Don't have a Tesla yet but tyre blow outs at motorway speeds are not fun. Have had two blow outs over the years, both at motorway speeds, once when was stuck in between two 18 wheeler trucks and that was not fun as they couldn't be bothered and were blocking me from pulling into the side. I would err on the side of which ever tyre has less chance of blow out at highway speeds. It's not fun handling a car at highway speeds with a blow out in my experience. Just my 2p
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Ludicrous with 19s: dumb? or negligible difference?
- Thread starter disillusioned
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HankLloydRight
No Roads
I don't recall anyone reporting a blowout at highway speeds for any size wheel/tire combo. Sure, it can happen, but it's pretty rare, and in most cases, it's because there was a road hazard, the tire had a hidden defect, was past its usable life and shouldn't have been driven on. If 21" wheels had a propensity to have blow outs, I'm sure Tesla wouldn't be selling them on most of their cars. Tesla found one loose bolt on one seat belt in Europe and is recalling the entire fleet.
Once it was a nail in the rear tyre and could safely pull over on the motorway. The other time it was again the rear tyre at max motorway speed and vehicle jolted and had to grab the wheel harder to keep it in lane and could see pieces of tyre flying off in my side view mirror. Took longer to get to the hard shoulder as the 18 wheeler took its time giving way to me to pull over, the 18 wheeler behind him didnt give way either and he certainly would have seen the pieces of my tyre flying all over. By the time i pulled over I was on my rims nearly with only a few bits of rubber left on the rim. I was surprised i got away without injury. And no the tyre and vehicle was in mint condition (like all my cars, apart from any debris dropped on the carpet by my child), always main dealer serviced with all tyres replaced long before legally need to be replaced, alignments etc done regularly and safety checks done at main dealer before any long travel, winter etc etc, even replace parts that dealer themselves say can probably replace in the future. So maintenence wouldnt have been an issue. I have no clue how common blow outs are at high speed, may be it was just luck but it wasnt a pleasant experience and have been driving a few decades. May be my fault was that i would almost always buy the more expensive tyres meant for the car from the main dealers and maybe they were tyres with higher performance but more chance of blowouts. Lesson learnt now i read reviews and dont just go by whats recommended by manufacturer / authorised dealer
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HankLloydRight
No Roads
I had a very similar story in my '05 MB SLK350 I had just bought. I knew it needed a new RF tire, but it was nowhere near the limit, just more worn than the other tires. I was on the highway, top down, with two small dogs in a crate on the front seat (crate was belted in). But still, when I had that tire blow out, I was also in the left lane right next to an 18-wheeler. Had to maneuver to the shoulder, and hoping not to hit an edge and flip the car with the top down. Anyway, we all survived.
I don't think that's the case, if anything, higher performance tires (under normal circumstances) I think would be less likely to blow out. I think the problem here started with this comment:
I still assert that blow outs on 21" wheels/tires are no more likely than 19" wheels/tires as a result of the size of the wheel (21" or 19"). Yes, if you hit a huge pothole which causes rim damage on 21" rims, then the chance of a blow out increases, and the change of damage from the same pothole to 19" rims is less. So in that one specific instance, yes, 21" rims might lead to a blow out, but that is entirely dependent on the road hazard. Again, under normal driving conditions, no road hazards, no tire or rim defects, the random chance of a 21" tire blowing out is no different than a 19" tire... and of course, that itself is highly dependent on the TIRE itself, regardless of size. I'm sure I could find plenty of 19" tires that are more susceptible to blow outs than 21" tires. So to just make a blanket statement like:
Is really disingenuous and implies that by just by being 21" wheels/tires, they are going to lead to more blowouts.
And curb rash is entirely avoidable if you just pay attention when parking.
Well, the 21" inch wheels combined with the lower profile tires and the reduced sidewall height means that there is much less cushioning than with the 19" wheels and tires. A bit low on pressure plus a pothole has a far greater chance of tire and/or wheel damage than the same conditions with 19".
I think there may be a difference in what is meant by "blowout" between the U.S. and the U.K. In the U.S. it means a sudden rapid deflation--typically a nail doesn't cause that.
Oops I didn't realise a blowout meant rapid deflation in the USA. I meant literal blowout of the tyre where pieces of the tyre are flying off the rims!
HankLloydRight
No Roads
It means both. How else would a "rapid deflation" happen if not for a tire defect or a road hazard?
jerry33 said:
Yeah, that's exactly what I said.
What's funny is that GT race cars tend to use smaller wheels than their street counterparts.
For example the Corvette Stingray with Z51 used 19" wheels but the C7-R uses 18".
The Tesla 19" wheels don't handle as well because they are all-seasons, not because they are 19".
CarlK
Active Member
If you drive a Porsche or BMW, especially top performance models from those brands, you will have no choice but to use low low profile tires. If you drive a Lexus or Honda you will have no choice, unless you go aftermarket, to use tires with tall side wall. That should pretty much answers the question about connection between type of tire and car performance. You certainly could use any tires with top performance cars but people who buy those kind of cars usually want whatever additional edge they could get.
Some people mistaken that low profile tires are just for looks. Yes they do look nice but that's just a case of form follows founction. They look cool only because people saw them used on Ferraris, Porsches and other supercars. There is a reason those cars that need to squeeze every second off at the Nürburgring use those kind of tires. Beleive me if every supercar uses tiny wheels (because they are better for what they do) than tiny wheel will be the one that looks cool.
With that said there is nothing wrong of using 19" if you are willing to give up some handling edge and cooler look for a better ride and lower cost although again the former rather than the later is what most people who buy a high performance car are lookin for.
My 2c on tire blow out I totally agree with HankLloydRight. A nail pucture, which has the same probability to happen to a 19" as well as a 21", would not cause tire blow out or thread separation unless you continue to drive after air leaked out. That is almost impossible to happen with car equiped with TPM. Or in rare cases it will happen with defects in the tire but again 19" or 21" would make no difference. So that worry is really unwarranted.
Some people mistaken that low profile tires are just for looks. Yes they do look nice but that's just a case of form follows founction. They look cool only because people saw them used on Ferraris, Porsches and other supercars. There is a reason those cars that need to squeeze every second off at the Nürburgring use those kind of tires. Beleive me if every supercar uses tiny wheels (because they are better for what they do) than tiny wheel will be the one that looks cool.
With that said there is nothing wrong of using 19" if you are willing to give up some handling edge and cooler look for a better ride and lower cost although again the former rather than the later is what most people who buy a high performance car are lookin for.
My 2c on tire blow out I totally agree with HankLloydRight. A nail pucture, which has the same probability to happen to a 19" as well as a 21", would not cause tire blow out or thread separation unless you continue to drive after air leaked out. That is almost impossible to happen with car equiped with TPM. Or in rare cases it will happen with defects in the tire but again 19" or 21" would make no difference. So that worry is really unwarranted.
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Uhmmm, 21's only get curb rashes cuz people.....wait for it......HIT CURBS!!! If drivers would just not hit curbs with their cars, they wouldn't get curb rashes!! Has nothing to do with 21's or 19's!!
CarlK
Active Member
19" have *stronger* off the line acceleration than 21".
Considering only dimensions, the improvement of 19" is about 0,3% or 0.01s better 0-60 time.
Also (stock) 19" wheels are also lighter than (stock) 21", so there is even bigger difference.
Why 21 than? Better looks, better cornering and steering response because of less sidewall height (from 4,3" down to 3,4").
The best off-the-line performance is achieved with lightest possible 19" wheels and tires.
I would recommend getting the base 19's and with the money you save go aftermarket. My TSW 20" Bathurst wheels weigh 8lbs per wheel lighter than the 19's and 12lbs per wheel lighter than the OEM 21's. That's 48 pounds of less unsprung weight!!! It's crazy how heavy the factory wheels are. If you want improved performance, aftermarket is the way to go. Also the 20's are the best blend of looks, handling, and ride of the three sizes.
CarlK
Active Member
I concur. And go 265 if not wider on the rear while at it. That said you don't need to worry about tires if you never want to try things like making fast maneuver or test the limit at mountain road or freeway ramp but you will appreciate the better tires even if you want to do it just once.
That could be a misconception. Drag tires have tall side wall but that's only because they would flex more and resists skid which is the biggest killer of drag race. With the "D" skid is not that much an issue not to mention the 21" uses more grippy compound. I don't think 19" could out drag the 21" if not the other way around.
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Tall sidewalls on drag cars allow a greater contact area when run at the very low pressures used in drag racing.
Long and narrow gives more forward and braking traction than short and wide if the tires are equal otherwise.
Since no one seems to have mentioned it yet, sidewall stiffness/play vary widely by tire. So even if the car feels slightly squishy on model y tire, it may be much tighter on model z tire. Additionally, comparing the Tesla provided all-season tires on 19" to the performance summer tires on the 21" is adding the weaker sidewalls of the all-season into the comparison, which is not fair. Slightly stretching the tire will also enhance stiffness, this also has to be taken into account when comparing two different wheel setups. You can tell visually that the 19" setup has slightly narrower rims for the given tire width, which further skews the comparison. It's perfectly possible to get 45 ratio tires to have tight responsive handling.
Sidewall height alone has nothing to do with it. 245/35R21 have a bit bigger diameter than 245/45R19, so they also have a bit bigger radius. Bigger radius and same torque results in smaller accelerating force.
You are going to need some really sensitive equipment to measure any difference in accelerating force between 751 and 757 RPM (It's the RPM of the tire that sets the gear ratio). What the increased sidewall height will do is allow a lower tire pressure on the dragstrip resulting in a larger contact patch area and additional traction. Of course, the tires might not last very long at that kind of reduced pressure
Reduced tire pressure further reduces effective radius and thus increases acceleration force.
bigger contact patch enables 'translation' of that force into acceleration instead of wheelspin.
bigger contact patch enables 'translation' of that force into acceleration instead of wheelspin.
