Technical > Transmission

Thorn Nomad chain replacement + sprocket & hub question

<< < (2/2)

KvBCycles:
Morning gents, thank you for the advice.
What I've managed to do is visit a bike hire shop here in Rovinj and borrowed a pair of their pedals, unfortunately cnc persisted.
Before putting my spd's back on I got some grease from the shop and greased the pedals nicely and fitted them back on. I then removed the seat post, greased and fitted. I then went over what I could, tightening the fore and rear panniers, chainring bolts and EBB bolts.
Took a ride up a hill and it seems like it's sorted...a lot quieter with an occasional click. Having a rest day today so will find out tomorrow if it's sorted.
Thanks again!
Karl

John Saxby:

--- Quote ---seems like it's sorted...a lot quieter with an occasional click.
--- End quote ---

Glad to hear you've made some progress, Karl. I had similar problems with my Raven in June/July, and following the same drill as you, I've reached the same spot as you.

Not quite a "conclusion", but for the moment, there's no major problem.  So, I've decided to adjust my expectations & live with "an occasional click".  (Until it bugs me enough that I repeat the whole bizness...)

Enjoy your tour!

KvBCycles:
Afternoon all, so quick update...
CNC returned with vengeance! I'm on the Croatian islands and there are no bike shops as such, more bike rental shops. The extent of their help has been to lend me a pair of pedals for testing, fine, and some crazy suggestions like my entire drive transmission is finished and needs replacing (this typically after they see the eccentric bracket) haha :)
I gave up with these guys. Found a scooter mechanic, asked to borrow his tools, no problem, popped off the crank nuts, couldn't remove cranks, need the tool, cleaned best I could and then used his spray lube to flush dirt and lube...decided not to muck about no more...just get me to Zadar :)
Put it back together, test of tasty hills over 20km and its now MUCH better, slightest of clicks so think I'll replace bb anyway. Found a shop in Zadar with the shimano un55 bb so going to head there and replace when I can. There's a decathalon in Zadar too so may use their workshop to do the job. Downloaded bb instructions off sjs website (so handy) and it looks straight forward, just need crank puller and spline tool, hopefully decathalon has them, usually they are really good. As far as I'm aware there nothing special to do when removing and installing due to it being within the ebb.
Otherwise, Croatia has beautiful riding, lots of gravel track if you like and the Thorn, despite CNC, is handling it all with aplomb! :)

geocycle:
Thanks for the update.  You could well be correct about the BB and/or a crank arm.  I've replaced a BB in an eccentric twice.  The first time was challenging as the BB was pretty stuck.  I eventually felt it move against the bolts and they scored a 5mm groove in the EBB -not terminal but annoying.  I then removed the whole thing, used a vice to secure the EBB and put some big levers on the BB.  The second time on a different bike all went very smoothly.  I simply tightened the EBB bolts a bit more and removed the BB as you would in a standard frame.  Hope your extraction goes smoothly

Pleased your trip is going well!

mickeg:
You mentioned UN55, so I assume it is a square taper crank.  Using a crank puller is pretty simple, but on occasion I have seen used crank arms for sale where the threads that the puller goes into have been stripped.  Not sure if the puller was not threaded in far enough or if some other problem happened.  But is does suggest you need to make sure it is threaded in far enough.  The other way that could happen is if you did not remove the bolts before you put the puller in, then the crank is still held onto the bottom bracket and the puller can't remove it.

I have to pull my crank arms off to fit my bike in an S&S case, so I carry a crank puller in my tool kit.

The Shimano UN55 bottom bracket is pretty reliable, but any component can go so maybe that is it.  I had a subtle clicking noise on my Nomad for maybe a thousand miles, could not diagnose it.  Finally decided to change the bottom bracket (I had a UN55 installed).  Pulled off the crank arms, then when I went to pull off the left side bottom bracket bushing, it was not loose but it was not as tight as it should be.  So I tightened it up instead of pulling the bottom bracket off the bike.  Decided to see if the not quite tight enough bushing was the problem, so I reassembled the crank, and it has worked fine since.  That was three years ago.

On the bottom bracket, one side is left hand threads (like pedals).  I do not recall which side is left, an internet search would tell you which.  Remove the left side first.  Upon reassembly, install the left side last.  Make sure both sides are tight when you assemble it.

I have no clue what length spindle you would need on a replacement UN55, it varies by crankset.  My spindle is about 10mm shorter than would be ideal on my bike, thus my chainline is off by 5mm.  But that was intentional as I did not want my pedals to be wider on my Rohloff bike than on my derailleur bikes.  But if you could only get a UN55 with a spindle that is more than 10mm different than your old current bottom bracket, your chainline might be off enough to cause more wear on some of the parts.  If the spindle is within 10mm of the correct length, I think that is good enough.

The Nomad eccentric is Aluminum, the UN55 threaded parts are steel.  So, putting some grease on the threads could prevent future dissimilar metal corrosion.  A new one also likely has some blue threadlocker on the threads to help keep it from coming loose, that would also help prevent corrosion.

Good luck.

Navigation

[0] Message Index

[*] Previous page