Couple of weeks back had the bike out for a blast down to Squires then to the Sun Inn and home again , topped up tyre pressures before setting off , all was ok when i parked the bike up in the garage , didn't use the bike again till 4 days later , was a lovely sunny day so thought i'd take the bike to work for a change , not this time tho the front tyre was completely deflated , following night after work pumped the tyre back up again, couldn't hear any hissing and no visible signs of a puncture , have had the bike out for a few blasts on a night after work just to see if the tyre was going down while the bike was being ridden , the tyre has not deflated again since . Any ideas on this mystery tyre deflation , got me baffled as i live on my own and only me that has access to the garage

Jock I had the same thing with a car a couple of years back and it happened every so often for over a year until I got the tyre changed. It turned out it was a tiny bit of corrosion on the rim where the bead sits. The garage said it was intermittent cos it depends where the corrosion was positioned when I parked up. If it was at the top it leaked and at the bottom it pushed harder on the bead with the weight, stopping the leak.

If it keeps happening it might be worth taking the tyre off and cleaning the rim with a soft wire brush or abrasive paper. Thats what the garage did and it never leaked again                                                                                                                                                                              

Am hoping it doesn't happen again Terry , got a 425mile ride on Friday . Gonna put a small paint mark on the tyre to note it's position when parked up to see if it does go down in a certain position . Cheers for the info                                                                                                                                                                             

Hi Jock, what RK has said is a distinct possibility. Corrosion between the rim & tyre is a very common occourrence. As the tyre in question is your front one .. .. I would not even think about carrying on riding it without having the tyre removed for a check and a clean up of the rim. At least with the rear, you got half a chance of staying in control should you get an unexpected deflation. With an unexpected deflation on the front, that chance is reduced considerably.   got a 425mile ride on Friday   Your user name suggests that you may not always ride in a sedate manner. Now chuck in the variable of an unexpected deflation on the front tyre .............................................................                                                                                                                                                                             

Well mine never ever went down while I was driving, only ever when it was left standing overnight so if it's the same thing it should hopefully be ok mate                                                                                                                                                                             

Just possable that the valve had not reseated correctly on 1st time and let air though slowly then on 2nd time reseated                                                                                                                                                                              

thinking jpharley's valve suggestion could be more like the problem , as it's on painted alloy rim . Got the day off on Thurs so will go down to Ripon tyres n get it checked to be on the safe side . GT it was once suggested that i should change my username to 'supersonicjock', lol can't think why tho !!!

I know its messy but still put a bit of spit on the valve head and check before putting dust cap on,  I use truck caps as thay have sealing rubbers so if the valve leaks you dont get a flat                                                                                                                                                                             

great idea with the truck caps , will have to get some                                                                                                                                                                             

I noticed after getting tyre changed(front) they put new valve in,the caps arnt deep enough so when on they were touching the valve stem over days tyre loses pressure, so could be the same,try the truck caps  .                                                                                                                                                                             

Perhaps it's just me breaking into your garage and letting your tyres down for a laugh?

lol                                                                                                                                                                             

Its the dust mites finding somewhere to sleep                                                                                                                                                                             

i wouldn't put that past ya Geoff lol .                                                                                                                                                                              

ive had this on push bikes and motorcycles just put it down to muc in the valve,let a good long blast of air out of the valve,that should make sure its cleared                                                                                                                                                                             

Same same some shit in the valve one thing as well when you get your tryre changed make sure you get the valves done they do give out and not all tyre places do it as standard.