Chain Guide

[Goughy75]

Hi. My trouser got trapped in the front chain guide and tore the guide off. Is it necessary to have the guide or can I get away without it? Thanks.

 

[Gary]

From the abundance of information you've shared.
I'm not sure how anyone can accurately predict whether or not you'll get away with running no top chainguide but if/when you do lose your chain you'll know the answer yourself.
Replacement top guides/full chain guides are readily available.

 

[steve_sordy]

With narrow-wide rings and clutch mechs, most riders won't need a chain guide at all. If you absolutely must have one but don't want to pay the high prices, try a different type, like a dangler.
The best known dangler is the Bionicon chain guide(Google it), but consider the RSP Chain Director chain guide instead as they are about £13 instead of £30 for the Bionicon. I've had both and I can't tell the difference.

PS: I used a dangler chain guide on several different bikes for years to stop the chain from slapping about, but my current bike has a one like yours and it works well (in conjunction with the clutch mech and narrow-wide ring).

 

[Gary]

@steve_sordy lower chainstay mounted chainguides like you're recommending are fairly pointless with a decent clutch mech. As all they really do is add tension to the lower chain and reduce chain bounce/sway. Which is exactly what the clutch is doing. It's also even less required on an Ebike where the chainring doesn't rotate backwards when you backpedal the crank. this is often where/why the chain becomes derrailled from the lower chainring teeth so with a chainring that no longer rotates backwards this entire part of the issue is pretty much resolved.

Not that we have any specific information on which motor or bike were specualating upon

 

[Frankieboy]

Prevention is better than cure.

 

[Goughy75]

Thanks for the reply. Its a Giant Trance E +3 with Yamaha Motor.

 

[steve_sordy]

@Gary I hardly made a ringing endorsement for a dangler, just gave the guy an alternative if he really had to have something that wasn't like what he had broken.

I had a Norco Sight (analogue bike) with a narrow wide ring and a Shimano XT clutch mech that came equipped with a dangler. When it eventually wore out I didn't bother replacing it because of the points you made (narrow-wide plus clutch). But whenever I went over rough ground, the lower strand slapped fiercely on the chainstay, so I replaced it and all was quiet. And yes the clutch was engaged.

I had a YT Capra (another analogue) that came with an e13 bottom guide (they are not cheap!) I had to remove it very quickly because it was causing more problems than it solved. Twice it had jammed and the chain gouged the end of the alloy chain stay. I didn't bother with a dangler because it didn't need one. That was a SRAM clutch mech (different design to the Shimano one).

I've never had a problem with chains derailing when backpedalling, so I had not considered it as an issue. Another learning day.

 

[Gary]

I had a YT Capra (another analogue) that came with an e13 bottom guide

the double chainring version?
I have a Capra here. it has an E13 guide too. it has no lower guide, just lower taco (bash guard)
BTW E13 later admitted their top guides were a flawed design and could open in use and replaced them.

I've never had a problem with chains derailing when backpedalling, so I had not considered it as an issue. Another learning day.

Non-eebs and DH bikes:
See when you ride very choppy terrain feet level (forward foot slightly higher) and every single bump/hit causes your rearward foot to drop slightly?
or see when you ride close successive corners and you alter your crank position for each one by dropping your rearwards crank arm?
Both of these scenarios causes the chainring to rotate backrards slightly. if the chain is bouncing at the same time (particularly if at an angle (chainline or G-force) this can all contribute to causing the chain to derrail.
I've ridden and worked on bikes with chainguides of all sorts for 30 years now so am ridiculously experienced in their various shortcomings.
Just sharing some of my findings over the years

I had a Norco Sight (analogue bike) with a narrow wide ring and a Shimano XT clutch mech that came equipped with a dangler. When it eventually wore out I didn't bother replacing it because of the points you made (narrow-wide plus clutch). But whenever I went over rough ground, the lower strand slapped fiercely on the chainstay, so I replaced it and all was quiet. And yes the clutch was engaged.

Yes. if primarily noise recuction/chainslap is your main concern a lower guide as you're recommending will serve this purpose well. one downside is that it also adds yet another drivetrain part to clog in severely muddy conditions.
one of the NEW issues concerning chain retention/slap is actually the introduction of massive range cassettes. As they cause both excessive chain length requirement AND even poor(er) chainline in extremes.
This is part of the reason I prefer not to run super wide ratio cassettes on any of my bikes.

Bottom line is for chain retention a top guide is of far more use than a lower guide.
But simply keeping an eye on chainring tooth/chain wear with a good NW ring, clutch mech and as short a chain as possible is all most riders will ever need.