On 2018-11-23 12:45, wrote:
On Friday, November 23, 2018 at 10:10:23 AM UTC-8, Joerg wrote:
On 2018-11-23 09:48, wrote:
On Friday, November 23, 2018 at 9:29:33 AM UTC-8, Joerg wrote:
On 2018-11-23 08:07, Sir Ridesalot wrote:
On Friday, November 23, 2018 at 10:59:18 AM UTC-5, Joerg
wrote:
On 2018-11-22 20:59, John B Slocomb wrote:
On Thu, 22 Nov 2018 16:05:54 -0800, Joerg
wrote:

After installing a new Sunrace 40-11T cassette (minus
one cog), a new chain and a new rear derailer the road
bike can now climb hills much better. 40T as biggest
cog versus 32T before. Woohoo!

However, on the middle and three larger cogs (it's now
a 7-speed) there is a distinct vrrrt .. vrrrt sound
when under heavy load. Maybe from the chain because
with a derailer setup it'll never run 100% straight.
Hard to say. The noise appears briefly twice per pedal
crank rotation and always on the power strokes.

The chain is a KMC Z50 that should be suited for
7-speed and I looked, it doesn't rub against a neighbor
cog. Maybe a "teeth exit grinding"? On the 3rd cog from
the largest it's really weird because that has an
almost perfect chain line when on the small chain ring
up front.

Anyone heard that before? Can it simply be ignored? Or
maybe it'll go away over time?

I've had a noise from a front derailer due to the chain
rubbing on the derailer "cage".


It's definitely not that. The chain visibly doesn't rub
anywhere.

-- Regards, Joerg

http://www.analogconsultants.com/

You've checked that whilst riding? I find it interesting
that the noise ONLY happens on the power stroke.


While slowly riding up a hill under high power and then again
with applied brakes leaning against a wall. However, on Sunday
I'll have a friend take a close look while doing that.

What's really weird is that it also emits this noise while on
the largest 40T cog where it doesn't have a chance to rub
against anything in the cassette. I can clearly see that it
doesn't rub at the front derailer. My guess is that it is some
sort to "teeth disengangement" sound.

Another thing I found out is that one has to carefully and
somewhat slowly shift onto the largest cog, else the chain
flies over it and into the spokes. That is no problem though
because I'll only use that on really steep hills. For most
hills the (for me new) 36T will suffice. When I service this
next time maybe I'll take the cogs off, make an aluminum
protector disc, drill it and the 40T cog and mount that towards
the spoke side. Should catch the chain.

-- Regards, Joerg

http://www.analogconsultants.com/

Joerg - in my experience this is because the rear derailleur is
ever so slightly out of alignment. If it is towards the higher
cog it will often "hop" and towards the lower side it will growl.
This sort of misalignment general is only 1/8ith or less of a
turn of the rear cable adjuster.


I have friction shifters and tried all sorts of fine adjustments.
The growl is independent of it.


You can also have a problem with a 7 speed chain on your reduced
cassette. While 7 and 8 speed gears have the same spacing
between cogs and the same cog width, some manufacturers are using
10 speed components supposedly with wider spacers that may be not
wide enough for 10 speed cogs.


Ok, but it doesn't rub against a neighboring cog which is about the
only thing that could happen with a chain that is too wide. The
growl even happens when on the largest cogs an in perfect
aligment.

-- Regards, Joerg

http://www.analogconsultants.com/

Is this growl actually coming from the front derailleur? Also - is
the chain lubed? Third - is the Freehub properly tightened? Last -
Are the wheel bearings in rough condition?


Not coming from the FD, it doesn't touch the chain anywhere. Chain is
new out of the box, factory lube. The freehub is tightened at full
torque spec but has the usual bearing play of 0.050" or so. They all
develop that on my bikes after 1000mi. It's about 5000mi old and
freehubs mostly last about 10000mi on my road bike depending on
terrain/weather. Since the freehub doesn't move versus the wheel under
load I can't imagine that making a growl.

The wheel bearings are old but adjusted well. I don't think they could
make this loud a sound.

--
Regards, Joerg

http://www.analogconsultants.com/