(Apologies if this belongs in the general section, but I figured things are a little more 'technical' in here.)

So while taking the ferry with my bike, I sometimes like to think about, or plan for, what I would do in an emergency situation. Naturally this led me to consider the fate of my bike/bikes as well. The ferry I take does not allow bikes in the passenger cabin area, so they are generally left out on the front deck, and I never put mine on the racks provided (they flop and bang around...)

This brings me to my question: should something bad happen, would my bikes be able to float if they were free from entanglement? I know that the tires and tubes probably provide some buoyancy, but would it be enough to compensate for the weight of the bikes?

To make it a little more complicated, here are three spec levels that pretty much cover the range:

1. Aprox. 25 lb steel frame, plastic fenders, 700 x 35c tires
2. Approx 21 lb steel frame, 700 x 25c tires
3. Approx 18 lb aluminum (or carbon) frame, 700 x 25c tires

Thoughts?

Nope

In any scenario in which this question is relevant, I think you will have more important things to worry about than whether your bike can float.

Sink like a brick...

Some of you guys never rode your Spyder bike into a lake off a homemade ramp built at the end of a dock, and it shows.

Are you "nope" guys speaking from experience, or just hypothesizing? Both are fine, of course.

My father is a big boater so I grew up spending a lot of time around the water, and the buoyancy of some small objects can be impressive. That's what made me think it was impossible. And to be clear, I'm not necessarily expecting a strong bobbing around on the surface, but maybe frame down with just the contact patches of the wheels barely staying at the surface.

I thought it went without saying that this is really just a thought exercise, and I'm not going to risking my life, or anyone else's, for a bike. For a little more background, this ferry crosses the East River, which can get a nice little rip going but generally isn't particularly wide.

Owned Three BOATs.

My bike has pretty big tubes, pretty big tyres, and is made from titanium. But, unfortunately, it has breathing holes in the frame tubing. I am certain it won't float. Just remember that if a bike weighs 15 kgs, it has to have at least 15 litres of air trapped to keep it from sinking. I am certain my bike won't float. At least for more than a minute.

Down here we all float

I was once at a Deep River Boat Ramp.
Divers were in the water.

A New 25 Ft Boat Owner with a Brand New Tahoe sank both of them.
Nothing Floated.

Oh, maybe I should have googled at bit first:
I know, it's carbon, but those are some skinny tires and it seems to be floating easily.

It also has stupid-deep dish wheels, and I'm betting every hole in that the frame, seatpost, handlebars etc. are closed up on purpose.
So, is your bike that light? Does it use foam tape on carbon handlebars, have a carbon seatpost and saddle and so on?
It's a question of displacement. In other words: Volume vs. weight. If the volume is bigger than the weight, it will float. If not, it'll sink.
And no, I'm not dipping my bike in saltwater or chlorinated water to test it. I'm not even doing it in fresh water. Salt water, btw, is more buoyant than fresh water. You do the test with your own bikes.
Hell, even my handlebars wouldn't float, but then they're not carbon (Ti), and they're not covered in foam.

Check these photos of the Amsterdam canals when they're drained for cleaning. https://www.google.com/search?q=amst...HVwGukTmYUY_RM
And video.

An experiment is the only way to be certain...

Maybe.

Is it a Kona Humuhumunukunukuapua’a?

But I’d install a Fox Float just in case.

John

As CargoDane noted below, I'm not too keen on the idea of subjecting my bike to any variety of water. That's why I'm asking, otherwise I would have tried by now...

I realize it is carbon, but that isn't even close to sinking. As you might have seen, none of the bikes I asked about are anywhere close to 15kg, so I think it might be close. What is the volume of a 700 X 25c tire?

Not enough. Do you have waterproof deep-dish wheels?
As for 15 kilos - it doesn't matter. If it's 7 kilos, it has to displace 7 litres of water to float.

In all seriousness, if you are concerned you can buy a mast float that is normally attached to the top of a sailing dinghy. I’ve have used one when the wind picks up and the mast will take in water if it capsizes.

I think there are ones you can fold up and then blow up if you need to. For that matter any study inflatable bag will work. You will have to figure how much buoyancy you need. Maybe use a surf leash to keep the bike close when you’re in the water.

As others have said, you’ll have more important things to worry about, but...

John

In a still pool for a short period of time. There's a lot of volume in those carbon rims and the frame. The problem is that frame and rims aren't water tight, so once water starts getting in, it'll go down. Cars also "float" in a similar fashion.

After the rims and frame filled up (this would take a while), it might have a tougher time floating. He might have specially prepared the frame to be water tight. Rims would be tougher (rubber washers on the nipples?).

I think once you get up to 2" tires on a 25-lb bike you have a good chance of floating the bike even if the frame fills up with water.

This bike weighs close to 50lbs and floats quite well with its 4" tires.

I think I have a test you can do: Take the wheels off, lube the wheels everywhere (and I do mean everywhere) with a good thick coating of silicone grease. Put them in a big homemade pool (with freshwater) or a kiddie pool or something. Do the wheels float by themselves?
Secondly, take your now wheel-less frame etc. Coat everything there with silicone grease too (also the internals of the shifters and whatnot, plug up all the holes of your frame (maybe do this before applying the grease). Does it float?

After that, use actual soap with no water contents to wash your bike. Bronner's is a good one.
When you are finished with that and you are sure every little bit of grease is gone (maybe you need to disassemble the thing), you use 99.9 % percent undiluted isopropyl alcohol to remove the soap (again, don't use water). After that you can regrease the parts that's supposed to be greased and put it back together again.

For an easier "test" that can't be taken as a positive ("yes it'll float") but certainly as a negative if it sinks is to vacuum bag the rims/tyres/nipples and the hub. If that sinks, then it will also sink without the vacuum bagging. If it floats, well, it might just be the added volume of the vacuum bagging.

Other than that, if you had a wheel you'd take apart anyway, you could tape the spokes to the rims, tape over the nippleholes and tape the hub with the holes tapes over onto the rim too. If it floats, then at least the wheels by itself will float. They have to float enough to make up for the solid and narrow tubes at the ends of the frame/fork.

It'll float, until it doesn't.

I think he should get this for himself (Switlik one-person liferaft):








And this for his bike (a packraft):

Are you just curious about this as an academic musing or are you serious with your worry?

If the former, you can certainly determine for yourself empirically (or go through some rather ponderous calculations like I did on my boat to determine whether my buoyancy chambers were sufficient for my planned ballast).

If the latter, why not consider attaching a self-inflating CO2 float bag to your bike.

You must have one of those tinkly masts.

If a typical steel frame with normal sized tires, no, it will not float.
Yes, this response is based on Practical Experience.
Signed,
Mr. Scuba