Sounds like I was listening to Professor Brian Cox 😁

@ReviveMyRide

4 ай бұрын

I'll take that! lol! My wife has a "weird crush" on him, so brownie points for me 👍

Good info . Thx!

@ReviveMyRide

3 ай бұрын

Cheers!

Sidewall collapse is the culprit, which Manufacturers should highly put this on their top list of things to improve or innovate …reinforcing the sidewall without sacrificing stiffness and performance and also may be look into other compounds that can improve the sidewalls of tires, as mentioned wheels got bigger and tires side walls got thinner.

Wondering if you have any insight into the following tire problem I'm having. My 2012 BMW 650 xi has run flat tires with a staggered setup, 245/35/20 on the front and 275/35/20 on the rear. I wanted to move off the run flats and start using non run flats. As soon as the non run flat tires were installed, I noticed that the rubber was slipping on the rim. I was able to feel this happening when accelerating as if felt like the tires were skipping. In order to determine that this was in fact happening, I marked the tire at the point were the air valve stem pointed, drove the car and replicated the skipping sensation. Sure enough when i compared the mark on the tire from it's starting point, I could see that the rubber had slipped on the rim. The tire shop then ordered a different brand of tire and after installing them I experienced the same slipping. We tried 4 sets of tires, all of which were premium brands with the exact load index/speed rating as the OEM Dunlop Sport MAXX Run Flats. It seems that no matter what tire we tried the only way to prevent the slipping was to use the run flats. Same exact scenario occurred when trying to move off winter run flats. Had to keep the Pirelli Sotto Zero winter run flats to avoid slipping. A mechanic friend seems to believe that the soapy solution the tire shop used when mounting the tire was to blame. He believes the soapy solution was not drying properly and causing the rubber to slip on the rim. I don't believe that to be the case since the run flats were put back on using the same soapy solution and there was no slipping. A bystander in the tire shop observed all this going on and said that because my vehicle is heavy and has a lot of torque when accelerating, the tires need a very strong sidewall to keep them from 'squishing' when under accelerating down force is present, and the only way to achieve that with this car is with run flats. The theory is sound, but all the non run flats that we tried met or exceed the load and speed index specs. So again, not sure what to think. I've even stopped a few drivers on the road with the same car running non run flats and asked them if they'd had any slipping issues. So far none have confirmed my issue. It could be that its actually happening but they don't notice it?? Do you have any thoughts on what may be causing my issue? Oh, and I actually have a rear rim in for a crack repair. That's how i came across your video. Also, I spoke with 3 BMW dealerships about this issue and they had no explanation. They just said to keep using the run flats and come see them when a tire's sidewall bubbled as a result of hitting a pothole. 🙂

@ReviveMyRide

Ай бұрын

Thank you for the really interesting comment above! I was really intrigued because like you, I also don't really like run flats (for lots of various reasons) and I thought all you have to do is swap them out for similar sized non run flats. Looking online, lots of BMW owners doing it and I couldn't for the life of me find someone that has had similar problems as you. I don't doubt you by the way because from your write up, I can see that you have been very thorough in your investigation. Just to comment a little, I agree that the run flats will grip the wheel much harder due to how stiff the tyres are, you only have to watch a tyre fitter trying to get the tyres on and off to see this but not long ago we didn't have run flats and we still had powerful cars. I'm sure the soap isn't helping but you wouldn't think it would be the defining factor. Oh yeah, just remembered that instead of soap, some tyre fitters will put a rubber sealant around the edge of the wheel rim, this helps with old alloys that have become a bit distorted and leaky but it should also make the wheel grip the tyre better. If you can face it, just a suggestion, go for tyres fitting again, clean the rim super well, apply the rubber sealant instead of soap and fingers crossed, once it has flashed off you might be lucky and it solves your problem! If you decide to pursue it, would love to hear how you get on! Cheers, Phil

Great video. I have suffered my first cracked rim (245/35/20 - Front) on my E43 AMG this week which I had welded up. I think the issue goes a lot deeper than just RFTs being the culprit, my previous 435i had 19" with RFTs and never suffered a crack in 9 years of ownership. The E43 has Goodyear MOE (Mercedes Original Extended) Run on Flats which are a non ISO approved RFT version for Mercs which are softer, and by virtue of that are supposed to provide a smoother ride with some limited run flat capability. Think of it as an XXL version of an XL tyre, and indeed softer than standard RFTs as the welder commented it was a lot easier to break the bead on compared to a standard RFT. For context, it's a new tyre which had only covered 30 miles and I suspect the big tyre company (who shall remain nameless) are actually the ones who cracked the rim. I don't think running out and ditching the RFT tyres for standard versions is the silver bullet to solve the issue, it's actually the traffic calming measures and general state of our roads which require a lot more cautionary driving habits. In short, never straddle cushion speed bumps and drive slower on badly maintained roads - it's a difficult discipline at times. And of course avoid tyre companies who really don't give a toss about babying your rims when changing the rubber.