Shinko Tires Losing Air

[Guest]

I wasn't having this issue until recently on my new Shinko 712's. The bike was sitting for a week waiting on repairs except for a short ride on Friday. I checked the air pressure Monday night and the front was down to 24PSI and the rear was 10PSI . Wtf?

I reinflated 28 front/32 rear and took it to work Tuesday and Wed (today). The bike has been sitting in the warehouse all day and I just checked and it's down to 24 front/28 rear. I checked with soapy water on the bead area and stem but no bubbles, and the tire doesn't have any cuts or nails in it.

Any ideas?

[Steve]

How long ago did you mount the new tires?

Did you really CLEAN the bead before mounting the tires?

.

[Toasty]

They were mounted about a month ago by a local MC shop. They do tons of tires and I didn't have any issues until recently.

[Big T]

Are your rims marked for tubeless?

[Nessism]

Did you install new tubes or reuse the old ones? I'd blame the tubes before the tires.

[musicman]

If you're running them tubeless on a tube rim they'll leak like that. My rims didn't have the type of lip you'd see on a tubeless rim, so Im running tubes, its a 79 though. I've also heard of the early rims being porous and weeping air through the aluminum itself.

[tkent02]

If you're running them tubeless on a tube rim they'll leak like that. My rims didn't have the type of lip you'd see on a tubeless rim, so Im running tubes, its a 79 though. I've also heard of the early rims being porous and weeping air through the aluminum itself.

But he had no problem until the last tire change. Take them back to the tire place, they screwed it up.

[lurch12_2000]

I've run a few sets of tires without tubes on rims not marked tubeless and don't lose any pressure after months of use, including a set of Shinko 712's now. Rims should be cleaned well before mounting new tire and that the new tubeless valve stem is seated properly, and verify the bead was seated properly by following the rubber molding line in the sidewall against the rim edge. If they used tubes then sometimes a little pinch when mounting will cause a slow leak. You won't know unless you take the tire off and pull the tube to inflate and test in a bucket of soapy water for leaks. Some guys have no problems mounting tubes, but I've had issues with a small pinch (which will slow leak) sometimes when not real careful.
I push my old GSes hard in the corners and don't worry about bead problems with tubeless tires on usable tube type rims, but the Shinko 712's can squirm and slip when leaning real hard and I will not buy them again.
Note: and I run my tires at 35psi front/ 38psi rear. They will read about 3-4 psi higher each when run hot.

[hikermikem]

Are you using aftermarket stem caps? You know, the pretty ones?

I had the same issue & turned out it was the little chrome (pretty) stem caps were the culprit... something about them pushed down on the air valve & the tires slowly lost pressure. Switched back to the ugly black plastic caps & the problem vanished.

[musicman]

You got rear ended right? Maybe the rim is bent from the collision?

[Toasty]

You got rear ended right? Maybe the rim is bent from the collision?

I suppose it's possible that the rim is a little bent. The stems are normal black ones, they put on a new set with the tires.

I'm running the tires without tubes, and tbh I'm not sure if the old Dunlops that were on before had tubes or not. The shop might not have cleaned the rim well enough, or the bead got unseated some when it got hit, or maybe it's a little bent. I've taken the bike to work (~120 miles) a few times after the accident and gone on weekend trips down the coast without issue. I wasn't really checking either ( I know) and Im pretty sure I aired up the tires a bit not too long ago.

.
Note: and I run my tires at 35psi front/ 38psi rear. They will read about 3-4 psi higher each when run hot.

Is that with the tires cold? How do they feel at 35/38? I've been going off the sticker on the rear bumper.

[Nessism]

Are your wheels labeled "Tubeless applicable" (or something to this effect)? If they aren't designed to run tubeless, you may have trouble getting them to hold air.

[Toasty]

Are your wheels labeled "Tubeless applicable" (or something to this effect)? If they aren't designed to run tubeless, you may have trouble getting them to hold air.

They're just regular old 1981 GS550L wheels, no tubeless labels either. I guess it depends on each set of wheels , some people can run them tubeless.

[bbjumper]

I put a set of Pirelli Angels on the Beemer last summer, they leaked air for the first 500 or so miles then sealed up. I have talked to others that have had the same experience, I guess it's just PFM

[lurch12_2000]

....Is that with the tires cold? How do they feel at 35/38? I've been going off the sticker on the rear bumper.

Cold, and after running 20 miles or so a hot reading would be about 37/40 for me. New tires can run higher psi than the old original stuff, and still have a nice ride. You can go with 32/35 too see what you like, and then increase some if you're a more aggressive rider.

Check your pressure in the same condition, meaning like 1st thing in the morning before riding. Things like sitting in the sun, 40 degree nights , etc...will affect the psi by a few pounds either way so stay consistent on when taking the tire pressure reading.