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.
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.