Modern Vespa

so i'm heading down the A2 early this afternoon on the way to meet up with our own Mr. Village for some cornering lessons. i'm cruising along at a happy 70mph with a big smile on my face, when all of a sudden the scooter started to behave very oddly indeed - it was drifting all over the lane and the handlebars were swaying back and forth. i backed off the throttle just about the time that the slight sway started to turn into a full blown tank slap. my only thought at that point was 'i am not throwing the scooter down the road' not after all the dosh i've spend getting it just the way i like it. so i locked my elbows, let go of the throttle, and focused on getting onto the hard shoulder. i'm happy to report that self and scoot made it safely to a full stop. the back tyre had completely deflated - not an explosive blowout, but a very rapid loss of air.

thank goodness it all ended happily. a bloke behind me in a van stopped to see if i was ok, and told me that he was expecting me to go down. i'm very, very lucky that i didn't.

while we were waiting for the van to turn up we had a look at the tyre and discovered what i presume to be the problem - see the pic below. the valve cap (which was screwed down tightly by me earlier that morning when i put some air in the tyre) had been pulled all the way up the valve stem, it's cross-threaded and really jammed on there tight. i'm not sure if the valve stem failed, or if the cap caught on something. the scooter is going in to my mechanic next week for a full examination - i don't want this happening again. i'm also going to replace the Pirelli with a Pilot City or a Heidenau K61 - it was down to the wear indicators after less than 3000 miles.

anyway thank you to the very nice man in the breakdown recovery van (and thank god for breakdown insurance otherwise i'd be £180 poorer) and to bill for coming and waiting on the side of the road with me and for riding me back to london

I' e had that happen to me twice, so I know the horror of which you speak. Glad you're okay!

Looks like possibly centrifugal force on that valve stem bent it out far enough to whack the cap against something good. whack whack whack whack whack! The stem is still somewhat bent out from it. Curious if the air leaked from the side of the stem, or from the core. I'm guessing the core, since it seemed to happen quick. My gf and I had a nasty little blow-out occur when our aftermarket fancy-dancy pressure-reading valve caps tapped something and broke...insta-flat, faster than a cat in a dog pound.

That's an unusual valve cap, is that aluminum I'm looking at?

Good to see you're up and typing. Thank your lucky stars it was your rear wheel and not your front.

Looks like the valve stem got whacked pretty bad and maybe the rim got dinged too. Your experience sounds scary. Nice job getting off the road to a full stop.

What if it had been the front tire that blew out? Has anyone had that experience?

I replaced my Pirelli's at 4,400 miles with K61's. I've got 3K on the K61's and they hardly show any wear yet. I like them a lot. (Though the wobble when decelerating around 30 mph has come back somewhat after I thought the Heidenau's had fixed it.)

indeed, that is a fancy-schmancy anodized aluminium valve cap you're looking at. it's been on there for months with no issues - i check the tyre pressure every couple of weeks and it's never shown any sign of unwinding itself. that's why i'm wondering if the valve stem itself failed. i guess i'll never know and yes thank feck it wasn't the front tyre or they'd probably still be scraping me off the A2

it's really hard to control a front tire blow-out. The effect on steering is more pronounced and erratic. If it happens, regardless if it's front or rear, it's best not to apply any brakes. If you *must* apply brakes...choose the rear brakes. and hope it didn't happen in a turn.

Genie,

1. Glad your OK

2. Well done done keeping it upright. I've had my share of punctures and they can be scarey moments.

3. Looking at the photo I'd check that that valve isn't rubbing against anything.


Once again, glad your OK though.

hmm. i seem to remember a post from quite a while back (over a year, i think) where a metal valve cap caused a blowout on a gts

glad you're ok. that sounds really scary. well done for staying shiny side up.

which reminds me. can you pm me details of your mechanic. the front end of my gts has not felt right for a few weeks now and i'm sure something is loose (steering head bearing?). i want it checked out by someone who knows what they're doing. my regular dealer (geographically convenient but somewhat uninspiring) fobbed me off with some bullshit.

Well, for us, one scare was enough to make us put the regular plastic caps back on. To hell with fancy-dancy if it means having to wonder about my tires, right?

oh yeah. the boring old plastic caps will be going straight back on as soon as the scooter comes back from the mechanic.

Way to hang in there!!

Glad everything worked out ok for you

OMG. That sounds really scary. Well done. I would stick with the Pirellis though. Grip vs wear. You ride in all weathers and Pirelli grip is supposed to be the dogs.

Damn, nice to hear you're okay after that

Genie - Helluva way to start the weekend! I'm very glad to learn that you came through alright; and, way to go on keeping your scooter upright!

That would have put the scare in me for sure!

I was told never to fit aluminum valve caps as the extra weight over the standard plastic one's will make it do just what yours has at speed , With the extra weight bending the valve stem over till it fails

Glad your ok and no damage done ( apart from new tyre , valve and underware )

cheers for your good thoughts everyone .... and cheers to the folks who have posted on here in the past about how to handle loss of tyre pressure at high speed. it's only because of their good advice that i didn't grab the brakes.

the funny thing is i was so focused on getting the scooter safely to the side of the road that i didn't once feel anxious or panicky. nor do i now. i'll probably have terrible nightmares tonight tho

i believe we have our answer. where were you when i bought the damn things???

That's one for the notebook. Good advice.

Hey Genie, glad your ok...

Dont take the michelin when you change tyres.Heidenau is good, Bridgestone Hoop also. I have this one now under the gts.
And if you like, i have some blue caps here.... its nice on a midnight...

Love,

I suspect they'll work better on vehicles that don't slant the valve stem out, and stubbier valve stems perhaps. But...I'll never find out fer sure.

Ack! Suck!

Genie

Glad all turned out OK. Will have Souma (the local grape mash whiskey) waiting for you when you get here.

A&A

Well controlled! That valve stem wasn't replaced 3000 miles ago, that's an old dog of a valve stem. Whoever replaced your tyres last time should be shot - always replace the valve stem. The aluminium cap is irrelevant - but why use one? It's only a dust cap, plastic originals are just fine.

Old or new, I suspect it wouldn't have mattered. You see the scuff marks on the rim? The cap weighs too much. It was getting bent over pretty hard at the higher speeds, relaxed at lower speeds...over and over. Just a matter of time I think before it's too much.

Well spotted Sherlock!

An ali cap won't had had so much weight as to deform a decent new valve stem. An old shagged one, yes of course. The brass at the end of the stem weighs far more than the ali.

Cripes! Glad you're ok!

to be fair, those scuff marks on the rim weren't there this morning. the valve cap hadn't been hitting the rim for very long, if at all, before the eventual failure of the valve stem. whatever the case, i'm going back to plastic.

jim, i had the aluminium valve caps installed because they look hot ... knowing how devoted you are to total practicality, i'm assuming you won't get it

wow Genie! Awfully glad to hear you were able to get off the road safe and sound and with no damage to your scoot as well. Very well done! The Gods must be smiling on you!

Had them installed? Didn't you manage to do that yourself?

PS. Don't tease jim. He's in particularly carmudgeonly mood tonight, and besides he's about to buy a pair of Crocs. Who says he doesn't care about stylin' ?

Well, that's true. Whether it's the weight, or the bangin' around that its obviously gone through...it's definitely not a welcome addition on *that* particular scoot. Btw...it doesn't have to weigh *that* much more. It has the multiplier by the fact that it's swingin' around at 70mph.

The stem looks like it has dry rot - just older

I'm not convinced about the ali caps being so much heavier that they caused this. What is the weight difference? Ali is almost as light as plastic

If you want style Genie, use the plastic as recommended and then start a new fad by painting them with nail polish

no way i'm going to do something as complicated as valve caps on my own - i leave that sort of stuff to experienced mechanics

on a more serious note ... i've decided to have my mechanic replace both valve stems when he changes the rear tyre ... and i'm probably going to go with the Heidenau K61 - i've spent the last hour reading about how great they are. might even get the front replaced at the same time. i've been peering closely at it this afternoon and have noticed some cracks in the sidewall.

The next time you go outside look up in the sky and say "Thank You".

Correct. Black ones of course - practicality'n'all. Oh, I bet they don't do black.

Genie, you have some great scooter control skills going there. Glad you stayed upright and got safely to the shoulder.

Genie
Good to hear you are OK, and I am off to check the state of my valve stems. I had a rear tyre fitted. I hope the mechanic did the right thing
Coggo

I don;t buy the ali, valve stem, weight thing, bend at speed, crrraaaap. My guess is a rock or some other foreign object got thrown up in there or something fell off the scooter and wedged itself temperarly in there before doing the damage, on an obviously old valve stem and rim before flying out the back and watching you muster all your skills to weave to a stop. Check that you are not missing something on the scooter like a piece of chrome or cover off something. Before you worry about a valve cap if you got add ons, that is the stuff that comes off especially the very dangerous front fender, bumper things.

Genie,
That does sound scary! I am glad to hear you are OK. And well done for keeping you and scoot upright.

Have a couple of beers for bed, might help with the sleeping!

Marc

Good job keeping your cool and remembering to do the right thing. Glad it worked out okay. I'm a safety-minded kinda guy, so I vote with the folks who say safety first with anything to do with tire, tire valve stems, cap, etc.