Pedals forward but virtually no drive to the bike at all 😭

[Turbo Vado Pip]

Pedals now slipping on my Vado 4. Doesn’t matter if the bike is on or off, manual or eBike mode. Pedals slip forward providing almost no drive to the bike. Seems like the clutch in the motor has gone. Bike has done around 8000 miles. Is this an expensive fix? Has anyone else had this same problem?

 

[Stefan Mikes]

Perhaps your drivetrain is ruined?
When I had my Vado motor broken, the symptoms were completely different. It was a terrific noise followed by immediate system shutdown. Still, I could pedal my Vado with the motor off.

I expect your cassette might be heavily damaged/worn. It might affect the chainring as well. How often did you replace the chain?

What country are you from?

 

[Base]

What country are you from?

based on previous posts I would think the UK.

In my mind this symptom could be caused by a sticking freehub on the rear wheel. pizza couriers here use a trick with a too high tension on the freehub of their delivery bikes to be able to ride them without pedaling, with the tension on the freehub to high the chain keeps on turning the rotation sensor based crankset so the e-bike motor keeps turning, a bit of a throttle function.

 

[dblhelix]

Pedals now slipping on my Vado 4. Doesn’t matter if the bike is on or off, manual or eBike mode. Pedals slip forward providing almost no drive to the bike. Seems like the clutch in the motor has gone. Bike has done around 8000 miles. Is this an expensive fix? Has anyone else had this same problem?

I had the same thing happen with a Bosch motor out-of-warranty and had to walk the bike back. Swapped in a new (to me, had 2k miles on it) motor and all was well. Not sure why you should assume drivetrain. If you grab the pedals and rotate manually, do you hear unhealthy sounds despite lack of resistance? It's the motor.

 

[Base]

I had the same thing happen with a Bosch motor out-of-warranty and had to walk the bike back. Swapped in a new (to me, had 2k miles on it) motor and all was well. Not sure why you should assume drivetrain. If you grab the pedals and rotate manually, do you hear unhealthy sounds despite lack of resistance? It's the motor.

could have solved your problem? Might have been cheaper than a replacement BDU

 

[Stefan Mikes]

We are NOT talking a Bosch E-Bike motor, @Base. I kindly ask you to give advices only in your field of competence, thank you.

Not sure why you should assume drivetrain.

Because the symptoms on the broken Specialized Vado (Brose) motor are different. The first reason for the failing motor is a broken internal belt drive, and you cannot mistake it for anything else.

I was asking @Turbo Vado Pip for the country because (given the drivetrain is sound; otherwise chain skipping is the norm) the best way is to visit a Specialized dealer for diagnosis. Before the inflation started, I paid the equivalent of pound sterling 1,000 for the new motor. Perhaps services to repair the motor do exist in the UK.

If this is indeed a broken motor.

 

[Base]

I was refering to the motor wap of

dblhelix​

Since the OP has to comment on the drive-train issue we suggested to look at, we still have to wait for extra info to guide the OP to a dealer with a clear picture in mind.

btw, my field of competence is 30 years in the Bike industry, so I might know a few tricks and tips. and yes I have a lot of hours working on spesh products

bearing overhaul kit would be this one for the Mahle DU

 

[Stefan Mikes]

and yes I have a lot of hours working on spesh products

E-bikes?

 

[Base]

E-bikes?

100%

I've started to work on Spesh e-bikes with the Go-Swiss system. so thats a few years back in time. Also a former bikeshop where I've worked now carries spesh e-bikes after recommendations.

 

[Stefan Mikes]

So you worked for them a decade ago. The Stone Age of e-bikes.
If you want to prove you know Specialized...
...please tell me what the mandatory action to be able to route the wires between the TCU and the SL motor is Been there, done that.

 

[Base]

replacing the S196800021 Specialized Wiring SL System Main Harness Motor Battery TCU?

enlighten us

stone age of e-bikes is more like mid '90. For Europe

 

[dblhelix]

View attachment 192128

could have solved your problem? Might have been cheaper than a replacement BDU

Actually, no. As mentioned, I replaced w/ a used motor.

 

[dblhelix]

We are NOT talking a Bosch E-Bike motor, @Base. I kindly ask you to give advices only in your field of competence, thank you.


Because the symptoms on the broken Specialized Vado (Brose) motor are different. The first reason for the failing motor is a broken internal belt drive, and you cannot mistake it for anything else.

I was asking @Turbo Vado Pip for the country because (given the drivetrain is sound; otherwise chain skipping is the norm) the best way is to visit a Specialized dealer for diagnosis. Before the inflation started, I paid the equivalent of pound sterling 1,000 for the new motor. Perhaps services to repair the motor do exist in the UK.

If this is indeed a broken motor.

Noted on the engine's belt drive.

 

[Stefan Mikes]

replacing the S196800021 Specialized Wiring SL System Main Harness Motor Battery TCU?

Removing the fork and then a plastic collar inside the head tube. It is something you'll never find in a service manual.

 

[Base]

I was afraid you were going to mention this indeed ;D, logical step for a bike mechanic.

 

[dblhelix]

By way of explanation -

I'd just replied to OP about cranks on a Bosch bike in a separate post and completely missed that this was in the Specialized sub and a different bike.

And I priced the overhaul kit on eBay. The motor cost me $50 more, but well worth it. The engine failed near my boat in Baltimore. I walked it back to the dock, where I landed up doing the work on Feb-10 outside. It was a quick job on the first day above freezing. Totally worth it. And the engine failure was not premature -- I got an additional 1500 miles or so on it after the bike fell in the Chesapeake Bay.

 

[Base]

For the OP I was thinking what to ask to determine the root cause. It would be wise to check the chain/cog wear with a chain checker. Also, get the bike in the air and while blocking the crancks move the rear wheel backwards. If this last test lets the wheel to turn backwards it would be the freehub in most cases unless the chain is that worn that the chain skids on the cogs of the casette or the chainwheel at the DU.

 

[timbo46]

If the pedals slip and the chainring doesn't move it is probably the sprag clutch in the motor: Mine went at 18000km and I had the motor repaired and upgraded (better seals, belt, clutch etc) by one of Ebike motor repairs partners, cost was 400€, and took less than a week including transport.