14 Sep 2013

Mounting tight tires

Webmaster

Sometimes it can be difficult to mount a specific tire on a specific rim. It should be simple but feels impossible so you’re not happy at all. Don’t give up hope!

Setup

Rims and tires are built to different tolerances but within a range that lets them work together. Tolerances are not all the same. If you’re having problems with a particular rim, what kind of rim tape are you using? A thick cloth tape (e.g. Velox) exacerbates tightness. Try Veloplugs or a thin tape like Stan’s. If you’re using tubeless-compatible rims, definitely use Stan’s.

Tools and techniques

  1. While working a given bead, ensure the mounted part sits centrally in the inner channel. There’s more room in the center where the channel is deepest. The bead can migrate as you work so keep this in mind and reset as needed.
  2. Work the second bead starting opposite the valve.
  3. If working the bead in one place causes it to unmount in another, hold the mounted part in place with a strap acting as a third hand. A toe strap works well.
  4. It’s natural to work by pushing under the bead but the bead can be pulled too. Push and pull.
  5. Lube the tire beads and rim sidewalls with a diluted dishsoap solution. This can make it easier to push the bead over the top. Bike-specific products exist but the soap from your kitchen is fine.
  6. Lube your tubes. Premium tubes come pre-coated with talc but you can shake tubes in a bag of powder as well. Dusting the inside of the tire is good too and less messy. Talc acts like tiny bearings that help the tube slide against the tire.
  7. Use a tool like the inexpensive Kool Stop bead jack. This tool is better than a tire lever because it’s more rim friendly and works faster. The bead jack works by pulling the bead against the far edge of the rim so less force is required compared to a tire lever on the near side.

Of course some of these strategies are only appropriate in your home shop. The good news is tight tires can break in after the first few rides so fixing a flat on the road gets easier.

Another perspective

A tight tire may be a blessing in disguise. What happens in the event of a blowout and sudden total deflation? A loose tire may roll off the rim leading to a crash. Tight tires tend to stay put.