Thanks to a fortuitous meeting with a fellow cyclist and tape engineer a few weeks back I ended up with a quantity of Intertape Polymer Group‘s TPP350 (PDF Techncial Data Sheet – photo) tape in 96mm width (photo) for testing. This polypropylene strapping tape, with rubber adhesive, is exactly the product I’ve been trying to find for use in fat bike tubeless setups. I have very high hopes for this tape, as a narrower and similar tape — IPG competitor Scotch’s Strapping Tape 8898 — has worked fairly well on my Mukluk for the past year. While similar, the narrower 8898 has been a problem for some setups because the width necessitates multiple passes which is hard to seal. For reliable tubeless setups I prefer that the air-holding part of the wheel have as few seams and gaps as possible, and using tape that’s too narrow requires overlapping passes which results in wrinkles and small gaps. These ends of the wrinkles and gaps will get filled with tubeless tire sealant (eg: Stan’s or Orange Seal), but with the side effect of exposing the adhesive to sealant. This in turn weakens the adhesive, resulting in larger gaps which eventually the sealant can’t plug. Thus a leak and a flat tire.
Fat bike rims effectively come in two styles: those with weight-reducing holes cut in them (eg: DT Swiss BR 710, Surly Holy Rolling Darryl, SUNringlé Mulefüt 80SL) and those without (eg: HED Big Deal, Nextie). Hole-less rims are relatively easy to set up tubeless, as only a thin strip of sealing tape is needed to cover the spoke holes inside the rim., but for a hole-y rim an air-tight seal needs to be built up between the tire beads. There are a few ways to accomplish this (eg: split tube, Fatty Stripper, oversized vinyl rim strip), but I prefer a simple, reliable solution that’ll both hold up to repeated tire swaps and allow the locking bead prefer something that’s as simple as possible: a rim strip and full-width tape.
In this case I’m using the stock DT Swiss TRSXXXXS68559S rim strip and 96mm wide TPP350; a very promising configuration. (The DT rim strips are 61g/ea and One wrap of TPP350 on 26″ rims is approximately 20g. Actual tape mass ended up lower, as the tape was trimmed back to the bead seat.)
One of the biggest benefits, but also the biggest downside to this setup, is the width of the tape. Ideally there would be tape that fits exactly within the rim, bead to bead while conforming to the inner shape of the rim, but except for a few cases there isn’t. While a few manufacturers make this available (eg: SUNringlé with a 78mm tape for their 80mm rims) most rims are currently without a solution. Thus, an oversized tape like 96mm TPP350 that can be trimmed to fit is a very good choice. A combination of the lack of stretchyness of the tape and width resulted in wrinkles along the inner rim surface, but as the ends of these wrinkles are outside of the formed air chamber sealant will not be able to leak in and thus are not a concern.
Here are the high-level steps that I used to set up the DT Swiss BR 2250 wheels (based on the BR 710 rim) and Bontrager Barbegazi tires on my Salsa Blackborow. Even without sealant this configuration held air, a testament to the combination of rim, tire, tape, and valve stem. I intend to use this same process and configuration for other test setups, including Specialized Ground Control Fat tires on Stout XC 90 wheels:
- Fit rim strip.
- Apply tape around entire rim, smoothly along top edge of rim wall, overlapping by a few inches at the valve stem hole.
- Press tape down into center of rim. Do not attempt to smooth the tape by wiping along the rim as this will promote large wrinkles.
- Fit tire and tube, inflating until bead is seated. This will press the tape into the bead seat with excess tape overhanging the rim.
- Deflate tube, but before full deflation is reached, dislodge one bead to allow air in. (If this is not done, the collapsing tube and air-tight nature of the wheel assembly will pull the rim strip and tape away from the rim).
- Remove tire and tube.
- Using a sharp blade, trim the tape at the junction of the bead seat and sidewall. Be sure that tape remains in the bead seat.
- Press tape into place along bead seat to ensure it’s smoothly in place.
- Reinstall tire and tube, inflating until bead is seated.
- Deflate tube, again dislodging one side before deflation is complete.
- Remove tube.
- Install tubeless valve assembly.
- Re-seat loose tire bead and inflate until bead is seated.
- Add sealant (3oz) via valve stem and reinflate tire. Shake wheel to distribute sealant.
Due to the thin rim wall the cone-shaped gasket on the NoTubes Valves cannot be sufficiently tightened with just the provided locknut. This can lead to leaking, an issue which I experienced on my Mukluk with SUNringlé Mulefüt 80SL rims. This is easily fixed by adding a rubber washer inside the rim beneath the cone-shaped valve (photo) and a nylon spacer to the outside beneath the lock nut (photo). Specifically, I used a 1/4″ interior diameter rubber and nylon washers purchased from Lowe’s small parts bin, although any similar parts will work. Another style of tubeless valve, such as those from American Classic will not need the rubber washer inside the rim.
After a few hours of semi-hard riding at Potawatomi (fast, flowing, and occasionally rough Southeast Michigan trails) I’m confident in this setup and cannot think of a better existing product for making different kinds of fat bike wheels tubeless. It allowed for the usual tubeless benefits (reduced weight, increased tire compliance) on a solid, air-tight setup. I expect it to continue reliably as a solid tubeless setup throughout the winter; a time when I definitely don’t want to be stuck with a flat. I really hope it becomes widely available, as there are many fat bike riders who’d love access to tape like this.
Here are my pro/con thoughts on using IPG TPP350 tape for fat bike tubeless setups:
- Tape made by a commercial manufacturer. (Although not yet available for order at this width in small quantities…)
- Wide width should accommodate most rim sizes with a single pass, meaning minimal inner seams and lower weight. Wrinkles are a non-issue.
- Tape film and adhesive types (polypropylene film and rubber-based adhesive) are well-tested within tubeless bicycle applications.
- Adhesive firmly holds tape to both rim and rim strip, yet is removable.
- Wide tape width is challenging to handle.
- Tape width and elasticity prevents wrinkle-free application around rim. (Additional material adds weight, may be unattractive if wrinkles are visible through rim strip.)
- Trimming excess tape is inconvenient and potentially error-prone.
- Rim strip required to prevent tape from stretching through cutouts. (Adds weight.)
The result is that I’m quite happy with TPP350 and would recommend it to others for fat bike tubeless use. I’ll soon be trying this out on some other rims.