Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take part in the June Giveaway for a brand new Merida Matts 6.5 bicycle


Leaky Dunlop valve
#1
I've got a cute little Japanese Asahi bike that I am told has Dunlop type tire valves. The last time I filled the tires, using a Presta valve adapter and an air pump, everything went OK with the tire inflation, and there were no leaks after filling. This time, the front tire inflated just fine, but the back tire leaked air constantly from around the valve and its attached adapter, and when I unscrewed the adapter, the tire rapidly deflated to the point of flatness, and even with the cap on, there was still the sound of leaking air. I did remove the pin inside the valve after this, since it slipped out very easily. At the base of the pin, there appears to be a small rubber gasket that looks intact, as far as I can tell. The small flanges on this pin fit right back in the grooves on the valve stem, so I don't think I disturbed the pin that much. I tried wetting it down with a bit of spit, but when I attempted inflation again, the same thing happened.

I really don't know much about these valves, and I can see why they wouldn't be very popular. What I'm wondering is if I can fix this valve myself, and I'd appreciate any input. Fixing this myself would help me avoid ridicule from the local bike shop guys who would much rather sell me something new than fix anything. Thanks for your advice!
  Reply
#2
OK, main problems with Dunlop valves are valve not seated correctly (the nut is loose) and a damaged rubber tube (though they now use a different technique). As both things seem to be OK, you can try replacing either the rubber tube (might be porous) or the complete valve. If that doesn't help replace the inner tube. Spare valves and the little rubber tubes used to be included in most patch kits here (at least in Germany). This kind of valves is now a bit less popular, I guess because you can refill tyres with Schrader valves at the gas station. Dunlop valves had the advantage that they were simple and you could replace them very easily. People used to patch the tyres so the valve had to last for quite a while, nowadays many just throw the tubes away after a puncture.
  Reply


Possibly Related Threads...
Thread
Author
Replies
Views
Last Post
 
9,068
05-11-2014, 09:34 PM
Last Post: DaveM
 
11,637
04-15-2014, 10:56 AM
Last Post: nfmisso
 
7,584
11-13-2012, 10:51 PM
Last Post: Bill
 
13,175
05-04-2011, 01:37 AM
Last Post: Bill

Forum Jump:

[-]
10 Latest Posts
Merida Matts 6.5 Bicycle | June 2020
Today 03:45 AM
Rear brake tension
Today 03:20 AM
Modernizing my Fuji Gran Tourer
Yesterday 10:33 PM
Hello from south west Florida :)
Yesterday 09:27 PM
Where are you from and What is your favo...
Yesterday 06:43 PM
Fuji are suspending the sale of police b...
Yesterday 06:23 PM
Buying my first road bike
Yesterday 06:18 PM
Holes in my road tires
Yesterday 06:07 PM
Dia Compe Versa C5 spring issues
Yesterday 03:56 PM
Downtube Shifters on 1991 Miyata 721
Yesterday 01:37 PM

[-]
Top 5 Posters This Month
no avatar 1. Jesper
28 posts
no avatar 2. CharleyFarley
18 posts
no avatar 3. Painkiller
16 posts
no avatar 4. Joe_W
12 posts
no avatar 5. G_M
9 posts