Reason requires argument.
Fixed gear / drivetrain wear distribution
- Thread starter silva
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It's the other way around - it's those endless amounts of hassle I wanted to dump with this last bike, only that the dealer screwed it up - failed to meet what I had demanded. Requiring DIY by me. 2 years later, the problems solved except one (the chains tension variation), although partly solved by changing that recommended but stupid 48/16 ratio to 47/16.
See, my usage of the bike isn't your usage, I'm not you remember?
I
SkipdiverJohn
Deplorable Brexiteer
- Location
- London
So, in order to eliminate endless amounts of hassle associated with normal bikes, you've now spent the last two years trying to eliminate the issues that your "hassle free" bike was meant to avoid? Makes perfect sense to me......
Well yes, there has been elimination, results are there - drivetrain now run 3 times the miles before. 18 instead of 6 months.So, in order to eliminate endless amounts of hassle associated with normal bikes, you've now spent the last two years trying to eliminate the issues that your "hassle free" bike was meant to avoid? Makes perfect sense to me......
- 5 mm wrong chainline has been identified, and solved by spacers between brake disc mount and cog.
- the dealer recommended gear ratio 48/16 that concentrated wear and increased the chain tension variation over usage, solved by changing it to 47/16
At the moment I'm working on the idea to mount a type 420 (415 also option) motorcycle chain, current problem could be (different specifications on the web) that the roller diameter is 8 mm instead of bicycles 7.75 mm, meaning that it would need sprockets with wider valleys between / shorter teeth. Meaning some material has to be removed in order to prevent a rough wear in period.
And also the idea of a chromoly steel chainring. The (rear) cog I have used on this bike is made from chromoly steel, proved itself, and a chainring also that material just sounds logical, the added weight is a nothing in my bike application.
In my opinion, the chain is the by far major factor in wear. Recently, I had to mount a new chainring due to another crank spider mount, I kept the old chain, and the chain ate the new chainring towards its own wear level in just a week.
So the initial wear (longer becoming under tension) of a chain is the biggest drivetrain mileage killer. It's useless to mount chromoly / whatever harder/strongermaterial sprockets - the impact is just a fraction of the chains impact.
In order to reduce that initial longer becoming, bigger bearing surfaces have to be realized, ex 1/8" instead of 3/32" (=50% more bearing surface). The thicker link plates / longer pens of 3/16" chains increased the bearing surface further. The entry cc level motorbicycle chains increase the roller / pen bearing surface, and also feature full / separate / solid bushings.
Added to that: on a same 1/8" wide sprocket, the chain has sideways moving room, which may compensate in a degree for a chainline deviation.
I hunted a drivetrain lasting a year.
Reached 1,5 years.
Now I'm hunting 3 years.
I don't judge that as a BOO.
Anyone here does?
Racing roadkill
Guru
The term Cogged gearwheels ( often abbreviated to “cogs”) include sprockets, and chainrings, but I find it’s useful to differentiate where possible, to avoid confusion.
Ok. The UK firm where I found and buy these drivetrain parts uses cog on their site solely for the rear sprocket, hence I took the terminology over.
So for clarity, my "cog" referred to the rear, sprocket, rear gearwheel.
Today and yesterday I spent quite some time (hours) to search the web for motorcycle chain specs (I knew near to nothing about them). In the past I have tried a stainless steel 08B industrial chain (not on purpose, found some lengths on flea markets at bargain price). I tried to mount it and failed, I could only lay it over a part of the chainring teeth. Later on I found the specs and the cause had been a roller diameter of 8.5 mm instead of the bicycle 7.75 mm.
Wikipedia states it wrong:
Apparently, "420" has several specs out there.
Today I measured (with a caliper) the roller diameter of a new Gusset Tank chain, it was precisely that 7.75 mm.
A search for the specs of a type 420 motorcycle chain also delives different results.
The Regina General Catalogue 2020 shows under "Urban" a type 420 chain with 7.75 mm as roller diameter. Also some other sites (alike a DID chain on http://www.wemoto.be/parts/picture/bc-3010640/ specified as 7.77 mm).
But http://www.gizmology.net/sprockets.htm specifies under "Bicycle and motorcycle..." a roller diameter of 5/16" for the type 420 chain, which is 7.93 mm. And other sources, expressed in inches and converted to metric, even 8 mm.
Hence I decided to send a mail to the shop I want to order these from, to ask what their type 420 roller diameter is.
In the case of a bigger roller diameter, I could still try such a 7.93 or 8 mm roller on worn gearwheels (using your terminology here). In the end, my Velosolo gearwheels are now worn enough to allow bigger rollers to sit down. But it's ofc a mess to make that a common practice for the future. Likely a little 420 chain wear makes the rollers to eat gearwheel teeth totally away hehe.
Purchased chain brand/model as mentioned above and the shops guy measured correct (enough) - it was 7.75 mm and thus compatible with bicycle sprocket teeth shapes.
Today I made such Regina 420 Urban chain on length (105 links + 1 closing link), using a YC-324 chain tool bought from UK Velosolo. Despite it is specified for 3/16" bicycle chains, it was usable / worked for this motorcycle 420 chain, with 1 problem though: the pin jammed in the base plate hole of the tool - I had to hammer it back out with a punch.
Apparently, the pin diameter of the 420 motorcycle chain is bigger than the one of a bicycle chain, rather surprising because since the roller outer diameter is the same, either roller inner diameter must be bigger (so thinner roller) either bushing thinner. I looked it up and found a 3.57 mm pin diameter for bicycle, and 3.94 mm for motorcycle 420 chain.
So the chain tools hole must have been deformed (to bigger) - I measured the pin and it still was the same.
An option is to drill out (to 4 mm - since a standard drill size) the chain tool and reserve it for these 420 motorcycle chains.
I didn't try to mount the chain yet, I need the bike nearly daily so it's something for an occasion early in the weekend, so that I have time to test ride. Also, I want to replace all 3 drivetrain parts same time - not mix worn / new.
The last potential problem is chain > frame clearance.
Due to the excessive chainline, with the hub moved 5 mm away from the center towards the dropout, and the rear sprocket / cog moved a further 5 mm away from the IS disc brake mount, there is little free room.
My current chain (Gusset bmx model "Tank" pin length is 11.6 mm, this Regina 420 Urban chains pin length is 16.1 mm, so the latter is 4.5 mm wider thus 2.25 mm more room to 1 side.
Since the inner width increased from 3.175 mm doubled to 6.35 mm, the motorcycle 420 chain has 3.175 mm sideways play on a sprocket meaning that the total possible sideways space requirement to one side is 3.175 + 2.25 = 5.425 mm.
I just checked and this distance could be too much.
In case, one option is to reduce the cogs total spacers from 5 to 4 or 3 mm, the chainline will be off by the same but since the motorcycle chain will have 3.175 mm sideways play on the sprocket teeth, the chain has room to move towards the shortest / straigth running path.
And finally, if above works out, the motorcycle usable, an eventual wear benefit will come at the cost of a harder to pedal bicycle.
A Gusset bicycle bmx Tank chain link weights 550 gr / 102 = 5.4 gram / link.
A Regina 420 Urban chain link weights 965 gr / 134 = 7.2 gram / link.
That's 1/3 more weight to pedal 'round.
Good for training.
An option is to compensate this along a lower gear, now 47/16, to 46/16. Wear related benefit could be back to the even numbers of teeth (as Yellow Saddle explained in a post somewhere - allowing links to wear in and thus mesh properly with sprocket teeth) I had with 48/16 - the ratio I dumped due to integer and thus wear concentrating, unlike 46/16.
Today I made such Regina 420 Urban chain on length (105 links + 1 closing link), using a YC-324 chain tool bought from UK Velosolo. Despite it is specified for 3/16" bicycle chains, it was usable / worked for this motorcycle 420 chain, with 1 problem though: the pin jammed in the base plate hole of the tool - I had to hammer it back out with a punch.
Apparently, the pin diameter of the 420 motorcycle chain is bigger than the one of a bicycle chain, rather surprising because since the roller outer diameter is the same, either roller inner diameter must be bigger (so thinner roller) either bushing thinner. I looked it up and found a 3.57 mm pin diameter for bicycle, and 3.94 mm for motorcycle 420 chain.
So the chain tools hole must have been deformed (to bigger) - I measured the pin and it still was the same.
An option is to drill out (to 4 mm - since a standard drill size) the chain tool and reserve it for these 420 motorcycle chains.
I didn't try to mount the chain yet, I need the bike nearly daily so it's something for an occasion early in the weekend, so that I have time to test ride. Also, I want to replace all 3 drivetrain parts same time - not mix worn / new.
The last potential problem is chain > frame clearance.
Due to the excessive chainline, with the hub moved 5 mm away from the center towards the dropout, and the rear sprocket / cog moved a further 5 mm away from the IS disc brake mount, there is little free room.
My current chain (Gusset bmx model "Tank" pin length is 11.6 mm, this Regina 420 Urban chains pin length is 16.1 mm, so the latter is 4.5 mm wider thus 2.25 mm more room to 1 side.
Since the inner width increased from 3.175 mm doubled to 6.35 mm, the motorcycle 420 chain has 3.175 mm sideways play on a sprocket meaning that the total possible sideways space requirement to one side is 3.175 + 2.25 = 5.425 mm.
I just checked and this distance could be too much.
In case, one option is to reduce the cogs total spacers from 5 to 4 or 3 mm, the chainline will be off by the same but since the motorcycle chain will have 3.175 mm sideways play on the sprocket teeth, the chain has room to move towards the shortest / straigth running path.
And finally, if above works out, the motorcycle usable, an eventual wear benefit will come at the cost of a harder to pedal bicycle.
A Gusset bicycle bmx Tank chain link weights 550 gr / 102 = 5.4 gram / link.
A Regina 420 Urban chain link weights 965 gr / 134 = 7.2 gram / link.
That's 1/3 more weight to pedal 'round.
Good for training.
An option is to compensate this along a lower gear, now 47/16, to 46/16. Wear related benefit could be back to the even numbers of teeth (as Yellow Saddle explained in a post somewhere - allowing links to wear in and thus mesh properly with sprocket teeth) I had with 48/16 - the ratio I dumped due to integer and thus wear concentrating, unlike 46/16.
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This morning I mounted that Regina 420 Urban motorcycle chain (1/4" internal width)
It succeeded - some 3 mm clearance left between inner side of crank arm and between rear cog and dropout.
The rest of the day I rode 50 km with it. But there was alot head/sidewind so don't know yet the impact on my average speed.
I did have the impression that I should have been faster sometimes.
Time will tell, also about my goal to reduce wear / replacements.
It succeeded - some 3 mm clearance left between inner side of crank arm and between rear cog and dropout.
The rest of the day I rode 50 km with it. But there was alot head/sidewind so don't know yet the impact on my average speed.
I did have the impression that I should have been faster sometimes.
Time will tell, also about my goal to reduce wear / replacements.
Can you take a picture?
Question, unlike bicycles oiled chains, this motorcycle chain is delivered greased. Kinda sticky white grease. Also present on the connection link with a reminder card to not touch the pens as to keep the grease on it.
Why the difference?
According to what I've read here, and what I also belief myself, is that the lubricating agent is during tension pushed away from the bearing surfaces and flows back during the unloaded part of the cycle. I assume grease gets pushed away too (wrong?) but grease doesn't flow back.
I now don't know what to do, normally I put oil on a chain, both to lubricate and protect against rust.
If I put oil on this chain, likely the grease drops in viscosity and can sneak out.
Maybe that last is different between motor and bicycle chains, this motorcycle chain has full bushings (so an inner and outer roller, unlike a bicycle where the inner plates have ridges "simulating" rolling). Maybe the motorcycle chains bearing surfaces are closed environments.
Edit: already found out oil is a necessity: quite some brown spots on the chains rollers: rust - had rain yesterday.
Likely the motorcycle chain is ment for a protected running environment - grease (alone) does not suffice.
So I just put an oil drip on every roller, and a brush to cover the outside in oil.
Why the difference?
According to what I've read here, and what I also belief myself, is that the lubricating agent is during tension pushed away from the bearing surfaces and flows back during the unloaded part of the cycle. I assume grease gets pushed away too (wrong?) but grease doesn't flow back.
I now don't know what to do, normally I put oil on a chain, both to lubricate and protect against rust.
If I put oil on this chain, likely the grease drops in viscosity and can sneak out.
Maybe that last is different between motor and bicycle chains, this motorcycle chain has full bushings (so an inner and outer roller, unlike a bicycle where the inner plates have ridges "simulating" rolling). Maybe the motorcycle chains bearing surfaces are closed environments.
Edit: already found out oil is a necessity: quite some brown spots on the chains rollers: rust - had rain yesterday.
Likely the motorcycle chain is ment for a protected running environment - grease (alone) does not suffice.
So I just put an oil drip on every roller, and a brush to cover the outside in oil.
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A correction -that was a wrong judgement I made, when I replaced rear cog and chain few days ago with a same new cog and the motorcycle chain, I had initially intended to also replace the chainring despite running only some months.
But I laid the new over the old, and there wasn't a clearly visible tooth shape difference. The tips abit rounded off but no edge wear. So I decided to keep the chainring.
The tooths of the rear cog, already been flipped once, however showed clearly visible further wear, to the point that a tooth could break off alike someone showed a picture of somewhere on the forum.
Maybe the latters removed material caused the spike of black grit on the chain after that weak.
Probably the cleaning made it easier to judge tooth shape differences.
It has also been a repeating story. The previous drivetrain's cog also started ticking (hook shaped), I flipped it, ticking changed from pushing / pedaling forward to pushing back to slowdown, with some uglier noises during the moment forward>backward.
So I know it's cog and chain end when I get the ticking in both directions, and when the teeth became shorter in the middle of their hight than at their top.
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