Some tasks are objectively simple but manage to be humiliating the first time you attempt them unprepared. Changing a bicycle inner tube is one of them. Once you've done it twice it takes about ten minutes and feels like nothing — the trick is getting to twice.
The Lazy Person's First Line of Defense: Green Slime
Before we talk about tube replacement, let me make a case for the lazy approach — which I say with affection, because I've used it and it works.
Tire sealant goes by several brand names but everyone calls it green slime. The concept is elegant: liquid sealant inside the tube coats the inner surface, and when a small puncture lets air escape, the escaping air pushes the slime into the hole and seals it.
You inject it through the valve stem with a small bottle and nozzle — about thirty seconds of work. For an existing pinhole flat (from a thorn, a piece of glass, or a staple), you add the slime, pump the tire back up, and ride around for a few minutes. You might need to re-pump once or twice while it sets, but then one day you notice the tire is still holding air a week later.
I wrote in a recent post about plumbing about how Richmond's mineral-rich water will sometimes self-seal a slow drip in a fitting if you wait long enough. Green slime is the same idea, but intentional.
The asterisk: slime only works for small punctures. A glass cut, a sidewall blowout, or anything larger than a pinhole will defeat it, and you'll need to change the tube. Slime also makes a mess if you do end up having to change the tube — and if you keep adding slime to remedy successive flats, the tire gets noticeably heavy. (Don't ask me how I know.)
When You Actually Need to Change the Tube
Okay. Here's the process, stripped of mysticism.
What you need:
- A replacement inner tube (matching your wheel size and valve type — check the sidewall of your tire)
- Two plastic tire levers (not metal — metal levers will pinch the new tube)
- A pump
- Nitrile gloves, if you have them
- Some bicycle experts apparently use baby powder or something, to add between the tire and the tube. None of those are still reading, so I'm going to skip that step.
On the gloves: this is not a dirty job exactly, but tire rubber and rim tape leave a grime on your hands that takes real effort to wash off. A pair of disposable nitrile gloves — the kind you probably have around if you do any painting or plumbing — makes the whole thing cleaner and actually improves your grip. Highly recommended.
The steps:
Remove the wheel. Most bikes have a quick-release lever; e-bikes with hub motors may require a wrench and — on rear wheels — disconnecting the motor cable before the wheel will drop free. Note how the cable routes before you disconnect it.
Let out whatever air remains. Press the valve pin on a Schrader valve (the car-style one), or unscrew the lock nut and press on a Presta valve (the skinnier one).
Use a tire lever to pop one bead of the tire off the rim — hook the lever under the tire edge, lever it over the rim wall, and then slide it around the rim to free one side of the tire completely. The second lever gives you a starting point if the first inch is stubborn.
Pull out the old tube. Before you throw it away, find the puncture. Hold the tube up to light and slowly squeeze it; you'll usually hear or feel the air. Finding the hole tells you where to look on the inside of the tire for whatever caused it — a shard of glass, a wire, a thorn. Run your fingers carefully along the inside of the tire to find it and remove it. Skipping this step means your new tube meets the same fate within five minutes.
Put a small amount of air in the new tube — just enough to give it shape, not enough to be firm. This keeps it from bunching or getting pinched as you install it.
Work the tube into the tire, starting at the valve. Seat the valve stem through the rim hole first, then work the tube around inside the tire. Tuck the valve stem straight before you proceed — a crooked stem will cause problems when inflating.
Work the tire bead back onto the rim by hand, starting opposite the valve and working toward it. The last few inches are always the hardest. (That's the part that can drive you crazy, until you've done it a couple times.)
Inflate slowly, stopping partway to check that the tire is seating evenly on the rim — there's usually a small molded line on the tire sidewall that should be visible and consistent all the way around. Then inflate fully.
Reinstall the wheel. On e-bikes, reconnect the motor cable before you forget.
That's it.
A Word on E-Bikes Specifically
Same thing, only with extra cables, and the back wheel is a bit heavier due to the motor.
The Honest Local Option
To be upfront: if you can get your bike there, Outpost Richmond at the corner of Forest Hill and Westover Hills will change your inner tube cheaply, especially once you factor in the cost of the tube. If you can lug the bike there, that might genuinely be the right call for your first flat.
But sometimes the bike is at home, you have a trip planned in two hours, the car isn't available for bike transport, or you simply don't want to deal with any of it. That's where doing it at home has a real advantage. And if I'm already at your place for a tech house call — running a virus scan, cloning a hard drive, something that involves waiting while a progress bar does its thing — tire maintenance is a good parallel task to take care of in the meantime.
The Guarantee
I'll stand behind my inner tube work, unless you find yourself riding down Belt Boulevard, which is a Bermuda Triangle of shattered liquor bottles (especially the stretch under Midlothian Turnpike).
Ride safely, bring a pump, and keep some green slime in the house.
Need a hand with a flat — or a hard drive? Get in touch. RVA Tech Help serves Forest Hill, Westover Hills, Carytown, and the surrounding neighborhoods.
— Johanna