What does 5kw do to a MTB drivetrain/groups set? CyC X1 Pro

[mbgjt1]

I'm in the process of buying the gen 2 cyc x1 pro and installing it on a Giant Fathom 29" hardtail mountain bike.

With the BAC2000 running at 72v, is it realistic to try and pull 250 Nm of torque and 5kw of power through the standard 11 speed bike cassette and drive train?

I'm worried that this will snap chains and bend derailleurs and brackets.

Has anyone experienced this type of setup? If so what is your advice?

I can downgrade the cassette to an 8speed and use a wider chain. Would this work ?

Or is the only option a single drive?

 

[E-HP]

I'm in the process of buying the gen 2 cyc x1 pro and installing it on a Giant Fathom 29" hardtail mountain bike.

With the BAC2000 running at 72v, is it realistic to try and pull 250 Nm of torque and 5kw of power through the standard 11 speed bike cassette and drive train?

I'm worried that this will snap chains and bend derailleurs and brackets.

Has anyone experienced this type of setup? If so what is your advice?

I can downgrade the cassette to an 8speed and use a wider chain. Would this work ?

Or is the only option a single drive?

You might want to consider a small sport bike rather than playing around with bicycles. More bang for the buck and you don't have to worry about the drivetrain. :thumb:

 

[mbgjt1]

I'm in the process of buying the gen 2 cyc x1 pro and installing it on a Giant Fathom 29" hardtail mountain bike.

With the BAC2000 running at 72v, is it realistic to try and pull 250 Nm of torque and 5kw of power through the standard 11 speed bike cassette and drive train?

I'm worried that this will snap chains and bend derailleurs and brackets.

Has anyone experienced this type of setup? If so what is your advice?

I can downgrade the cassette to an 8speed and use a wider chain. Would this work ?

Or is the only option a single drive?

You might want to consider a small sport bike rather than playing around with bicycles. More bang for the buck and you don't have to worry about the drivetrain. :thumb:

Thanks I have considered this

But I'd really like to keep using a bike and have a stealth look so I can still rise trails and mtb tracks

 

[E-HP]

Thanks I have considered this

But I'd really like to keep using a bike and have a stealth look so I can still rise trails and mtb tracks

Using that much power on mtb trails could make a few enemies.

 

[mbgjt1]

Yes might be a problem.

Doesn't answer my question though, have you experienced this ?

 

[calab]

bicycles are not meant for that much power lets hope you dont hurt anyone else but yourself

 

[mbgjt1]

Useless answer

If you do some research online there are plenty of people pushing this power and torque from a bike. I need to figure out the components used.

If you're illiterate and have no experience in the subject then keep your opinion to yourself

 

[mbgjt1]

Useless answer

If you do some research online there are plenty of people pushing this power and torque from a bike. I need to figure out the components used.

If you're illiterate and have no experience in the subject then keep your opinion to yourself

 

[calab]

not that hard to figure out that bicycle components wear out faster then motorcycle components

 

[Chalo]

But I'd really like to keep using a bike and have a stealth look so I can still rise trails and mtb tracks

Don't be a d!ck.

If you want a motorcycle, put on your big boy pants and own a motorcycle. Stepping on bicycle rights-of-way with a motorcycle makes you a sucky human.

 

[mbgjt1]

But I'd really like to keep using a bike and have a stealth look so I can still rise trails and mtb tracks

Don't be a d!ck.

If you want a motorcycle, put on your big boy pants and own a motorcycle. Stepping on bicycle rights-of-way with a motorcycle makes you a sucky human.

:lol:

 

[Mad Matt]

Keeping the chain speed high helps. An 8 speed setup works better as sprockets etc are thicker. Try and use a cassette that is pinned or screwed together so you don't strip the hub splines. Also try not to load up the smaller cogs on the cassette as the chain will likely skip

 

[Comrade]

I'm worried that this will snap chains and bend derailleurs and brackets.

What brackets? Derailleurs don't carry loads. Chains have well documented yield strengths you can find using Google. From there it's simple math.

 

[Chalo]

I'm worried that this will snap chains and bend derailleurs and brackets.

What brackets? Derailleurs don't carry loads. Chains have well documented yield strengths you can find using Google. From there it's simple math.

Abnormally high chain loads wear out sprocket teeth, which then transfer their wear to the chain. When meshing between worn teeth and worn chain links becomes erratic, you get skipping and other bad behavior that can cause chain sideplates to detach. While this doesn't always cause the chain material to yield, it "breaks" (as in unlinks) the chain which can catch in the derailleur cage and make an expensive mess. Typically this kind of failure will bend or break off the derailleur hanger, and it can badly damage the rear wheel if the derailleur gets caught in it.

If I had to put 5kW through bike parts-- which I don't-- it would be with a steel 1/8" chainring and a single 1/8" freewheel or rear sprocket with at least 22 teeth. I'd use 3/16" heavy duty BMX chain. No derailleur, no tensioner.

 

[electric_nz]

With 3kw I found a 7 speed cluster to be the most resilient with plenty of gears, 8 speed wore out fast and bent sprockets sometimes likely due to the wider diameter. never had an issue with the basic Shimano 6-7-8 speed chain. Bought a Surly 34t stainless chainring for the front which is a bit more durable than steel.

 

[MoneyPit]

Running up to 4k on a Cyclone that died from getting hit by a car and I also have a Cyc X1 gen1 on an enduro.

In addition to the wear items Chalo mentioned above, the cassette can be expected to die young. Standard advice is to use a DT 350 hub. Preferably the 350 Hybrid that is stressed and beefed up for ebikes and tandems. The standard 350 uses an 18T ratchet engagement which will beat out any 3-5 pawl mechanism and was the go-to before the 350 Hybrid came out. The Hybrid has solid ratchet wheels with 24T - the most you can safely use although with 5kw who knows. Also a beefed-up hub body and - maybe most importantly - a steel cassette body. 5kw will cause a cog to dig into your cassette body like a knife into cheese. Thats why you also want a cheapo steel cassette body that is pinned together. My personal favorite is the Shimano HG200-9 or the HG400-9. So... 9 speed. I also have a bike with the SRAM EX-1 drivetrain with the tool steel cluster - on my Cyc-powered bike - but for $400 a pop I would not do that again. I have had excellent luck with the Sunrace CSMS7 11 spd cluster which is steel cogs on top of steel spiders. But I am running that with only 1750w.

If you want a really wide ratio on a 9 spd, Box Components Prime 9 Box 2 derailleur and shifter work great. I am using the Box Three cluster 11-46T which I discovered is a Sunrace CS-M983. At 5 kw I doubt it would survive and instead I'd go with the Shimano 9 spd with the 12-32 range.

The SunRingle hubs that WattWagons uses on their Hydras are reportedly (in a statement by the owner on another forum) able to handle even more torque than the DTs.

Keep your rpms up high or I guarantee you will walk that bike home. Stay off the gear combos where the chain isn't straight. The survivability of the build will come down to attention to detail on the drivetrain.

https://talesontwowheels.com/2020/10/02/how-do-i-ride-a-mid-drive-ebike-without-breaking-it/

 

[Chalo]

With 3kw I found a 7 speed cluster to be the most resilient with plenty of gears, 8 speed wore out fast and bent sprockets sometimes likely due to the wider diameter. never had an issue with the basic Shimano 6-7-8 speed chain. Bought a Surly 34t stainless chainring for the front which is a bit more durable than steel.

Did you measure the chain for wear at any point? With only 750W nominal, my BBS02 went through chains at several times the rate I do on my pedal bikes.

Surly stainless steel chainrings are awesome, but there's no way I'd use anything as small as 34T when it's being driven by a motor. Getting the chain tension as low as feasible is key, and that means using big sprockets.

 

[BalorNG]

With 3kw I found a 7 speed cluster to be the most resilient with plenty of gears, 8 speed wore out fast and bent sprockets sometimes likely due to the wider diameter. never had an issue with the basic Shimano 6-7-8 speed chain. Bought a Surly 34t stainless chainring for the front which is a bit more durable than steel.

Did you measure the chain for wear at any point? With only 750W nominal, my BBS02 went through chains at several times the rate I do on my pedal bikes.

Surly stainless steel chainrings are awesome, but there's no way I'd use anything as small as 34T when it's being driven by a motor. Getting the chain tension as low as feasible is key, and that means using big sprockets.

If you want a pedalable, geared drivetrain with *real* 5kw of power (provided that this power is mostly about low-end torque, not achievable at 60 mph only, which is easy to do), than only solution that will not eat your drivetrain for breakfast and spit out the remains is a jackshaft that has human drivetrain on the input and combined human plus electric assist (which sounds funny given that it is more than an order of magnitude more powerful than human component) as output using at the VERY least 219 chain, single speed, huge cog on the actual wheel (think 60T+ like on Carts)... but stealth it would not be.

Going with left side drive only (again, using something like 219 chain and huge rear cog) is likely easier, cheaper and better... also not 'stealth', but neither should it be, not actually would be, unless you have a fist-sized nuclear reactor as your battery. Any battery that will last more than 10 minutes at such power will NOT be stealth in any shape or form.

 

[MoneyPit]

... there's no way I'd use anything as small as 34T when it's being driven by a motor. Getting the chain tension as low as feasible is key, and that means using big sprockets.

You can do it, although I wouldn't run any 5k thru one on full throttle. I don't have a picture of it installed but this bike now uses a 36T Lekkie bling ring since I dedicated it to trails and overland/boondocks riding. No issues. 1750w with a BBSHD running 30a and a 14S pack. Chain is a KMC 11e with something like 210 links and so far about 1600 miles on it. Although most of that was fire roads and street cargo detail (loads up to 500 lbs though). Also a Sunrace CSMS7 steel cluster in back along with one of those DT hubs and a steel cassette body.

It was either the 36T or the 30T Luna Mini and I chose the 36 based on Karl Gesslein's review. Haven't regretted it one bit.

Its all about building and using smart. Although a longtail like this lets you get away with a lot more chain misalignment than something with normal stays.
Works great collecting wood in the Sierras - when the forests are actually open... :-( If I find a paved road on the way back to camp I can zip up into ... the low 20's? Don't recall exactly I only tested top speed once after the install.