Hi MTB-ers - a bottom bracket question

Hi all

Spend most of my time in the road section as that’s what I spend most of my time doing, but recently had a calling for a retro MTB to satisfy a nostalgic daydream after a walk in a local woods I used to ride in in the early 90’s!

Back then I was the lucky owner of a Raleigh Apex, resplendent with its Flexstem and pink pearl paint.

I’ve just picked up an early 90’s Claud Butler Pagan with the idea of swapping everything over onto an Orange frame, as this was my ultimate dream years ago that I never fulfilled.

My question regards bottom brackets. All my road bikes are more modern affairs with threaded BSA external bottom brackets which I’m more than happy messing about and tinkering with and understand.

What and how does it work with retro MTB’s? We’re they all universal or were there differences?

If I find a nice Orange frame, will I be able to swap the BB and chainset over is the question?

Thanks in advance

Si

The donor bike in question......

Well....that Alivio crankset is classic C16R fitment - very in-period for a nice early C16R build. WHat size frame are you looking for?

And re BB - it will be square taper and UN51 or 52 probably, so you will need a crank extractor and the big Allen key for the bolts...then a serrated cup tool which fits INSIDE the two end caps - eg

https://www.amazon.co.uk/Pasway-Extract ... B01M4IUXHF

The best way to get the BB out still is to clamp the tool in a vice and turn the frame around the tool - if you have a bench vice which will allow this.

Then the issue is getting the right length BB axle - your donor bike may or may not be the right length - but probably just trial and error....put the donor one in and see what the chainstay and bb clearances are....

Wow, thanks for the info, most appreciated

I’ll get the necessary tools, have a bench vice so all good there! Good to hear the groupset will look period too.

I’m 6’2”, but have always liked a smaller bike as I came from BMX. I’ve read the Oranges come up a bit small, so I would say potentially a 19”? Does that sound about right?

It’s going to be a fun bike/woods hack, so I won’t be hammering the hell out of it.

Length will be fine between the two bikes, in fact everything other than the cables will move over. (always worth new cables).

Assuming you buy a frame and forks orange.


It'll be worth a look at the early and mid 90s articles here.
viewtopic.php?f=9&t=53227

Excellent news again, thank you

That link is awesome too, that’ll keep me entertained for a few evenings

Cheers

Hmmm re frame size I think you might be looking at the xl rather than the large:

viewtopic.php?f=1&t=254867

I would go onto the orange size charts in the catalogues - they are on here - I am 5-7 and on P7s and c16rs which are 15 centre bb to centre top tube.

Oh and with bb remember threads are LH on the drive side (remove clockwise) and normal on the non drive side (remove anti clockwise).

Yep got you on the reverse threads cheers, had already read up on that.

I’ll keep my eye out then for a larger frame, fingers crossed something nice will turn up.

When you get close to removing the bb from the donor bike, steel yourself for it being difficult to remove. If you want to remove and keep bb then the ‘in the vice’ method usually works. If it proves very difficult at first, you may need plusgas on the bb to get the cups out. Sprayed on and left for 48 hours, then in the vice. But this will denature the grease inside the BB so it will be out, but unusable.

For installing this one again, or a new one in your new build, do use copper-based antisieze in liberal amounts on the BB threads - makes removing the BB a doddle in future....

Have a practice getting it out and in, it's the same as your external you mention, just different tools and do drive side first. (normally, though a quick nudge on the none drive side can help loosen it too)
the bike looks in good condition so hopefully not a problem.
I use a Hugh adjustable wrench on my tool or a bar and large socket set over the tool.


Oranges measure the length of the seat tube, 19" seems a good size if you like smaller.
(Saying that as a ~5'10" ~34" proper inside leg, and find the 19" OK.)

I wouldn't say they come up small, my 18.5" Rocky Mountains are too small for me, but 19" Kona are good, 20" being much comfier, if a little long sometimes.

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My old Alu-O bike a few years or seven back for reference.