3 ms·

The timeline of this development exceeds the timeline of my own experiences since the 90's. I've always driven cars with rack and pinion steering while wheels

by yason 4y ago

The timeline of this development exceeds the timeline of my own experiences since the 90's. I've always driven cars with rack and pinion steering while wheels went from something like a typical 185-65x15 to 245-40x18. So, wheels are larger and the profile is much smaller (more rim and less rubber between the car and the road). Higher power warrants bigger brakes and bigger brakes warrants larger rims but for the average car rims have grown way oversized. Many cars have the space to take rims that are 2-3 inches smaller than what comes as standard. My anecdotal and average empirical results is that cars with wide rims and little rubber mostly seem to reduce comfort, increase noise, and make the steering very susceptible to unevenness, slopes and grooves of roads and layers of snow and ice and thus requiring constant steering response from the driver. I've had both kinds and the difference is huge, and exaggerated by bad road conditions that we find on our roads. On my older vehicles with a higher and narrower tyre profile I barely have to steer at all but just keep my hand relaxed on the wheel while the car ploughs pretty much through whatever in a direct line. Of course, I keep the wheel geometry of all my cars well-aligned so they shouldn't wander around.

lloeki 4y ago
My car is on 225/40/18, has no floating behaviour, and just the right amount of feedback still to feel what happens on the front wheels, whether it's wheel placement, movement, gripping/slipping... It's an absolute joy to drive, whether on long journeys or spiritedly. > just keep my hand relaxed on the wheel while the car ploughs pretty much through whatever in a direct line I would avoid small potholes still but that's basically my feeling on that car. I did slightly bend a rim once when running through a pothole I did not see, and the car ploughed through as described. I recall reading an article a couple of months ago about steering, feedback, and suspension geometry design. It rang very true to my subjective experience that many car suspensions are designed for "comfort" (vs "sporty"), which results in a lack of relevant direct feedback, which makes the car uneven and floaty, like you're somehow disconnected from the road, and still suffer from bumpiness as you have to rely on indirect cues to compensate, which makes for increased latency and overcorrection. I wish I could find this article again, IIRC it all comes down to one angle/offset, which you can't really fix by tuning geometry because it's basically baked in the suspension design. EDIT: it's related to that one[0], but was more detailed regarding that part: > To make matters worse, the suspension geometry often further compromises steering feel in favor of things like putting less load into tie-rods [0]: https://arstechnica.com/cars/2022/01/new-cars-have-lost-their-steering-feel-heres-why-that-matters/ https://arstechnica.com/cars/2022/01/new-cars-have-lost-thei...
throwaway0a5e 4y ago
It's the wide tire contact patch and not the big rims that are causing most of the problems you describe. This is typically papered over with tons of steering assist and geometry that favors minimal feedback in order to alleviate the propensity of wide tires to be greatly impacted by changes in road shape. This steering solution feels numb and disconnected from the road which is a common complaint with modern cars. The wide tires that are at the root of the problem are a key element of modern car performance so they're not going anywhere. Additionally, if you move the wheel surface far enough from the center of the tire you can get more room for wheel bearing and axle shaft hardware without increasing the size of the wheel bolt circle and bore though this isn't a big consideration in a lot of applications as there is ample space either way.

by yason 4y ago

lloeki 4y ago

My car is on 225/40/18, has no floating behaviour, and just the right amount of feedback still to feel what happens on the front wheels, whether it's wheel placement, movement, gripping/slipping... It's an absolute joy to drive, whether on long journeys or spiritedly. > just keep my hand relaxed on the wheel while the car ploughs pretty much through whatever in a direct line I would avoid small potholes still but that's basically my feeling on that car. I did slightly bend a rim once when running through a pothole I did not see, and the car ploughed through as described. I recall reading an article a couple of months ago about steering, feedback, and suspension geometry design. It rang very true to my subjective experience that many car suspensions are designed for "comfort" (vs "sporty"), which results in a lack of relevant direct feedback, which makes the car uneven and floaty, like you're somehow disconnected from the road, and still suffer from bumpiness as you have to rely on indirect cues to compensate, which makes for increased latency and overcorrection. I wish I could find this article again, IIRC it all comes down to one angle/offset, which you can't really fix by tuning geometry because it's basically baked in the suspension design. EDIT: it's related to that one[0], but was more detailed regarding that part: > To make matters worse, the suspension geometry often further compromises steering feel in favor of things like putting less load into tie-rods [0]: https://arstechnica.com/cars/2022/01/new-cars-have-lost-their-steering-feel-heres-why-that-matters/ https://arstechnica.com/cars/2022/01/new-cars-have-lost-thei...

throwaway0a5e 4y ago

It's the wide tire contact patch and not the big rims that are causing most of the problems you describe. This is typically papered over with tons of steering assist and geometry that favors minimal feedback in order to alleviate the propensity of wide tires to be greatly impacted by changes in road shape. This steering solution feels numb and disconnected from the road which is a common complaint with modern cars. The wide tires that are at the root of the problem are a key element of modern car performance so they're not going anywhere. Additionally, if you move the wheel surface far enough from the center of the tire you can get more room for wheel bearing and axle shaft hardware without increasing the size of the wheel bolt circle and bore though this isn't a big consideration in a lot of applications as there is ample space either way.