[albertw]

Long term readers of this forum might recall that I've been obsessed with the lack of on-centre feedback in my M240i. Previously I had dismissed the idea that tires could make a difference because other complaints about this issue were just about as likely with PS4S tires as with the Pirelli runflats on my car.

Tire Rack tire tests recently started commenting on steering feedback, both on-centre and during cornering loads, and they have reported appreciable differences among tires. Interestingly, neither the Michelin PS4S nor the AS4 rate well on this issue. This might explain why tires don't seem to make a difference to complaints, as few people here stray from Michelin.

I've done a bit of an experiment by accident. My rear runflat Pirellis wore out much sooner than the fronts and I wanted to try a go-flat all season replacement. My tire shop strongly recommended staying with the same brand when changing only two tires so I got Pirelli P-Zero AS Plus tires and had them put on the front. I noticed a small but definite reduction in the width of the centre dead zone, but no change in feedback at the cornering limit.

When the second set of runflats wore out I tried a pair of extreme performance summer tires. While PS4S were the obvious choice, I was changing only 2 tires so I had P-Zero PZ4 tires put on the front to see what effect they would have on steering. To my surprise they were much worse than the AS Plus tires, and even worse than the original runflats. The centre numb zone was wider and strangely the tires would follow minor grooves in the road without any information filtering up to the steering wheel to tell me that the car was turning.

I was so annoyed with the PZ4s wandering on the freeway that I garbaged them and went back to all seasons. However, the AS Plus had been discontinued and I had to get the new Pirelli replacement, the AS Plus 3. Sadly, these tires are noticeably worse than the AS Plus, and probably a bit worse than the runflats. Tire Rack recently posted a comparison test of all season performance tires and gave the AS Plus 3 a rather poor rating on steering feedback, which confirms my impression.

The one tire that Tire Rack rates highly for what they call "steering firmness" (resistance to turning the steering wheel, which is what gives feedback) is the new all season Bridgestone Potenza Sport AS. If I were sure I was keeping the M240i I would get a pair to see if they improve steering feedback appreciably. If anyone reading this far has these tires or plans to get them, please post a comment on changes in steering feedback.

After a test drive I've put a deposit on a CT4V Blackwing. The steering feedback on that car is magnificent! But it is not clear that 2025s will be produced and the very limited allocations to Canadian dealers mean I will have to wait about a year to get one if they are produced. If I can't get one I will keep the M240i as there is nothing else on the market that meets my needs. I'd love a Cayman but it won't work as my daily driver. If the Bridgestones magically solve the steering numbness I would cancel the order and keep the BMW, but I'm not ready to throw another $600 at an experiment that probably won't be successful enough.

[freakystyly]

Assuming the tire PSI and road surfaces are consistent throughout the experiment. That's good info. I haven't gone through a lot of tires but I definitely am enjoying the PS4S summers (even if their lifespan is a bit short, I feel they are worth the money).

I've done minimal research but more than a few people on the f30post side claim that monoball control arm bushings will help immensely with steering feedback and lessen the deadzone. Unfortunately they cost nearly 3x the price of a regular control arm which is why I'm on the fence with them. Of course, if you choose that route, don't expect life altering steering feedback.

I'm sure the CT4 BW would be a huge step up from these cars.

[Nickies]

OP, I don't think it was a good idea to mix run flat with non run flat tires because they are not the same design and construction. There is no surprise the car and steering have not the same balance.

If you want the ultimate performance, you have to replace the 4 tires at the same time.

[albertw]

On centre feedback has just about zero to do with the rear tires. The fact that you would raise this issue indicates that you don't understand what on centre feedback is. Your frequent posting of irrelevant platitudes has annoyed me enough over the years that I can't bring myself to ignore you (as I should) when you criticize my post.

[Nickies]

Originally Posted by albertw

On centre feedback has just about zero to do with the rear tires. The fact that you would raise this issue indicates that you don't understand what on centre feedback is. Your frequent posting of irrelevant platitudes has annoyed me enough over the years that I can't bring myself to ignore you (as I should) when you criticize my post.

You don't know what you are talking about or you don't want to understand. You have runflats at the back and conventional tires at the front. How can you believe you car can behave at its best if you have stiffer tires construction at the back and softer ones at the front?

If you are too cheap to buy a full set of tires when needed, this is your problem.

[cooolone2]

I had Bridgestone Portenza's on another vehicle and loved them... But alas, Potato or Potatoes... This discussion could be akin to talking about which OIL is best, lol.

[albertw]

Originally Posted by cooolone2

I had Bridgestone Portenza's on another vehicle and loved them... But alas, Potato or Potatoes... This discussion could be akin to talking about which OIL is best, lol.

It doesn't have to be. It is possible to be quite objective about the width of the centre numb spot. Simply turn the wheel a small distance, enough to start a very gentle turn, hold it there for a second, then let go of the wheel. If it stays where you left it instead of returning to centre, you are in the numb spot. When you move it far enough it will return all the way to centre. That is the end of the numb spot. Note that the crown of the road helps the return to centre so typically the numb spot will be narrower on the left side.

My numb spot on the original Pirelli runflats was about 3/4" to the left and 1" to the right. The various tires I experimented with varied that by 50% at most. For comparison, the dead spot on the Blackwing I drove was essentially zero - less than 1/8".

I appreciate that this may seem like a first world problem to some. However, I think it is a symptom of the nearly numb steering feedback at the cornering traction limit. I can feel the reduction in turning force required to hold the steering wheel in place as the front tires start to slide, but it is so weak that it takes a lot of concentration to detect it. I'm not an exceptional driver, so more definite steering feedback would allow that concentration to be better spent on the rear wheels.

Cornering traction feedback is a lot more subjective than the centre numb spot. Although it is the more important issue, I don't think there is much point in asking about it on a car forum since that likely would be more like an oil discussion.

[cooolone2]

You're talking about tire feel with run flats? Come on now, really?

I just changed my rubber, tires were 5 yrs old and put the PS4S on, now I'll need some more miles of course but can say that I never had much of a 'dead spot' I've read about and with the new PS4S's really don't feel it either. Maybe it's a suspension issue otherwise? Dull feel, slightly yes, as is well know. But dead spot response, not so much. Let ya know in a few thousand miles, lol.

Like I said, had Bridgestones, loved em', old generation Contact Supremes as well, those were great too but sidewalls were very thin, didn't hold up well. But again, that was way back, lol.

Again, I truly feel this general topic is as bad as discussing OIL. Because if I got in your car and drove it, I would feel what I feel... And we wouldn't drive the same either. So there's that.

Good Luck though in your search

[albertw]

Originally Posted by cooolone2

You're talking about tire feel with run flats? Come on now, really?

Three of the four tires for which I measured the width of the centre numb area were not runflats.

[cooolone2]

Ok, so which have you liked better by feel?

[albertw]

I discussed the width of the centre numb area in detail in my first post. My subjective impression is that the feedback from the steering while driving straight matched the width of the centre numb area. I rate this aspect of steering feedback, best to worst, as: AS Plus, the original runflats, AS Plus 3, PZ4 (all Pirelli).

The AS Plus and AS Plus 3 were supposed to be the same tire with some minor upgrades for the Plus 3, but in this regard they are very different tires.

I didn't see a lot of difference in steering feedback at the traction limit, but it is so weak in our cars that small changes would be difficult for me to spot. (I didn't get to test the PZ4 because the AS Plus on the rear lost traction before the PZ4 on the front started to slide.)

[MechEngineer]

Originally Posted by freakystyly

Assuming the tire PSI and road surfaces are consistent throughout the experiment. That's good info. I haven't gone through a lot of tires but I definitely am enjoying the PS4S summers (even if their lifespan is a bit short, I feel they are worth the money).

I've done minimal research but more than a few people on the f30post side claim that monoball control arm bushings will help immensely with steering feedback and lessen the deadzone. Unfortunately they cost nearly 3x the price of a regular control arm which is why I'm on the fence with them. Of course, if you choose that route, don't expect life altering steering feedback.

I'm sure the CT4 BW would be a huge step up from these cars.

I have the upper monoball control arms on my M235iX. It made a substantial difference, even in comfort mode. Most people only do the upper, I might do the lowers later in the year to see if that makes more of an improvement as well.