Steelman54 

Life has been good, I've been riding the bike I built up and probably have 400 miles on it. Yesterday, the front tire flatted, no big deal, looked like a pinch flat, but I didn't recall hitting anything hard.

Today, looking at the tube, I see the leak is on the rim side of the tube at a spoke hole. Rims, tires, tubes have ~400 miles on them as noted above. I can see marks on tube corresponding to each spoke hole, don't recall seeing this before. Have not broken any spokes and the rim is lined with Velox tape and it covers all the holes. Before each ride, I let out a bit of air and pump up to ~110 psi. I'm running 23 mm Conti GP 4000 tires with Michelin tubes.

Anyone seen this before, and do I need to correct something.

Thanks.

Bill Kapaun

I've had rim tape want to migrate and allow a "sliver" of a hole to be exposed.
It was after I'd inadvertently moved the tape enough with a tire lever when repairing a flat to kind of "break" the glue bond.. it was a couple days after the "repair" before it went down.
This was on a rim that was kind of "between sizes" re: rim tape and I'd used the narrower choice. I went to the wider choice and all was/is good.

AnkleWork

Hmmm, lets see:
1. Has both tube and rim in hand but does not examine them closely -- check.
2. Posts vague description without photo -- check.
3. Asks anonymous internet jokers if they "seen this before" -- check.

Answer: No, nobody including the OP has "seen this" yet.
Clue: A close look under good light plus maybe magnification while prodding, etc. will reveal everything quicker than writing a post here. Good luck.

Steelman54 

Bill, thanks for input. I've looked at just this and did not see any obvious issues, but oil had leaked from nipples (while I was chasing a creaking/clicking issue) and was on the rim tape at each hole. I had some rim tape so i replaced it. We'll see how it goes.

Ankelwork, if i had not looked at it, how would i have known i had an issue. You didn't have to waste your time responding.

Andrew R Stewart 

When pressured up even Velox can sink into a spoke access hole and then with no pressure look fine. Like Bill said this is more likely with slightly narrow rim strips or with access holes that are real close to the bead seat wall.

BTW I see you are still running skinny tires that really want very high pressures to keep the rim off the pavement. How much do you weigh? Pinch flats can happen with a side/glancing contact with a pebble/rock. They don't need to be from a direct "hit". Andy

DiabloScott

I was getting multiple flats on my commuter that appeared to be spoke pokes even though the rim tape looked fine.
Finally gave up and put a second layer of Zefal over the first layer of Velox. Overkill FTW.

Bill Kapaun

That was a major contributor to my problem. back when I weighed 240-250 on 25mm tires, I ran 120/110. Now that I'm down to 190, I run 20 PSI less and have several days "seepage" before I need to top them off. Basically when the front is down to 80.

Steelman54 

Andrew, good point. Thinking i'll look into somewhat wider rim tape. I clock in at 160 lbs. Been running 23 mm for years. Could move to 25's for next set i guess.

Steelman54 

I just checked the width of the H Plus Son rims, the TB 14, and see it is 23 mm. I am using 16 mm Velox tape, would 19 mm be OK or too wide?

Andrew R Stewart 

Steelman54- I would not be able to answer your question without the parts in hand. Published rim widths don't include the width of the rim's interior falt portion that has either the spoke access holes or the spoke base (as in a single wall rim). What the rim strip "sees" is not what the manufactures refer to as width. Some rims (more and more currently with the move to tubless compliant designs) have a raised tire bear seat, the seat raises off the floor of the rim (be that the upper wall of the box or the spoke base of a single wall). It is the width between each side's bead seat that the strip must fit within.

I just linked to H Plus Son's site and see that the TB14 does not have the raised bead seat shape though. The upper wall of the box (with spoke access holes) is smooth all the way from one side wall to the other. I would certainly consider using a strip width that extended to the side walls. The Velox 19mm strips will be better then their 16mm ones and the 22mm strip might fit as well. The only concern I have about the 19mm strip is whether it's application will be straight enough to not also effect the tire's seating consistency. Or if the strip is under one side of the tire but not the other side will the tire fit deeper into the rim on the uncovered side.

Rim strip choice isn't rocket science but also isn't always only based on mere math. At work we frequently test fit a short section of a strip (be it Velox or other) to make our final choice. Since the strips are fairly low cost (as compared to getting a flat when descending) I suggest getting both widths and doing the test yourself. Andy

Steelman54 

Andrew, thanks for the comments. I just did a nice 20 mile ride and thought about this and think the 16 mm is probably too narrow for these rims. As you noted they do not have a raised area on each side. I think when fully pressurized it is possible the rim tape could shift a bit and maybe expose the edge of an eyelit, but when deflated all may look good.

I'll take tire off and look again, but it seems that at least 19 mm is appropriate here.

Thanks for the feedback.

Mike

Bill Kapaun

How much is uncovered between the edge of the tape and the tire bead seat?
I had to run my wider tape almost all the way up the side, just barely short of the tire seating area.
I think I used 16mm tape on a 13.5mm width? (SunRims M13II)
I had to be VERY precise to keep it centered.

canklecat

Fairly common problem. With deeper holes in double wall rims I often see tubes with dimples corresponding with spoke holes. Over time the tube extrudes into the unsupported holes and eventually splits -- not a puncture but a split if you check closely with a magnifying glass or loupe.

I'm having fewer problems with cloth tape like Velox, but I still inspect my tubes every few months if I haven't had any flats. I've been using some of Continental's ultra-thin tubes in my spares kit (only way I can fit a tube, CO2 rig, lever and minitool in a Lezyne Road Caddy) and noticed after recently using one that within a few weeks the new tube was already showing dimples even with Velox tape. With Conti Race 28 Light tubes, there ain't much material there to withstand fatigue from extruding. With thicker tubes it can probably go months or years without problems, even with visible dimpling.

I'm considering trying Schwalbe's supposedly more rigid plastic rim strips on one bike, or at least one wheel, to see how it goes.

Steelman54 

I've been fiddling with bikes for lots of years and think I'm reasonably knowledgeable, but you guys blow me away with your knowledge. Cankelcat, great info. Probably something for me to do here, although I checked my other wheels and do not have this issue.

I took tire off the rim and did some measurements. 16 mm is definitely marginal probably even if perfectly installed just by looking at it. There appears to be adequate room for an additional 3 mm (0.120") if I use 19 mm Velox. But some measurements are in order to verify before I kill yet more time.

Using my calipers, the rim checks at 22.98 mm out to out. Inside is 17.65 mm with a 2.67 mm wall at the hook (times 2 of course), this adds up to 22.98 mm, perfect! Did this a few times to verify.

Best measurement I can get says the hook is 0.050 to 0.060" (1.25 to 1.50 mm) proud of the rim wall. This leaves the wall at approximately 1.4 mm using the thickest choice from my measurements. Keeping it simple this says out to out of 23 mm minus 2 * 1.4 or 2.8 mm leaves 20.2 inside to inside.

Seems like 18 mm would be the ticket, but Velox makes 16 and 19 (among others). So, my plan is score a pair of Velox 19 mm rolls and carefully install. I'll search to see if an 18 exists for the heck of it.

Thanks.

ThermionicScott 

19mm gets my vote. With the slight curve of the rim bed, you'd need something very slightly wider than the wall-to-wall width straight across, anyway.

Steelman54 

Just an update as i just finished installing new rim tape and remounting the tubes/tires.

I now realize an earlier flat on the other wheel was also on the rim side and due to rubbing on the eyelet.

I wanted 18 mm tape, but all i could find was the Conti strip that most said was a real pain to install, so i went tried and true with my old pal Velox rim tape. They make a 19 mm.

Not rocket science as someone earlier stated, but I took my time to make sure the tape didn't run too far to one side or the other. Tires seemed to sit in the rim as they should.

Pumped up to 100 - 110 psi, we'll see how we do on tomorrows ride.

Thanks for the help here.

Bill Kapaun

I'm glad everybody else could help.