[albertw]

There has been speculation in a few threads that this disappointing characteristic of some, but not all 2 series is caused by overtightening of a nut that compresses a spring on the steering rack.

Below is a link to a thread in which the assembly is replaced to cure a knock in the steering, in which it is stated that the nut should be loosened if the steering fails to return to centre on its own after a turn.

https://www.2addicts.com/forums/show....php?t=1798185

As delivered my car had roughly 3/4 inch of travel on either side of centre from which the steering did not self centre when the wheel was released. (The car turns slowly but noticeably when the wheel is moved as little as 1/4 inch, so this is not a free play issue.) The car I test drove did not have this issue, so I know it is not universal. I've already tried replacing the front runflats with the same Pirelli performance all season goflats, which made no difference. I also had the alignment checked and only the camber was out of spec, but it was off in the direction that should improve self centering so I left it as it was.

To try to fix this I got the Chinese eBay wrench and tried loosening the nut. After 1/4 turn the problem was significantly improved. There was no numb spot on the left (where the crown of the road helps the self centering) and it was reduced by about 50% on the right. Unfortunately this introduced a slight knock in the steering which happened most often after backing up, then turning the wheel while starting to move forward.

I tightened the nut in small increments and the numb spot enlarged while the knock became less pronounced. Eventually the knock went away when I got the nut back to the spot the factory left it.

It might be that the only way to fix this is to get a new steering rack and hope to get one that doesn't have the problem.

I don't understand the function of this "thrust piece" but clearly if it wears it causes a steering knock. Perhaps the tolerances of manufacture cause some racks to knock until the nut is tightened enough to cause the numb spot. And perhaps that is how the factory builds them. They may have some way of predicting the knock on the assembly line and tighten the nut until that cannot happen. If that happens to cause a numb spot, well, BMW doesn't really care about the steering of its cars so they aren't going to replace a $10 part (their cost, based on the repair kit cost) to make it better.

Rather then getting rid of the car (I like it a lot except for this minor issue) or spending thousands on a gamble that a new rack will fix it, I think I might order the repair kit and see what that does.

Opinions on the repair kit or on the function of the thrust piece would be welcome.

[XutvJet]

I'd be curious to know for those reporting this issue, if they're running run-flats or non-run flat crappy Pirelli Cinturato P7 or narrower than stock tires. It seems to be that the people reporting this issue tend to be in the Northern states or Canada where I'd imagine most 2 series are sold with all season Pirelli Cinturato P7.

[albertw]

This has been discussed in numerous threads, including many that started on other topics so can't be found easily. I haven't kept a running total but I've read every one of those posts carefully. My recollection is that after you exclude cars with a free play problem rather than numbness, the problem is just about as common on cars with Michelin extreme performance summer tires as it is on cars with Pirelli all season runflats.

Here's an interesting post on another forum that includes what appears to be an official description of the BMW electric steering:

https://www.bimmerfest.com/threads/s...issue.1420386/

It's quite technical, but to the extent that I understand it the inertia and friction of the system are so large that all "feel" comes from computers monitoring numerous parameters to figure out what the driver is doing and trying to reproduce the feedback that comes from an unboosted system. If that's correct, the muted but detectable sense that the steering effort decreases as the front tires start to slide (which is really important to me) is entirely artificial. And, it would it even harder to understand the car-to-car variations in on-centre numbness and the fact that it can be changed by varying the tension on the thrust piece spring.

[aerobod]

Originally Posted by XutvJet

It seems to be that the people reporting this issue tend to be in the Northern states or Canada where I'd imagine most 2 series are sold with all season Pirelli Cinturato P7.

In Calgary, the majority of cars at the BMW dealers I use are equipped with summer tyres with an additional set of winter tyres, it is the SUVs that tend to have all-seasons

[aerobod]

The steering rack doesn't seem to require power to self-centre, so centering is still provided by the steering and suspension geometry. I often roll the car out of my garage without unnecessary engine starts and on to the sloping driveway, where the steering will provide a return to centre as the car rolls on the driveway..

This may be due to my specific car having lower steering stiction than some (I may be lucky, but don't have the dead spot). I also have the S2VL variable sport steering (standard on the M240i), so don't know if there is any variance in steering feel based on different options.

[leftoverture]

Originally Posted by XutvJet

I'd be curious to know for those reporting this issue, if they're running run-flats or non-run flat crappy Pirelli Cinturato P7 or narrower than stock tires. It seems to be that the people reporting this issue tend to be in the Northern states or Canada where I'd imagine most 2 series are sold with all season Pirelli Cinturato P7.

Doesn't matter what tires I have on it. This seems to be a design flaw with the electric steering. Problem 1 is that it is overboosted like a 70's Buick Electra. Problem 2 is that there virtually no steering feel. My Lincoln MKZ, which has moderate steering feel, is much better than my BMW. That's kind of sad, really.

[albertw]

Originally Posted by aerobod

The steering rack doesn't seem to require power to self-centre, so centering is still provided by the steering and suspension geometry. I often roll the car out of my garage without unnecessary engine starts and on to the sloping driveway, where the steering will provide a return to centre as the car rolls on the driveway..

This may be due to my specific car having lower steering stiction than some (I may be lucky, but don't have the dead spot). I also have the S2VL variable sport steering (standard on the M240i), so don't know if there is any variance in steering feel based on different options.

That's interesting. Maybe there is reason to hope that lowering friction by changing the "thrust piece" to one that might fit better and work properly at lower spring tension will improve the on centre feel.

Stiction is the right word. What I haven't mentioned is that if I take my hands off the wheel and tap it sideways a small distance it returns to center in what looks like one continuous motion. It's only when I move it up to 3/4 inch in either direction and hold it there briefly that it stays stuck there when I release the wheel. And when I move it say an inch and hold it there, then release it, it starts moving back to centre. To the left it makes it all the way back to centre (with help from the crown of the road) and to the right it moves most of the way back.

[albertw]

I installed a new thrust piece following the link provided in the first post. Bottom line is that I got a slight improvement.

If I turn the wheel a half inch to the left, hold it a second, then let go of the wheel it usually self centres. To the right it does not, presumably because the crown of the road works against self centering from the right. Overall the numb area is roughly 2/3 as wide as it was.

The new thrust piece is constructed differently. The body is metal with plastic inserts where it slides over the rod in the steering rack. (Looking more carefully at the structure it appears that the spring applies pressure to the worm gear in the rack.) The body of the original thrust piece is all plastic with a metal insert down the middle. In principle the new part should be more rigid, but that doesn't appear to be crucial.

If anyone decides to do this, note that the 51 lb-ft torque value provided in the thread referenced in the first post seems to be wrong. The original part as assembled by the factory started turning at approximately 35 lb-ft. With the new part there was a slight clunking in the steering at 20 that went away by 30. I wound up leaving it at 35 since lower values didn't improve the numb spot.

[F22leo]

Originally Posted by leftoverture

Doesn't matter what tires I have on it. This seems to be a design flaw with the electric steering. Problem 1 is that it is overboosted like a 70's Buick Electra. Problem 2 is that there virtually no steering feel. My Lincoln MKZ, which has moderate steering feel, is much better than my BMW. That's kind of sad, really.

You're not wrong about the lack of steering feel. The one major difference I felt immediately was deadness, coming from a e92 328i with hydraulic steering it was a major downgrade. That's not to say literally every other aspect of the m235i blows my 328 out of the water. But I do wish there was more feel in the front of the car especially at the breaking point of traction. It's why I find this car is harder to push to its limits compared to other vehicles I have driven that are easier to feel what's going on. IMO steering is definitely good enough for me though, and doesn't take away from my enjoyment of my car.

[d1a1s1]

Originally Posted by F22leo

You're not wrong about the lack of steering feel. The one major difference I felt immediately was deadness, coming from a e92 328i with hydraulic steering it was a major downgrade. That's not to say literally every other aspect of the m235i blows my 328 out of the water. But I do wish there was more feel in the front of the car especially at the breaking point of traction. It's why I find this car is harder to push to its limits compared to other vehicles I have driven that are easier to feel what's going on. IMO steering is definitely good enough for me though, and doesn't take away from my enjoyment of my car.

I hear ya! I just made the move from a 15 M235i to an 18 M240i and wow is the steering lost...what a shame.