Multiple pin hole punctures in front tyre. Pirelli ST

[Robwebb]

For the past couple of weeks my front tyre has been slowly loosing pressure - a couple psi in a couple of days. The bike has done 18035 km and this is the original front pirelli ST. Went out tonight for a play and it was flat. Last ridden Tuesday and put 38 psi in it. (I run 38 because it was cupping).
Did the soap and water trick and found 7 pinholes around the centre of the tyre. Nothing foreign in any of them.
The rear is not showing any problems but is a relatively new Pirelli GT. Had to replace that one just after 10000km because I picked up a big bit of steel whilst riding through roadworks.
Anyway, the only reason I can come up with is that I live on a badly corrugated, crappily maintained very twisty sand road covered in small sharp stones which may be perforating the tyre. Ride 20 kph to 50 kph on the sand.
The tyre is still legal but it was going to be replaced anyway because of the uneven cupping.
Had been hoping for a few more weeks though.
Another thing I noticed is that there appears to be hairline cracks off the edges of the tyre. Looks similar to the cracks in a very old tyre, only much finer, but could be due to the 18 km of unbelievable twisty bitumen that has to be travelled before getting to a relatively straight main road.
Another possibility is the age of the tyre. I do not know what lifespan these tyres have. Mine was built in the 14th week of 2013.
Anyone have any ideas?  - at the moment moving house is not an option .

[trophied]

The BMW K1600 forum has numerous posts regarding flint punctures from members who like to ride a lot of back roads that are paved with that type material.  Small punctures from pointy particles.  Sometimes in the tire, sometimes not.  Some of those members live where that is a common product in paving and have a constant battle with it.  Sadly, I really don't have an answer or solution, but maybe another member has some input to help you.

[rpeters549]

Age-wise you should be fine.  Up to about 5 years old is a commonly accepted age limit for tires, especially on a MC.  But use and storage can have an effect on that time length.  Sunlight (UV radiation) degrades rubber, as does ozone (emitted from electric motors).  Try to park in the shade and not right next to the fridge in the garage.

[pantoscoop]

Please, do you have any pictures???

[Robwebb]

Do have photos. All too big. Hopefully the cracking is a small enough file to post.
The larger of the holes are what you would expect if you pushed a drawing pin or thumb tack into the tyre. Had another go at the road surface but no go. Sorry.

[GarminDave]

Hi Robwebb,

I think, as an experienced high'ish mile rider, most people use their tyre to the limit and really do not save too much in cash terms.  In UK motorcycle tyres are allowed on the road with a tread depth of 1mm (for cars it is 1.6mm)  Other countries have deeper tread legal limits.

I usually change my tyres at 2mm which is a compromise that I feel comfortable with.  It surprises me the distance some achieve on their tyres and I see you have 18k Km on your front which would be way past what I would like to use.

Having good rubber with at least 2mm depth give a better, safer ride and I get less punctures.  I never (now I've said never you watch!) get a puncture on new tyres, it is always as the tread depth gets lower that I experience punctures.

I can get a pair of tyres fitted at about £240 and at around 7,000 miles.  This works out at £0.035 per mile.  If I used them to 10,000 miles, which would probably still be legal then it would work out at £0.024 per mile.  For the extra penny a mile I feel safer and for sure the bike rides better on the newer rubber.  Currently in UK I pay about £0.11 per mile in fuel cost so for about £0.145 per mile is a cost I can live with and riding on less than optimal rubber makes no sense to me.

Just my $0.02 worth.

Love, light and kindness,

Dave

[trophied]

   Nice breakdown of the cost to levels anyone can wrap their head around, and makes good cents. 

[Travelling2bob]

G'day Robb, ditch the ST and replace with A class Pirelli Angel GT.