Yet Another Cycling Forum
General Category => Freewheeling => Tandems => Topic started by: dr ziff on 29 January, 2017, 04:59:18 pm
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I recently acquired an old tandem from a junk shop. The frame is in good condition but it really needs a respray. However, on dismantling the headset I found this interesting set of bearings on the crown:
(http://i1339.photobucket.com/albums/o706/drziff/tandem-headset_zpsn2s1zujy.jpg)
Anyone seen one of these before? I doesn't seem to come to bits so I guess I'll need to remove it in one piece but the base of the crown is 1 1/2" wide so I can't get my usual crown race remover on. I'm a bit reluctant to start tapping away with a hammer and screwdriver as I suspect it's pretty firmly attached and I don't imagine a replacement is going to be too easy to come by ...
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I don't know, but in case it leads to any help, there's reference to a "sturdy" lower taper roller bearing on a 1930s Selbach Peerless here:
https://tandem-club.org.uk/files/public_html/cgi-bin/db_config.pl?noframes;read=10963
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Could be original. Actually looks like the inner rear hub bearing on an old Golf/Scirocco...
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Looks to be in good nick, if the other surface (in the base of the head tube) is OK. Why take it off? That's a hefty bearing and will probably last indefinitely given some maintenance.
In any case, I'll bet it's a fairly common size, if you want to change it take it to a bearing shop, bet they'll have them on the shelf.
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Stronglight perhaps? They are the only brand I am aware of who used needle / roller bearings.
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Stronglight roller bearing headsets are completely different.
I'm impressed by that headset, though I've never seen that exact type on a bicycle before. It should be bombproof, provided the steerer tube doesn't flex too much.
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Stronglight roller bearing headsets are completely different.
The roller bearings in a Stronglight headset are, as I recall, much more…needley looking, than this one.
I have a pair of similar but even more chunky roller bearings in my motorbike's head tube.
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Presumably Dr Ziff wants to remove the headset for the frame respray. It could be masked instead - with something more effective than ordinary masking tape if necessary.
Stronglight needle bearings are much smaller and are on loose rings in a cartridge system. I don't know if they've always been like that, though.
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It is a taper roller bearing and will be bombproof. Assuming it was part of the original design it's somewhat overkill. As Torslanda mentioned it's the type of thing often found in car wheel bearings. We use them in the pumps we sell here at work for offshore oil and gas duties, 3500 rpm for three years continuous running in a harsh environment. A bit more than a bike steerer would be expected to cope with!
If you do take it off look up your local bearings supplier online, it will be a standard size. There's likely to be a race inside the head tube for the bearing to run against, it will be an interference fit.
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Thanks for the replies. The Selbach link was interesting - since Selbach was based in Kennington and I found the bike in Dulwich (not far from Herne Hill velodrome) I can fondly imagine it to be a classy racing tandem from the 30s. It seems to have some similarities with the 1929 Selbach Taper Tube Tandem - the Timken Roller BB, Patent Head Clip and Novel Seat Lug, described here:
/http://www.oldbike.eu/museum/1930s/1935-2/1935-selbach-peerless-tandem (http://www.oldbike.eu/museum/1930s/1935-2/1935-selbach-peerless-tandem)
(http://i1339.photobucket.com/albums/o706/drziff/tandem_zpsthpnrahj.jpg)
Sadly it has been hacked about a bit - so while the frame is true and all the bearings run smoothly, it has had a couple of unfortunate paint jobs (yes, brushmarks...) and it would be nice to get a proper job done. Colour-tech in Dartford advertise a tandem respraying service, but I will need to get the race off before I hand it over.
I see Timken still make taper roller bearings - might be too much to hope that the design is compatible with something from the 30s though.
So I still need a non-destructive method of removing the crown race - preferably without shelling out £200+ on a crown race puller. I guess it's off the the LBS for me.
Thanks again.
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FYI. That is a Timken taper roller bearing.
If it overhangs the fork crown it can be drifted off with a flat punch without any fear of damage. Just refit the top nut to prevent any thread damage and turn it upside down on a block of wood.