Mechanics and Fixing Any Questions Answered

The bung and stem can move separately, ie. the bung gets hammered up, but you've just ridden down something on the drops so the stem is at its lowest. Still loose, but there's no visible headset gap but there is now a visible bung to steerer gap. That's what mine did quite often before I replaced all the bungs, etc as per previous comment.

Inverse space?

Sometimes the hammer is up, sometimes the hammer is down.

Found it. Got its own thread: https://www.lfgss.com/conversations/375117/

Y-8JZ05000
Y8JZ98010

Okay, check if any inverse space has opened up.

That isn't not much clearer.

What's this metal bit for? Some sort of spring to keep it in place?? (It's on the plastic lock thingy of a Shimano crank)

1 Attachment

It should locate into a hole in the crank spindle - I’ve always assumed it’s a go/no go check that the nds crank arm is correctly positioned on the spindle.

a go/no go check that the nds crank arm is correctly positioned

I guess it's a good reference. But since the splines aren't all even, it's only going to tell you if compression was right. It's probably not the best indicator for that either really.

Okay thanks!

Not sure what you're saying there?

The point of that plastic bit is merely to verify the BB width / spindle insertion depth is within spec. At least practically speaking... Shimano might say it's to stop the crank falling off, but if that's what it's doing, bad things have already happened.

The uneven splines mean the crank can only go on two ways. Which is better than one way... Not only for storage and second-hand shipping, but also for handicapped cyclists who pedal with their hands.

With regad to 4700 chainrings try unite they have a 20 off code at the moment
https://uniteco.bike/product-category/drivetrain/chainrings/?gad_source=1&gbraid=0AAAAACdHwipC9ym_Tt9pFWVfc7D3xgXwi&gclid=EAIaIQobChMI9KXc4N_BiAMVN5FQBh0sQB4GEAAYASABEgL-nvD_BwE

Don’t seem to have Shimano chainrings in stock though! So the 5800s sit like this; I don’t care too much for the aesthetic as long as it is safe to ride - is it? I note a really small gap between the chainring arm and crank arm but seeing as the bolts go through the hole I’m presuming that shouldn’t be an issue?

4 Attachments

Buddy has brought me a bike (mid 2000s Trek 4300). He mentioned the seatpost keeps slipping and so I checked it, confirmed it is 3mm (!) under spec, the slot was completely closed at the top. I opened it up to make the slot parallel again and reamed it out , but this only brings it to 29mm, still far off the 31.6 Trek specifies. Where do we go from here? He doesn’t want to spend much, but I would recommend going to a LBS and have them look at it, either to fit a post to the current dimensions or open it up to spec or? The frame is aluminum.

Where do we go from here?

https://www.ebay.co.uk/sch/i.html?_nkw=trek+4300

Or whatever you use in the frozen north, the point is you can probably find a fresh one for less than the lbs is going to charge to tell you it's fucked

You could easily get a 29.0 seatpost https://www.ebay.co.uk/itm/133459989643

really small gap between the chainring arm and crank arm but seeing as the bolts go through the hole

It's certainly not ideal, but as long as it sits snug on the sleeve nuts it should be okay. A bit of non-permanent Loctite on the hopefully torx bolts might be a good idea, otherwise just make sure they're good and tight, and check them once in a while.

Or, you could make it a bit better with some epoxy - spray the crank spider with something oily or waxy to work as a release agent, and dribble the glue in the gap. Or sprinkle bicarb and follow it with superglue. Won't be pretty, but that obviously won't bother you

it's fucked

Fraid so, especially since ally.

If you can find a clamp to go on the post itself to stop it sliding down (you may need to take a lip off the clamp) you can probably horribly bodge it though.

Thanks, to buy one locally would cost at least 50, the LBS will charge little to nothing if they decide it's fucked.
I warned him not to get that specific bike as the whole thing looked cobbled together but he's a cheap ass.
We'll see what the shop says as he's agreed to take it there.

Yep, I know, thanks.

Always a possibility, he'll go with the cheapest option regardless, thanks.

What's the forum-approved headset press?

I won't say money is no object, but I don't mind spending a bit more on something that will do a better job / be easier to use / last a long time.

I would vote for something with a quick release nut, but not the Park HHP-2, that thing is way overkill and manages to pinch my skin everytime I use it. I like the modularity of the Wheels Manufacturing press, and their bearing removal kit is nice too.

Thanks!

I have the WMFG hub bearing press, so I know their stuff is really nice. I'll take a look over there.

(I agree the Park offering would be overkill)

The joy with Park ones is that you can often pick them up second hand quite cheap. Think I got mine for £50