Should I drill a hole in my BB?

[Danny]

The latest issue of C+ suggests you should drill a hole through the underside of your bottom bracket to provide drainage to "keep the inside of your bottom bracket dry".

Is this really a sensible thing to do??? Has anyone tried it?

 

[Dave5N]

I used to. I don't now. Firstly, I don't have any recent steel frames.

Secondly, the little hole was a prime spot for rust to start.

 

[kyuss]

I haven't had to drill a hole in any of the frames I've had. There's already been a hole under there for the cable guide bolt so just undo the bolt after any particularly wet rides and any water comes out (just don't underestimate how much mucky water is in there, and don't do it on a carpeted floor in a rented flat without putting something down first or the landlady might get a bit angry and spoil your chances of getting the full deposit back ). Or you could just make sure your bottle cage bolts and seatpost are greased and the water will have no way in in the first place.

 

[mickle]

My colleagues wife's bike was in the workstand recently being stripped, I turned it over and about a pint of rancid rusty water pished out of it. Bleh.

 

[asterix]

Although I have used a bike for commuting since the 70's - the first one for 18 years - and done my own servicing, I never found any water collecting inside the frame. The BB on the original bike had a plastic guide bolted on underneath, hardly a drainage point.

As the frame of this bike looked in fine condition inside, I had it re-enamelled then someone nicked it. The replacement bike has a large T-shaped drainage hole beneath the BB.

How can water enter the frame of a well oiled bike?

 

[ASC1951]

How can water enter the frame of a well oiled bike?

Usually, down the seatpost, although a good layer of grease should stop that.

Not being a physicist I suspect that it will get in to the frame of any bike because even if it is watertight it won't be airtight. Take it out of your warm house, the air in the frame cools and sucks in moist air from outside, that condenses on the inside of the frame and water droplets trickle down to the BB.

 

[mickle]

And through the breather holes.

 

[peanut]

How can water enter the frame of a well oiled bike?

usually because despite claiming otherwise people leave their bikes outside in all weathers.

 

[Chris James]

I remember when i did my MSc in Corrosion that one of the case studies was drain holes in car doors, working on the principle that water will always get in and it is better to let it out than let it build up.

Personally I doubt it makes much difference eitehr way. If you know your bike has been ridden through a lake it may be an idea to try to drain it, otherwise don't worry too much.

Likewise I have had frames with sealed and open breather holes and have not noticed either being more long lived.

 

[02GF74]

I may have done then covered it up with some red insulation tape afterwards.

 

[asterix]

Usually, down the seatpost, although a good layer of grease should stop that.

Not being a physicist I suspect that it will get in to the frame of any bike because even if it is watertight it won't be airtight. Take it out of your warm house, the air in the frame cools and sucks in moist air from outside, that condenses on the inside of the frame and water droplets trickle down to the BB.

Ah, I see. My bikes are never kept in warm houses - maybe that's the solution: Those who live in warm houses shouldn't store bikes.

 

[ASC1951]

Those who live in warm houses shouldn't store bikes.

Nor those in grass houses stow thrones, as I recall.

 

[fossyant]

All my bikes are steel....and non leak... grease the seatpin. Fortunately they all do not have the 'vent holes' like my old Raleigh had.....

My Ribble has slots in the BB casing, and it is a rust prone area - mainly due to chips and hard edges - not water in the frame as it's bone dry.....better off properly sealed up BB like on my 18 year old best bike......

 

[Danny]

All my bikes are steel....and non leak...

Neither of my two bikes have every leaked (as far as I know) which is why I was so surprised at the advice in the original C+ article.

However it seems from some of the previous posts that some people's bikes take on water at a phenomenal rate.

 

[Dave5N]

I remember when i did my MSc in Corrosion that one of the case studies was drain holes in car doors, working on the principle that water will always get in and it is better to let it out than let it build up.

Personally I doubt it makes much difference eitehr way. If you know your bike has been ridden through a lake it may be an idea to try to drain it, otherwise don't worry too much.

Likewise I have had frames with sealed and open breather holes and have not noticed either being more long lived.

I bet your knowledge is a bit rusty now though...