Mechanics and Fixing Any Questions Answered

A friend of mine has asked me to help her reinstall the gears on her bike. Apparently she had a nice campagnolo RD stolen along with the downtube shifters. She took it to her lbs at the time (several years ago) and they gave the option of buying spenny new parts, or converting to a ghetto single speed, and she chose the latter. The mechanic apparently said that doing it this way would mean she can convert back to geared later without having to buy a new cassette.

I reckon I could do this for her but wanted to consult the wise people of this forum before I get started:

• Is it possible to reuse this cassette? If so, how do I reassemble it with the spacers in the correct place? Any pointers to some useful online literature would be most helpful.
  
• Given that she's happy staying with downtube friction shifters, am I right in thinking I could fit a shimano RD (given that they seem to be cheaper and more available) with no problems?
  
  

Cheers

Any derailleur will work if it's friction and it can cover the whole gear range, you should just be able to take the cassette off and put it back on in order with a spacer between each cog, I think some campag ones have slightly different spacers towards the end of the cassette, hopefully it'll be obvious which ones but if not you might need to Google and use some verniers. I'd also wager that might be pointless if she's been using much though as the cog it's on is probably too worn to use with a new chain.

Centering a chainring. I've read Sheldon's technique. Am I meant to be tapping the chain behind the chainring (seatpost area) or tapping the chain at the 3oclock position on the chainring? Thanks

I just bought this used Thomson Elite seatpost cheaply, but I noticed a horizontal scratch/gouge, about 15mm long, prominent under a fingernail. Could this present a problem in the future and instigate a crack or a failure at that point? I planned on using it in a frame where the seatpost collar would be directly over the scratch, clamping on that area. I could also probably put it to use on another frame, where the clamp would be well below the scratch. Not sure whether it would make any difference. The scratch placed at the front of the seatpost and slightly to the right, if that even matters, considering it is a inline seatpost, where all the difference is the logo orientation. Cheers all.

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Looks like someone has marked it for height, probably fine.

I'd also wager that might be pointless if she's been using much though as the cog it's on is probably too worn to use with a new chain.

It is possible to buy individual cogs for Campag cassettes. Not sure how easy or cheap it is though.

Cheers @snottyotter and @Brommers. Good point about the one cog being a lot more worn than the others, hadn't considered that.

I've got a 9 speed Deore gearset with 9 Speed bat ends.

I also have a 7 speed low spec 90s Dawes MTB with a shagged pair of 7 speed shimano 100gs trigger shifters.

Trying to do this on a budget and thought I could get some of those shifter mounts and either run the bar ends in friction mode or see how the indexing works.

Any thoughts on whether this will work?

Cheers.

Well I can't see any reason for the bar end shifters not to work in friction mode.

As for indexing, have a look at Sheldon's cassette spacing crib sheet.

If Deore 7 speed is IG then you have a chance at fudging it. If it's HG then probably not.

A quick Google suggests your 100GS (1991/92?) rear mech is probably HG, as IG only appeared (briefly) from 1994/95 onwards.

So I'd say friction is your only option with that combination.

The other option would be to just sell the 9s bar end shifters (plenty of demand for them) once you've bought some correct 7s shifters.

Cheers. That's really helpful.

Seems a shame to sell as they're good things to have.

I sold some 8 speed bar end shifters that I now regret. Even more so when I see what they cost now.

Mainly though the shifter mounts from sjs are similar price to some shifters, but theres still a chance the mechs are fucked too.

Had a look on ebay and Altus shifters seem to be c.£15 so you may be right and just buying new shifters is the way to go.

https://www.ebay.co.uk/itm/Shimano-Altus-SL-M310-3x7-21Speed-Stainless-Steel-Cables-Shift-Set-for-MTB-Bike/184753184002?hash=item2b0425dd02:g:RHMAAOSwLxNgbroS

They're low end, but reviews seem to say they function fine and it means I don't have to spend time changing everything. The RD maybe a bit shit, but from a quick pull of the cables it moves. So provided it's straight and nothings chewed I should be able to get it to work. FD's are usually so simple that should be fine too.

Excellent. Fingers crossed for seamless shifting (or at least functional shifting).

I'd suggest double checking the IG/HG thing though. I was only going off a 5 minute Google with incomplete info.

Someone at work has stripped the thread out of the disc mount on a Rohloff hub.

Normally I would just send it to Rohloff and they’d probably replace the hub shell, but the turnaround times have gone pretty crazy and I am still waiting for them to return 2 of our hubs. Been a couple of months whereas last year it would have been about a fortnight turnaround.

Anyway, i was thinking of inserting a helicoil for the time being.

Can someone please advise if this is the kit I need?

PowerCoil 3523-8.00K M8 x 0.75 Thread Repair Kit https://www.amazon.co.uk/dp/B00MV1PE02/ref=cm_sw_r_cp_api_glt_i_MGDFMGBX7J1M8WPYMDYW?_encoding=UTF8&psc=1

The rotor bolt has the same dimensions as a chainring bolt, just a bit longer.

Thanks

cross-posting from my current projects thread a bit, but I'm assuming this might be a better place to ask this sort of question. My partner has recently got an early 90s steel MTB for commuting and touring. It's been pointed out to me that the forks are a bit weird and stick out too far forward, kind of like a beach cruiser. I agree they look a bit funny, but assumed it was a quirk of smaller framed MTBs of that era, or something like that.

So, my questions are:

Do these forks look weird/bent/damaged to you? Do people ever bend forks on purpose to change their handling? If they need replacing, what measurements/other considerations do I need to make in order to find some new ones?

Are the forks original to the frame?

They certainly look weird.

Considerations I can think of are: steerer diameter and length, threaded or not, Axle to Crown length, tyre clearance, brake mounts, mudguard and rack mounts. and you may want to consider rake, but prob won’t be necessary.

It does look a bit gawky, but if it rides well and it hasn't fallen apart yet then I'd say it's all good.

I'm not sure if they're original as the whole bike's been sprayed black. From a half-arsed google I think it's an early 90's trek singletrack.

Cheers that's really helpful. I think I'll probably replace them just to be on the safe side and it seems like there's plenty of 26" forks on ebay

My brother in law wants a speedy road bike and bought himself a frame, an Olympia Leader disc from 2015. I'm helping him build it up but am not sure about headset bearings. From a bit of googling I found that "the head tube is tapered with 1 1/8in - 1 1/2in bearings". Also found out that some bearings have different angles for different cups? It doesn't make a lot of sense to me, yet.

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1 1/8in - 1 1/2in bearings

That’s the inner diameter of the top - bottom bearing, respectively.

There’s a few different type of threadless headsets (which that bike would have): integrated, zero stack and external. I can’t tell from the pic if yours is integrated or semi-integrated/zero stack.

In reverse order...
External headsets have cups that are pressed into the headtube, and they sit the bearings beyond the lip of the headtube. These are older tech and can have loose ball bearings or bearing cartridges.

Semi-Integrated headsets also have cups that are pressed into the headtube, but they situate the bearings inside of the headtube. Instead of the whole cup, only a small lip protrudes beyond the headtube. They usually use bearing cartridges.

Integrated headsets have the headset ‘cup’ built into the headtube. This headset only uses cartridge bearings, without any cup being pressed into the headtube.

35/45 deg refer to the angle of the contact surfaces of the cartridge bearing. It’s important to get the right angle or you’ll wear/damage your kit.

Alright, thanks! This helps a lot. From what I have seen I think the frame is integrated then. So that means I only have to figure out the angles, right? Is there any clever way to do this?

Googling is your best bet. There might be a spec sheet somewhere that tell you what headset it has/needs.

Perhaps someone else knows an at home way of accurately measuring mating surface contact angles?

The angles will probably be written on the side of the existing bearings.

Alright, thanks! Learned a bit more, so all that's left then is more intensive googling and/or contacting Olympia. Cheers.

A couple of pages back I asked about removing seat tube shim from Ti bike. Just spoke with Ted James. His view is that many ti frames have thin wall seat tubes and are then shimmed and this is not a great construction technique. Frequently the seat tube isn’t reamed before the shim is bonded in so the shim doesn’t have a great fit. If the shim is removed and the seat tube then reamed it could well result in a weakened tube. Often the seat tube will deform a bit when top tube and seat stays are welded to it. Given the thin tube of the seat tube reaming off any metal might make it too thin to be structurally sound.

It was great to chat with him and he was really patient explaining it all in layman’s terms.