Cycling UK Forum

also, it isn't a bad idea to make some ~0.25mm brass shields for the bearings; these have a bore of 15.2mm and a 30.9mm OD, and can be sandwiched between the bearings and the cups. If you want to get fancy, you can add concentric ridges to the brass parts to make them springy. With efficient shields in place, 99% of the crud doesn't make it as far as the bearing seals, which is a major improvement.

Pneumant wrote: ↑15 Apr 2024, 7:24pm......I did attempt to knock the bearings off but they were reluctant. I could have used heat but chose instead to remove the spacer and use a puller........

once the cups have been removed,you can always knock the sleeve aside. My favoured route for disassembly of such worn bearings is to remove the seals, then break the cages up and take them apart.There is nothing to stop you from taking the sleeve out as soon as one bearing is dismantled. Once a bearing is apart, you can take a view on whether it is worth trying to save the races or not. If the answer is 'not' there are any number of different ways to destructively remove the inner races, including grinding and smashing them to bits (they are very brittle).

The only real reason for keeping the races is they might be of some use in a DFC specification bearing. If so, it is probably a good time to start the conversion process, by grinding the special loading slots while the inner parts are still on the spindle. There should be enough balls of the correct size from two standard bearing to populate one DFC bearing, and the per ball loadings from the puller are about halved. This means the chances of breakage or damage being caused by the puller are about halved too. So I recommend rebuilding the bearings to DFC specification (even if it is only going to be temporary) using the old balls, prior to using the puller.

Needless to say, I would convert any new bearings to DFC specification too. If rebuilding without a sleeve, I would also use something (anything, even a piece of loo roll tube would do) to help stop crud from getting in the bearings from the inside, just like we had to BITD

Oval crank tech wrote: ↑15 Apr 2024, 5:58pm OK now I am stuck, the 8 speed freewheel is so spaced it does not line up with the front chainline, is there a way make it work?

eh? A photo would help enormously, if you can manage it.

colin54 wrote:......weirdly two of the holes for the screws have a square hole (to resist turning) in the saddle top and two circular - the middle pair.......

I have never had one of these in bits but I would say that very probably all the holes were square until the thing inside them was turned many times and/or got hot. I'd have been tempted to hold the Al parts with a peg spanner, having first drilled two small holes in them.

Revolution wrote: ↑12 Sep 2022, 3:34pm I have a Brooks C17 Cambium saddle which after 5 years of light use has started to split along the underside of the front.......

I would probably attempt to repair that, by using a patch on the underside, trapped between the frame and the top. The front of the patch, being trapped, would see no 'peel' forces. The rear of the patch could be a lot larger, with a pointy edge, so there isn't an abrupt transition. The patch itself would need to contain a strong but flexible element. such as a woven nylon fabric. The body of the patch needs to be able to flex slightly, so maybe the best thing would be to first 'cast' the repair patch in situ, using a barrier layer (eg. cling film) to prevent adhesion. The patch itself could be made of multiple layers of woven nylon fabric, held together with PVA adhesive, a sort of synthetic leather if you like. Finally, the patch would be bonded in position using a different adhesive, eg. a contact adhesive.

It certainly won't hurt to file a nice radius onto the Al nosepiece, but alone, it is unlikely to be effective as a cure, because there is a stress concentration here anyway; this is where 'proper' Brooks saddles sometimes split too.

drossall wrote: ↑14 Apr 2024, 11:53pm........ chain widths are a little more variable than I stated.....

Nonetheless, your advice re chainrings is probably correct. Any chainring meant for 3/32" (3,4,5,6s derailleur) chain will almost certainly be no more than 2.2mm wide, in which case 9s (and higher) chain will fit and run OK, but not in a derailleur setup with more than two chainrings (or one, if you are being really fussy).

ncutler wrote: ↑15 Apr 2024, 9:32am my boat has anodized aluminium spars with a collection of stainless steel fittings and none of 'em are even slightly rusty.

maybe I should have added a few caveats there, such as 'on a bike' (crumbs, anyone'd think this is a cycling forum) and 'anodised high strength aluminium alloy'. As another poster has already pointed out, they use different materials on boats. Needless to say, there are no barrier layers used in your discs. The braking surfaces are probably made from a 400 series stainless (if so, a magnet should stick) and wherever the brake pads don't touch, it might be painted or lacquered to help ward off corrosion. The rivets are probably made of a similarly corrosion-resistant material, but being bereft of any passivation or coating, they will be amongst the first things to look rusty.

lightweight, attractively priced, stiff; choose any two. That amount of flex is quite normal if you try and make an Al frame very lightweight.

Jezrant wrote: ↑15 Apr 2024, 10:34am........It’s quite possible for a new alu frame to flex that much and that easily (as seen in the video the OP posted)? Is that really normal? And how long would it then take to harden fully?

First I should say I don't remember seeing the video. Second, 'flex' is a term normally attributed to purely elastic deformations. No aging treatment can greatly alter the stiffness of a frame. only really the yield point, ie. when the deformations become plastic in nature. Normally frames age ~80-90% in a few weeks ie. in the boat from Taiwan, but this does depend on the ambient temperature.

would it not be just as easy (if not even easier) to make a spacer to be fitted to the spindle? I suspect that you can make something suitable out of an old spoke. btw if the bearing outers are a sliding fit in the cups (or the inners a sliding fit on the spindle come to that), it isn't a bad idea to use bearing fit compound or similar.

BerlinMatt wrote:..... I presume it's meant as a contrast to the painfully tasteful bikes he builds otherwise https://meerglas.org/blog/category/randonneur

I see what you mean; there's only one bike with mudflaps in the link above.

alexnharvey wrote: ↑8 Apr 2024, 8:45pm I'm a bit bewildered by the width of these huge rear flaps. What is the point?

obviously they have to be wide enough for pictures of dolphins?

I suggest gravel bike with dropped handlebars, set higher than you would have them on a road bike.

the oil in red rubber grease is usually some kind of vegetable oil. In brakes, it is best used beneath the dust boot. 'Copper greases' vary wildly in copper content, from ~1% to ~50% so they are very far from being all the same and should certainly not all be tarred with the same brush.

Cyclothesist wrote: ↑14 Apr 2024, 8:36am......OK you have me there Brucey, maybe a third as good?

I bought the 'reassuringly expensive' spurcycles bell as a gift for a friend and they were delighted. Another friend had their nearly identical bell pinched off their bike whilst it was parked. In the latter instance, the thieves made off with a copy which cost about £5, so presumably they were fooled, anyway..