Holdsworth Bottom Bracket

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Steve10
Posts: 3
Joined: 14 Mar 2018, 9:12pm

Holdsworth Bottom Bracket

Post by Steve10 »

I'm a first timer, so forgive me if I don't use correct lingo/protocols etc...

My Holdsworth is, I believe, from the 1970's or 1980's. It currently has fitted a TA Cyclotouriste Pro Vis 5 single chainwheel with
matching TA cranks.
I intend to change this setup so that I have a double chain-set using the existing cranks.
Question: Do I need to get a longer square taper bottom bracket and, if so, what length should it be? Is the length critical? In addition, will it be okay
to use a sealed cartridge bottom bracket and will this type be compatible with my frame?

Here's hoping for some definitive guidance!
Brucey
Posts: 44522
Joined: 4 Jan 2012, 6:25pm

Re: Holdsworth Bottom Bracket

Post by Brucey »

Older TA chainsets use BBs that have their own taper and lengths. They do not interchange well with other cranksets, and (I think) an older set of TA cranks will use a different BB taper from a more recently made set of cranks. How old are your cranks, exactly?

I'd suggest that you buy a crankset and get the recommended BB to go with it (which could be shorter or longer, there is no logic to this BTW). Spa cycles sell some that are good for touring bikes. What size chainrings do you need?

Your BB should be 68mm wide and tapped to BSC, so any BB should fit. Occasionally a sealed unit is obstructed if there is something (like a cable guide) bolted through the BB shell, but it is usually easy enough to resolve such issues.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Steve10
Posts: 3
Joined: 14 Mar 2018, 9:12pm

Re: Holdsworth Bottom Bracket

Post by Steve10 »

Not sure of exact age of the TA cranks - I reckon they are similar age to frame.
I have already been looking at items on the Spa Cycles website.
I did not make it clear that I intend for the double to be a direct replacement of the same brand [Cyclotouriste Pro Vis 5] and that
I have decided to go for chainrings of 26T & 40T.

Good info - thanks.
Brucey
Posts: 44522
Joined: 4 Jan 2012, 6:25pm

Re: Holdsworth Bottom Bracket

Post by Brucey »

you might be lucky and be able to fit a second chainring without getting another BB anyway; there is often enough room to do this, and the correct spindles are only 3mm different in length anyway. But what I was driving at was that sourcing a suitable BB that fits your (old?) cranks properly may not be easy, and if you fit the wrong one, the cranks are quite likely to be ruined. I have seen plenty of older TA cranks ruined in exactly this way.

Quite small differences in taper shape will make the fit poor and often result in the cranks working loose in service, cracking, or (in the case of the RH crank) causing the chainring to run out of true. If your TA cranks are as old as the bike they probably are not 'pro vis 5' cranks; that model did not exist long ago and the 'cyclotouriste' model that did has different tapers, even if it accepts the same chainrings. If you tell a potential supplier of BBs that you have 'pro vis 5' cranks when you don't, you will get the wrong BB.

Also, once a crank has been used with a specific BB spindle in it, it is usual for the crank to take an impression of the spindle, such that other spindles (even if they have the same nominal taper angle) don't fit properly, because the size and shape of the flats is different, and doesn't match the impression in the crank.

You will often get bad advice on this point because (frankly) most other folk neither know nor care about such things; commonly a used crank is fitted on a different spindle and the crank gets 'resized' as it is fitted. Needless to say this can be a bit hit and miss, to say the least.

FWIW you should check the cranks to make sure that they are not cracked anyway. There is no point in persevering with a set of cracked cranks and these cranks do crack quite often.

Finding correct TA BB spindles for older cranks is not very easy. There is usually a fair chance of finding something here

http://hilarystone.com/bottombracketengStronglight.html

The advice that the taper is 'fairly close to JIS' is code for the cranks being heavily resized with risk of damage/loosening etc if you swap to a JIS spindle.

Anyway if you need another BB spindle and you cannot find the correct one, it may be prudent to fit and use a different chainset in the meantime whilst you try and source the correct thing, rather than try and fit the wrong thing to your cranks.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: Holdsworth Bottom Bracket

Post by Roadster »

Steve10 wrote:My Holdsworth is, I believe, from the 1970's or 1980's. It currently has fitted a TA Cyclotouriste Pro Vis 5 single chainwheel with matching TA cranks.

I very much doubt that the TA cranks are original to your machine. Most Holdsworths of that era were fitted with SR (Sakae Ringyo) chainsets as standard, the only exceptions being the top "Competition" and "Professional" models which featured Campagnolo Super Record. As Brucey suggests, I'd simply replace the lot with a modern double chainset of your own choice together with a matching bottom bracket.
Steve10
Posts: 3
Joined: 14 Mar 2018, 9:12pm

Re: Holdsworth Bottom Bracket

Post by Steve10 »

Thank you both for your input.
As a short term solution [up to a year!], I have ordered a new chainset and while this is being used I
will have time to sort the TA equipment out to replace it later on.
For the record, my existing chainset was installed when the bike was customised and overhauled by
my father, so it is not original equipment! My father was a qualified engineer and very long term
member of the CTC.

Best wishes,
Steve
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