Chain keepers on Tour bikes

[kiwirider]

Have been wondering for a while ... how come so many of the teams in the Tour are using chain keepers on their bikes?

I mean, wasn't that long ago that the only time you'd see them on roadies was during the spring classics (cobbles and all that). At the moment, they seem more commonly used in the road peloton than they are by cross racers.

I am currently living in a country renowned for crap road surfaces and don't have any problems with jumping chains on my Record 10 equipped road bike. Similarly my crosser (also Campy 10) and my MTB (XC bike with SRAM X.0) don't have chain keepers - and I have no problem with dropped chains. So, how come the need for them in races where - in comparison to where my bikes are taken - the road is smooth as?

I know that some people will cite Andy Schleck's "little issue", but to my mind, that's more an issue of chain slipping on the chainring while shifting under load that I doubt if a chain keeper would've actually helped with ... (ie., wasn't actually a dropping off of the chain) ...

Be interested to know what theories people have ...

 

[RDV4ROUBAIX]

Chain keepers are xtra insurance.. No brainer.

I don't know that what happened to Schleck is entirely his fault, you could blame the Saxo wrenches for that one. Remember Cancellara breaking a chain last year at De Ronde? That didn't happen because he's a quadzilla, it's because the mechanic didn't replace the pin right when reducing a new chain to length. Looks like Saxo could use some new mechanics.

 

[twothirds]

Like RDV said, it's extra insurance. Plus with the bikes being so light these days, easy way to put some "functional" weight fairly low in the bike, even though it's maybe 10 grams.

 

[forty four]

the k-edge is 10 grams im getting one for my sl2 sworks if the chain comes off and gets jammed in between the frame and crank it can be very hard to remove and could damage the frame or chain. besides that once its stuck between the frame you have to dismount to fix it and cannot use the front derailleur to get the chain back on very lame imo. my fuji has clearance so no issue there the chain cant bind up. but on most new carbon bikes it can and will get stuck.

 

[kiwirider]

Chain keepers are xtra insurance.

Yeah, I know that ...

But that's not actually my question ... Perhaps I should've written it as:
Why the perceived need for the extra insurance of a chain keeper on what are essentially (the stage into Arenberg excepted) smooth roads? What has changed in bike drive trains over the last few years that makes riders/mechanics/teams think that they need this extra insurance?

 

[RDV4ROUBAIX]

Why the perceived need for the extra insurance of a chain keeper on what are essentially (the stage into Arenberg excepted) smooth roads? What has changed in bike drive trains over the last few years that makes riders/mechanics/teams think that they need this extra insurance?

Chains are thinner, less margin for error when setting up modern drivetrains. Don't assume that if you're on regular tarmac it's always smooth. As we have just witnessed a lot can happen over a month of racing, not just in the Arenberg.

Hey Team Saxo Bank; Have skills, will travel. Call me.

 

[ElChingon]

Back to the original question.

The chain keepers are useful because you are not always shifting in a perfect situation, which would be the bike is perfectly perpendicular to the ground and you are not always in a position to gently, smoothly shift it up or down.

In the event that you are not in a perfect position to shift and you need or want to shift the bike maybe going over rough road, a bump or you maybe attempting to accelerate and maybe even jump the bike a bit, then you might also have the bike at an angle other than perpendicular to the road due to the conditions of the ride. In that event it (chain keeper) will keep the chain from shifting off the small chain ring by preventing it from going down past the small chain ring. Because even a perfectly tunned front derailure can fail or allow a chain to fall off the small chain ring if given the wrong situation.

In Andy Schlecks case the front derailure was properly tuned or so we will assume since none of us can go see for our selves if its not. Under the race condition when it fell there was a picture taken:

Link to High Res Version: High Res Picture

Here's a close up examination of that:

Andy had attacked in the big chain ring and either the 13 or 14 rear cog, at this point there was some cross chaining going on but ok by usual terms but the chain was still under high tension under his attack and he's going up hill so that alone has the chain under higher tension than normal. Then he attempts to downshift after his initial attack to then proceed at a high spin (I'm assuming). Under these conditions and maybe he had the bike at a slight angle when he initially shifted (? need video) the chain dropped past the small chain ring. Now anyone of you can try this at home to see if it is possible because I know it is and was probably the choke of the race for him or at least for losing the yellow jersey on this stage.