Author Topic: Noisy rohloff  (Read 779 times)

neil_p

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Re: Noisy rohloff
« Reply #15 on: February 27, 2018, 08:37:39 AM »
yeah chainline is really tricky to measure. I have tried several times with wildly inconsistent results & no idea why!

Maybe try measuring the chain stretch with a tool... did you somehow get an old chain mounted by accident? Seems like all the obvious bases have been covered, so double checking strange things is probably what you're stuck with.

Did you just switch the type of sprocket, from screw-on to splined?

I bought new everything and fitted in one go. Went from a rohloff chain to kmc. Yep went from screw sprocket to carrier type.  My first carrier was standard sort, SJS advised a switch to the slim carrier which I did.

The chain has been used for 1000m mostly indoors... If it's worn I want a refund! :)

neil_p

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Re: Noisy rohloff
« Reply #16 on: February 27, 2018, 08:40:50 AM »
Ear Plugs (the advice from my LBS when I took one of my bikes in which creaked and I'd changed and greased just about everything)
If SJS say it's OK then it probably is.

Unfortunately they only checked the wheel which I'd posted to them. They haven't seen the whole bike, so although the hub itself has received a clean bill of health, lots of other factors still to eliminate.

They did say the original carrier (non slim) had worn on the sides, and changed for a slim carrier to improve chain line.

Donerol

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Re: Noisy rohloff
« Reply #17 on: February 27, 2018, 01:29:32 PM »
It's easy enough to measure chainline with a cheap vernier caliper like this:


(You can also get ones with a digital read-out)

1. Measure the diameter of the seat tube just above the chainring.
2. Measure the gap between the seat tube and the centre of the chainring.
3. Add half of measurement 1 to measurement 2 to find your chainline.

Even I have done it successfully!

The recommended chainline can be found here: https://www.rohloff.de/en/products/speedhub/equipment/

Andre Jute

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Re: Noisy rohloff
« Reply #18 on: February 27, 2018, 01:45:39 PM »
They did say the original carrier (non slim) had worn on the sides, and changed for a slim carrier to improve chain line.

Now, by a process of elimination, we're probably there. It's very likely a still-skew chainline, with the effect aggravated by an extra-thick Thorn chainwheel, an extra-stiff X1 chain, and the extra width imposed by the new sprocket fixing method (even the slimmer one is wider then the original threaded one). What you're hearing is rather likely to be the corners being worn off the teeth of your gears by your stainless chain.

You need to fix your chainline by one (or more in combination) of these measures:
*spacers to bring your chainring into a straight line with the sprocket,
*refitting the bottom bracket with spacers to bring the chainring in line with the sprocket,
*or, possibly, if the chainline isn't too far off, a thinner chainring might be a temporary bodge (fit your old chainring temporarily and see if the noise goes away)

MEASURING THE CHAINLINE
The chainline is the distance from the centerline of the bike to centreline of the chain.

To measure the chainline take a measurement with the chain fitted at the front over the chain ring and at the back over the sprocket.

You might find your wife (or mother in law's) hemming measure a useful tool.

To use the bike frame and component hard points (as distinct from guesstimates about centres) as your references:

FRONT: Use vernier callipers to measure from the left side of the seat tube to the right hand side of the chain. Measure the tube diameter and the chain width separately. Subtract half the tube diameter and half the chain width. The result is the chainline at the front.

REAR: You should not have to measure at the rear because the chainline there is a published number you can look up for all the available and heritage sprockets.

RESULT: The difference between these two numbers is the distance you must move the chainring for a straight chainline.


PH

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Re: Noisy rohloff
« Reply #19 on: February 27, 2018, 03:06:53 PM »
Plenty of advice for measuring your chainline, it can be a little awkward but take your time and it probably isn't as daunting as it sounds.
But before you start measuring, it's simple to check the existing one, it only requires a known straight edge, I use a piece of angle aluminium that started life as a bit of kitchen edging.  If the straight edge sits flush on both the chainring and sprocket (Preferably in several places) it's spot on.
A friend uses a laser pen to check theirs, I haven't seen them do it but if you have one it can't be hard to work out. 

neil_p

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Re: Noisy rohloff
« Reply #20 on: February 27, 2018, 05:21:11 PM »
It's easy enough to measure chainline with a cheap vernier caliper like this:


(You can also get ones with a digital read-out)

1. Measure the diameter of the seat tube just above the chainring.
2. Measure the gap between the seat tube and the centre of the chainring.
3. Add half of measurement 1 to measurement 2 to find your chainline.

Even I have done it successfully!

The recommended chainline can be found here: https://www.rohloff.de/en/products/speedhub/equipment/


Mine comes out as 56.5mm

mickeg

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Re: Noisy rohloff
« Reply #21 on: February 27, 2018, 05:29:35 PM »
My chainline is off by about 5mm.  I intentionally set it that way to have a bottom bracket spindle about 100 mm shorter than I would have needed for ideal chainline.

I suffer no ill effects from that chainline error, but I use standard 8 speed cheapo chainrings and the cheapest KMC 8 speed chains I can find.  I have not tried the higher end stuff like you cite.