Slow puncture/leaking valve/just needs pumped up

hairyslug

The bike has been in the shed for the past 2 weeks or so. Hopped on it today and noticed that the rear was slightly deflated, only when I sit on it is it noticeable. As it hasn't been on the road in quite a while, would it not have deflated more.

Del2005

Depends on how big the hole is. After pumping to the correct pressure cover the wheel in soapy water to see if you can find the leak. If it is not obvious you can just pump before you go out.

CJhaughey

Tighten the valve in the valve stem as well. It could be loose.

Wonda-Boy

If the bike is sitting on concrete even with no puncture air escapes from tyres......do all the above but if it lasted 2 weeks and is not totally flat I doubt its a puncture.

LLewellen Farquarson

Is it a tubed or tubeless tyre. Tubed will deflate immediately if punctured. Tubeless will lose air gradually (hence are safer if punctured when riding), provided whatever punctured the tyre is still in it. Also tubeless can lose air from the seal between the tyre and the wheel.

Also, how much are we talking about, a few psi over two weeks, or half the air in the tyre?

hairyslug

The tyre is tubeless, it's stuck in the shed until tomorrow atleast so can't bring it down to the pump.
I've attached 2 photos, it looks worse when looking down on it but it's definitely deflated somewhat, can't see any puncture or anything sticking out of it.

LLewellen Farquarson

Well, it's not flat anyway

What I would do is pump it up to the correct pressure, then monitor it and see what it is losing, if anything, over a few days.

Tyres lose pressure over time in any event. Also if you checked it two weeks ago, when the temperature was over 20 degrees, and you checked it again this weekend, when the temperature was more like 15 degrees, you will get different readings.

As Del2005 suggests, mix up a bottle of water with a small bit of washing up liquid in it, and wet the tyre, valve, and tyre rim. Watch carefully for bubbles which will show any air leaks.

And you asked in your first post if it would have deflated more? Not necessarily. My tires don't lose that much, even over a month.

And that, boys and girls, is why you check your tyre pressure before you go out for a ride, especially if the bike/car hasn't been used for a while.

hairyslug

Thanks, got a new shed a few weeks back, used a few planks of wood to run the bike into the shed (it's about 7in off the ground), skip arrives a few days later and those pieces of wood got dumped as I was going to get myself a fancy new ramp, ramp got lost in the post, waiting on new ramp, so once I get it out of the shed I'll get it sorted

hairyslug

Went down to the petrol station today, sweet mother of god €1 for 5 minutes if air with a piss poor pump. Hooked it up, it showed 12psi, I don't trust this though as surely, if it's ment to be 42 and it's 12 then it'll be nearly flat.
Pumped it up, took it for a 10k spin, bought a pressure gauge and it read 39.5, another 5k home and it still read 39.5.

CJhaughey

Tyres are stiff and may not look like they are flat even if they have very little pressure.
This is what you need, http://www.halfords.ie/workshop-tools/garage-equipment/tyre-inflators-pressure-gauges/michelin-analogue-single-barrel-footpump

LLewellen Farquarson

Yep, don't trust the gauges in petrol stations. Use the pressure gauge you bought, and get a foot pump, as Mr Haughey linked. I have an aldi/lidl one which does fine.

If the tyre maintained pressure after a 5k run, then I'd say it just lost pressure while standing. Just monitor it over the next week or so, especially before you go for a spin.

Hotblack Desiato

You'll be a long time pumping up a near-flat rear tyre with a foot pump.

Your bike has a nice source of 12V power available so why not get something that does the hard work for you.

Is there any sealant in the tyre? If the bike is left sitting and there is a small hole in the tyre near the top, the sealant can run back out of the hole and let the air out. If the bike is ridden often enough to keep the sealant moving around inside the tyre it's less likely to happen.

Del2005

hairyslug wrote: »

Went down to the petrol station today, sweet mother of god €1 for 5 minutes if air with a piss poor pump. Hooked it up, it showed 12psi, I don't trust this though as surely, if it's ment to be 42 and it's 12 then it'll be nearly flat.
Pumped it up, took it for a 10k spin, bought a pressure gauge and it read 39.5, another 5k home and it still read 39.5.

What pressure did you put in from the garage and how close was it to the gauge you bought?

Don't bother with a single barrel foot pump. You can get a 12V pump for not much more than the pump linked earlier.

hairyslug

Del2005 wrote: »

What pressure did you put in from the garage and how close was it to the gauge you bought?

Don't bother with a single barrel foot pump. You can get a 12V pump for not much more than the pump linked earlier.

I brought it up to what the pump said was 42, was about 8k till I measured it next and then another 7k till I measured again.