Drilling Bottom Bracket Shell

[Dirtbreath]

Does anyone have any opinions on drilling a hole in the bottom bracket shell to drain water that gets into the frame? I have heard both for and against and am considering putting a little hole there.

 

Anyone done it? Horror stories/Success?

[GIRR]

Do you have a carbon bike.....

[Dirtbreath]

No. Aluminium mtb.

Some older bikes used to have holes in them as standard. Some even had elaborate shapes, like the Colnago logo for one.

[ChrisH]

I asked Raleigh if I could drill a 2mm hole in my frame at the bottom of the BB housing to help drain water. I got this back from Al Retief.

 

 

Hi Chris,

 

Your warranty will be secure as long as the hole is no bigger than the 2mm you suggest. I have the same problem (and I implemented the same solution).

I am sure that I don?t need to mention this, but don?t forget to remove the BB and crank before drilling the holes.

 

Thanks,

AL

[Dicky DQ]

OK so now the next question is if you can drill holes in a structural part of a frame, why have I been told that I will void my warranty if I drill out the cable housings so that I can fit a Through Cable for the gears??

[Dicky DQ]

OK all of this was based on 2nd hand info from bike shops. So I think I will discuss with the suppliers.

[Dirtbreath]

Very surprised that a manufacturer doesnt void a warranty.

 

Did you do it Chris?

 

As for the cable guides that is what I would expect from a manufacturer.

[ChrisH]

Very surprised that a manufacturer doesnt void a warranty.

 

Did you do it Chris?

 

As for the cable guides that is what I would expect from a manufacturer.

I did indeed do it, to both my own and my wife's Raleigh MTB's. No ill effects yet. I stripped the bikes this evening to clean and grease and it is still 100% perfect inside there after a year.

[WillemT]

If your bike is under warrantee and drilling the hole will void that then don't do it but from a structural point of view drilling a hole in the BB shell at the bottom will do nothing as it's not in a crucial area where you will compremise strenght or anything.

For me it will simply feel to wrong to drill a hole in my cannondale!!! but then again it's manufactured with holes in the bottom of the horizontal rear stays so al the water goes out there...

[Dirtbreath]

I'm with you there NT. Really need to know that this works before I touch anything. Does it help. If you are riding wet does water get in and cause more damage?

[WillemT]

I don't think water will cause to much damage to aluminium. My bike does get wet inside when I ride in extreme wet weather. But then again the other day that I noticed a lot of water inside the frame was most likely because I submerged my bike in the eerste rivier in jonkershoek to get the mud of so I can shift gears. Don't think you'll get to much water inside if you stay out the rivers... hehe

The other thing is water can only get inside the frame if there's a opening, quite simple. So if your frame is sealed then it shouldn't be a problem. I've nerver had any water inside my scott in the past.

[Dirtbreath]

Just been up and down the Spruit and it was a bit wet. Hosed the mud off after the ride and then tooked the seat post out and flipped the bike over. Some moisture on the seat post but certainly not enough for me to start drilling my frame.

 

I have however seen a bottom bracket remove where so much water poured out that it must have been up the seat tube. Bearings were rusted and the grease and water looked look something after someone has had water removed off their knee. I never found out what abuse took place to get the bracket to that state.

[Johan Bornman]

Drilling holes in your BB with neither affect the structural integrity of the bike nor void your gaurantee. Besides, a 2mm hole is not big enough. Don't mess around, drill a 6mm hole in there. Our law ensures that you will not be prejudiced with your gaurantee unless the hole itself is the cause of the frame failure, which it won't be.

 

As for filing out the cable guides. Do it as well. Again, the manufacuturer cannot prejudice you unless that itself was cause of failure. I can assure you that should your filed frame fail, say at the head tube or other area that has nothing to do with the cable stop, the frame supplier won't even know you have filed the stops. It is invisible unless you know what to look for.

 

I have drilled many, many BBs and all the owners are happy and have never reported any problems. In my classes we disassemble bikes each Saturday and without fail one or two of them have water in the BB. Water in the BB spells BB problems and it shouldn't be there in the first place.

 

As someone else here mentioned, many bikes have a cutaway there that's the shape of the frame maker's logo. Some are big enough to put your finger in.

 

Someone also mentioned holes in their chainstays. Those are not there as drainage holes but a remnant of the frame making process. Without holes in those tubes the welding will bubble as gas inside the tubes expand and look for a place to escape. Usually it is via the molten metal at the weld, making for an ugly weld. The frame maker then drills holes in those tubes so the gas can escape. I like to fill in those holes since water often gets in there and do bad things.

 

I once saw a photo of a Cannondale that had its chainstays (or seatstays, I can't remember) cut off in a mysterious way. It turned out that the stays were full of water, the bike was hung up in the owner's garage (or stoep or something) where it froze during the night. The expanding ice cut the stays right off on both sides.

 

We don't have that problem here but even aluminium corrodes.

 

One top for drilling the BB is to make sure you drill the hole at the lowest point in the BB. If you place the bike on its saddle and handlebars upside down, the lowest BB point is not evident. You have to mark the point when the bike is standing on both wheels and then invert it to drill. Don't botch the job, use a centre punch to properly guide the drill. A 2mm hole will block very quickly and will be virtually useless. Remove the burr, that too could prevent the water from draining properly.

 

 

[KDEE]

 

Very surprised that a manufacturer doesnt void a warranty.

 

Did you do it Chris?

 

As for the cable guides that is what I would expect from a manufacturer.

I did indeed do it' date=' to both my own and my wife's Raleigh MTB's. No ill effects yet. I stripped the bikes this evening to clean and grease and it is still 100% perfect inside there after a year.

[/quote']

 

How did you manage to do this. I took my cordless drill to do a test and for the life of me could not work out how to get the drill bit to go straight.... the chuck and body of the drill hit the frame and makes the drill it go in at an angle?

 

Thanks in advance for a handy hint...

 

[Johan Bornman]

How did you manage to do this. I took my cordless drill to do a test and for the life of me could not work out how to get the drill bit to go straight.... the chuck and body of the drill hit the frame and makes the drill it go in at an angle?

Thanks in advance for a handy hint...

\

If you send me your e-mail address via a PM I'll send you a Word document with detailed instructions.

 

Better still, join my Bicycle Repair and Maintenance class this weekend and learn how to do it.

 

 

[TNT1]

 

Do you have a carbon bike.....

 

Even if he did... drill the mother...