Cause of two flat tyres at rear

Russinating · 29 Oct 2023 at 10:11

Had all 4 tyres replaced a few weeks ago, have done about 1,700 miles since (we did the NC500!). Traveled to see some friends an hour away yesterday, all fine, drove to a Chinese takeaway (30 min round-trip). No issues just quite a bit of flood water down country lanes. Went to head home this morning and we've got two flats at the back. Checked the tyre pressure and the last update (Tesla Model 3) was 14 hours ago (so 7/8pm yesterday) and they show as 32-35 rather than 42 like the fronts, so they weren't completely flat a few hours after I drove last.

Driver's side has a very visible large gash on the side wall. Can't see anything on the passengers side. Photos below.

Seems so odd to get two flats, and both at the back (ie opposite sides). Their village is safe and we were parked on their driveway, just wondering if something else happened whilst collecting the Chinese or popping to the shop. What does the gash look like to you guys? I'm a total novice here - never even had a flat!

Russinating · 29 Oct 2023 at 10:34

Nemiyen said:
That looks like some toe rag nobba has stuck a knife in the sidewall of the tyres. If you'd done that while driving I'd expect it to have scrape marks or be horizontal, as apposed to vertical. Although it does look like some scrape marks exist, maybe you hit the edge of a sharp pavement. Did you turn around and drive the same way back and hit the other side in the same place?!

Edit: Do your friends really like you?

Was pretty much entirely Somerset country lanes on all the journeys we did, so no curbs just big puddles with the rain. I've also lost the front drivers side aero hub cover...

The first time the car shows an air pressure alert in the notification history is at 19:47 and we got back at 19:52.

Russinating · 29 Oct 2023 at 10:35

Bug One said:
That is very unusual damage to not have been intentionally knifed.

I suspect you'll find another similarly sized gash somewhere on the other tyre.

Did sentry mode catch anything?

No, don't have sentry mode on unless charging at home.

Russinating · 29 Oct 2023 at 11:11

Car is almost 4 years old, the alloy damage is well old/over time.

Didn't feel anything at all on the drives and also didn't come back the same way. Did the drives with the friend we're staying with and he didn't notice anything either.

I use Teslamate but can only access it locally but will be interesting to see if it tracks tyre pressure frequently, might be able to see exactly where they first dropped.

Anyway, currently awaiting a tow and ordered two new tyres for fitting on Weds. Another £400 in 3 weeks!

Russinating · 29 Oct 2023 at 11:29

Hades said:
To me those tyres look like they have been driven on while at low pressure. So the problem might have started before you parked.

Jesus, 400 for two tyres.

I mean that would make more sense. It's highly unlikely they would have got slashed on my friends drive (tiny village, set back from the road, etc). If it was malicious it's more likely when I was parked at the shop or Chinese.

Also not saying it is at all, I have no idea, just seems so odd for both back ones to go after such a short, uneventful drive.

Russinating · 29 Oct 2023 at 12:13

Finglonga said:
Silly question probably but they are EV tyres they fitted as they are designed to handle the extra timber the EV has.

Yeah, they're the same as the ones fitted as new; Michelin Pilot Sport 4 Acoustic (Tesla (T0)) 235/45 R18 Y (98).

Russinating · 29 Oct 2023 at 15:15

sigma said:
If the tyres are not that old then could it be a manufacturing defect? Worth asking.

Yeah it was a thought but not sure. They were brand new 3 weeks ago. I've got another 2 coming for a mobile fitting on Weds and I'll ask the fitter what he thinks.

The front 2 were also replaced at the same time so...

Russinating · 29 Oct 2023 at 18:36

Bug One said:
Have you checked the other tyre all over? Might not be in the sidewall.

No, not yet. Will take a look when it's removed.

Russinating · 29 Oct 2023 at 21:29

bazzastan said:
Problem here is if it has been done intentionally getting new rubber fitted so quick they may come back.

We live over an hour away from where it happened (whatever it was).

Russinating · 30 Oct 2023 at 23:29

Vanquish-Storm said:
Something to consider when you are out and about though I guess. Not sure why I just didn't think it would use much but it makes sense that it would do.

It uses a fair amount and it's a turn on/off rather than anything more intelligent than that. We park on street at home and the headlights come on when activated which is a) annoying for us and neighbours b) attracts more attention of passers by and c) would go off every 5-10 minutes before midnight where we live, if not more frequent.

And if something happens then what? You have to watch 50 activation clips to find some barely identifiable teenager.

I only ever turn it on when charging in a weird place like a dodgy multistorey carpark, mainly for the notifications. Oh and dog mode

.

Russinating · 4 Nov 2023 at 14:03

Well, it just gets more confusing. Guy from ATS came to fit the tyres (via Blackcircle) and he started on the driver's side. He said 100% a knife, no hesitation. We then took the passenger side off and it's a small puncture on the tread. Almost 100% not a knife. He was just like "coincidence?". Who knows!