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If I recall it was technical reasons that BMW couldn't fit their R&P system underneath the V8 oil pan, etc. The 540i was the same way. I also suspect it was an ego thing, "The BMW recirculating ball is better than most other R&P systems, so why change it". :) The only systems better in '97 were the BMW R&P models. Now with the increased competition, the e60, etc have rack & pinion across the board.
 

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Here is what I read in a review about this.


"The quick-ratio power steering has a 14.7:1 overall ratio and M Servotronic power assist. Compared to the engine-speed-sensitive variable assist of lesser 5 Series cars, the M5's system varies power assist according to vehicle speed. The system is calibrated for a firm road feel and the recirculating-ball steering gear has an automatic pressure-point adjustment that eliminates free play in the straight-ahead position. The result is precision comparable to that of rack-and-pinion steering while retaining what BMW says is the superior suppression of road shocks offered by the recirculating-ball mechanism"

Hmmm

Dennis
 

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It don't fit, but the 540 has a R&P, this could all be found under the search tab.
 

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Jayson said:
It don't fit, but the 540 has a R&P, this could all be found under the search tab.
I had a '99 540i. It was definately recirculating ball. The 528i I test drove had better steering feel but I prefered the power of the 540i. When switching to the M5, it was a noticably quicker ratio and the sport button gives more weight to it than any situation in the 540i but road feel was similar. The 545i and 550 are rack & pinion.
 

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The BMW V8 engine is large and tall (deep), so it does not leave much room for R&P without compromising ground clearance or raising the motor...which compromises cg/handling. I also think the V8 install was somewhat of an afterthought for later E34 and at this juncture, the recirc ball was a better match. Since this E34 V8 suspension & steering chassis was basically carried over to the E39, we were stuck with it (again).

They obviously rethought this decision for E60.
 
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