Tubeless Tire Repair Testing: What I Learned Slashing Tires and Sewing Them Back Together

As a bikepacker and tubeless tire convert, I’ve dutifully followed the standard advice for many thousands of miles: carry a needle and thread for sewing sidewall gashes and other damage too big to fix with a plug tool. 

But as luck would have it, until I began designing a tubeless-specific repair kit for my Adventure Kits project, I had never actually needed that needle and thread! Despite plenty of rough riding in places remote enough to tempt fate, my tubeless tires had never (knock wood!!) needed repair.

When I started slashing tires and testing my supplies, I was surprised by how hard sewing a tubeless tire can actually be. Maybe it would be easier with the right materials?

So I gathered various needles and threads, some old tires, a knife, and my patience, and set about testing until my fingers bled I found a combo that works.

Below I’ll share the exact tubeless tire sewing supplies that work best for me and some important tips for using them. In my opinion all bikepackers, and adventurous mountain bikers who ride in remote places, should carry them.

You can compile these supplies yourself, or you can pick them all up in one fell swoop (along with a handy instruction booklet) in my Tubeless Tire Repair Kit. I buy the bits in bulk at lower markup, divvy them up, and pass the savings on to my fellow bikepackers.

The Best Needle

A curved upholstery needle is the standard recommendation for tubeless tire repair, allowing you to sew up a gash without unseating the tire bead from the rim. But while struggling to jam a variety of needles through thick rubber I learned not all such needles are up to the task. 

Based on my tests, you want a “C shape” curved needle intended for upholstery or leather in a size of 2” or 2.5” (ideally one of each because they can break). The size is measured along the curved length from eye to point.

I tested both longer and shorter curved needles, but 2” and 2.5” were the sweet spot. For one thing they make stitches of about the right size. Also the whole needle scales with length, so smaller needles are thinner and larger ones thicker. Smaller needles were too flimsy and larger ones too difficult to push through the tire.

The Best Thread

Everyone has their own favorite when it comes to thread. I’ve seen experienced bikepackers swear by fishing line, nylon upholstery thread, waxed thread, and the old DIY favorite, dental floss. 

I tested them all and my favorite was braided fishing line made from UHMWPEf, a mouthful of an acronym that stands for ultra-high molecular weight polyethylene fiber. The 50 lb rating is the best balance of strength and diameter in my opinion (larger diameters are stiffer and harder to pull through the tire) but it comes in rated loads from 6 pounds all the way up to 80 pounds. 

Braided fishing line has all the properties you want for sewing tubeless tires: strong, abrasion-resistant, low stretch, low friction (easier to pull through rubber), cuts cleanly (easier to thread needle), easy to knot, and low memory (doesn’t stay kinked if it’s been tied or wrapped). It even comes in bright colors, making it easy to see clearly while you’re sewing. Who knew fisherpeople and bikepackers had so many needs in common?

So what about the other contenders? I repaired a test gash with each of them, and also tested their strength in the highly scientific manner of pulling on them until they broke. Here are my results:

Regular fishing line: Stiff, hard to work with, hard to see.

Dental floss: Not bad, a simple cheap material you probably already have (unless you’ve been lying when the dentist asks how often you floss…). But I found that it breaks easily under tension and can be tough to pull through thick rubber. 

“Extra strong” nylon upholstery thread: I tested this stuff and it was a bit too stretchy and thin, stronger than floss but weaker than braided fishing line. 

Waxed thread for leather, carpet, etc: I tested this and it was not very strong, and also hard to work with. Despite the wax coating it was still hard to pull through rubber, which turns out to be the crux of sewing a tubeless tire. The thickness also makes it hard to thread the needle. 

There may be better versions of those threads out there, but I got tired of ordering spools on Amazon and I suspect most of my readers would too. I stand by my choice of UHMWPE cord / fishing line and it’s what I carry now.

Here’s a quick video of my highly scientific strength tests:

Unexpected Innovation: Rubber Thimbles

When I first tried sewing a tire gash, I was surprised by how hard it was. People make it sound so casual! Just sew up your sidewall by headlamp in the rain in the middle of the night and keep pedaling! Well, it wasn’t that easy for me. 

The crux of sewing a tire is pushing / pulling a needle and thread through strong, sticky rubber, over and over, ideally without jamming either end of the needle through your skin. 

For this purpose you want one of two things: pliers (I use the ones on my Leatherman PS) or – now hear me out on this – rubber sewing thimbles.

I wanted the Tubeless Tire Repair Kit to be comprehensive enough that no one would be stuck for lack of supplies, but pliers are bulky and expensive and some folks already have them. I eventually hit on the idea of grippy rubber thimbles and I’m quite proud of this innovation! 

Rubber thimbles are small, light, and cheap, and they massively improve the sewing experience if you don’t have pliers. Use them to push the needle through the rubber without puncturing a finger, then pull the point of the needle out from the other side to finish the stitch.

Bonus: Other Tubeless Tire Repair Supplies

What else should you carry in a comprehensive tubeless tire repair kit, the kind that can get you out of a sticky situation on a bikepacking trip or a long and adventurous MTB epic?

First, obviously, a mini pump and extra sealant. I never pedal out of my driveway without these. 

I also carry a spare tube and tire levers so I can, in theory, put in a tube if I fail to repair a tire. In practice I’ve wondered how I would ever remove all the thorns and sharp things from my tire so as not to instantly pop the tube. I’m still waiting to find out, but pliers wouldn’t hurt.

A tubeless tire plug kit (inserter tool plus rubber “bacon strips”) is a basic essential, even moreso than needle and thread. It’s used to plug punctures that are too big to self-seal and too small to need sewing. It’s good to carry both small strips and big strips, but in a pinch you can use multiple small strips to plug a larger hole.

Sometimes a tire plug or sewing job needs extra reinforcement. That’s where a mini tube of Super Glue or similar comes in. Use it to hold things in place and fill in gaps while you try to get sealant into the crevices. 

If worst comes to worst and you need to put in a tube, you’ll also want tire boots (I make my own from Tyvek but I’ve heard dollar bills and food wrappers work) and tube patches (I like the glueless kind). 

Gorilla tape and a couple alcohol swabs round out my tire repair supplies. The tape can help with gnarly repair jobs or leaky rim tape. The alcohol swabs can make repairs and patching easier by cleaning the rubber surface first. 

For longer bikepacking trips where finding spare parts might be tough, I suggest carrying some valve bits: a spare valve core, core remover tool, entire spare valve stem, and a Presta-to-Schrader valve adapter in case you need to air up from a Schrader pump.

You can compile all these bits yourself, but if you’re starting from scratch the cost adds up fast. I’ve put it all together (except mini pump, sealant, and spare tube) in my Tubeless Tire Repair Kit, where I buy the bits in bulk for lower cost and pass the savings on to customers.

Bikepacking friends, share your tubeless tire sorcery in the comments below! Do you carry something I didn’t mention? What’s been the most valuable thing in your repair kit so far?

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