Punctures on the inner quadrants of the inner tube

[Farrina]

I have recently acquired a new set of 700c wheels hand built by a reputable local builder. Rims. hubs, tyres (23c Michelin Lithium), rim tape and spokes are all shiny and new.

So far I have ridden approximately 3/400 miles on them and they have been fine apart from one rather important matter - I regularly experience punctures in the back wheel. I can go a few rides with no issues (say 100 miles) and then its back.

Checking my inner tubes (Michelin Air Stop 18-25 622) the punctures have all occurred on the inner 180 degree face of the tube. Each time it has occurred the puncture holes are very small, almost pin head sized.

The rims are a "V" section so the spoke nipples are deeply recessed and nowhere near the inner tube.

So far I have replaced

The inner tube with a brand new tube.

The existing rim tape with Continental 16 mm easy tape (rated to 220psi) taking great care to ensure it is centralised and covers the inner section of the rim.

Carefully inspected the rim for any sign of sharp edges, loose swarf etc. Likewise on rotating the rim I cannot hear any swarf rattling around.

As you might imagine this is all rather frustrating and I wonder whether the readers have any pearly words of wisdom or suggestions as to what I might try to resolve this issue ?

[superbagneres]

Perhaps the issue is with a bad batch of inner tubes if you are using the same brand, can you try with another brand?

[mig]

are all the holes in the tube in the same place in the rim?

i.e all at "ten past the hour" clockwise in regards to the wheel etc

or do they occur randomly?

[2_i]

Identify the location on the rim where the punctures come from. Examine the rim in that area in detail. Pass a cotton swab through there to see whether it gets caught by anything that your hand might not find. There is some rational explanation there for these punctures.

[Marcus Aurelius]

Pass a cotton wool ball over the entire rim and look for any snagging, check all the new tubes for existing problems by inflating them and dunking them in a bowl of water. Make sure that there isn’t any semi loose swarf at the valve hole that you may be dislodging into the rim as you swap tubes.

[Brucey]

is it possible to see a photo of the rim tape in situ?

What type of rim is it?

cheers

[Farrina]

Thanks to all for the helpful suggestions and observations.

I don't presently have any cotton wool to hand, but will take this further once I have an opportunity to obtain the same.

The holes in the inner tube are NOT in the same place and seem to occur randomly (albeit only in the rear wheel so far!).

Typically the punctures take the form of a slow puncture - it almost appears that over a period of time a microscopic particle is abrading the tube until it eventually punctures. Obviously there is no sign of this once the tube is extracted.

To answer Brucey's question the rim is badged as a Pianni - not a brand I have heard of before. I believe that the wheel builder may source them direct from Italy (?) and badge them himself. Given the lamentable quality (braking thickness) of most modern rims this did not cause my any concern. It should be noted that I have another pair of built rims of the same brand that have caused me no issue.

Pictures attached as requested (unfortunately the rim tape is black so little contrast to view situ)

[foxyrider]

wasn't Pianni the name Pete Mathews adopted for his rims?

[Farrina]

wasn't Pianni the name Pete Mathews adopted for his rims?

Well given that is the name of the wheel builder, you’d be correct !

[Brucey]

is it possible that the rim tape is slightly to narrow for the rims, and the edge of the tape is causing the punctures? The rim appears to have a kink in the well just where the rim tape might be if the edge of the tyre bead isn't over it, which would tend to hold the edge of the rim tape up, turning it into a chafing instrument.

Problems of the sort you describe are nearly always a problem with the rim tape.

If the tyres are not already a stupidly tight fit I would suggest using a (preferably self-adhesive) tape that is definitely so wide the tyre beads will sit on it.

cheers

[MikeDee]

Are you using tire levers to mount the tire? Do you have some air in the tube to prevent pinching?

[cycleruk]

With reference to Brucey's suggestion - run some electrical insulation tape over the rim tape edges and try that. I had a similar happening recently and now seems alright since replacing the old rim tape.

[Farrina]

Thanks to all for the further suggestions/observations.
Have gone with the electrical tape suggestion and will report back (fingers crossed)
Cheers

[Farrina]

Thought I would post a follow up (probably tempting fate by doing so mind!) to say that since adding electrical tape to the mix, my puncture problem has ceased.
Fingers crossed, long may it continue.
Cheers

[Brucey]

IMHO electrical tape is good for diagnosis/short term fix, bad as a long term repair. When new it can slide around, stretch, wrinkle and/or ruck up in use or when you remove tyres. Eventually it goes hard and brittle; the edges can then cause punctures in their own right, much as you have had already.

So my advice is still to get some proper rim tapes, if you want the problem solved in the long term.

cheers