@judy avatar
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World Traveler
2007 LX150 Daring Plum Leonardo Da Vespa
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@judy avatar
2007 LX150 Daring Plum Leonardo Da Vespa
Joined: UTC
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UTC quote
So about 3 weeks ago my front tire went flat after i came thru a really bad section of road (patches on top of patches). Had to be towed to my mechanics and the valve stem was sheared. Fast forward to last week when my rear tire went flat after doing the same section of road. My problem is i have to take that section of road unless i want to go around the island to get to honolulu. Only a couple of ways out of here. While i'm sitting awaiting the tow truck,who by now, has my phone number on his phones contact list. Laughing emoticon i think i figured out what was making the valve stems go bad. My TPMS Tire Pressure Monitoring System sensors . I put them on my scooter about 4-5yrs ago. Obviously our roads have really degraded over time. While the sensors aren't particularly heavy i think their just heavy enough to cause the valve stems to move enough, so that the valve stems cause the air to come out of the tire. The reason i put them on was because it's a real PIA to get to the rear tire to check the tire pressure. Front one no problem. I like to check my tire pressure weekly so this system was perfect (until it wasn't ). I always found it to be accurate, maybe 1-2 PSI off. So now their in the garbage. I hate it when good things go bad.
UTC

Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
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Posts: 3766
Location: East Anglia, UK
 
Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
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Posts: 3766
Location: East Anglia, UK
UTC quote
Yeah, I think you have it nailed. It is something that can (clearly) happen with the tpms setup. Glad you have it figured!
@dooglas avatar
UTC

Veni, Vidi, Posti
GTS 300ABS, Buddy 125, Buddy Kick 125
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@dooglas avatar
GTS 300ABS, Buddy 125, Buddy Kick 125
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UTC quote
I had a similar problem with right angle metal valve stems. I suspect it was caused in much the same way. The large metal valve stems are heavy and the weight is off center.
@judy avatar
UTC

World Traveler
2007 LX150 Daring Plum Leonardo Da Vespa
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@judy avatar
2007 LX150 Daring Plum Leonardo Da Vespa
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UTC quote
Thanks S. I'm a slow learner. Laughing emoticon While i knew the roads bad news the fact that i had them on for years without any problems skewed my thinking that they could be the cause.
@turboblew avatar
UTC

Hooked
"MY WIFES" 2010 GTS FASTER & BETTER ENGINEERED THAN YOURS!!
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Location: STAYOFFVILLE
 
Hooked
@turboblew avatar
"MY WIFES" 2010 GTS FASTER & BETTER ENGINEERED THAN YOURS!!
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Location: STAYOFFVILLE
UTC quote
Dooglas wrote:
I had a similar problem with right angle metal valve stems. I suspect it was caused in much the same way. The large metal valve stems are heavy and the weight is off center.
youre talking a few grams in weight difference at most. If you put right angle stems that arent threaded & properly gasketed on both sides... that is problematic as well.
Amazes me in 2018 bikes still come with cheapo rubber stems that make it impossible for a lay person to take pressure readings accurately.
UTC

Hooked
Joined: UTC
Posts: 437
Location: Philadelphia, USA
 
Hooked
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UTC quote
I loved the idea of them too. Bought it and a month later I removed them because they intermittently lost air. bummer!
@web-tech avatar
UTC

Veni, Vidi, Posti
2008 MP3 500, 2013 BV350, 2020 Vespa Sei Giorni, 2008 Vespa S150
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Location: Ashburn, Va. Home to the Internet
 
Veni, Vidi, Posti
@web-tech avatar
2008 MP3 500, 2013 BV350, 2020 Vespa Sei Giorni, 2008 Vespa S150
Joined: UTC
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Location: Ashburn, Va. Home to the Internet
UTC quote
Re: Valve stem problems.
judy wrote:
So about 3 weeks ago my front tire went flat after i came thru a really bad section of road (patches on top of patches). Had to be towed to my mechanics and the valve stem was sheared. Fast forward to last week when my rear tire went flat after doing the same section of road. My problem is i have to take that section of road unless i want to go around the island to get to honolulu. Only a couple of ways out of here. While i'm sitting awaiting the tow truck,who by now, has my phone number on his phones contact list. Laughing emoticon i think i figured out what was making the valve stems go bad. My TPMS Tire Pressure Monitoring System sensors . I put them on my scooter about 4-5yrs ago. Obviously our roads have really degraded over time. While the sensors aren't particularly heavy i think their just heavy enough to cause the valve stems to move enough, so that the valve stems cause the air to come out of the tire. The reason i put them on was because it's a real PIA to get to the rear tire to check the tire pressure. Front one no problem. I like to check my tire pressure weekly so this system was perfect (until it wasn't ). I always found it to be accurate, maybe 1-2 PSI off. So now their in the garbage. I hate it when good things go bad.
I tried telling you that can happen, no one listened to me. Told me I was full of it.
@judy avatar
UTC

World Traveler
2007 LX150 Daring Plum Leonardo Da Vespa
Joined: UTC
Posts: 29304
 
World Traveler
@judy avatar
2007 LX150 Daring Plum Leonardo Da Vespa
Joined: UTC
Posts: 29304
UTC quote
Web If one worried about what "could" happen we'd never get out of bed. I had 4 years of trouble free use out of them. It's the roads. But for them being so bad i'd still have them on. I have no choice i have to take that road to get to Honolulu. I also have 48,600 miles on the LX at the time i took them off. So "i told you so" doesn't cut it.
@web-tech avatar
UTC

Veni, Vidi, Posti
2008 MP3 500, 2013 BV350, 2020 Vespa Sei Giorni, 2008 Vespa S150
Joined: UTC
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Location: Ashburn, Va. Home to the Internet
 
Veni, Vidi, Posti
@web-tech avatar
2008 MP3 500, 2013 BV350, 2020 Vespa Sei Giorni, 2008 Vespa S150
Joined: UTC
Posts: 8935
Location: Ashburn, Va. Home to the Internet
UTC quote
judy wrote:
Web If one worried about what "could" happen we'd never get out of bed. I had 4 years of trouble free use out of them. It's the roads. But for them being so bad i'd still have them on. I have no choice i have to take that road to get to Honolulu. I also have 48,600 miles on the LX at the time i took them off. So "i told you so" doesn't cut it.
It is not what could happen, it happens all the time with these type of tire monitiring systems. Just like putting those HUGE valve stem caps on does the same thing.
I wasn't guessing, I have see it more than once.
That is why aftermarket companies are finily coming out with the in wheel valve stem sensors like OEMs use.
@roadster avatar
UTC

Molto Verboso
Kymco AK550
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Location: UK
 
Molto Verboso
@roadster avatar
Kymco AK550
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Posts: 1163
Location: UK
UTC quote
Sometimes generic tubeless valves which are fitted when tyres are replaced are too long for scooter wheels. In hot condition they are prone to bend sideways partly as a result of centrifugal force. I have had a broken one which destroyed itself by hitting the brake calliper like this. Special short stemmed valves are much better.
@jkj-fz6 avatar
UTC

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BV400, Primavera 150, Yamaha Zuma 125
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Location: Twin Cities, Minnesota
 
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@jkj-fz6 avatar
BV400, Primavera 150, Yamaha Zuma 125
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Posts: 4224
Location: Twin Cities, Minnesota
UTC quote
Would replacing right angle stems with short straight ones solve the problem?
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