Which brands/models chainsets / chainrings have perfect centering?

[Stompier]

There is probably no such thing as a perfectly round chainring or sprocket - some are more round than others, but you will get tension variations on even the most expensive kit. Maybe if you ran a Sugino Zen chainring and a EAI Gold Medal Pro sprocket you might get closer to 100%, but for that price, who knows.

Just accept the tension variation. As long as the chain is not unshipping - or binding, there is no issue. And if it is dropping, it might be more to do with your chain line than chain tension.

There is a school of thought in track racing (not one I necessarily subscribe to fully) that says that you should run your chain as 'slack' as possible - the definition of 'possible' being if you spin the crank/wheel, hold the bike up horizontal and the chain doesn't fall off, then it's not too loose. Most people seem not to go that far, but it's a useful measure nonetheless. The ideal behind the 'slack' chain is the lower the tension, the lower the friction loss, up to a point.

Also - just a point on NJS. The NJS stamp on some track kit is a mark of 'compliance' - not necessarily a mark of 'quality'. Most of the NJS kit is pretty good anyway, but the NJS stamp doesn't necessarily make it better than something without the stamp.

 

[rogerzilla]

If it bothers you, you either have to pay hundreds of pounds for the accurately-made kit, buy another cheap crankset and hope you strike lucky this time (cheaper ones aren't made to be bad but there is a bigger range of accuracy, so some will be spot-on) or - at no cost - centre the chainring on the spider.

I know you say there is no space between the chainring and the spider, but you can create some. Get a file and take half a millimetre off the inner five tangs of the ring. That will give you enough wiggle room to eliminate, or greatly reduce, the tight spot. Fasten the bolts fairly loosely, fit the chain, find the tight spot and then tap the chainring towards the sprocket with a mallet. Keep doing this until you get as little tension variation as possible, then tighten all the bolts firmly using a cross pattern (don't tighten adjacent bolts).

 

[silva]

The bike costed over 4000 and you say that I bought cheap cranksets?

Really lol, I've better things to do than filing off cranksets spider places and centre chainrings all the time. Because tell me, if I would succeed in this, at a next ride, a push forward and a push back to slowdown, the thing can move again offcenter, with me having to recenter it again, and again and again.
Fact is that my 2 previous bikes (also singlespeed>fixed gear) both didn't suffer a chain tension variation, and costed a fraction.
Apparently it doesn't need big bucks to get a decently centered crankset. And hence I asked here. Price tag clearly proved as no quality indication.

 

[rogerzilla]

Well, the problem won't fix itself, however much you complain about it on the Internet.

 

[silva]

See this topic... trying to find a well centered chainset... tried octalink but actually wanted a similar hollowtech 2 setup since that proved itself as well centered on my previous bike.
That's what I'm after, "complaining" is stating the problem, and I don't want ersatz solutions that inflict me the extra work caused by the chain tension variation just somewhere else, shifting problems is not solving problems.

 

[presta]

Here's a few engineering facts of life: no components are made exact because it's not possible to make anything exact, so they are made to a tolerance, and components aren't made to a tighter tolerance than necessary because it's expensive. Components made to an unnecessarily tight tolerance won't be competitive against ones that aren't. So that begs the question what tolerance is necessary.

You've made a case that chainrings for a fixie rather than a derailleur are better with a tighter tolerance, but is anyone actually marketing precision chainrings specifically for fixies? I don't know the market, but I've not noticed any. How many fixie riders would even notice the difference let alone be willing to pay extra for it? You refer to better rings you've had before, but were these made to a tighter tolerance, or were they wide tolerance parts that just happened to be close to their nominal size? If you pick a component from a batch made to a wide tolerance some will inevitably be 'accurate' just by chance alone, but that's a random lucky dip, you can't just go to the LBS and expect to be able to buy another like it.

 

[Stompier]

Agree 100%. Tolerance is compensated for on single speed and fixed wheel bikes by running a somewhat less than drum-tight chain.

 

[silva]

Here's a few engineering facts of life: no components are made exact because it's not possible to make anything exact, so they are made to a tolerance, and components aren't made to a tighter tolerance than necessary because it's expensive. Components made to an unnecessarily tight tolerance won't be competitive against ones that aren't. So that begs the question what tolerance is necessary.

You've made a case that chainrings for a fixie rather than a derailleur are better with a tighter tolerance, but is anyone actually marketing precision chainrings specifically for fixies? I don't know the market, but I've not noticed any. How many fixie riders would even notice the difference let alone be willing to pay extra for it? You refer to better rings you've had before, but were these made to a tighter tolerance, or were they wide tolerance parts that just happened to be close to their nominal size? If you pick a component from a batch made to a wide tolerance some will inevitably be 'accurate' just by chance alone, but that's a random lucky dip, you can't just go to the LBS and expect to be able to buy another like it.

100% disagree.

Be sure you notice it, pedaling feels like a pulsation, pushing back has a dead range due to the chain having to tension first then a shock, tensioning the chain lasts 10 times longer because you have to find the tightest spot first and keep it there in order to not have have a binding wheel and not end up ruining bearings, and it causes asymmetrical wear on the chains links, aggravating all the problems.

In contrast to what you seem to insinuate here - it's not a pickpecking problem, it's a major one.

I have had two previous bikes without derailer- I'm riding singlespeeds since a decade and fixed gear since 2017, 2 different brand bikes, bought with 1 year inbetween, the last one with the hollowtech 2 bottombracket, the first one with square taper. I didn't suffer that chain tension variation. Maybe ALL batches those days were produced with GOOD tolerance?
And that GOOD tolerance back then didn't quadruple their price.

It's very simple, I was sold crap, there are still producers out there that are more honest, the question of this topic asks for those, and the most reliable answers are from other people that bought from them, not from dealers.

 

[silva]

Agree 100%. Tolerance is compensated for on single speed and fixed wheel bikes by running a somewhat less than drum-tight chain.

I noticed how you try to minimalize the problem with that "somewhat less".
You also had to ignore with it the basic of the problem: drum tight on one spot couples to a superslack other spot.
According to many sources a chain tension is stated as a 1 cm up and downwards movability, that's what I do and since that is the general consensus it's NOT "drum tight". In the bikes first period, the superslack other spot started with 3 cm up and down, and grew to 5+ cm up and down. Yeah, I DID notice it during riding lol. And it also was dangerous since I tend to push back rather than use the brakes and the dead range (to get the chain tight in that direction - the lower part - the return run), unpredictable on the moment, inflicted me the need to always use the brakes too, "in case".

 

[Stompier]

I don’t think anyone can help you, by the sound of it. And you still haven’t said what bike you have that is giving you all these unfathomable problems.

 

[silva]

I don’t think anyone can help you, by the sound of it. And you still haven’t said what bike you have that is giving you all these unfathomable problems.

That's just pessimism, in the past I found durable components, along positive posts found on forums here and there.
See, that's something I noticed over time: what is advertised most, usually is biggest garbage. The qualitative stuff you have to search and discover.
So your thought is just what it is, your thought. If you tried to help, thanks.
About the bike I talked about.... it's just the one in my avatar... since my presence on this forum. Thanks for your attention.

To illustrate my point of view and my attitude along a today story: my rear mudguard is broken (divided) at a mount place. Why: because the hydraulic brakes are mounted on a fork that cannot be removed without nearly entirely disassembling the bikes rear so dealer probably forced it in its place, causing the plastic to develop cracks (due to the width of the rear mudguard (62 mm tyres)). Adding to the problem is that this brake mount fork (horseshoe shaped) has to sit entirely till the fender to reach its 2 mount points at the brake modules locations.
Due to the break, mud gets sprayed on my chain and rear bags.
So I just removed brakes and wheel and saw a part off from a mtb fender I found along the road (which is btw typical me haha), my soldering iron is now heating up, I will heat up the plastic while bending it so that its cross section follows the required curve to fit in the inside of the broken fender, then I will drill a hole on the place of the frame mount then I will put this fender part in front (inside seen) of the current broken one, and fix it to the frame. And then I will fix both ends of the broken fender on the "new" made-up fender along drilling holes and hooks from washing line bend as needed.
And yet another problem that had to be "complained" about, and addressed / fixed. Only that I didn't need to ask questions to find a solution.
.

 

[Stompier]

The pic tells me nothing - other than you seem to cart around a lot of stuff. Just the make and model would be useful?

 

[keithmac]

Have you considered Gates Carbon Drive?.

I wouldn't go back to a chain now.

 

[silva]

The pic tells me nothing - other than you seem to cart around a lot of stuff. Just the make and model would be useful?

I think that will tell you little more, hence I didn't find it useful to mention - it's a local brand specialized in travel bikes: Santos, frame model "travelmaster 3+", a kinda specialized frame designed to serve for several drivetrain and tyre width configurations.
And yes haha I cart arount alot stuff, my biggest load was 70 kg on a 30 km trip. A kinda unique occurrence but it happens regularly that I carry a backpack with 20-30 kg fruit on top of standard load.
Sometimes when I read that people chose aluminium bolts to save a couple grammes I can't avoid shaking my head.
Basically, I only have some bikes, don't want a car anymore, and when you have to live like that and not rely on others, you NEED luggage capability like that.

 

[silva]

Have you considered Gates Carbon Drive?.

I wouldn't go back to a chain now.

I have considered that from the beginning, and initially thought to chose it, but upon reading about it (not only the advertising but also user reviews) I came to the conclusion that it wasn't what I want my bike to be - it's too expensive in parts, way less common, too critical in mounting, much easier to damage than a steel roller chain, and DIY harder.
btw the bikes producer and dealer also came to that conclusion, on which reasons I don't know, also I heard on other subjects given reasons that turnt out to not have been the real ones.
But feel free to sum up your positive experiences with belt drives. It's not like that I'm locked up with roller chains, only that at that moment a belt drive appeared as a more con than pro.
What is for sure is that I never want gears back. Way too fast wear and other trouble (alike wet/frozen>sudden freewheeling in both directions and there you are in the middle of nowhere and rain / frost with nothing you can do).
Fixed gear rules my day. I understand things are different for other people, but not in my case / usage.
Likely the real reason for bikes producer/dealer was that if it was already that hard to get a straight chainline on their frame (the best they achieved with roller chain was 5 mm off, the rest I had to find a solution for myself), that for a belt drive this would be even more problematic - and it's more critical than a chain on this.

Edit: addition to that much easier to damage - know what: just parking your bike somewhere between other bikes, with no other choice, is already a recipe for disaster in the belt case, a steel roller chain can take a beating / a sharp object, a belt not. Just look in a city at all the bike wreckage around. I once returned to see my bike displaced with its chain mangled in the bike parking frame so that I had to use force to free it. The chain didn't end its life there, a belt certainly would. Hell, just look at how you have to fold a spare belt in order to not damage it.

This is a large version of my avatar pic.

Now it has more luggage capability, the wire basket on top of the rear rack has now twice the size and I mounted a small backpack (one I found thrown away along the road - a kid one) under the handlebars. I've put my bike tools and spares in because concentrated weight and thus counterbalancing the bike when alot loaded on the back.
I had to move forward my front and move backward my rear light due to the modifications.

My roller chain weights 550 gr - it's a 1/8" model with 3/16" plates so that a little rust or salt isn't fatal.

The pic is taken at the time that the chain hung tilted 45 degrees due to the 5 mm wrong chainline.
That plate below is a mudguard for the chain - mud and snow sticks and travels the entire rear wheel mudguard circumference to deposit itself near the bottom bracket (and chain). That made a hell of a difference.

I made mudguards for my shoes too:

So now you see how desperate I am.