 5/6mm, as that seems to be all that OP friend has done...worn tread?

 

[whitenemesis]

One has to maintain the speed differential of each axle to within the tolerances set. It's if the rear wheels spin faster than the front (or the other way round) that upsets the CC, the car thinks you are skidding or out of control.

 

[Benzowner]

So this means that anyone who modifies a w211 and changes the wheels without perfectly matching the factory rolling radius will mess up their cruise control?

Surely this logic is flawed even when considering standard wheels. This would mean that either the CC works when you have brand new full tread, or when it has reduced by 5/6mm, as that seems to be all that OP friend has done...worn tread?

My Old W220 S Class with the old Comand 2.5 had an adjustment program for part worn tyres, not sure if this was for CC or something else.

 

[ernie]

If you check and if need be, correct the tyre pressures, then reset the tyre pressure monitors on the OBC, I think you will find the problem will disappear.

Ernie

 

[merc85]

Just a update, thankyou all for the replies, A pair of New rear tyres sorted the issue