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#1
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19" wheels = no cruise control?
I put 19" wheels on my w210 e430 and now my cruise no longer works over the speed of 75mph. Is there a fix for this(other than taking of the wheels)?
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#2
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That means that the rear tires are SLIGHTLY smaller in circumference than the front ones!
The traction system doesn't like that!
__________________
MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
#3
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curiousity prompts me to ask: why does it have to be the rear being smaller
than the front? could it ever be vice versa? also, how much differential must there be between front/rear before the traction control (cruise control, et al) begins to balk?
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-- raymond~ 47º 34'N 122º 18'W |
#4
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On cars with ESP and some with ASR, only a 3/8" difference can cause issues.
Since the cars are REAR wheel drive, the traction system is always looking for slippage of those rear wheels. So if they are going faster that the fronts, it is designed to intervene.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
#5
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great info - thanks, doc !
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__________________
-- raymond~ 47º 34'N 122º 18'W |
#6
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I've checked different brands of tires they all have different outside diameters.Double check yourself O.D.
__________________
1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt |
#7
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well, I had hoped to be able to posted a follow up of my success but it wasn't to be.
The cruise control regularly shuts off at 70 mph the rear tire's circumference is 79.5". the front tire's circumference is 78.5" which means the rear tire is *larger* than the front by by 1.25%. next step will be to swap out the front tires with ones providing a 0% differential and test the cruise control again.
__________________
-- raymond~ 47º 34'N 122º 18'W |
#8
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Quote:
my favorite tire interchange engine is this one, and for the 235-40-18 it shows the circumference to be 79.5 which is what I really need. just to be thorough, I asked the vendor to measure the tire I was contemplating purchasing (235-40-18) and he came back with 78.5" there is 'theoretical' and there is real life. guess there is no ISO standard
__________________
-- raymond~ 47º 34'N 122º 18'W |
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