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I hear "Run Flats" are bad... can I get a little more information.

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TOBASH

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Supporting Member
God blesses NYC with both 4 seasons, and with a road repair crew comparable to the Keystone Cops. Water here gets hard in the Winters, and roads take a beating. Then the city government refuses to hire additional road crews until March.

For these reasons I have decided to go with aftermarket rims and tires in order to prevent destruction of the Tesla rims.

Without a spare I would prefer to not play Russian Roulette every time I go out, especially as I'm an Orthopaedic Surgeon so I can't afford to get a flat and delay my trip when I'm called into the hospital.

My other car just got 2 tires pierced 2 weeks ago and again one a year ago, so I'm no stranger to flat tires. That car is a truck with a custom rear bumper mounted spare with the stock spare under the car, for a total of 2 spares. Both get regular work outs.

As far as the roadster and its ZERO spares... I just would prefer not to take a chance.

Run Flats seem logical.

That was until I heard run flats kill mileage and affect performance, but I don't get it.

Hard sidewalls should handle better, no?

Are these tires so much heavier than stock that acceleration and rolling weight will be affected so severely as to kill my car's range?

Please educate me, and thanks in advance.

T
 
Re: tires:
- The stock tires are optimized for low rolling resistance in the going-forward direction, yes.

- For weight reasons, the roadster decides to not carry a spare and rely on the compressed-air-and-goo-canister in the trunk to re-inflate a bit and fill small punctures well enough to limp you to your destination.

- People here who have replaced their rear tires have had grip difficulties during those more-often-occuring-than-you'd-report-to-your-insurance-company gleeful acceleration moments, and some have even had traction control kick in during heavy regen braking. I cannot summarize further, unfortunately, as I confess to not having read the entire 56-page(!) discussion thread on this exact topic ( 2.0 / 2.5 Roadster / Roadster Sport Tire Thread ), and I live in a place with only one season and easy tire requirements.


Re: rim and tire weight:
- Usually devolves into discussions about unsprung weight and its aid in acceleration. ( Unsprung mass - Wikipedia, the free encyclopedia )
 
Tobash,

I'm a Roadster owner also and an Ophthalmologist (Retina specialist). So far I have got stranded or needed to use the goo.

Also have Tesla roadside assistance and my Insurance towing policy.

But to answer your question about "run flats' being bad....they aren't

I would say
Cons:
Heavy
stiff sidewalls will increase the stiffness and harshness of the ride
more expensive

Pros:
don't have to worry about flats.

I had runflats on my GT-R and they definitely saved me one day. But I found tires that gave me more performance then them. Also, with a non-runflat sidewall the ride is more comfortable. With that being said, Dunlop came out with a new tire that is OEM but made for the Nurnberg edition of the Nismo GT-R that has incredible grip and 100 wear rating! I might have to try them next.

So I would say, I really wouldn't worry about it but if you are you can try to hunt down a set of runflats, BUT I don't even think they make them in our size, honestly.
 
I have historically had run flats on my prior Lexus SC. I liken them to the restaurant where not only is the food bad but the portions are small too. The choice of tires is very limited as to tread pattern, ride comfort, etc, the ride is hard, they are expensive, and tire shops hate to install them (stiff--hard to get onto the rim). Other than that---great.

BTW, I'm a doc too, with colleagues who have Porsches and BMWs without spares OR run flats. Sometimes you're gonna be late to the OR...
 
It was noted in another thread that there's another disadvantage to run-flats, especially on the 21" rims. The stiffer sidewall transfers more force to the rim, and increases the chance of bending the rim when you hit a pothole. The result is a flat tire on a run-flat when you may not have had one at all on a normal tire.
 
My last car came with run flat tires that I could not get rid of soon enough. The ride quality was very bad which I could have lived with if the handling was good, but it was not. As a parting shot, the tire shop damaged one of the wheels enough that it had to be replaced (and refused to remove the others, but did pay to replace the wheel) while trying to removing the run flat tires. They said the combination of low profile tires and run flats was too much for their (probably old) equipment.

I'll stick with regular performance tires and the goo. I also carry a small plug type tire repair kit.
 
If you want to see a lot of real-world debate on run-flats, check out some BMW forums. It seems BMW went almost exclusively to run-flats in recent years, removing the spare to save weight and meet efficiency standards. For some reason my used 760Li had run-flats when I bought it, despite also having a full-size spare. I swapped to a better tire immediately and it was a huge difference in road noise.
 
I had Conti DWS run flats on my BMW 335d. I thought they were decent tires, I wouldn't hesitate to install them on another car.
I think you're mistaken. I don't believe the DWS is available in a run-flat. I opted for the DW's, and they were a great tire. Keep in mind that any mileage warranty will be void (or cut in half) since you can't rotate the tires. That was the difference between DW and DWS for me, and, since the DWS warranty was worthless, I went with the DW's.