I recently bought a bike off the side of the road to fix up and restore. It’s a bright red Ross road bike from the 1980s or 90s. I’ve made my way to the wheels with fairly little trouble, but the rim tape has caused a few snags. The dimensions of the wheels are fairly unconventional, according to the Internet, at 27” by 1 1/4”. I was told that 700c rim tape would work well, however when I installed it, my tubes got about 6 or 7 punctures. In mm, the dimensions of the wheel are 630x17, while the rim tape is only 16mm wide. What size rim tape should I use, and where can I find it? Also, the nuts that hold the spokes to the rim jut out about 3mm from the inside of the rim.

For older bikes, I use to use tape that was at least wide enough to cover the spoke holes with a couple millimeters or overlap but narrow enough that it didn't get up on the bead seat of the rim. So depending on the inner profile your 17mm wide rim, it depends! <grin>

Velox was considered among the best. But I used what ever cloth tape I could find. It's gotten hard to find the wide variety of widths we use to find in it. I haven't looked in a long time though. Tubeless and tubeless ready rims are a slightly different concern and we don't use cloth tape any more. I suppose you could get some of that too.

Just ask at your bike shop what they use and get what they have or any online seller you care to use. It's not the rocket science that some make it to be. Just make sure to cover the spoke holes or spoke nipples. Whichever is closest to your tube.

Odds are the rim tape wasn't the cause of your flats.

FWIW the rims profile is sort of like this I-__-I, with 2 shoulders where the tire fits, and a lower center where the spoke nipples sit. The correct tape will be the width of that center well. My personal preference has always been cloth surgical tape because it's cheap and effective.

As long as the spoke nipples are covered, and no spoke is poking through, that's not the problem.

Odds are your flats were caused by poor mounting technique, and not the rim tape.

That’s very possible. I’m a complete novice when it comes to installing tubes. My current method is prying one bead of the tire onto the rim, then sort of haphazardly cramming the tube in while prying over the other bead. That being said, when I removed the rim tape, there were little pin holes where some of the nipples hit the tape. Also, the holes in the tube were on the inside, and similar in size and location to those on the tape. Would it be a waste of time/stupid to try and file down the sharp edges of the nipples?

The nipples can't have sharp edges, burrs or spokes protruding beyond the head. A rim tape/strip has limits.
A Dremel or similar & grinding stone can be used to smooth down "sharp" spots.

I presume these are single wall rims since you mention the nipples.
On a double wall rim, I've found rim tapes that are a bit narrow may leave s spoke access hole slightly uncovered.
I like rim tape width that "just barely" starts to run up the wall, but not enough to be involved in any bead seating issues.

i don't know enough about what you're asking to hazard a guess, but i do feel the Gods of Rubber & Planing smile down upon me when i coat both the inside of the tire & the tube with talc powder.

i bought a bottle in '14 and it's still about 60% full. it was about $7 + tax

like Brylcreme, a little dab'll do ya.

Tube mounting technique sounds fine. Add a little hit of air to help avoid oinch flats.

Spoke nipples sound bad.

For 17mm internal rim width, your rim tape should ideally be around 18-19mm wide to fully cover the spoke holes and provide better protection. The 16mm tape you're using is likely too narrow, allowing the spoke nipples to come into contact with the tube, causing punctures.

Also...look for rim tape that is specifically made for 27" wheels with a width of at least 18-19mm. You can search for "27-inch rim tape" or "630mm rim tape," and check the width in millimeters. Velox or Continental rim tapes are often recommended and come in wider options. Alternatively, fabric or thicker rubber rim strips can provide better protection than standard plastic rim tape.

For mounting and dismounting the tire bead, are you using bicycle tire levers, or just a flat-blade screwdriver? Genuine tire levers are essential. I like high-strength plastic ones as they don't scratch the rims, and they are strong enough. As someone else on here pointed out, it may seem counterintuitive, but for a tire with a really tight bead, hard to get on and off the rim, you want to dismount/mount the tire opposite the valve stem first, and at the valve stem last; This is so the part opposite the stem, you can set the bead down into the "drop center" on the rim, to allow more slack when mounting at the valve stem. After mounting tire with tube, inflate tube about halfway, let air out, then inflate tube fully; This helps straighten out any twists and wrinkles in the tube. I personally think it's better to just barely inflate the tube so it stays straight, place it inside the tire, mount one side of the tire onto the rim, then do the other, and if not easy, let air out of the tube and then put on the rim fully, and reinflate.

Q: (related question) Are rubber rim strips a thing of the past?

Nope. My bike currently uses them.

Now, a wheelset I bought for my road bike 25 years ago, came with a thick strip permanently heat-bonded together at the overlapping end, looked like plastic, but when I had a couple flats I saw it was a thick fiberglass package banding strips, which had spit at the nipples and exposed the fiberglass, causing the flats; Got rid of that and put on Velox.

perhaps the rim strips are not covering the spoke nipple heads...they can be sharp
rubber rim strips work great and last a very long time
the rim strip you describe should work fine as long as it is covering the heads
very possibly user error

I hope you're not using tire levers to do all this "prying."

Update: I removed all the spoke nipples and rounded them over so they’re weren’t any sharp edges. Then, I reinstalled the rim tape I had before with some talc powder on the rim, tube, and inside of the tire. So far, it’s holding pressure, and I can’t hear any leaks.

If you’re careful with the tube, this is fine, surely?

Not too sure what else I’d use…

Your hands, of course.

Definitely not recommended. 27 x 1 1/4 tires are probably some of the easiest to install without levers.

The drama about finishing a tough install with a tire lever is ludicrous. My grandsons balance bike has the worst to install rim tire combo I have ever encountered. I use the Park TL-6 steel core tire levers to remove and install the tire when he has a flat. For those who don't think this is a good idea, I say you should leave this kind of problem up to the professionals.

There is no drama—or new tube punctures— when tire levers aren’t used. This professional never used them once in his 10 year career.

smd4: I have never put a puncture in a tube using a tire lever to work the last little Section of the tire over the rim. It is easy to do if you are not observant in what you are doing.

Maybe not you, but countless others have. It’s definitely not a “best practice.”

27x1-1/4" isn't anything special, it was one of the most common sizes but hasn't been fitted on many new bikes since the 1980s. Many 27x1-1/4" bikes can use 700C wheels, with a much wider choice of rims and tyres -

I think you’re maybe more likely to pinch a tube rolling the last bit of tyre on using your thumbs (and some tyres are a lot tighter than others - edit: just saw your comment about this particular size - that’s a good point) as a tyre lever can help push the tube away fron the rim.