Headset cartridge Bearing-Shimano BC1-help please

For discussions about bikes and equipment.
Post Reply
User avatar
bikes4two
Posts: 1306
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

Headset cartridge Bearing-Shimano BC1-help please

Post by bikes4two »

The lower cartridge bearing in my 1989 Dawes Galaxy has suffered water ingress and requires replacing but I am unable to find anything on the web when I search for "Shimano Cartridge Bearing BC1" or similar phrases.

There may be alternatives of course, but I do not know how such bearings are described. I have meaured the internal and external dimensions and the overall thickness, but I do not know what the angle of the bearing tapers are.

The cap covering the bearing cups says Shimano 105 if that helps?

"Shimano Cartridge Type Bearing BC1"
Internal diameter - 27mm/ 1.063"
External diameter - 41.7mm/1.642"
Thickness - 7.7mm/0.303"

Can these bearing be split and just the balls replaced? At a push I could put the top bearing on the bottom cups and re-grease the damaged one, but it is a bit rough at the moment.

All assistance/advice/information gratefully received - thank you.
Attachments
Shimano BC1.jpg
Without my stoker, every trip would only be half a journey
Samuel D
Posts: 3088
Joined: 8 Mar 2015, 11:05pm
Location: Paris
Contact:

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Samuel D »

I believe you need Shimano part number 78V 9803. These are very hard to find because Shimano stopped making them. Cyclebasket had them until recently (just one in stock a couple of months ago) but they’re now sold out. I see it here for £25, but I have never heard of that shop so can’t vouch it.
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Mick F »

Can't help specifically.
I have a headset with bearings similar to that and asked on here about replacements for them as and when they need replacing, as I too couldn't find them anywhere.

The advice was to buy a complete new headset and use the bearings from it. If all you need is just the one bearing, you'll have a spare.
Mick F. Cornwall
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by fastpedaller »

Sounds like good advice... I once looked at the possibility of replacing bearings in a cartridge ST bottom bracket, but the bearings were more expensive that just buying the whole new item.
User avatar
bikes4two
Posts: 1306
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by bikes4two »

Samuel D wrote:I believe you need Shimano part number 78V 9803. These are very hard to find because Shimano stopped making them. Cyclebasket had them until recently (just one in stock a couple of months ago) but they’re now sold out. I see it here for £25, but I have never heard of that shop so can’t vouch it.



Thanks Sam, the picture in the link to bicyclist.cc at least shows that part# 78V 9803 is the part I'm looking for, but unfortunately they are out of stock too.

As MickF suggests, maybe the complete part leaving one for spare might be the way to go!

EDIT - just found some related info in this thread from Brucey - I'll see where that leads me!
Without my stoker, every trip would only be half a journey
Samuel D
Posts: 3088
Joined: 8 Mar 2015, 11:05pm
Location: Paris
Contact:

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Samuel D »

bikes4two wrote:[Thanks Sam, the picture in the link to bicyclist.cc at least shows that part# 78V 9803 is the part I'm looking for, but unfortunately they are out of stock too.

That’s interesting because it said “in stock” when I posted. I wonder if another forum member who needed the bearing got to it before you.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by gregoryoftours »

I take it that is one of the old threaded headsets in 1" variety? If you can't find the same headset or suitable replacement bearings there are plenty of decent quality ISO 1" threaded headsets around. You will have to watch out for stack height though as of 105s are quite short. If it's only the bottom half of the headset that needs replacing then any 1" ISO standard headset will do, threaded or threadless, just use the bottom bearing, cup and crown race.
User avatar
bikes4two
Posts: 1306
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by bikes4two »

I might be getting confused here in that I'm following various parts and part numbers and am wondering if I've arrived an equivalent part or not.

> In a post above my 'BC1' is PN 78V-9803
> in this post here (6th post down) Brucey links in a document plus other info which leads to 78V-9803 being the same as 787-9803
> 787-9803 appears to fit HP-M740, HP-M563, and HP-5500
> this in turn leads to another Shimano number, Y-78798030

Y78798030 is available from at least two German sites and another in the Far East - the big question is, can I have confidence that this part is the one that will work for me?

Many thanks.
Last edited by bikes4two on 6 Mar 2019, 9:17pm, edited 1 time in total.
Without my stoker, every trip would only be half a journey
User avatar
bikes4two
Posts: 1306
Joined: 12 Jan 2010, 10:14pm
Location: SE Hampshire, UK

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by bikes4two »

gregoryoftours wrote:I take it that is one of the old threaded headsets in 1" variety?
yes

If you can't find the same headset or suitable replacement bearings there are plenty of decent quality ISO 1" threaded headsets around. You will have to watch out for stack height though as of 105s are quite short. If it's only the bottom half of the headset that needs replacing then any 1" ISO standard headset will do, threaded or threadless, just use the bottom bearing, cup and crown race.


That's a good way forward - thank you.
Without my stoker, every trip would only be half a journey
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Brucey »

FWIW I think you can dismantle these cartridges and fit them with new balls, and also that yes you ought to use the less worn one in the lower race. Good grease and good adjustment often make headsets that are less than perfect quite acceptable to ride on, and I speak as someone who can't abide any form of notchiness in a headset bearing.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
User avatar
Gattonero
Posts: 3730
Joined: 31 Jan 2016, 1:35pm
Location: London

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Gattonero »

bikes4two wrote:The lower cartridge bearing in my 1989 Dawes Galaxy has suffered water ingress and requires replacing but I am unable to find anything on the web when I search for "Shimano Cartridge Bearing BC1" or similar phrases.

There may be alternatives of course, but I do not know how such bearings are described. I have meaured the internal and external dimensions and the overall thickness, but I do not know what the angle of the bearing tapers are.

The cap covering the bearing cups says Shimano 105 if that helps?

"Shimano Cartridge Type Bearing BC1"
Internal diameter - 27mm/ 1.063"
External diameter - 41.7mm/1.642"
Thickness - 7.7mm/0.303"

Can these bearing be split and just the balls replaced? At a push I could put the top bearing on the bottom cups and re-grease the damaged one, but it is a bit rough at the moment.

All assistance/advice/information gratefully received - thank you.


That is a "semi-cartridge" type of bearing that was used by may Shimano headsets, IIRC from the 105/Deore level above.
You can open the cartridge with a thin flat tool (i.e. an old kitchen spreading knife that's been ground off) and replace the balls (1/8", if I'm not wrong) and give a light ground to the races with a small emery wheel for the Dremel.
Depending on the severity of the damage, it may work reasonably well, though it won't be back as per new.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by Brucey »

Gattonero wrote:…..replace the balls (1/8", if I'm not wrong)....


IIRC they are 5/32" balls inside?

e.g.

https://si.shimano.com/pdfs/ev/EV-HP-7410-1379A.pdf

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
windysmithy
Posts: 178
Joined: 10 Dec 2009, 8:03pm
Location: Blackdown Hills, Devonside

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by windysmithy »

Has anyone found stock of these bearings 78V 9803 anywhere, for the same headset as discussed above?

Google sent me to bicyclist, but unfortunately i didnt check the part no it directed me to, and i have just had a 1 1/8" set of bearings delivered. 78W 9803. my mistake.
GideonReade
Posts: 410
Joined: 4 Jul 2010, 10:46pm

Re: Headset cartridge Bearing-Shimano BC1-help please

Post by GideonReade »

Hi WindSmithy, or anyone... Did you find any?

And also, though it may be acedemic, just how does one get the cartridges out? They seem pretty well wedged in. If I pry inside the tube I'm trying to pry the two races apart, which seems bad. If I pry outside, only possible at top, it appears I'd be prying the disposable cartridge steel part off from the alloy non disposable frame housing, likely to damage the latter.
Post Reply