ChainGUARD or chainGUIDE?
The one you linked on Amazon appears to mount between BB & frame.
Looks like it would work for a chainguide (light duty) but personally I wouldn't run a bashguard on it.
For that I'd want factory frame-mounted ISCG05 tabs.
=sParty

 

I am guessing you do not have ISCG tabs on your frame, but you want a bash guard. The problem with any adapter like the one you linked, and a bashguard that gets sandwiched between the bottom bracket and the frame is that they will turn when you hit something hard. They might turn so far as to jam up your drivetrain until you can loosen everything up and re-adjust. Back in the olden days before ISCG was even a gleam in my eye, there were guards/guides that even had integrated tabs with set screws to drive into the BB shell in hopes of stopping the guide from rotating. All they did was rip grooves out of the BB shell.. What you need is a chainring mounted bash guard. I just googled it and was surprised at the number still available, you just need to get one to fit your crank arm/chainring.


DT

 

I am guessing you do not have ISCG tabs on your frame, but you want a bash guard. The problem with any adapter like the one you linked, and a bashguard that gets sandwiched between the bottom bracket and the frame is that they will turn when you hit something hard. They might turn so far as to jam up your drivetrain until you can loosen everything up and re-adjust. Back in the olden days before ISCG was even a gleam in my eye, there were guards/guides that even had integrated tabs with set screws to drive into the BB shell in hopes of stopping the guide from rotating. All they did was rip grooves out of the BB shell.. What you need is a chainring mounted bash guard. I just googled it and was surprised at the number still available, you just need to get one to fit your crank arm/chainring.


DT

Thanks! Wouldn't the threading keep it from turning if the adapter is flush against the frame? Any hit on the guard would cause the adapter to tighten.... (assuming the hit on the guard forces it clockwise).

EDIT: I'm correcting myself. I don't see any threading inside the adapter.

 

Here's an ethirteen version. Looks thicker. E*Thirteen

or Search results for "GP0094" | CANYON CA

 

Here's a different one that clamps to the outside of the BB shell. ISCG-05 Adapter Clamp

Not sure what sort of damage the frame will take, but this version seems like it would be less likely to rotate when hit.

 

This csix clamp on would not hurt the BB when forced to turn with a hard impact. Nice find! It would be even better if it had a flange to fit under the BB cup as well for even more resistance to turning, with the huge benefit of having a fixed offset to locate the mounting points from the center of the chainring. I suggest having an allen key that will reach the pinch bolt when the whole system is assembled just in case an impact on the trail rotates the bash guard, you can quickly re-adjust it. Maybe never need it, but it would not take up much room in your kit.

There is no replacement for proper ISCG (05) tabs though. The reason I created a fixed chain guide mount on the early DHR was that all the guides of the era would move when hit. I worked with Mr. Dirt who made chainguides at the time to create the original ISCG tab, later the bolt pattern was expanded in anticipation of larger diameter bottom bracket shells.

Have a good ride,

DT

 

yeah, the ones that pinch between the bb cup and the frame are going to put all the impact stresses onto the bb. specifically the threaded portion of it. You'll have less thread engagement to the frame than usual, so you run the risk of destroying your bb.

that one that clamps to the bb shell looks interesting. You'd want to make sure that you have enough bb shell to clamp to, though. I could certainly see some frames having welds that come too close to the end of the bb shell for there to be enough left to clamp to. And it looks like the mfr comments on that possible trouble. Me, personally, I'm not sure I'd be comfortable filing the adapter to work around welds. Though doing so will give you maybe a little extra help preventing it from rotating. Not that you'd run into major safety/injury issues if that adapter failed on you since it's a noncritical part.

I'd just rather use a chainring mounted bash guard than go to hacking and modifying. The Wolftooth BashSpider is a pretty elegant solution. It won't really prevent you from folding over a chainring in an impact (I saw that happen to a guy once, on a log, not a rock) the way a taco bash can, but it'll at least protect your chain from getting beat to hell.

These days, I won't even buy a frame unless it has ISCG05 tabs.

 

Thanks for the advice!

the BB is only 41ish-mm with very little overhang.

I’m also coming across another complication. The BB is square taper. Does the adaptor ring work with square taper?

 

the spacer type ones won't work with square taper. They're meant for external cup bbs because those have more material from the bb pressing the adapter (or spacers, since those type adapters are meant to take the place of a bb spacer) into the outer edge of the bb shell. Perfectly good for a chain guide. Borderline for a bash guard, though you can buy "downhill" external cup bb's made out of steel with extra long threaded portions so you don't lose thread engagement. There aren't many, but they exist.

Dunno what the dimensions of that clamp-on one are, but you definitely have less to clamp onto where your downtube welds onto the bb shell. The clamp-on ones don't care what your bb type is - they even make one that'll fit pressfit bbs (probably BB92 ones).

If you're wanting this for a chainguide of any sort, all bets are off. It'll depend on the chainguide and how much adjustment it has for different chainlines. If that's what you want, then you might be better off with a top chainguide that clamps to your seat tube and/or a bottom guide that clamps to your chainstay.

Given that you have a chainring that uses some chainring bolt pattern, I think your best option is to get a bash ring that attaches to your crank spider. No worries about folding over a chainring with an integrated bash ring, so there are honestly no drawbacks to this method.

 

If you're wanting this for a chainguide of any sort, all bets are off. It'll depend on the chainguide and how much adjustment it has for different chainlines. If that's what you want, then you might be better off with a top chainguide that clamps to your seat tube and/or a bottom guide that clamps to your chainstay.

Given that you have a chainring that uses some chainring bolt pattern, I think your best option is to get a bash ring that attaches to your crank spider. No worries about folding over a chainring with an integrated bash ring, so there are honestly no drawbacks to this method.

Thanks! It would be for both a chain guard/guide system. Yes, looks like I might be out of luck. Even with the clamp-on adaptor... there's not much space. I've emailed the manufacturer of the clamp adaptor as I did not see a 41mm option and to advise on minimum space for installation.