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[Specter]

Was talking to a friend today about electric bikes and explaining how a hard regen setting can really pump some power back to the battery.  Ive seen 24 kw or so of regen going back on some faster / longer regen's.   with that.  How does that wear on the chain.  I mean, before e bikes, chains really only bore stress in one direction really, or one vector.  Ok bigger bikes had some engine braking but that wasn't as severe as some of the regen settings can put on a chain, or for as long either Id assume.

Are chains manufactured to take the stress in BOTH directions equally, or is their 'strong force bearing vector' just really in one direction?
If the chain is getting worn /stretched, is the slap slam of really loading them up with 30 to 40 hp equivalent power just wallowing them out all that much faster.

In normal braking, the brakes are taking the brunt of the force, in a regen braking, the chain is taking the brunt really, it's transmitting the force from the wheel to the generator which is keeping the steady stress on it, unlike an  engine which is idling down.

Just wondering how much faster a chain is going to wear with strong regen .vs. no regen or a non regenerative type bike overall.  Given it's not a super tight circuit with the chain, the backlash /slap could be pretty significant from power to regen shift.

Has any study's been done on this at all?

Just curious.

aaron

[smithy]

Wear will be neglidgible, 24kw or about 32hp is nothing compared to the 100+kw which potentially goes into it from the other direction. I suspect it's the torque which would do more damage to a chain.

There are bikes out there these days with in excess of 200+hp, but nowhere near the torque of an Energica.

The chain doesn't know what direction it's going and can be fitted either way.

Smithy.

[Richard230]

It might be different with an old style chain with a circlip fastening the master link, but won't make any difference with chains with a pressed-on master link. Those are not directional, so the chain should work just as well in either direction.

[Specter]

Wear will be neglidgible, 24kw or about 32hp is nothing compared to the 100+kw which potentially goes into it from the other direction. I suspect it's the torque which would do more damage to a chain.

There are bikes out there these days with in excess of 200+hp, but nowhere near the torque of an Energica.

The chain doesn't know what direction it's going and can be fitted either way.

Smithy.

Although it does not know which direction it is going, it still just goes in that one direction over and over, except with maybe a little reverse, until you get regen or heavy engine braking which now is pulling it back, essentially in the other direction very strongly.   All the wear, or perhaps I should say stretching is mostly in the one direction and pieces tend to stretch fit into each other nicely in that wear model.  Now keep thowing a backing force, a backlash on it, where you loosen all those nicely fitting parts and smash them the other way into each other.

Just curious if it's causing significant extra wear or negligible really.  Speaking of torque,  the backlash and slap when transversing a driving force to a driven one must be pretty significant as well.

Maybe energica should do a front wheel drive bike, put the weight up front and front wheel regen, that'll save even more energy   or an all wheel drive bike. left chain drives the back, right drives the front.  Wouldn't have to worry about the wheels ever getting out of sync, they are lock trained now, bye bye death wobble!   </sarc.off>  Maybe Damon can snag the idea to keep his bikes stable at the what 260 mph they are capable of

[TheRan]

If you pull on a chain it doesn't matter which end that force is being applied from. Say you had a chain attached to the tow hooks of two trucks facing in opposite directions, it doesn't matter which truck puts their brake on and which tries driving away the force on the chain is identical in every way. The only difference with a chain and sprocket setup is that the opposite side of the sprocket teeth and the pins in the chain are being loaded (the rollers rotate so it all evens out), but that's not going to increase the wear over not using regen in any way that matters unless for some reason your regen was greater than your forward torque.

[Ashveratu]

A reverse force on the chain has never been an issue with motorcycles. Regen can almost apply as much reverse force on a chain as downshifting does (on a petrol bike) and am I pretty sure nobody (well, very few) worries about and their chain life and downshifting. Engine and transmission wear are the greater concern there.

[Demoni]

Modern (quality) motorcycle chains are extremely strong, most are rated at 5-8klbs tensile strength. They are so strong that the Energica used in MotoE ran 520 pitch chains vs the 525 size used on production bikes. A 520 chain is lighter and still had more than enough strength to handle the bikes torque.

Chains on ICE bikes experience the same reverse loading when you release the throttle due to engine breaking. Bikes with smaller pistons (lower displacement or many cylinders) will apply less load to the chain off throttle. Big displacement twins can actually apply enough engine breaking to lock up the rear wheel when you close the throttle or down shift.

Under drive the chain rollers will put load on the left face of the front and rear sprocket teeth. Under regen that load will be supported by the right side faces of the teeth.
Over time this load results in wear on the sprocket teeth and the chain rollers. The left side of the sprocket teeth will experience more wear since they are under load more often and see higher peak loading.
This uneven wear on the sprocket teeth is why the chain noise sounds different when a bike is under regen.

[jotjotde]

For anyone who is interested in the details of chains and chain drives.

A motorbike chain consists of rollers, bushings, pins, seals and the links. In comparison, bicycle chains come without seals and without bushings.

There is lube between pins and bushings which is (theoretically) sealed by the x- or o-rings and is not replaceable.
The lube between bushings and rollers is what you renew by appyling lube spray, drip oil or whatever.
(Refer to https://womanrider.com/2019/03/motorcycle-chains-101/ )

In an ideal world there is no relative movement between the roller and the sprocket surfaces. The rotation movement is between roller and bushing and pin.
(See attached sketch, the diameter d1 is the same for sprocket and roller.)

In real world, due to the lube deterioration (breakdown of molecules due to load and temperature as well as ingress of e.g. moisture) the surfaces begin to wear and the chain is lengthening.
(Please note: The chains are made for high load and thus the lengthening is not due to the applied stress.)

This lengthening in turn leads to a relative movement between rollers and sprocket which causes abrasion, furthering the wear.
(In this article this is described quite nicely https://iopscience.iop.org/article/10.1088/1757-899X/174/1/012049/pdf )
The unavoidable presence of dirt (usually consisting mainly of highly abrasive silicium dioxide) is increasing the wear of the surfaces. Thus over time the sprocket teeths are abraded on the loaded side, resulting in the famous shark teets apperance.

[Specter]

Thank you for the info.
My chain is making a lot of noise lately and ive done the maintenance on it and had the dealer as well when I had the bike in for some warranty fixes and the annual since it was there.  Mayb im just paranoid but I can hear it rattling and almost like a grinding noise from the motor side when it's in heavier regen.  Not sure if thats normal, especially now that it's COLD out and everything is grumpy or what, but didn't seem that loud before and am concerned, and not sure if I need to be or not.  I DO also ride my bike kind of hard as well, so it's not being pampered in the HP zone either.  Just wondering if I wore out the chain already at 9k or is this normal?

Ill keep an eye on things and see

Aaron

[jotjotde]

I assume you hear the rattling at low speeds (at higher speeds other noises become prominent). In my experience this is a sign that the chain needs to be tightened, maybe just a 1/8 turn of the hexagon screws will do the trick.
9 k is surely not much, but thinking about my disastrous experience with the 'low maintenance' Regina HPE which ended after only 10 k, it might be that your chain is near the end of its lifetime.
As already discussed in other posts here, the longevity of a chain depends on several factors. I've often read you like to push your bike  , so death of your chain at 9 k does not appear impossible.

If you want to be sure, get one of these chain gauges for less than 20$. Then you know for sure what is going on.

[Dryer667]

My front sprocket was REALLY done at 11k and I am very good about routine maintenance. It began making very loud clacking noises even when adjusted in spec.

Remember you need a specific socket to remove the front sprocket that most dealers (including Energica dealers) don't have! Even Tytler's cycle in WI, the one doing all the racing, didn't have it.

[Specter]

So where did you get your sproket at Dryer?

jono, agreed, that generally signals the chain is loose and you hear it dragging over the cover down there, however in this case it's not so much a dragging sound, and the chain, TBH if anything is probably a bit tight this time, I DID adjust it, it was  loose again before.  It sounds more like it's coming from the front sproket area, I don't want to say, it sounds like bearings, god I hope not.

One thing I have noticed is if you chain is too tight you get a lot of I guess you could call it, motor noise on it, and  looser quieted it down, until it starts dragging.  Ive been romping around town this week so Ill check it again tomorrow, give it a real good cleaning and see what we got.  i'll have to get a chain gauge just to have, seems like a handy tool.

The chain is supposed to be 30 cm play in it,  normally about 500 ish miles or so mine is about 33 to 34 and Ill adjust it in, with a flat or two on the nut, this time is was pushing about 38, I could hear it was really sloppy.  This is what is making me wonder, if it's getting towards it's end because it's wearing more???  Maybe this is normal wear, I honestly don't know.  Besides for that, about how far 'down the adjuster' does one generally end up at before the chain is considered ready to replace?

Aaron

[Dryer667]

I picked up all my sprockets from sprocketcenter.com.

[Specter]

thanks and what about the socket that you say is hard to get?
What exactly IS it so others can go find it

thanks
Aaron

[jotjotde]

@ Aaron:
The demise of a chain accelerates towards the end, the same as with ball bearings etc.
That can be explained e.g. by the loss of available surface on which the load can be distributed - when it gets smaller, the load per surface area rises, causing more damage which in turn leads to higher/quicker wear.

I think you are right, keeping the chain rather above the 30 mm play to be on the safe side. So 33 to 34 seems totally OK to me and should by itself not be a cause for increased wear of the chain.

For removal of the sprocket you need a grooved nut key (translation of the German 'Nutmutternschlüssel') KM5. See the attached pictures. Cost should be in the range of 15 USD.

Sprocket is a PBR 2078 with 15 teeth (Ribelle RS). Alternative would be a AFAM 61801-15 or JT-Sprocket JTF704
Rear sprocket is AFAM 92630 with 44 teeth (the same for all Ribelles). Alternative could be Superlite RSX SKU#92630RX.


@Dryer667:
Your sprocket looks quite worn with clear beginning of the shark teeth. Really only 10 k?
Mine looked much better after 22 k.
Did you ride in rainy/wet conditions often?