Reminds me of Millar when their team boss opted to go 1x10 and he had a dropped chain which cost him the W.

Next thing you know, people will be getting rid of the cassette and RD and freehub! :D

Ditto this question. It sounded like GH went through some work to arrive at that positioning and product - so share.

The leading edge of the pulley is too squared, and chamfered on the sides of the tooth rather than more towards the top corner that first meets the chain. Second, the thickness of the tooth where the roller of the chain rests in is not adequate. Sram lower pulleys are slightly thinner than the upper ones, which I'd guess is part of their 10,000 CAD effort (aeroglide!) to reduce the racket of their notoriously noisy drivetrains. The best fix is to take an upper pulley and chamfer the whole damn thing yourself, but that takes practice and those things can be expensive. A second, almost as good fix is to take the original bum pulley, round off the leading corner a bit and then go back and give it a sharper edge. 220 wet or dry sandpaper at first, then smooth with 400-600.

Is good to first see if it needs all this worrying about. Put bike on stand, pedal at speed and tweak the chain about a bit, bounce it from side to side. On my new Wifli it took nothing for the pulley to dechain and then the chain would get sucked up into the cage. No way would I have ridden it like that, not worth the risk. If it seems that this happens so easily it makes your gut a little uncomfortable, then a fix is appropriate.

the one in photo is a ceramic xx lower wheel, kept as a spare. Its a bit overdone but illustrative.

Chainkeeper design and positioning is best explained in a short video and I can't upload those here.

In bold above is wrong...or you just can't explain why the two pulleys have different geometry.

I've got an idea! How about 2 x 5!!! 2 chainrings and 5 cogs in the back. It gives you 10 gears. Why hasn't anyone thought about that!

We'll be there. Likely the only Orange and Yellow tandem with Zipp 808's.

Brilliant!

I run a 50/39/24 crankset and a 48/38/22T crankset and with an N-Gear jump stop, I never drop the chain either.

I don't lose 10 (extra) feet everytime I shift my front derailleur (at least not when I've tuned it correctly). And for my troubles, I get almost a factor of two in gear range.

All that being said, nicely done! This is what you wanted and it looks to be done nicely. :)

This concerned me earlier in the thread. I fear the can is open and the worms cannot be put back in.

One day, this will be the norm[shudder]:
http://bikeforums.net/attachment.php...hmentid=308518

Jesus I could complicate an ice cube. If the sram pulley thing is a problem, JUST ORDER A G-D SET OF ULTEGRA WHEELS OFF AMAZON. The desired tooth profile/chamfering is what I am describing above. Mine are an awkward version of that.

http://m.youtube.com/watch?v=xVNzS17...ure=g-high-fbc

Boy you can smell a stoker a mile away. But thank God they sit behind you, right?

bad joke. look forward to seeing you! I'm usually not too much of a strain to pick out.

Gerry, why does the 10 X 1 setup need a chain keeper. There is none on a 10 X 2 setup and the FD doesn't touch the chain except when front shifting. Why can't the chain just sit there all alone? Doesn't the RD manage the chain sufficiently?

Robert

I'm not Gerry but my 1x9 started out with no guard, and would drop the chain off the front. It wasn't common, but if I was rapidly accelerating and banging down through multiple cogs, the chain would fall off the outside. This was with an unramped unpinned Surly chain ring. I ended up having to put a bash guard to the outside.

It never once dropped a chain to the inside, or fell when shifting to larger cogs. Only on fast shifts to smaller cogs, 3 or four in succession, and much worse in wet weather. I can't explain it.

Same here, I even started a thread asking opinions about chain keepers. I wound up making my own from a cable clamp and pc slot cover, which is why I was curious about Gerry's.

Exactly.
I don't know why it is primarily if not exclusively during upshifting, but the chain dropping into its new cog starts this harmonic side to side bounce wave sort of thing on the top side of the chain. What looks like a mild shudder is actually some pretty wild action going down; it's just so fast your eye can barely see it. Without the derailleur or chainkeeper plates to interrupt the bounce, the chain will heave itself off the ring. Even doing your shifting under power, which youd think would be enough to keep the chain wrapped tight around the ring, is not enough to overcome it. Sometimes id bounce the chain off on a hard bump but 8 times out of ten it was during an upshift.

what is interesting is that the further the chain/chainkeeper "bounce interruption point" is away from the chainring, the more effective it is at stopping the bounce. I at first thought chainkeepers should be designed basically like derailleurs that couldn't move, with the plates super-close to the chainring. Those kept the chain on most of the time, but not always, and then there was still the typical chain-rub under power.

But think- if two kids are jumping rope, where's the easiest place to bring that rope to a sudden halt? Near your kids hand (the chainring)? Or somewhere nearer the middle?

so I simply started making longer chainkeepers, and the only place the chain ever touches during that "bounce interruption" is at the very end that is furthest away from the crank.

these I can put the bike on a stand and zing up and down gears and pluck on the chain like 95 lb crossbow and it will never, ever come off. It stop the jumprope every time.

A few years back I built up a 1x9 for my partner. She never dropped the chain

Critical question: are you still together? How were your sexual relationswith her during this interval with no chainkeeper? Please answer this in the same thoughtful detail that I have more than generously supplied you.

I run a 1 x 7 on my MTB and I love it for cleanliness and sexiness. I have often thought about 1x10... Despite all the skepticism and subtle mockery that you have received, I say rock on.

Ah, most of them are too easy targets to fire back at. 1 x 7 is the GRAIL man. You rock on back Jack.
Nite.

I run a 2x10. I never see a 1x10 around these parts, at least not in front of me.

Yes and excellent.

That's interesting. On my 8/9 speed the chainkeeper is about where the DR would be, on the theory that the optimal position for moving the chain to a gear is close to optimal for keeping it there. It works, and there's not much force in the undulations so it just needs a touch to guide it. Maybe the 10 speed chain bounces off at a smaller angle, due to the narrower chain, and needs a tighter control which is easier further away.

Studying chain behavior- man, it's one of the black arts, no question about it.

i've had exceptions to every single thing I've stated as a general rule or probability.

Like chaulky, my first 1x setup on a particular bike that had no chainkeeper and it never dropped once. It never occurred to me that one might need a chainkeeper. It was a Kestrel Airfoil- know those freaky UCI illegal tri bikes with no seat tube?

the next bike would toss it every single upshift. Absolutely maddening. The only difference between the two bikes was chainstay length. That has a great deal to do with the harmonic wave formation, so I suppose that is it.

But here's how the design has evolved over the last couple years. Note the generous amount of space near the chainring where a der does it's stuff. The chain will never, ever touch the plates there. The only place I will see a mark is at the hindmost part, furthest away from the ring. Because, exactly as rugged indiv hypothesized, it requires only the gentlest touch there to stop the harmonic wave and keep the chain on track. It's quiet. It's the chainkeeper I can see but never hear. The shorter keepers I've had needed to be considerably narrower, their plates closer together, and with those came the same issues that come with derailleurs- making them just narrow enough so they can do their job of controlling the chain, but wide enough apart so that they don't rub the chain under high power. It was generally an impossible balance to find. Then it finally hit me: "make them LONGER you idiot"http://bikeforums.net/attachment.php...hmentid=308659http://bikeforums.net/attachment.php...hmentid=308660

These were made with a drill, hacksaw, and miles of sandpaper.

I dunno. These are neat problems to work out, and I am endlessly fascinated by the interaction between chain and sprocket teeth. But I don't think the perfect 1x10 rates as a significant potential contribution to cycling. It was put together only to compensate for a personal deficiency: I know I have an acute enough mind to get hip-deep into this esoteric stuff, enough manual skill to actually build the things we are talking about, and strong enough aesthetic sense to make them pretty to look at as well as functional...but when it comes to trying to ride a bike with TWO shift levers, man, I struggle! I am the the kid picked last for kickball. I don't know what it is. So despite all my claims of the superior virtues of a 1x set-up, make no mistake- it's really just a disguise for a personal handicap.

And now I need to get the heck off the internet. In two days I'm leaving to ride in a 170 mile event on this brand new bike that has all this prototype junk on it, a handlebar drop that no pro would go near, that I've ridden a grand total 5 blocks (it performs to belt-drive quiet perfection, btw) with no training other than clomping around the woods in a 50lb weight vest.

and I'm just a bit nervous about all of that, if you know what I'm saying.

You can also use a front derailleur as a chain guard and just use the limit screws and no shifter...

You seemed confident enough about it in your OP.

Sounds like a personal problem. :)

Bit early to be drinking, isn't it gramps?

Its always happy hour somewhere.