1995 Kona Kula weird bottom bracket treading

[Irukandji]

Hi,

A few weeks ago I bought a 1995 Kona Kula. The bike had a XTR M970 crank and a shimano bottom bracket but when I was disassembling it, I noticed that the BB Cups where switched, the one marked "drive side" was on the left side and vice-versa. So the frame treading is like this:

- Drive side - right hand tread
- Non drive side - left hand tread

The bottom bracket untreaded and treaded easily and the treads seem to be in good condition.

I cannot match this type of treading with any other type I know (French, Italian, Swiss ...)

Can someone shed light on this?

Thank you in advance.

 

[Juanabe]

Re:

it is possible that the previous owner had the cups on the wrong side. This might have cross-threaded the bottom bracket threads but its worth trying the drive side with the drive side, and vice versa. This kona should have standard 24tpi threads like most english bottom brackets. 68 mills x 24tpi (english).

(^_^)

 

[hamster]

Konas are completely standard; 68mm shell, English thread. Some idiot has forced the BB in the wrong way round - a steel BB shell will easily cut its own way into aluminium.

Try very carefully to refit the right way round - if it won't go easily get the thread re-tapped by your local bike shop.

 

[Rampage]

Re:

Any pictures of the thread?

I have a Raleigh Torus the same, but it has an aluminium BB insert with the threads on that had been put in the wrong way around.

If the threads look good and the BB tightens up ok then I'd leave it how it is!

 

[Irukandji]

Re:

Thanks for the answers.

As they are, the threads don't offer any resistance when treading in.

My guess is that when the frame was restaured (it was repainted in a diferente color) some idiot taped the threads the wrong way ...

The only problem with leaving the threads this way, is that limits the type of bottom bracket that can be used, which is Shimano external BB cups (ex: BB-51, BB-70 etc...)

I will take some pictures today.

Thank you.

 

[Rampage]

Re:

You can use any BB as long as the chain line is ok.
My Torus has used a square taper and a ISIS without ever having a problem.

 

[hamster]

The risk with leaving them as-is will be that they will unscrew. That's why there is the peculiar arrangement with left hand threads in the first place. I would get them right. In the last resort you can fit a frame saver BB that doesn't use the threads at all.

 

[Rampage]

Re:

That's what I meant above, I have a bike the same and it's never come undone.

I'm struggling to believe that the BB thread could be tapped in the wrong direction and look like it's meant to be like it.

My guess is that it was like it from the factory.

 

[hamster]

A scary absence of quality control if it really did leave the factory like that!

 

[Rampage]

Re:

Yes
Did raleigh have quality control? Have you seen the welds on their lower end bikes?