.. could I get a bit more pressure to wash the bike?

So hose is connected to the mains water supply, I get 0.5bar on a good day, rubbish really. I was wondering what would happen if I put a pump in the circuit? Would it be able to drag the water out of the main at a better pressure or would the pump just die from pulling too hard?

All purely theoretical of course.

No. You can’t suck more water out of the tap! However, fill a barrel and drop a submersible pump into it and you might have more luck!

You can’t suck more water out of the tap

Thanks PP, I do like a nice succinct explanation – not what I normally expect from STW! Nobody’s even asked what diameter of hose or whether I’m using carbon-fibre couplings..

I think what you’re describing is called a pressure washer.

pressure washer

Beaten to it again, my inventions are always 20 years too late!

but you can send less water at a higher pressure so you can have more pressure and less water

Q=AV

but you can send less water at a higher pressure so you can have more pressure and less water

Or you could do away with water altogether, just use loads of pressure & clean it with air alone?

The possibilities are endlessly limited. (or something)

You could even add a brush & use an underpowered hosepipe.

Bucket+Brush=Winning.

Trickling hose and a brush it shall remain then..

Thanks STWers

If you’ve got a water but in the garden you could drop a submersible pump in and use the glut of rainwater we bound to get over the winter .

Stick your thumb over the end of the hose.

+1 for thumb 🙂

APF

You want a brush attachment for the end of your hose AKA the Brose. Best thing ever for cleaning bikes without needing lots of water.

Love Onzadog’s post. For those that did not get the brevity:

Flow (q) = velocity x area

So if the flow remains the same then you have to decrease the area to make it faster (stick your finger over the end). I don’t have much else useful to add, but an elegant equation is not something you see when browsing on STW 🙂

IA – Member
You want a brush attachment for the end of your hose AKA the Brose. Best thing ever for cleaning bikes without needing lots of water.

Brose before hose?

Very well done, josh.

Best set up to a punchline ever

I hear that sand-blasting is good for getting off the dried mud.

No. You can’t suck more water out of the tap!

Why not?

I think you probably can…

Anyway just get a pressure washer. Don’t believe the horror stories. Get a basic model with low pressures and don’t point it at your fork seals, you’ll be fine, your bike will be spotless in 5 mins and your chain will be free of grit without any messing about.

You definitely can suck more water out of the tap. The force driving the flow is proportional to the difference in pressure between the source (pumping station or water tower) and the exit. Add a pump and it can give you another bar of pressure by removing the atmospheric back pressure. So that’s your first gain in flow rate. Your second gain in flow rate is that you’re actively driving the water down the hose, therefore removing any resistance from the passive load (like the difference in flow rate between tap on its own and tap with hose pipe attached).

I speak from experience – when I was growing up in the ’80s we had a big centrifugal pump bolted to the wall next to our garage tap and then the hose pipe attached to that. We got way more water out of the hose when you switched the pump on!

I think that putting my mouth over the end of a slow running tap and then sucking much more water out to get a drink may have been the sort of thing I investigated as a child…

You definitely can suck more water out of the tap

I think you might be onto something there. Browsing a catalogue I saw a pump that’s designed for connecting the water main. Seems it’s not necessarily illegal, it’s the flow rate that matters:

Mains Water Pump

Isn’t that how power showers work anyway?