Sealant into partially inflated car tyre?

[mustang1]

My car needs 39psi in the tyres. One tyre has a slow puncture and is currently at 29psi.

Can I insert sealant into a partially inflated tyre, or does the tyre need to be almost flat before inserting the sealant?

Ps: I'm using the puncture repair kit/electric air pump/sealant bottle that came with the car.

 

[fossyant]

I think you'll need less pressure in it for the pump to push the sealant in it.

TBH if it's slow, aren't you best pumping up, taking to garage and getting fixed, as you'll likely write the tyre off sticking in the sealant (garages won't usually repair a tyre that's been gunked). Those tyre worms work well enough for a temporary repair if you've got some distance to get to a garage.

 

[Dadam]

If it's a slow puncture don't use the sealant, it usually means the tyre can't be repaired. There's a good chance they can repair a slow puncture unless it's in the sidewall.

 

[Ming the Merciless]

Must be a heavy SUV to need 39 psi

 

[mustang1]

Thanks @Dadam and @fossyant . The front tyres need replacing and the rear tyres are at about 4mm (the puncture is in one rear tyre, all 4 are runflats) so I was thinking of getting all 4 replaced soon. Yeah, maybe I'll just keep the rear inflated with a tyre pump and look at what to do in the new year.

 

[mustang1]

Must be a heavy SUV to need 39 psi

Pfft... yeah all cars are heavy these days... but yes, heavy SUV!

 

[Dadam]

A lot of sporty cars with lower profile tyres have higher stated pressures these days. Efficiency and runflat tyres might be a factor - the sidewalls are stiffer on runflats. My car (3 series BMW) states 38 (2.6 bar) on the rears.

 

[fossyant]

Do you know where the puncture is - e.g. screw ? If so, I'd be getting a worm kit, fixing it then getting the car booked in for 4 new tyres soon.

The worms do work really well, but you don't really want to be leaving a screw in the tyre.

 

[mustang1]

Do you know where the puncture is - e.g. screw ? If so, I'd be getting a worm kit, fixing it then getting the car booked in for 4 new tyres soon.

The worms do work really well, but you don't really want to be leaving a screw in the tyre.

Worm kit? What's that, like the one you get for tubeless MTB tyres of the hole is too big for the sealant to repair itself?

 

[fossyant]

Worm kit? What's that, like the one you get for tubeless MTB tyres of the hole is too big for the sealant to repair itself?

Exactly the same.

 

[Venod]

We had a very slow puncture in the Quashqai, I couldn't determine the cause, I let the tyre down and put some Stans in, it was still holding pressure when we sold it some time later.

 

[I like Skol]

Stop p1ssing about and get new tyres!!!! Jeez, your expensive, heavy SUV is going to kill someone. The tyre laws state a MINIMUM tread depth of 1.6mm and you are trying to waste money fixing a questionable tyre that has maybe little more than 2mm of useable tread remaining.... and it's winter. You have two tyres that need replacing, a tyre that is damaged and a tyre that is not far from end of life. If you can't afford to run your big heavy SUV safely then either sell it for something you can afford or park it up until you can afford to use it safely. Do us all a favour

 

[Dadam]

Oh come on, 4mm is plenty and I don’t know where you got 2mm from.
It’s one of the OP’s rears at 4mm that have the puncture.

 

[fossyant]

4mm is near the limit TBH, and with other dodgy tyres ? We replaced MrsF's Conti's early with 3-4mm in November for Michelin Cross Climate 2. So far, they are really good on crappy cold roads and quiet. Worked in the snow we had recently.

 

[Dadam]

Chucking tyres at 4mm is shockingly wasteful and terrible for the environment.