the 'there's no such thing as a stupid question' bike maintenance thread

Effects · 26-11-2020 6:14pm

Nah, I didn't even mention anything about the price. He seems happy with his bike now.
I've mentioned to him before about them over charging, but he seems happy to pay it, and thinks it's worth it.

It cost just a bit over €400 altogether, with the rest going on new cables and housings, brake pads and bar tape. As well as a small rear mudguard. No front mudguard, as they "don't fit, and the down tube catches all the water anyway" apparently.

Type 17 · 26-11-2020 6:17pm

Effects wrote: »

I've mentioned to him before about them over charging, but he seems happy to pay it, and thinks it's worth it.

Well, it's his (wallet's) funeral..

Effects wrote: »

...No front mudguard, as they "don't fit, and the down tube catches all the water anyway" apparently.

So he'll be spending another few hundred (;)) in that shop on a new headset soon...

AndrewJRenko · 26-11-2020 6:29pm

Type 17 wrote: »

Pull the whole plug off, which consists of the grey inner and black outer part.

When you get it off, separate the two parts by pressing the trigger in with something small and pointy.

Touch the wires off the contacts on the hub while turning the wheel, to check which way around the wires should be (polarity) and then confirm which way to feed the wires back into the grey part.

Feed two wires back into the grey inner bit and fold the ends over into the grooves provided, and then slip the black part over the grey one, and press it back onto the hub.

That's really helpful, many thanks.

With a bit of digging, I came across this video which says pretty much the same thing in visual form. They say that the polarity doesn't matter.

https://youtu.be/LJbufBGdcio

Funny to see the comments showing how many others were similar stumped.

Type 17 · 26-11-2020 6:34pm

AndrewJRenko wrote: »

...They say that the polarity doesn't matter...

It usually doesn't, but some lights (a few, older designs from the days of bottle dynamos) still rely on the negative side of the circuit returning through the frame and into the hub, so if your light doesn't work after re-wiring the plug, you should try reversing the polarity.

magicbastarder · 26-11-2020 6:44pm

don't cross any streams though, until you're certain.

AndrewJRenko · 26-11-2020 9:35pm

Type 17 wrote: »

It usually doesn't, but some lights (a few, older designs from the days of bottle dynamos) still rely on the negative side of the circuit returning through the frame and into the hub, so if your light doesn't work after re-wiring the plug, you should try reversing the polarity.

Thanks, it is a fairly new bike, so hopefully it should be OK.

brownian · 26-11-2020 11:55pm

cletus wrote: »

If you're near Naas, I've calipers.

Just to say thank you to Cletus and Tomasrojo on this. Especially to Cletus for the generous offer to machine a new part from scratch.

As it turned out, I got a replacement screwin boss, cut off the shoulders and screwin bit with a hacksaw and mounted it all with a longer M6 bolt, and the rest turned out to be easier than expected.

I did end up with a nice shiny pair of vernier calipers, and learn how to use them 8-).

CramCycle · 28-11-2020 6:05pm

So old school square taper BB ie not sealed. Got the dust cap after drilling two tiny holes in it for leverage, that side came off quite easily after but the side you would use a spanner on (other side was a lockring spanner and one of those wrenches with the two pins that one can move on) is not budging. Best I can think of after everything is to pinch where the spanner is meant to grip on a bench top vice and use the frame for leverage. Its a lovely old school bike with shimano 600 throughout. Any thoughts on if this is stupid or not?

Type 17 · 28-11-2020 6:08pm

You're aware that the drive-side cup you're trying to unscrew is a left-hand thread*?

*unless it's an older Italian-made frame.

PS: The vice isn't a bad move, but you'll need an assistant to hold everything steady with you, as a slip will result in the lovely frame falling all over the sharp edges of the vice :eek:

CramCycle · 28-11-2020 7:33pm

Type 17 wrote: »

You're aware that the drive-side cup you're trying to unscrew is a left-hand thread*?

*unless it's an older Italian-made frame.

PS: The vice isn't a bad move, but you'll need an assistant to hold everything steady with you, as a slip will result in the lovely frame falling all over the sharp edges of the vice :eek:

I am aware, although every few minutes I would stare at it and make sure I was going the right way. The owner was not sure about this so I let them give a few tries in the other direction but it never bunched an inch. Everything so far on the bike has been really tight until you get that first mm of movement and then it has spun off easily. Terrified of damaging the frame s it belongs to my deceased friend and doing this for his son who does not want to go to a shop with it (his Dad put it together on his own, he wishes to do the same).

magicbastarder · 28-11-2020 7:40pm

do you have a heat gun?a bit of oil and a few minutes with a heat gun may help.

cletus · 28-11-2020 7:41pm

Just about to suggest the same thing

Type 17 · 28-11-2020 7:52pm

Fair enough, then.

If you can get it to move a bit, drop loads of oil into the threads and work it back inwards a bit, as you unscrew it outwards, to work the lube in, and to widen the range of looseness.

If things are really stuck, read on:

If you want better purchase on these cups, and you have an angle grinder with a cutting disc (don't try it with a grinding disc - too imprecise), you can cut the flats of the cup back a bit, which will lengthen the flats, meaning the vice can get a better grip on them. Be careful to keep the "new" flats parallel and perpendicular to the BB spindle's axis, to ensure the vice gets a good grip. Obviously, be really careful not to touch the frame with the grinder disc...

cletus · 28-11-2020 8:13pm

Type 17 wrote: »

Fair enough, then.

If you can get it to move a bit, drop loads of oil into the threads and work it back inwards a bit, as you unscrew it outwards, to work the lube in, and to widen the range of looseness.

If things are really stuck, read on:

If you want better purchase on these cups, and you have an angle grinder with a cutting disc (don't try it with a grinding disc - too imprecise), you can cut the flats of the cup back a bit, which will lengthen the flats, meaning the vice can get a better grip on them. Be careful to keep the "new" flats parallel and perpendicular to the BB spindle's axis, to ensure the vice gets a good grip. Obviously, be really careful not to touch the frame with the grinder disc...

That sounds like the sort of thing I would suggest to somebody, and then be told to feck off

If you can get a grip with the vice, you should have enough leverage with the frame

Type 17 · 28-11-2020 8:30pm

cletus wrote: »

That sounds like the sort of thing I would suggest to somebody, and then be told to feck off

Yep, not for the faint-hearted, but I've had to go that far on a few occasions (with modern, unremarkable bikes).

cletus wrote: »

If you can get a grip with the vice, you should have enough leverage with the frame

Yes, but when things are rusted-up enough, you'll find that no matter how carefully you rotate the frame, the cup pops out of the vice. Every. Damn. Time.

That's why making the flats bigger can help.

PS: all of the above is after heat and lube, BTW.

PPS: Hopefully, Cramcycle won't need to go that far...

tomasrojo · 29-11-2020 2:32pm

Is this the fixed cup you're having trouble getting out? I have a tool for removing fixed cups. Basically the shop version of this:

as mentioned here:
https://sheldonbrown.com/tooltips/bbcups.html

Means you don't need to try and get the wrench onto the tiny flats of the fixed cup.

Cram, I think you're in my part of town. Let me know if you want to give it a try.

Seve OB · 29-11-2020 11:50pm

Felt Z6 road bike,
Shimano 105 derailer
Microshift shifters
my rear gears are ticking as I ride, but sometimes will slip into another gear. Very annoying, especially if out of the saddle going uphill

I'm not really sure what I might need to do to fix, considering it might be best to leave into a bike shop and get a full overhaul done?
But maybe it's something simple that I can adjust myself?

gn3dr · 29-11-2020 11:56pm

Seve OB wrote: »

Felt Z6 road bike,
Shimano 105 derailer
Microshift shifters
my rear gears are ticking as I ride, but sometimes will slip into another gear. Very annoying, especially if out of the saddle going uphill

I'm not really sure what I might need to do to fix, considering it might be best to leave into a bike shop and get a full overhaul done?
But maybe it's something simple that I can adjust myself?

Sounds like you need to adjust the cable tension. As a quick check eyeball the alignment of whatever casette cog the chain is sitting on with the jockey wheels below on the derailleur. The upper jockey wheel should be straight under the cog. Adjust the cable adjuster on the derailleur until they align. Take it for a spin then to check. If it is slow to change up then the cable needs more tension.

cletus · 02-12-2020 10:57am

CramCycle wrote: »

So old school square taper BB ie not sealed. Got the dust cap after drilling two tiny holes in it for leverage, that side came off quite easily after but the side you would use a spanner on (other side was a lockring spanner and one of those wrenches with the two pins that one can move on) is not budging. Best I can think of after everything is to pinch where the spanner is meant to grip on a bench top vice and use the frame for leverage. Its a lovely old school bike with shimano 600 throughout. Any thoughts on if this is stupid or not?

Did you take the angle grinder to this yet?

CramCycle · 02-12-2020 3:59pm

cletus wrote: »

Did you take the angle grinder to this yet?

Not yet but my lame excuse for a bench vice in my office can't do it and slips, so I ma off to a bigger vice in the workshop which is bolted to the table.

BB does say 1.37 x 24T so I hope that means it is definitely English threaded.

Colombus tubing but no sticker (has the nice detailing at the lugs).

Frame is light guessing SLX tubing by the weight.

JerryHispano · 02-12-2020 4:27pm

Hi, I'm pretty new into this bike maintenance business so I'd appreciate any advice given.

I recently bought a Triban RC120 gravel and I find I'm hitting the top gear far too often. The chainring is 38T and I want to change up to 42 (which will be a 1:1 lowest gear). The chainring doesn't seem to be one which can be swapped with a few screws; the connection seems to be right in at the BB. I've ordered a crank arm puller, but while I wait for it to arrive so I can inspect it further, I'd like to be looking for a suitable replacement. Is there a common standard I can expect it to be?

https://www.decathlon.ie/ie_en/rc-120-disc-gravel-adventure-bike-microshift-en-s312397.html

(Mini review - the bike is nice but the tyres and gearing are perplexing. Practically road tyres in smoothness, but then the gearing gives a top speed of c.37kph. The flared drop bars are also very nice)

cletus · 02-12-2020 4:40pm

JerryHispano wrote: »

Hi, I'm pretty new into this bike maintenance business so I'd appreciate any advice given.

I recently bought a Triban RC120 gravel and I find I'm hitting the top gear far too often. The chainring is 38T and I want to change up to 42 (which will be a 1:1 lowest gear). The chainring doesn't seem to be one which can be swapped with a few screws; the connection seems to be right in at the BB. I've ordered a crank arm puller, but while I wait for it to arrive so I can inspect it further, I'd like to be looking for a suitable replacement. Is there a common standard I can expect it to be?

https://www.decathlon.ie/ie_en/rc-120-disc-gravel-adventure-bike-microshift-en-s312397.html

(Mini review - the bike is nice but the tyres and gearing are perplexing. Practically road tyres in smoothness, but then the gearing gives a top speed of c.37kph. The flared drop bars are also very nice)

A bit of googling suggests that the bottom bracket is a Shimanoi tourney, so likely a square taper.

JerryHispano · 02-12-2020 4:49pm

cletus wrote: »

A bit of googling suggests that the bottom bracket is a Shimanoi tourney, so likely a square taper.

Thanks, I undid the screw holding the crank arm on and it is indeed a square taper (the arm was strongly wedged on there so hence the need for a puller). I'm more wondering if I can just replace the gear and keep the arms I have and save a few quid? I don't have the terminology to search this effectively.

Maybe waiting for the puller is the best option before looking into a replacement...

velo.2010 · 02-12-2020 4:56pm

You'll likely have to invest in a new chain too if your sticking on a bigger chainring. The 38 tooth chainset does appear small when compared to similar single ring gravel bikes - most range between 40 to 44 teeth. Do you do a lot of road cycling with the bike which would cause you to spin out in top gear?

magicbastarder · 02-12-2020 4:58pm

probably would be best to take a close up of the chainwheel and post it here, it's not quite clear what it is on the decathlon page.

AndrewJRenko · 02-12-2020 5:21pm

Type 17 wrote: »

It usually doesn't, but some lights (a few, older designs from the days of bottle dynamos) still rely on the negative side of the circuit returning through the frame and into the hub, so if your light doesn't work after re-wiring the plug, you should try reversing the polarity.

All sorted now, thanks for your help.

JerryHispano · 02-12-2020 5:30pm

Ok, some pictures now attached. Thanks for the tip about the new chain needed, that's not something I would have thought of. More expense :-(

I do more road cycling than otherwise, but even along gravel canal towpaths I was looking for a higher gear with none to be found.

I appreciate all the help thus far.

Type 17 · 02-12-2020 5:36pm

CramCycle wrote: »

...BB does say 1.37 x 24T so I hope that means it is definitely English threaded...

Yes, 1.37(inches) x 24T(hreads per inch) is the English BB threading standard, so that means that the fixed cup (drive side) definitely unscrews clockwise.

velo.2010 · 02-12-2020 5:42pm

JerryHispano wrote: »

I do more road cycling than otherwise, but even along gravel canal towpaths I was looking for a higher gear with none to be found.

Hmm. Many 'roadies' including myself are riding in the small ring at this time of year. My gearing is 36-13/36-14 at 90 RPM or so, on mostly flatish roads. If your managing that sort of cadence in your biggest gear (38-11) on a gravel bike then your going well!

However, I suspect your cadence is lower at about 60 RPM which is typical for beginners. If that's the case you should work on improving cadence in smaller gears and you won't need to replace the chainring.

TychoCaine · 02-12-2020 6:46pm

JerryHispano wrote: »

Ok, some pictures now attached. Thanks for the tip about the new chain needed, that's not something I would have thought of. More expense :-(

I do more road cycling than otherwise, but even along gravel canal towpaths I was looking for a higher gear with none to be found.

I appreciate all the help thus far.

That's a one-piece crank/chainring. You'll have to replace the entire thing. Square taper 1x cranksets are thin on the ground. Square taper is an old standard, but 1x cranks are the new sexy. There isn't much overlap apart from old skool track cranks used on fixies, but they're either mega expensive or Chinese made junk.

You'll find some stuff on eBay, but it's of questionable quality. If it was me, I'd swap out the bottom bracket for a modern external bearing BSA model, and you have a lot more options when looking at cranks.

And you will need a new chain also. They're cut to size when installed, and the current one won't be long enough to go on the large cassette cog without making your derailleur explode.

the 'there's no such thing as a stupid question' bike maintenance thread

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