HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 108 posts ] 
Go to page 1, 2, 3, 4, 5 ... 8  Next
Author Message
PostPosted: Tue Oct 09, 2012 5:40 pm 
Offline
in the industry
User avatar

Joined: Sun Jul 29, 2012 2:59 pm
Posts: 612
Location: Ruidoso, NM
So... 340 owners... have you ever experienced a tire inexplicably blowing off the rim? Any details you can provide (even if the answer is no) would be helpful. Things like taping, tires used, tubes used, etc.

I'm sure this doesn't happen very often, else I would have heard more about it. But it has happened twice to me... and I recently discovered that is has happened 3 times to someone else. Lumping both of our experiences together:

Rims are the older 340 models (the light ones).
Tubed setup. Twice with latex tubes, the rest with butyl. Tires have been GP4000S x2, Michelin Pro3 x2, Vittoria Corsa CX.
Tires always blew off days and hundreds of miles after mounting. No warning or indication.
Neither of us has had a tire blow off any other rim... ever. We are careful with mounting. I have ridden ~200k road miles, and he has ~100k.
Pressure <110psi.
No braking or cornering or sprinting forces were involved.
Tires were either indoors or outside being ridden in <80 deg temperatures when they exploded.
Wheels were taped with two layers of Stan's 12mm tape. Tape comes partially onto the rim "bench" but does no extend into the bead socket.

I asked Stan about it. He mentioned that having the tape extend all the way to the bead socket is important. Notubes uses two layers of 21mm tape (not 12mm) and Stan says they haven't had any tires blow off the wheels they sell. I thought it was a potential problem to use 21mm tape because it is impossible to keep it out of the bead socket, but he said it didn't matter... that little hook in the bead socket didn't do much anyway... the tightness of the bead on the rim "bench" is what really keeps the tire on.

So does two layers of tape really make that much difference to the tire bead? I measured the tape and did some quick calculations, and it amounts to over 2mm of linear bead stretch. I can't tell if that makes a big difference or not, but it is something.

_________________
formerly rruff...


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 5:53 pm 
Offline

Joined: Fri Oct 07, 2011 2:08 pm
Posts: 1365
I got the older 340 on the front . Its got the yellow rim tape and I use michelin air comp tubes and zx clinchers. No issues what so ever . Psi is 110 /120 max . The wheel weighs 490 grms . 18 spokes .
On the rear 24 spokes, I switched to the new rim gained 10 grms ,692grms but running fine as well ...


Top
 Profile  
 
Posted: Tue Oct 09, 2012 5:53 pm 


Top
  
 
PostPosted: Tue Oct 09, 2012 6:03 pm 
Offline
in the industry
User avatar

Joined: Sun Jul 29, 2012 2:59 pm
Posts: 612
Location: Ruidoso, NM
Two layers of 21mm tape?

_________________
formerly rruff...


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 6:14 pm 
Offline

Joined: Tue Oct 09, 2012 5:49 pm
Posts: 1
I have one experience a GP4000S tire blown off the older Alpha 340. Tires ridden couple of hundred miles without problem, pump up the tire to 100 PSI the night before the ride, tire blew off 4 hours later. Reinstalled the tire with new tubes and have 2-3 rides with it without any further problem


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 6:41 pm 
Offline
in the industry
User avatar

Joined: Sun Jul 29, 2012 2:59 pm
Posts: 612
Location: Ruidoso, NM
Same question to you... how was the rim taped?

_________________
formerly rruff...


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 7:04 pm 
Offline

Joined: Fri Oct 07, 2011 2:08 pm
Posts: 1365
I just Have 1 layer of the yellow rim tape. Im pretty sure it's the tape Stan's recommend. It is all the way round on the flat of the rim , obviously with a hole to stick the valve in .It's very thin.


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 8:18 pm 
Offline
Shop Owner
User avatar

Joined: Wed Aug 04, 2004 9:18 pm
Posts: 241
artray wrote:
I just Have 1 layer of the yellow rim tape. Im pretty sure it's the tape Stan's recommend. It is all the way round on the flat of the rim , obviously with a hole to stick the valve in .It's very thin.


You need Two layers of 21mm tape all the way around.

_________________
http://www.motomatt.com/?p=3831
http://gallery.motomatt.com/v/My+Mountain+Bikes/Trigon+MQC05+Full+Carbon+Bike+15lb+89oz/IMG_1893.JPG.html
http://www.strava.com/athletes/motomatt


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 9:29 pm 
Offline
in the industry
User avatar

Joined: Sun Jul 29, 2012 2:59 pm
Posts: 612
Location: Ruidoso, NM
MOTOMATT wrote:
You need Two layers of 21mm tape all the way around.


Yep... for two reasons... keeping the tube out of the holes and keeping the tire on the rim.

_________________
formerly rruff...


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 9:42 pm 
Offline
User avatar

Joined: Sun May 31, 2009 8:47 pm
Posts: 879
Location: durp durp durp
I use wide velox tape (22mm) & ran a spatula around the rim hook to ensure clear. Have about 6k kms on two wheel sets, 3nr rims being the older lighter version. Run both butyl & latex depending on conditions & whats available.

All kinds of riding & conditions, no problems at all. Michelin Pro3 for about 4k kms & Pro4 for 2k kms.

If anything the michelin tire is too tight. You have to use a lever to bring the tire off & have to sink the tire into the recess all the way around the rim to get enough 'give' to even considering getting michelins off the rim.

Did have a couple of problems with pinching latex tubes when mounting initially but have learnt that the tube needs to be carefully inserted & then moved into the body of the tire by ensuring the beads of the tire seat on the middle channel prior to inflation. Bit fiddly especially if cold / wet, but its no biggie once done a few times over.

That's my experience with them. Hope that helps in some way :)
Nice rim, just a touch too expensive imo...


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 9:49 pm 
Offline

Joined: Fri Oct 07, 2011 2:08 pm
Posts: 1365
My wheels are handbuilt and I just presumed that was 1 layer of rim tape . Im know expert so I presume then that it is 2 layers , it is very thin . I have had no issues .


Top
 Profile  
 
PostPosted: Tue Oct 09, 2012 10:41 pm 
Offline
User avatar

Joined: Fri Dec 11, 2009 10:38 pm
Posts: 1044
Location: Toronto
Been riding mine all year. Tubed. PR3's at about 90/100psi. single strip of the narrow Stan's tape.

So far so good.

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


Top
 Profile  
 
PostPosted: Wed Oct 10, 2012 12:06 am 
Offline

Joined: Thu May 14, 2009 12:19 pm
Posts: 996
Location: Norway
A friend of mine experienced it. Going uphill, probably 20 kph. 20-23 degrees Celsius.

Image

Image

The rims had seen approximately 3000 km.

_________________
12 Canyon Aeroad CF 9.0 ETE
12 Canyon Ultimate AL
11 Cervélo P2


Top
 Profile  
 
PostPosted: Wed Oct 10, 2012 12:18 am 
Offline
in the industry
User avatar

Joined: Sun Jul 29, 2012 2:59 pm
Posts: 612
Location: Ruidoso, NM
Looks like the wide tape... only one layer, or two? And it's a GP4000, also...

Did he say how long the tire had been mounted?

Mine both came off while riding... but on a level road at moderate speeds. I'd hate to experience this on a descent... could easily be fatal.

_________________
formerly rruff...


Top
 Profile  
 
PostPosted: Wed Oct 10, 2012 12:34 am 
Offline

Joined: Thu May 14, 2009 12:19 pm
Posts: 996
Location: Norway
Well, we were at least 600 km into our training camp. Maybe more. I don't think the tire had been off recently.


Funnily enough I experienced a similar blowout on the same camp. I was going down the steepest descent from the Pico de las Nieves on Gran Canaria when my front tire blew off. Fortunately I was able to safely stop. The rim was warm but not hot. I was riding butyl tubes and GP4000s on new Mavic Ksyrium Elites. Tires had been running perfectly for about 1000 km on the wheels when it happened. No signs of damage to the tire except for that which appeared on the sidewalls when it was ridden and braked on wo air.

_________________
12 Canyon Aeroad CF 9.0 ETE
12 Canyon Ultimate AL
11 Cervélo P2


Top
 Profile  
 
Posted: Wed Oct 10, 2012 12:34 am 


Top
  
 
PostPosted: Wed Oct 10, 2012 3:01 am 
Offline
Shop Owner

Joined: Sat Jun 13, 2009 4:02 am
Posts: 1955
Location: NoVA/DC
djm,
your photos look like a thin/worn sidewall that has given way, leading to the blowout. i think the OP is talking about a blowout with no visible rim damage.
i used to have an old mavic MA40 that had this issue. never did find the reason, but it was more than 10 years ago. nothing recently, but i havent had that many alpha340s come through.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 108 posts ] 
Go to page 1, 2, 3, 4, 5 ... 8  Next


Who is online

Users browsing this forum: Bing [Bot], Exabot [Bot], HaroldC, Yahoo [Bot] and 56 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Tubeless tires with Campagnolo rims?

in Road

eifelschleicher

0

194

Tue Mar 04, 2014 5:41 pm

eifelschleicher View the latest post

There are no new unread posts for this topic. Alpha 340 wind sensitive?

in Road

fitty4

8

613

Fri Mar 14, 2014 10:09 pm

fitty4 View the latest post

There are no new unread posts for this topic. AX-Lightness Alpha weight limits ??

in Road

roadiesean

3

538

Sun Mar 09, 2014 8:59 pm

xsport View the latest post

There are no new unread posts for this topic. Moving a previously installed Alpha Q fork insert

in Road

FastforaSlowGuy

1

274

Fri Oct 11, 2013 4:03 am

goodboyr View the latest post

There are no new unread posts for this topic. Why are tires so much more expensive in the US

[ Go to page: 1, 2, 3, 4, 5 ]

in Road

Bantamben

68

3861

Sat Sep 14, 2013 8:41 pm

sawyer View the latest post


It is currently Sat Jul 26, 2014 4:11 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB