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Raleigh Grand Prix bottom bracket
 

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daddy-o
Joined: 12 Apr 2004
Posts: 3307
Location: Springfield

9/17/13 10:29 AM

Raleigh Grand Prix bottom bracket

A friend wants me to replace the crank in a cottered BB. It's a 1975 Raleigh Grand Prix mixte frame. About the first thing I read about it was it has proprietary threading.

Any suggestions?

BTW, it has a Campy Valentino rear derr. The bike's a low-mileage Craigs List buy, the seller was the original owner and she said she rode it "6 or 7 times." Is that derraileur worth anything above sentimental value?

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Andy M-S
Joined: 11 Jan 2004
Posts: 3377
Location: Hamden (greater New Haven) CT

9/17/13 1:59 PM

Maybe a threadless setup?

You can get a VO bottom bracket that will do the job (http://store.velo-orange.com/index.php/components/bottom-brackets/grand-cru-threadless-bottom-brackets.html) but I don't know if it's worth the money.

I had a Grand Prix from about that period and while it was a very nice bike (and in fact I bought another, well-used, when I got back into cycling in the mid-'90s) but it's nothing special.

On the other hand, the fact that it's a Grand Prix may be what makes it special to the owner.

At least the derailer isn't a Simplex. Plastic was swell for some things, but.

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dan emery
Joined: 11 Jan 2004
Posts: 6884
Location: Maine

9/17/13 2:23 PM

Hey now

A '72 Gran Prix was my first "adult" bike. It was an entry level, gas pipe 10-speed. It had a cottered crank, I'm thinking Stronglight but I may be wrong, and plastic fantastic Simplex Delrin derailleurs and shifters (worked OK for me, though I exploded a rear der on another bike when the wheel collapsed).

Can't help with the replacement, I have no idea how or why you would do that. Tell her those steel crankarms are wicked aero and she'd be nuts to get rid of them.

I doubt the Valentino is worth s***, but I dunno for sure.

Edit: I mistakenly wrote "cotterless" (I think it was autocorrected) but the crank was cottered for sure.


Last edited by dan emery on 9/17/13 3:31 PM; edited 1 time in total

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Andy M-S
Joined: 11 Jan 2004
Posts: 3377
Location: Hamden (greater New Haven) CT

9/17/13 2:44 PM

Cotters


quote:
Tell her those steel crankarms are wicked aero and she'd be nuts to get rid of them.


Yeah. Just keep an adjustable wrench handy. At least my (second) ancient GP needed occasional tune-ups that way.

The GP was a nice bike at the time. I kept mine (the first) for something like 13-14 years. It was great transportation in Chicago. I did have a front wheel stolen one time, before I learned correct locking techniques.

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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

9/17/13 3:33 PM

When I resurrected an old BSA bicycle for my sister many years ago, it had the same problem of using a very fine proprietary threading for the BB cups. I just re-tapped the BB shell with a set of English threading BB taps and installed a standard BB and cotterless cranks. She rode the resurrected bicycle around for several years while she was at university without any problems.

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Anthony Smith
Joined: 12 Jan 2004
Posts: 848
Location: Ohio

9/17/13 6:55 PM

It should be

British Standard 24x1.37x68. I worked in a Schwinn/Raliegh shop when that bike was new.

If the cups are somewhat offbeat, just replace the spindle and re-use the cups with some 1/4" loose balls and some good grease

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Andy M-S
Joined: 11 Jan 2004
Posts: 3377
Location: Hamden (greater New Haven) CT

9/18/13 4:09 AM

Should be

but often isn't. Worth checking first. Raleigh was apparently inconsistent in this regard. It's possible that the GPs that had standard English BB threading were actually manufactured by Gazelle in Holland during the bike-boom years, while Raleigh Central continued to use its own threading and shell width (71mm) I think into the early '80s. At least one of the GPs I owned had a "Made by Gazelle" sticker.

With neither of my Raleigh bikes did I look at the BB very closely; the first, because I didn't know anything about working on bikes, and as long as it worked, it was fine with me. The second, because I didn't have it long enough before replacing it with a "modern" (i.e., only ten year old) Bianchi CdI. Thanks to the Bianchi, I did spend a little time learning about BB threading...

This doesn't say anything about BBs, but does talk about Gazelle's role: http://www.kurtkaminer.com/raleighgrandprix_holland.html

The fork of the one in the photo on that page has an almost entirely different shape from the one in the photo from 1976 (or so) that I'm holding right now, BTW. Sort of reminds me of an old Johnny Cash song...

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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA

9/18/13 8:09 AM

Phil Wood

If it turns out to be Raleigh's proprietary 26tpi threading, Phil Wood makes bottom brackets with that cup threading. The PW is probably 10X the cost of the rest of the bike but it is available.

As Anthony Smith noted, you may be able to replace just the spindle with a standard square taper and reuse the okl cups. We did that with a friends '72 Raleigh that was definitely 26tpi threading.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

9/18/13 9:28 AM

"you may be able to replace just the spindle with a standard square taper and reuse the okl cups"

Exactly what i did with the Stella I made my SS/Fixed
out of a months back. I did not want to invest in a new BB to loose the cottered setup. I am sure a french BB would be less of an issue to source than a 26tpi threading BB. Just keeping it real [cheap] with the French Gas Pipe Yella Stella.

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