I'm a champion bike mechanic...

[bychosis]

Sons MTB brakes are a bit spongy. Ok when using the brakes downhill, but need pumping after rising the flat a bit, or a lot of pumping if the bikes been hanging off the vertical rack.

No worries, I’ll drop some oil in the top. Nope, still spongy. Whip out the bleed kit, all good until the hose pops off the calliper and I realise I hadn’t taken the pads out. Now I need to go buy brake cleaner and then put new pads in. *sigh*.

On a more positive note, managed to find some cranks in the parts bin to replace the SLX cranks on other kid’s MTB after a full load in high gear managed to bust the crank spider. There were two bolts missing, so suspect that the remaining two and high torque pulled the remaining bolts out of the spider.

[familyguy]

Pretty sure there are deeper things at work here. Swapped an old rim for new. Taped it along side, same brand/model, undid the nipples and swapped each spoke over as it came out. New brass nipples, same spokes, same rim ERD. Wheel will not even get close to centred. Cranked DS tension so high it's rounded 6 spoke nipples, NDS tension is almost wobbly. Time to measure hubs and get all new spokes and nipples I think. Wasted 28 good brass ones (24 plus 4 replacements for rounded ones) on this dog of a project already...

[elantra]

Pretty sure there are deeper things at work here. Swapped an old rim for new. Taped it along side, same brand/model, undid the nipples and swapped each spoke over as it came out. New brass nipples, same spokes, same rim ERD. Wheel will not even get close to centred. Cranked DS tension so high it's rounded 6 spoke nipples, NDS tension is almost wobbly. Time to measure hubs and get all new spokes and nipples I think. Wasted 28 good brass ones (24 plus 4 replacements for rounded ones) on this dog of a project already...

That’s bizarre !
Are you sure that the nipples are the same size (length) as the old ones ?
Is the lacing crossover number (usually 2 or 3) the same as before ?

I find that deconstructing things has a higher rate of success than reconstructing things.

Yesterday here (far north coast NSW) was a slightly stressful day with bucket loads of rain and concerns about floods etc.
The shed is the perfect place to seek security from the forces of nature like this.
Just gotta keep one window slightly open to allow some muted gale force wind to cool the steamy humidity

I pulled apart a 1980’s road wheel (rear).
Justification being to see if there was anything salvageable, such as the rim, looked to be a reasonable quality one.

All sorts of interesting stuff.
The axle was split in two !
The cone ball bearings were in races !
The 6-sp Shimano freewheel came off OK !
The spoke nipples (mostly) were not seized.
And at some stage one of the spokes must have been replaced caus it was nice stainless steel and all the others were rusty as.
And the Araya rim is in OK condition but not very useful as it is a 27 inch one !

[familyguy]

That’s bizarre !
Are you sure that the nipples are the same size (length) as the old ones ?
Is the lacing crossover number (usually 2 or 3) the same as before ?

That's what's so weird. I redid it by taping the two rims (same brand, same model, same ERD) together, undo one spoke and immediately put it in the corresponding hole right next to it. It's worked well for me a dozen time, but not this one. I will check the nipple lengths, but I wouldn't have thought that would cause quite this level of problem. Luckily I have spares for now, but will get these rolling for a nicer enduro road rebuild upcoming.

[find_bruce]

Thought there was something amiss with my front deraileur - intermittent failure to shift onto the big ring, no biggie. Then noticed there was a gap between crank & bottom bracket, thought's that's weird. Been meaning to tighten it for a while, go around to it today. Loosened the 2 clamp crews & got out the special shimano crank cap tool. Went to tighten it & cap fell out. Closer inspection revealed the remains were still threaded inside, but was able to extract that using the special little finger tool.

Fortunately I had a spare - nice shiny alloy one that I'd never fitted because I didn't have a big enough allen key - my sets only go up to 10 mm. Found a bolt with the right size head, added 2 lock nuts & Robert's your mother's brother.

As a bonus I found a small bottle of lens dye I'd been hunting for ages - nothing to do with bicycles, which is why I hadn't looked in that box. You always find things in the last place you look

[warthog1]

Thought there was something amiss with my front deraileur - intermittent failure to shift onto the big ring, no biggie. Then noticed there was a gap between crank & bottom bracket, thought's that's weird. Been meaning to tighten it for a while, go around to it today. Loosened the 2 clamp crews & got out the special shimano crank cap tool. Went to tighten it & cap fell out. Closer inspection revealed the remains were still threaded inside, but was able to extract that using the special little finger tool.

Fortunately I had a spare - nice shiny alloy one that I'd never fitted because I didn't have a big enough allen key - my sets only go up to 10 mm. Found a bolt with the right size head, added 2 lock nuts & Robert's your mother's brother.

As a bonus I found a small bottle of lens dye I'd been hunting for ages - nothing to do with bicycles, which is why I hadn't looked in that box. You always find things in the last place you look

I like that solution, thanks

[DavidS]

I replaced a chain on the Allegro last weekend. The idea is that I replace the chain when it gets to 0.5 stretch and not wait until it is 0.75. In the past I have waited until it is really stretched and replace the chain and cassette at the same time.

While this is on a Sram equipped bike part of the reason to do this is to see how well it works because the cassettes on the Auren are Campy so damned pricey.

Getting a little chain slip if I really push hard in a tall gear, apart from that it is fine.

Is this normal? I presume that the combo of a new chain and partly worn cassette will take a little while to work together.

DS

[uart]

Is this normal? I presume that the combo of a new chain and partly worn cassette will take a little while to work together.

If that's your first chain change and at only 0.5% I would have expected it to go smoothly without any skipping.

I find that if skipping is very minor (after chain change) then just putting a few easy rides on it, like plenty of spinning and not too much grinding, and it will generally settle in.

[DavidS]

Is this normal? I presume that the combo of a new chain and partly worn cassette will take a little while to work together.

If that's your first chain change and at only 0.5% I would have expected it to go smoothly without any skipping.

I find that if skipping is very minor (after chain change) then just putting a few easy rides on it, like plenty of spinning and not too much grinding, and it will generally settle in.

Yeah, it is minor and that was my thought. I am only thinking of 2 chains per cassette. Also, this only happens under a lot of load, too tall a gear, and of course there is the question of whether the derailleur is perfectly in place, especially given the bike has bar end friction shifters - I am pretty good at knowing where the gears are but not perfect.

DS

[elantra]

On the topic of chain wear and replacing a chain etc.
Perhaps I could have done it a bit sooner, the metal prong style wear measurement tool was “about 0.75 % wear, not quite 1 %”

Old chain was easy to remove, there were 2 quick links to chose from !

On went a new chain, cut down to the same length as the old one.
But transmission wasn’t happy with the new chain, a bit of mild “skipping” with the smaller rear cogs.

After reading your posts above I was reassured that it will probably wear in.
But I thought I would try using another wheel with a newer cassette. For a while, anyway.

Which I did, and although the cassette looked NOS, the wheel itself had all sorts of minor deficiencies.
Such as being out of true, not exactly circular, and axle length for a slightly wider hubspace than the favoured bicycle.
By about 2300 hrs last night, I thought that all of these issues had been overcome, just in time for this morning’s 0600 ride.

The bike performed brilliantly - for a while.
Yes, the rear wheel was not perfectly circular, but this was only perceptible on the smooth roads, which are the exception rather than the rule.
In fact it felt like the imperfect wheel actually made the irregular road surface feel smoother.

But things went downhill quite literally on a fast flowing descent.
The new chain came off the front while changing up at the top of hill.
I couldn’t get it back on without stopping but as I was now going downhill quite fast I thought to leave it until the road leveled out.
That was about 2 km later and by that stage the chain was quite convoluted.

It was a bit of an effort to get it sorted.
Jumped back on bike.
It went but with some new and unwelcome noises.
Another stop.
Inspection revealed the front derailleur was bent, but also the chain was bent in a plane that it’s not sposed to be bent.
I’ve never seen that before.
Was able to complete the ride, with a reduced amount of force and reduced use of the gears.
Another lesson for this amateur bike mechanic I suppose

[blizzard]

11+ speed is definitely best to replace at 0.5% to prevent excessive wear. Not all chain checkers are made equal, my favourite is the Park Tool CC4 because it accounts for roller wear.

[DavidS]

Yep, I had to get a new chain checker which would do 0.5%, I think it is Lezyne and seems to work fine.

We'll see how I go when the Auren with Campagnolo needs changing. No connecting link on that one (12 speed) so a slightly bigger challenge.

DS

[jasonc]

front brake lever was going all the way in. so had my first go at bleeding hydraulic brakes. saw the bubbles come out. rode it this morning. it's a lot better

[antigee]

^^^^ the good news is that you don't have do it that often
the bad news is that it means you don't learn the ins/outs specifics of each set up

after having a bolt extractor kit at the bottom of the tool box for 15 years finally got to use it
...dumb enough to swop over seatposts from memory and my memory was about 0.6mm out (error 1 forgivable)...Thompson seatpost clamp has a tiny hex key so when the seatpost slipped I just upped the torque wrench (error 2 and probably on my permanent record) this screwed up the hex bolt head...stainless steel so a trip to get a cobalt tipped drill to get a big enough hole to hammer in extractor and yes it worked and all fixed but some stupidity to power ∞ involved

[stevenaaus]

Haha. I somehow own two extractor kits. I had a go at using one for the first time last month, but had more success regrooving the screwdriver slot with an open hacksaw.

[elantra]

On the topic of chain wear and replacing a chain etc.
Perhaps I could have done it a bit sooner, the metal prong style wear measurement tool was “about 0.75 % wear, not quite 1 %”

Old chain was easy to remove, there were 2 quick links to chose from !

On went a new chain, cut down to the same length as the old one.
But transmission wasn’t happy with the new chain, a bit of mild “skipping” with the smaller rear cogs.

After reading your posts above I was reassured that it will probably wear in.
But I thought I would try using another wheel with a newer cassette. For a while, anyway.
< cut >
The bike performed brilliantly - for a while.
Yes, the rear wheel was not perfectly circular, but this was only perceptible on the smooth roads, which are the exception rather than the rule.
In fact it felt like the imperfect wheel actually made the irregular road surface feel smoother.

< cut >

Update time - nobody really wants to ride far on a wheel than gives a lumpy ride.
And the faster you go, the more lumpy it gets.

So there was another (old) wheel in the shed, in fact it must be 31 yrs old because it has a date stamp on the hub. 02-92 so must be 1992.

This wheel appears to be very true, with rim and spokes VGC.
But the freehub was indeed free - in both directions. Unridable, except downhill of course.

How do you fix a freehub ?
Look up a U-tube video, of course.

I thought it was a cartridge bearing hub and the freehub would just pull off once the DS locknut removed.
But no, removing the DS locknut only “exposed” a mobile and easy to unscrew drive-side axle cone

So keep going, out with the ball bearings, one missing on DS.
Bit of a clean exposed the splined removal bolt for freehub.
A 12 mm hex key fits - hooray
But no amount of force will unscrew it, even with a dirty big length of steel extender for added leverage.
So just spray into it with WD40, and give it a spin , and hey presto- it works now !

So this wheel is now back in business, after some more cleaning, some grease, repack the bearings (with an extra one from the shed to make up 9 on the drive side)

Old 6- speed cassette goes on, wheel in frame, adjust the cable screws at rear derailleur to get the indexing spot on.
And the limit screws for rear derailleur travel.

Actually it was a little bit more complicated than that, but I’ve harped on long enough, you get the gist of it !

[g-boaf]

Hub on the Xentis 2.5SL wheels is damn near impossible to disassemble. cannot get the freehub body off it.

So it's off to the bike shop to get them to sort it.

[elantra]

Oh dear, I hope that the title of this thread is tinged with sarcasm because my mechanical outcomes fall far short of being championship level

….

This time another new chain, another skipping freewheel !

But only the ones that get used on the local Railtrail, as this bike is almost exclusively used on the railtrail, so the big cog and the little cog don’t see much action.

But the 3 cogs in between, the ones that get used, momentous incompatibility with the new chain.

So the problem to be solved is how to get good function, on the Railtrail, with the “big” cog at the back wheel

The quickest solution that I came up with is to put a considerably bigger chainring on, bearing in mind that the one on the Crankset is only 42 tooth.
(Actually there are 2, a 39 tooth and a 42 tooth, but the latter is the one that works best)

I couldn’t find a bigger chainring that wasn’t needed on another bike.
But I did find a 48 tooth single ring Crankset.

So off with the what was on the old bike, and on went the “new” (actually 40 yr old) Crankset with the bigger gear.

Tightened her up and off I went.
I did forget to see if the crank arm is the same length as the one on the other side.

But it hardly matters because the functional outcome was excellent.
It gave me a 48x21 gearing driving a 700C wheel with 32 mm tyre.
Pretty well ideal for the relatively flat, gravel surfaced Railtrail

[uart]

But only the ones that get used on the local Railtrail, as this bike is almost exclusively used on the railtrail, so the big cog and the little cog don’t see much action. But the 3 cogs in between, the ones that get used, momentous incompatibility with the new chain.

It's a common problem, that the most used cogs at the back see the most wear, and not much you can do about it. Using bigger cogs does work to some extent, as they tend to wear a bit slower given that the wear is spread over more teeth.

The quickest solution that I came up with is to put a considerably bigger chainring on, bearing in mind that the one on the Crankset is only 42 tooth. (Actually there are 2, a 39 tooth and a 42 tooth, but the latter is the one that works best)

Are you saying that you were running a 2x (front), but with only a 3 tooth difference between chainrings? That's a fairly odd configuration.

[elantra]

Are you saying that you were running a 2x (front), but with only a 3 tooth difference between chainrings? That's a fairly odd configuration.

Yes, but only because it’s an old traditional 5-arm Sugino Crankset, which is easiest to make work as a 1x using 2 chainrings, any 2 chainrings, as long as one of them is roughly the number of teeth that works best for riding conditions.

The usual recommendation with 1x systems is to use a special 1x specific chainring, or use a FD to help stop the chain from periodically bouncing off.

In practice though, this old bike only really gets used on the Railtrail, which is fairly smooth, and the chain almost never “comes off”
(Well, actually it did once, but conveniently landed on the other chainring ! )

I could use a front derailleur for chain security, or even install shifter & cables for shifting between chainrings.
But I won’t because this would add very little benefit on the Railtrail.
And the crunch is (literally), the Railtrail is fine gravel, great to ride on, even in the rain.
BUT- when it rains, which is frequent here, the watery spray off the wheels deposits nasty mixture of fine gravel particles esp in bottom bracket and front derailleur etc
Mudguards might help, but yeah nah, I will just stick with mechanical simplicity on this bike.
It’s a 1977 Motobecane touring frameset, which has room for 700x32 mm tyres. Ideal for good gravel

[warthog1]

It’s a 1977 Motobecane touring frameset, which has room for 700x32 mm tyres. Ideal for good gravel

They are small tyres for gravel!
I have tried gravelking slicks in a 35 on my wide LBWR50 wheels (25mm int) which inflated to >37 mm on those rims. Ok on very smooth stuff like the O'Keefe but the 40s I normally run are preferred.
Some I ride with have tried 45 for rougher stuff but they are slower on the smooth stuff.
The 32s on your bike should be quite fast however

[uart]

Yes, but only because it’s an old traditional 5-arm Sugino Crankset, which is easiest to make work as a 1x using 2 chainrings, any 2 chainrings, as long as one of them is roughly the number of teeth that works best for riding conditions.

Ok, so you're running a 1x up front with only 6x on the rear, and obviously riding mostly flat terrain. That will work, personally though I'd get a 48T for the other crankset and run it as a 48/39 2x. You know, just in case one day you accidentally meet a hill.

[DavidS]

I seem to recall that bikes back in the 70s and 80s had close sizing for the chain wheels. Given it is a 1977 frame, this doesn't surprise me at all.

DS

[warthog1]

Ok, so you're running a 1x up front with only 6x on the rear, and obviously riding mostly flat terrain. That will work, personally though I'd get a 48T for the other crankset and run it as a 48/39 2x. You know, just in case one day you accidentally meet a hill.

48/32 and 36-11 11speed on my gravello. Just love that range and yes I have used all of those gears. 32-36 rarely but it is useful on rough, steep and sketchy climbs.
Nope, no gaps that really bother me either. Modern gearing is sooo much better ime.

[blizzard]

I think my torque wrench calibration is out. Adjusting the angle of my carbon bars. Tightening the stem bolts, got all 4 to 3.5nm. Set the wrench to 4.2nm, tightening a little bit a heat a crack, suspiciously like CF cracking. Stopped tightening, bars look ok, no damage and tight. I put my full 74kg on the drops and lifted my feet off the ground and no cracks or deflection. Going to ride as is.

I have now bought a t-handle 4-6nm wrench until I get time to test and calibrate the click style wrench (it's a Giant 2-15nm if anyone is interested).