andyman

Has anyone found a chain watcher that will fit on a Calfee? My smallest chainring is a 26t on a 26/39/53 triple. I am presently using tape for protection and I know the N-Gear Jumpstop won't work due to the seat tube tapering towards bottom. What are other Calfee owners using with similar setup? This chain catching looks promising, but it is only for doubles and quite expensive. https://www.acecosportgroup.com/content/

tandem rider

We used the Chain Shield from Tandem's East on our aluminum Santana. https://www.tandemseast.com/parts/chainrings.html
Sheldon and Martha Hall
Greenfield, IN

TandemGeek

Nothing... but then again, I don't have to worry about paint being marred.

However, with respect to those infrequent occasions when we go to shift into granny a bit too late and the chain overshifts, I've made sure the gap between the stoker's bottom bracket shell and cranks is wide enough to allow the chain to drop all the way to the square taper spindle without binding: it's the chain binding between the arms & mounting tabs of the granny ring and frame that creates the real damage on most bikes and tandems.

As you can see in the photo below, the carbon is formed and sanded in such a way that there's no shelf or lip around the bottom bracket. Therefore, unlike a conventionally built frame with a true bottom bracket housing that's welded to the seat, internal boom and chain stay tubes, there's really not anything for the chain to hang on.



I would think that Octalink and ISIS spindles would also allow for this and that the outboard bearing cup housings on MegaExo and similar outboard bearing cranksets would also serve this purpose.

Your use of 'tape' should provide that belt and suspenders protection to any paint. Although, if I had a painted frame I'd be using some 3M clear mask or Avery Stoneguard material.... the same stuff they use for clear-bras on cars and that chain stay protectors are made from. It's pliable, but very thick and would do a very good job of protecting the painted carbon from being nicked up by the chain.

Anyway, just my thoughts on the subject. Thankfully, I can count the number of overshifts we've had on our Calfee on one hand with a couple digits left over.

ftsoft

I looked for a link on roadbikerider.com, but couldn't find it to an article about fashioning a chainkeeper out of an old spoke. I did this on my Bianchi XL Boron because I was having occasional problems with the compact shifting off. Basically, you cut off a spoke, grind the end flat to fit the front derailleur hangar and position it hanging down so that it keeps the chain from going off the inside. It took me about 15 minutes and the thing works great, is hardly noticeable, and very light.

Frank

rmac

I use the N-Gear Jumpstop (with 26-38-48 chainrings). All you have to do is bend the top a bit so the derailleur clears the top. I'll post a picture tonight. I'm too concerned about gouging the cf not to use one even though as TG mentioned the chain would probably end up on the BB spindle.

andyman

I am going to have to recheck that. the N-Gear is at my bike shop. My bike shop and I were trying to fit it, but the Dura-Ace inner cage was hitting it and it did not slide low enough on seat post. It didn't look like I could bend it enough to fit either. A picture would be helpful.. Thanks.


The Chain Shield from Tandem East also looks promising since I have Gossamer triple crank.

rmac

That may work. However, I saw one from Mel and it felt like it weighed a ton.

Ritterview

I have a K-Edge on my BMC half-bike, and it works well. I contacted K-Edge to ask them about a version for a triple, for use on a Calfee tandem. The rep replied they are working on a triple version. He wanted to know the seat tube diameter for the Calfee, and I didn't know.



For Campy, the K-Edge would work with the braze-on, but not the clamp-on front derailleur. Calfee uses clamp-on. Calfee doesn't drill into their tubing, but adheres carbon limpet bolts, as depicted below. I wonder if this could or should be done to use a braze-on FD?

joe@vwvortex

Car clear bra material is pretty thin as is most chain stay protector material. I bought a couple sheets of some stuff that is about twice as thick from a Motorcycle shop. It's used to protect forks and other parts of offroad bikes. I don't have any specs on it or the name but i've been using it for a couple years now.

TandemGeek

You can use a braze-on derailleur adapter clamp on the Calfee just as Ritterview did on his BMC; the frame doesn't know the difference and Parlee even makes them out of -- wait for it -- carbon!

You can find a plethora of clamps here:
https://www.bikeman.com/Braze-On_Adaptor_Clamps.html

Of course, now that I look at the photos of (your?) Calfee it already appears to have an adapter clamp so you should be able to use the K-Edge if they (a) develop one for a triple or (b) if the one they make could be adapted. There are a lot of ways to address this annoyance, just use your imagination.

True; my 'clear bra' guy actually uses the Avery Stoneguard which is much more robust than the 3M stuff. However, the point being there are clear films that you can use to protect carbon frames from nicks and such and if you have a painted finish that you're concerned about they are worth exploring. As you note, MC shops often times have some really thick stuff, but I'm not sure how well they'd comform to a complex curve around a bottom bracket. A couple layers of Stoneguard would be pretty good insurance.

Man, I'm glad I don't have to worry about paint anymore....

uspspro

I like my chain watcher on the tandem... Allows me to set my granny shift limit slightly more aggressive without worrying about it throwing the chain, so that it always shifts into it fast.

Nothing sucks worse then timing your shift perfectly, only to get stuck in the 42 ring when you hit that 15% grade Then trying to give the drive train a little shifter english under high load at 50 rpm pedal cadence to get it to kick over..

So yeah, nice shifts with the chain watcher

joe@vwvortex

The stuff I use - sorry I wish I had the spec - is very easily manipulated and conforms fairly easily to curves and tubing shapes. It's probably similar to two layers of Stoneguard.

Ritterview

That my BMC has a braze-on FD on a clamp is sort of an accident, but I found it works with the K-Edge, so I've stuck with it. It is belt-and-suspenders redundant however, which offends my sensibilities. For my built-from-scratch tandem, if I am to have a braze-on FD, I'd like it to be actually brazed-on.

That Calfee in the pic is Calfee's multi-colored, S&S coupled Tetra, on display at Sea Otter.

Before the K-Edge I had protective film around the BB area. Dirt however, got under the edge and was perpetually unsightly. I'm glad to be rid of it.


What type do you have that works with a triple? A Deda Dog Fang?

uspspro

Just your standard Third Eye Chain Watcher.

I am assuming it won't fit on the calfee's beefy BB section. fits fine on our Arriva

osurxbiker

Third eye chain watcher does not fit on a Calfee. Our cannondale now has the one.

Ritterview

The seat tube on my BMC splays out near the BB area, and thus doesn't work at all with the likes of Dog Fang's or Third Eye's. The Calfee has a large diameter tube down to the BB area, but in the photo I posted above it looks cylindrical at the level of the granny gear, and thus that it would accept a Dog Fang, if only the right size. Does anyone know the diameter of the Calfee seat tube?

Deda Dog Fangs are sold in 28.6, 31.8 and 35 mm.

TandemGeek

35mm

But as to whether or not it will fit depends on each frame subject to where water bottle bosses are located and how much hand-wrapped composite material Calfee spec'd for use for the bottom bracket to get the necessary stiffness for the team's size / riding style.

That said, I will note that I played around with a couple of these things and have found that a little farm boy engineering goes a long way towards either modifying them to fit and/or adapting other things to accomplish the objective of keeping the chain from overshifting the granny ring. Again, a little imagination goes a long way.

Ritterview

Is this what you refer to as the water boss?



Instead of drilling into the tube, a bolt is adhered to the outside of the tube using a carbon limpet. I've seen these on Parlee's as well. Is this something unique to these custom carbon builders?

rmac

Here is the picture of the N-Gear Jumpstop on a Calfee. Notice that the metal top part is bent so that the derailleur clears it. The seat tube starts to expand just below the Jumpstop band. I don't think a Dog Fang could get low enough for a 26 toth chainring since it appears to be at the same height as the band.

andyman

rmac,

Do you have a Dura-Ace front derailleur? I do and it seems the inner cage actually hits the plastic on the N-Gear which is why I couldn't make it work. Hmmm? My LBS has the N-Gear and I will have to analyze this again to see if I can change something to make it work hopefully.

Thanks for the pic.

TandemGeek

Yes, that's what I refer to as a water bottle boss... the generic term for any fitting used to attach a water bottle cage. Before riv-nuts came along most frame builders would braze small, threaded bosses into their frames for mounting water bottle cages.



I believe Calfee calls their water bottle mounts 'stud plates' since they have a threaded stud instead of a threaded boss. Calfee uses them instead of riv-nuts to eliminate potential problems associated with creating a void in their carbon tubesets and/or having riv-nuts come loose over time. In fact, instead of using plated steel riv-nuts a lot of mass-produced carbon frames used the standard aluminum riv-nuts and, well, carbon and aluminum don't play well together and will eventually come loose as galvanic corrosion breaks the bond between the riv-nut and tubesets. Didn't realize Parlee used the stud plates, but did notice that Brent Ruegamer uses riv-nuts when I was looking at WheresWaldo's Ying/Yang gallery.

rmac

No, that's a Campy Record derailleur. On mine the inner cage was hitting the metal plate. I don't really see how the inner cage could hit the plastic since the metal plate sort of wraps over on top of the plastic. I'll have to look at a Dura-Ace derailleur.

andyman

I just got a reply from Mel at Tandems East and he said the Chain Shield weighs 2 ounces (lighter than a repaint)
https://www.tandemseast.com/parts/chainrings.html

Chris_W

I have the same issue on my carbon fiber single bike with the tube shapes around the BB preventing the use of a normal chain retention device. I therefore went with a DropStop from Jtek Engineering:



It was working well, but I saw a lot of pro riders using something attached to the FD braze-on bolt which seemed more elegant. As pointed out by Ritterview, the K-Edge chain catcher was recently released to the public, so I decided to try one of those:



As mentioned already, there is currently no version officially available for a triple crankset, but the real limitation is the difference between the largest and smallest chainrings. Mine is now working well with an 18-tooth difference; I run a super-compact double with 46-28 tooth chainrings. Kristin Armstrong, who the product was initially designed for, apparently also runs it with an 18-tooth difference, with 56-38 tooth rings. It may JUST be possible to make it work with a 20-tooth difference, and so a 50-39-30 triple crankset. But to do that, you'd need to drop the FD down as low as it will go, so an Ultegra 6600 FD wouldn't work, but a 105 5600 FD might (the 105 is designed for the smaller middle to big ring tooth difference, and so could be lowered sufficiently, whereas the Ultegra could not because it would catch on the middle chainring when shifting to the largest ring).

However, hopefully more versions of the K-Edge will be available soon, their website states "Stayed tuned…. we are working on solutions for Mountain Bikes, Cross Bikes, single speeds, etc."

ftsoft

I don't know what could be simpler than this. It works. I have to admit that I don't use it on the tandem, but I simply never experience shifting off the inside with the comotion.