mostaza

Hi all.

I bought a good condition Marin Farifax SC4, which i have converted to single speed yesterday:
*Replaced cassette and derailleur with a 20T sprocket, spacers, and tensioner
*Replaced the front chainset with a 46T SS chainring

This is the first major work i've done on a bike (but am pretty practical) and all looks right, and done my homework from 101 different forums and youtube videos.

Some references:
*I've checked the chainline: temporarily folded the tensioner up so the guide wheel touches the sprocket to allign it; and use a long (straight!) metal rule against the chainring to check that it's in line with the sprocket
*All lubed
*All parts compatible (3/32" chain/sprocket/chainring)
*(Not sure how to accurately describe this) I intentionally put the chainring on back to front and on the inside of the crank bolt holes - basically so it was closer to the old middle chainring position, rather than the old outer chainring position
*Chain doesn't have a direction
*Chain tension looks right - tensioner isn't at either limit, and there is about 1/2" play in the chain at the bottom if you gently press it up
*Parts were bought from Velosolo in the UK:
***Andel Cro-Mo SINGLESPEED 3/32" Cog - size: 20t
***VeloSolo SS Cassette Hub Spacer Kit (non-ano)
***Forged Singlespeed Tensioner
***Stronglight Single Chainring Bolt Set (correct shorter size for the SS chainring)
***KMC Z610HX 3/32" Singlespeed/Track Chain
***KMC 3/32" 'Snap-on' Joining Links (pack of two) - size: 3/32
***Gebhardt SILVER Singlespeed Mountain Bike 3/32" Chainring - silver chainrings: 46t

I'm unable to post photos (just get a response of "ALERT") and as I'm a new user I can't post URLs - both annoying as I've got quite a lot of detail, but hey, The Dude abides...

It is a constant "gentle" grinding noise. Not intermittent and doesn't sound sharp/as if anything is being damaged.
It is definitely not coming from the BB - this spins freely with no noise and no play when the chain is off (even when i tension by putting pressure on the other crank)
Below are also some other pictures of the setup if that helps.

Is this normal for a new SS chainring/chain?
Will it go away after a couple of hundred miles?
Is something seriously wrong?

Help!

------------------------------ EDIT ----------------------------

Seems I can now post picture and video URLs!
If any new and previous posters can have a look, it may give a little more insight:

PICTURES:
https://drive.google.com/open?id=1lT...zyENT5t0HTcSMg
https://drive.google.com/open?id=1uq...F7V2LzOHtpzn5d
https://drive.google.com/open?id=1bg...clAzdY8Xt0ID7O
https://drive.google.com/open?id=1cw...f_eTC1exqc6fy8
https://drive.google.com/open?id=1QM...UVMNuS3LfcPjC_

VIDEO:

--------------------------------- EDIT -----------------------------------

Another video to show the slight resistance (mentioned further down this thread) when each link engages/releases from the chainring:

hrdknox1

Have you checked the BB under load? There is a difference when the BB is under load (meaning chain attached and you pedaling preferably standing). Rule this out first, and then try another chain.

rhenning

Also do not tighten the chain to much. Roger

Litespud

Only things I can think of is that either your chain line is off (describe exactly how you used the ruler to measure it) or that the new chainring and/or sprocket need to be essentially “broken in”. I’m not familiar with Andel or Gebhardt, so I don’t know what level of quality they are, but I have encountered cheapish chainrings where the machining was a little rough, with the edges not well finished. Some use might quieten them down

Russ Roth

As litespud mentioned, cheaper parts might need a little break in, you're using a tensioner so if the bb was previously quiet or newly replaced with something decent it shouldn't be an issue, fixed gear can sometimes create a grinding noise at the BB and hub due to chain being too tight from rings that aren't round, a ss with chain tensioner shouldn't have this.
I would suspect that the chain alignment is off, not certain how you check with a straight edge. Easiest is to measure with the chain off; front chainring is a simple measurement, measure from the center of the seat tube to the middle thickness of the ring. For the back measure the distance from the outside of the lock nut to the center of the cog, your straight edge going across the lock nut would allow you to measure from the cog to the straight edge easily. Subtract the measurement from half the rear axle width and the result is how far you are from center. This number should be fairly close to the front number, only a couple mm difference, if not respace to get as close as possible.

mostaza

Thanks - I'm pretty sure the BB is fine. I had ridden it as a geared bike for about 3 weeks before converting.
The last week just in a single gear to work out which rear sprocket to order.
There was absolutely no noise or play in the BB before the conversion, even when really stamping on it setting off from lights.

mostaza

So with the chain tensioner I have, is it possible for it to be too tight?
It is resting about 1/3 to 1/2 way through its maximum amount of travel from one extreme to the other (sitting almost vertical).
The chain is tight enough that it's not sagging, but has a total of about 1" movement (1/2" up and down) when lightly pressed at the bottom.

mostaza

I laid a metal rule against the chain ring and sighted the rear sprocket by eye.
I've since taken measurements to the centre of the tube, and calcs of axle width minus sprocket from centre - it was only about 4mm off from my first "estimation".

I have to admit it was a fairly cheap chainring, but not bargain basement.
I'll check out all options and answers before I try wearing it in (to make sure I'm not going to do any damage).

mostaza

Thanks Russ - as in the reply to Litespud, I've since checked it any it seems fine by measurement and eye.

mostaza

An update:
I noticed when I was tweaking it last night, there is some resistance from the chainring/crank when turning them.
If I just use my little finger to gently push the crank arm, you can feel it ever so lightly resisting/relaxing with each chain link that engages (or released) from the chainring teeth.
A kind of (and I stress, the slightest of slight) judder as you slowly turn it - again, I'm positive this isn't the BB.
As above, is it possible to over tension the chain with a chain tensioner (if it's not at one extreme or the other and there is decent movement in the chain)?

tFUnK

Does it sound bad when you backpedal as well as pedal forward?

mostaza

As I tried to explain the post, I wouldn't describe it as "bad", it's just noisy. That is - it doesn't sound like damage is being done, it's just significantly louder than when it was geared with a derailleur.
It makes the same amount of noise when backpedaling - the noise of the chain on the chainring.

mostaza

Original post now edited with photos and video to help explain...

Litespud

your vids convince me further that it’s your chain line. Couple this with the fact (that I only just noticed) that you’re using a track chain, which has none of the lateral flexibility of a standard 3/32” road chain. It sounds and looks like your chain is clattering as it enters/leaves the chainring

mostaza

Thanks Litespud - I'll check it out again.

Last night I took the back wheel off, chain off, and measured to the centre of the frame from the chainring teeth centre; and also did some calcs/measurements to reposition the rear sprocket (axle length divided, end of axle to sprocket teeth centre); and realigned the tensioner by folding it down so the wheel touched the centre of the sprocket teeth. Everything measured to the closest mm.

Other than this, is there any other way to check the chainline that I'm missing?

mostaza

One thought - as stated in the original post, I've put the chainring on backwards.
Are chainrings directional?

FiftySix

I have that same KMC Z610HX 3/32" Singlespeed/Track Chain on my 8 IGH bike.

My bike's chain and sprockets were noisy for two reasons. #1 was the chain line was not straight, and #2 was the chain was too tight as I tried to overcome the chain trying to walk up the sprocket teeth under heavy load due to the bad chain line.

My bike came with a dished rear sprocket, and the original chain was not a true single speed chain, so the original chain had more lateral flexibility, plus the side plates of that chain were slightly chamfered to mesh with the sprocket teeth at a slight angle easily.

In my case, the options were to flip the rear sprocket, install a flat rear sprocket, or get a multi-speed chain. Flipping the sprocket just reversed the bad chain line from away from the hub to toward the hub. Installing a flat sprocket cured the problem and allowed me to relax the chain tension as well.

This is with a wide 8 IGH rear hub with no cog spacers for adjustment, though.

55murray

Is the chain also new?

2old

I had a SS GT Zaskar (magic ratio) for 15 or so years and got a "perfect" chainline by measuring the distance from the middle of the frame (using the water bottle mounts) to the middle of the chainring, then using that to measure from the end of the 135mm hub to the rear gear. The rear gear should be (135/2 mm + the distance from the frame to the chainring mm) from the end of the rear hub to the middle of the rear gear.. Turned out I could use a tensioner with a 19 cog in the rear for a couple of rides, then replace with a "20"when the chain "loosened" a bit. This was repeated when the chain had too much slack. If you invert the bike and pedal slowly backwards watching the chain as it exits the rear cog, you can see if the chainline is "perfect".

Litespud

I agree with 2old here - do the measurements to ensure that the chainring and sprocket are equidistant from the midline of the frame. Measuring from the bottle mounts is a good idea. However, even if the numbers look good, the "proof of the pudding", so to speak, is how the chain enters and exits the chainring. Put the bike on a stand, get down as vertical as you can over the chainring, backpedal slowly and see how the chain exits the chainring - it should disengage the teeth without the teeth rubbing either inside face of the chain or even skewing toward one side of the chain vs the other. If there's any "skew", that's what you have to address, regardless of the numbers. I imagine you can tweak the chain line with spacers at the rear hub. It'd be good if 79pmooney weighed in here - IIRC, he's been running track drivetrains on his fixies forever

2old

Litespud, thanks for your "translation" of my rather garbled statement. Wish I had you for a roommate in college.

mostaza

Had another tweak today.
The sprocket was out by about 5mm.
I've rearranged the spacers, and remeasured the sprocket and chainring, and they're within 1mm as far as I can see (also looks right by eye, and the chain meets and leaves each component true to the centre of each).
Still noisy but I'm going to put it down to being a new everything (chain, sprocket, chainring, tensioner) and see if it beds in.

tFUnK

Can you show us a drive side pic of the entire setup including the tensioner? Watching the video makes me think the chain is too tight.

mostaza

Sure thing. I'll get onto it tomorrow.

A question in the meantime - is it possible for the chain to be too tight if I'm using a sprung tensioner?
The tensioner is about half way between both extremes of its travel/limits.

tFUnK

No likely but I'm wondering what else can cause the noise.