Lawnmower tyre keeps deflating even after replacing

[MisterBoy]

I have an old countax ride on mower (c300 I think). The rear left tyre was constantly deflating so we had it replaced brand new...
But now it still leaks... Over a week or goes totally flat which can't be good for it.

Is it more likely I got another puncture or that the wheel has an issue and how do I tell/fix? I would rather learn how to maintain it myself in future where possible, want to coax a few more years out before replacing (it is likely 20yrs old)

 

[Mottie]

But now it still leaks...

Is it tubed or tubeless?

 

[Burnerman]

It’s a good idea to fill any tractor tyres with a sealing mousse.......your problem will be where the tyre meets the steel rim.
The mousse sealant prevents any problems here and also protects the tyre from thorns or whatever in the future.
John

 

[Mike13]

chances are that there is a thorn in the old outer tyre that has put a fresh puncture in the new one. You need to take them both off, clean them both in the sink and feel for any thorns that might have been missed the first time. Quick patch on the new inner and it should last.

 

[Mottie]

If tubed, they should have fitted a new tube as well. If tubeless, take the wheel off, lay it on the floor and soak it with some water with a little fairy liquid. Ignore bubbles that come naturally when you pour it on. Wait for up to 10 mins and what you are looking for is a definite patch of froth. Turn it over and repeat. If it’s not the tyre punctured, it will be corrosion on the rim where the tyre bead seats against it. Tyre needs coming off, rim needs wire brushing and some bead sealer (a type of liquid rubber solution) painted on. If tubeless, they should have fitted a new tubeless valve too as they go hard with time and leak where they are pulled through the rim.

 

[Burnerman]

Take a tip?
Keep the tyres tubeless as they were intended to be......inner tubes here are a pain and will always give problems. Injecting a tyre mousse (sometimes called 'Slime') will keep you trouble free for ages.
I wouldn't recommend you change the tyres yourself - the small rim makes them very awkward to do and dead easy to split.
Keep the tyres at around 22psi, unless the manual says different.......a deflated tyre, although not always so obvious has a huge effect on the cutting height.
John

 

[MisterBoy]

Thanks all. My understanding was they're tubeless but I'm not certain - certainly if it is tubed they replaced that too. Sorry if it's a silly question but how can I tell? It might be the 4 wheels are not all the same setup, wouldn't be surprised.

I've used 'slime' on my bike once, is that the same sort of stuff people mean here? It lines the inside and self-seals small punctures, not the same as pumping the tyre full of foam right (I saw someone recommending that so it cannot deflate)?

I have found pressures a bit odd too. On the tyres I can still read the markings, they all call for quite low values ~20psi but at least according to the gauge on my pump, I have to go closer to 40 to get them looking and feeling right.

 

[Burnerman]

Look at the valve......a tubed valve disappears into the valve hole, whilst a tubeless one is pushed through from the inside and sort of flares over the hole, creating a seal.
The slime is the same as you use on your bike......its pumped into the tyre, distributed by spinning the wheel and plugs any holes that occur.
The pressures for the machine won't be marked on the tyre, but the maximum recommended pressure will be. Around 20 to 25 psi is usually correct, and don't forget the tyres give you some sort of suspension too, so you don't want them too hard.
Keep your tyres tubeless......you can plug them from the outside if the inevitable happens.
John

 

[MisterBoy]

Would slime help if the issue is a bad contact with the rim on a tubeless tyre, or the only option then to have the tyre removed to clean up the rim as @Mottie mentioned? I assume you cannot simply deflate the tyre fully and push it out of the way while you work

 

[Mottie]

Would slime help if the issue is a bad contact with the rim on a tubeless tyre,

I doubt it - it is best for sealing holes in the tyre and wouldn’t find its way up to the bead. First thing to do is what I said earlier - find out where the leak is first.

 

[Burnerman]

With these small wheels, breaking the bead (tyre contact with the rim) is easy enough......removing the tyre itself is much more difficult.
Break the bead, wire brush and emery cloth the rust away, apply some tyre sealant (or even washing up liquid may do) and pump the tyre back up.
John

 

[MisterBoy]

Great thanks. These all seem like things I can do.

If there _is_ a tube, slime will still work, right? I think ripping out the tube and replacing the valve is getting a bit beyond what I'm happy with, at least during the summer when I can't afford to have it out of action.

 

[Burnerman]

Slime is supposed to work with an inner tube, but as the tube is under considerable tension, and damage is likely to make it split further I think success is less likely.
You can of course, fit a new tube without removing the tyre - it's a bit of a squeeze but do make sure any thorn or whatever is removed first from the tyre carcass inside.
John

 

[MisterBoy]

Slime is supposed to work with an inner tube, but as the tube is under considerable tension, and damage is likely to make it split further I think success is less likely.
You can of course, fit a new tube without removing the tyre - it's a bit of a squeeze but do make sure any thorn or whatever is removed first from the tyre carcass inside.
John

If the tube has gone I'd rather remove it, that's easy except I don't know how to redo the valve.

 

[Mottie]

With these small wheels, breaking the bead (tyre contact with the rim) is easy enough......removing the tyre itself is much more difficult.
Break the bead, wire brush and emery cloth the rust away, apply some tyre sealant (or even washing up liquid may do) and pump the tyre back up.
John

So it’s you! Washing up liquid is THE worst thing to use on the bead of a tyre. Cheap secondhand tyre shops use it. Washing up liquid contains salt and that is the reason that beads on rims corrode. Proper tyre lube contains a corrosion inhibitor.