Riding on 5 PSI in Rear Tyre

Originally Posted by squirrel_hunter

Things like this can happen.

There is a vicious rumour that one particular rider thought his bike felt heavy as he went round a round about but assumed it was due to the front tyre that needed replacing. So the rider proceeded to join the M4 from Swindon in the general direction of Cardiff. The rider may or may not have been travelling in excess of 120mph at points. I understand the rider stopped off at Magor services to partake of the facilities and did notice the steam coming off of the rear tyre as it was a wet day. It wasn't until he returned to the bike slightly lighter to discover the bike was also lighter owing to the fact the rear tyre had no air in it.

The rider now knows to recognise when the handling feels a bit off to check, as well as taking more notice of tyre pressures. But in my defence it was quite some years ago now...

Haha, well; we live and learn.. I'm sure every biker has made some sort of mistake like this before.. Glad you got off okay though, especially for doing over 120; you'd think riding on a flat is just setting yourself up for a crash; I'm surprised how well the tyres hold up lol

Originally Posted by Bibio

i've had a valve core come loose 3 times. i now carry a valve core tool.

I do have one but I've never really thought to carry it around with me. Perhaps I'll pop it under the seat with my little toolbox just in case

Originally Posted by Fen Tiger

This reminds us how good modern tubeless tyres are for safety in this respect. Not the same experience when you get a puncture with a tubed old school tyre! Had a BSA A7 some years ago and got a rear wheel puncture at 35 mph. It was a struggle to bring it to a safe stop even from that speed. Tubeless radial tyres are a huge advantage.

Haha that sucks. I've never ridden any older bikes to be honest; nor have I rode on tubeless tyres so I can't comment about that! But modern day tyres have come far for sure. I think tubed tyres are also more of a pain when it comes to changing them too

Originally Posted by Fen Tiger

Me too.

Anyone else in the habit of wetting the valve with some spit to see if it is leaking? Works well for me!

I've never thought of doing that, but I'll keep the idea in mind just in case!




Also, quick update for you all:
I had a thorough check of the tyre last night and can't seem to find any punctures or damage anywhere. I overinflated the tyre to about 45 psi to see if I could hear any air leaks, but nothing. I'm stumped, but as far as I can see, nothing is wrong with it

You might have sideswiped a kerb and allowed some air to escape and the tyre has reseated later, theres a few possible causes...

It definitely cant be that low due to environmental factors, if you cant find any probs with it, get back on and enjoy it

I got a nail pulled on my tyre last year.

It would only leak from a cold tyre and this would go down a couple of PSI overnight. When I first discovered the problem I was at 15 PSI!

I couldn't discover the leak myself so just kept the pressure topped up, I did a 300 mile journey and it didn't drop 1 PSI!!!

Anyway I got the nail found, pulled and tyre repaired during the soon the follow MOT, no internal damage to the tyre!

My point is I ran on low pressure for a while and it was checked over by a garage and deemed as safe to repair and carry on.

You have to remember that our tyres bend and mould into all sorts of funny shapes at high speeds and when corning etc so running low shouldn't 'bend' the wall much more than its designed to anyway.

Another explanation is some twazz has let your tyre down for shizz...

[robertw95]

Take the tyre off and my guess is youll see lots of small shredded balls of rubber, worked as a car tyre fitter for a few months and you could tell straight away if a tyre had a puncture at somepoint. Looked fine from the outside

Originally Posted by Corny Gizmo

You might have sideswiped a kerb and allowed some air to escape and the tyre has reseated later, theres a few possible causes...

It definitely cant be that low due to environmental factors, if you cant find any probs with it, get back on and enjoy it

Oh my God, I'm a fool! Your comment just reminded me! I was rear ended recently, not too hard but a good shunt. Perhaps that could be a factor that let the air out of my tyre? I had a quick check over after but it seemed fine, but that's probably when the bike started feeling a bit off..

Originally Posted by ManMango

I got a nail pulled on my tyre last year.

It would only leak from a cold tyre and this would go down a couple of PSI overnight. When I first discovered the problem I was at 15 PSI!

I couldn't discover the leak myself so just kept the pressure topped up, I did a 300 mile journey and it didn't drop 1 PSI!!!

Anyway I got the nail found, pulled and tyre repaired during the soon the follow MOT, no internal damage to the tyre!

My point is I ran on low pressure for a while and it was checked over by a garage and deemed as safe to repair and carry on.

You have to remember that our tyres bend and mould into all sorts of funny shapes at high speeds and when corning etc so running low shouldn't 'bend' the wall much more than its designed to anyway.

Another explanation is some twazz has let your tyre down for shizz...

I'm not sure, but see my comment above about being rear ended.. I'll have it checked over by a tyre fitter to see if they can spot anything. They'll probably have more of a keen eye than I do..

Originally Posted by robertw95

Take the tyre off and my guess is youll see lots of small shredded balls of rubber, worked as a car tyre fitter for a few months and you could tell straight away if a tyre had a puncture at somepoint. Looked fine from the outside

Well, I'm no tyre fitter but shredded rubber doesn't sound too good lol.. I'll get the inside checked out just in case. Thanks for the info!


For anybody curious, I got the accident on video - can't believe I forgot about it:

http://forums.sv650.org/showthread.php?t=221151

Oh my God, I'm a fool! Your comment just reminded me! I was rear ended recently, not too hard but a good shunt.

That might be what it was then, the shunt may have release a good few PSI and then its just got worse from there matey, get it checked out, im sure it'll be fine.

[timwilky]

Originally Posted by Bibio

i've had a valve core come loose 3 times. i now carry a valve core tool.

Brother had similar on his RSV4. He couldn't understand why he kept loosing pressure. It would be ok in the garage for a week, and down 10lb after a run.

He had to abandon one ride and get transported back as he had lost all pressure after 3 hours out.

When I pulled the core, they were flimsy cheap nasty things. Put in a replacement and problem went away.

[Red Herring]

Did I not read somewhere that at some of the speeds some bikes (an RSV4 for example) are capable of the centrifugal force is enough to actually cause the valve core to compress against it's spring and leak? Not sure how true that is, I'm sure someone cleverer than me can work it out, but the same article suggested that is why some high performance bikes have the angled valves fitted, quite apart from the fact that it makes it easier to get the airline on. I suppose fitting decent valve caps with the little rubber rings in them might also help.


ps: as soon I wrote that I remembered I was on the internet..... duh!

Here you are.....

http://www.eng-tips.com/viewthread.cfm?qid=248379

Originally Posted by Corny Gizmo

That might be what it was then, the shunt may have release a good few PSI and then its just got worse from there matey, get it checked out, im sure it'll be fine.

Yeah, looks to be that this was likely the cause. I can't seem to find any damage/wear anywhere else that points to any other possible causes.