Is it battery or motor rattle?

[Gutch]

Probably been discussed to length, as a new owner ive inspected my tolerances on the battery and all looks good. However, mainly when coasting over chatter, I get this rattle noise, irritating. So I gorilla taped my cables to the frame, same deal. So I’m asking “time riding the rail” where is the noise and how to eliminate it. Mines a 2021 9.8. Does anyone ride a silent Rail? Thank you for your help!

 

[Kernow]

I think there’s a rattle inside the motor , it’s a bosch thing I think . i Think a lot of the new generation motors do it .

 

[Dave_h34]

New owner here too. ? One thing I noticed when Invisiframe-ing was the speed sensor cable rattles quite a bit in the chainstay on mine. Worth a look?

 

[Gutch]

Thanks for the replies, I’m just curious if anyone rides a dead silent rail.

 

[Dave_h34]

And now I've ridden it properly can confirm it rattles. ?

 

[Doomanic]

I haven't ever really noticed it over all the other trail noise to be honest. I've even tried listening out for it on my GoPro vids and still can't make it out. My wife often accuses me of being deaf though, so maybe it's that...

 

[Doomanic]

Here's some footage a slow old bloke riding a bumpy trail. If someone can hear the rattle can they give me a time so I can listen for it?

 

[Dave_h34]

Here's some footage a slow old bloke riding a bumpy trail. If someone can hear the rattle can they give me a time so I can listen for it?

All the way thru! ?

 

[Doomanic]

What are you hearing? I don't hear anything that I don't also hear on other bikes.

 

[Dave_h34]

All your bikes rattle then! ? It's a rare thing to get a bike that doesn't rattle in my experience, and it doesn't last long, but for those blissful rides all you can hear is the buzz of the freehub and the noise of the tyres. Of course you could argue that if you're noticing rattles you're not doing it right!! ?

 

[Doomanic]

All your bikes rattle then!

Not just mine. Every bike I've ever ridden over terrain like that has rattled to a greater or lesser extent. What we're talking about here is the infamous Bosch motor rattle that some people seem to get their knickers in a twist over.

 

[Doug Stampfer]

A very quick & easy way to test is to cut 3 or so 20mm strips of thin foam & wrap them around the battery & insert. I have taped some permanently inside the compartment & noticed a lack of noise when I tried it first time. Just make sure you have the battery fully inserted properly & locked in with the key.
In fact after a service & pivot bearing replacement it sounds the quietest it ever has.

 

[lightning]

My STEPS E8000 rattles when applying gentle pressure to the pedals on rough ground.
l believe it's the clutch engaging and disengaging as the chain tension changes with suspension movement.

lt doesn't happen if you are not pedalling. Or if you are climbing under higher assist power.

l guess it's just the way it is. l believe the new EP8 motor rattles quite badly as well, there's a thread about it on here.

 

[Gutch]

All posts above on point. Just got back from a bike park that rents the Rails and talking to the mechanic that owns one confirmed it’s the Bosch clutches. He also mentioned the best way to tell if your battery is off is simply look thru the keyhole. If it’s lined up perfectly, you’re good. He said more battery alignment issues on the aluminum frames than the carbon.

 

[Barks507]

Probably been discussed to length, as a new owner ive inspected my tolerances on the battery and all looks good. However, mainly when coasting over chatter, I get this rattle noise, irritating. So I gorilla taped my cables to the frame, same deal. So I’m asking “time riding the rail” where is the noise and how to eliminate it. Mines a 2021 9.8. Does anyone ride a silent Rail? Thank you for your help!

My 2020 Rail 5 rattles pretty good. The chain play when not pedalling over rough terrain pulls on the chainring. With a little bit of play in the drive it creates a clicking sound which is amplified through the frame. Bugs me but Bosch says it normal. Can't see how it's normal when some do it and some don't. When we get out of this stupid lock down I'm taking mine back to Trek and opening a "claim". They probably won't do anything about it but at least it alerts them to another motor with the rattle. Maybe they'll do something about it in the future. ?!

 

[lightning]

My Shimano E8000 does this, on rough ground when you are pedalling and it's the chain tension changing as the suspension moves causing the motor clutch to engage/disengage
l think it's just a thing, depends on the type of rear suspension, some designs don't alter the chain tension as they move, and those bikes won't make the noise.

 

[RustyMojo]

So after giving my rail a proper shake down again this weekend, I can confirm it’s proper rattle central. To the point I pulled up twice on one trail at BPW as I thought something must be seriously lose. Whilst it’s annoying it’s not the end of the world, years ago I used to ride Orange 5’s before the days of clutch mechs…so I’m a little numb to it.

However it’s still pretty crap on a modern bike. I can’t see it being my battery as it’s more of a cable or content rattle, I think to me it looks like it’s the chain against the chainstay ‘rubber’ and/or the absolute dog shot chain guide. I’ve removed the chain guide now. All it did was force mud an detritus into the chain and chainring. I’ll give a decent who in a lower gearing. Just to see if it rattles and my chain theory is debunked. But in the highest gears the chain is very, very close to the chainstay.

bike is a 2021 Rail 5 by the way.

 

[lightning]

Did you read my post above about the possibility of it being the clutch in your gearbox?

 

[RustyMojo]

Did you read my post above about the possibility of it being the clutch in your gearbox?

I did yes thanks, but also read that you have a Shimano motor…not the Bosch as I.

Before I just put it down to a ‘feature’ of the motor I’m going to explore all the usual avenues. My buddies Bosch doesn’t make the ‘same’ sound. I got a couple of no cost things to try. I’m also going to do away with the stupid lock system. The bike is 2 rides old, I have checked all the hardware and it looks spot on. From what I can hear it’s only when I’m in the higher gears on very rough tracks, so I’m pretty sure it’s some form of chain slap. The chain guide is already in the spares box so I will try a few things this weekend

 

[lightning]

l am going to risk ridicule and say,

As the suspension moves the chain tension alters, l assume the Bosch has a one way clutch like Shimano, so the drive can disengage and you can pedal without assistance.

In this case it could well be the chain tension causing the clutch to momentarily disengage. l bet it doesn't do it on climbs when you are putting a fair bit of effort through the pedals? Because in that instance the clutch won't disengage if the chain tension alters.

 

[RustyMojo]

l am going to risk ridicule and say,

As the suspension moves the chain tension alters, l assume the Bosch has a one way clutch like Shimano, so the drive can disengage and you can pedal without assistance.

In this case it could well be the chain tension causing the clutch to momentarily disengage. l bet it doesn't do it on climbs when you are putting a fair bit of effort through the pedals? Because in that instance the clutch won't disengage if the chain tension alters.

Well no it doesn’t do it on climbs, but then you would never be moving at the same velocity over rough ground uphill. Like I said I think it’s chainslap, the chain sits very close to the chainstay in the higher gears. It also makes the noise with the motor off. I’m not saying it’s not the motor, but I would be very surprised given the pitch/sound and frequency

 

[lightning]

Mine makes a clattering noise, it's only a suggestion l could well be wrong.

Does your bike not have a rubber frame protector to stop the chain from hitting it. Also your rear mech will have a clutch and l take it that's engaged, it pretty much eliminates chain slap.

 

[RustyMojo]

The clutch will only elimate the chainslap in a traditional sense, it’s the chains proximity to the upper chainstay when in higher gears….I have been riding for many many years, so completely aware of how clutch systems work. Hence why I don’t think it’s traditional chain slap….There is a form of protector on there, which is why I think the ‘rattle’ is slightly numb, but also what makes me think it was the crappy chain guide.

 

[lightning]

Well, l hope you get to the bottom of it, mine makes a similar noise and l just put it down to the motor unit, if it's something else on yours you may be able to silence it.

 

[RustyMojo]

Well, l hope you get to the bottom of it, mine makes a similar noise and l just put it down to the motor unit, if it's something else on yours you may be able to silence it.

Thanks.

it will be fun trying to find it I’m sure, good reason to understand how the bike works in more detail. It’s my first ebike after being completely ‘anti’ for many years. The rattle caught me off guard a little after years of high end manual bikes, which were all absolutely silent. I’ll get to the bottom of it….or not! Who knows