Cyclocross bike and chain guide

Alek

Am I right by saying that dropped chain happens most often due to the rear mech bouncing when going over a large root or similar obstacle, causing the chain to loose tension at the bottom and "unwrapping" the chainring?

If so, what would be the cons for using this kind of chain tensioner, except for probablility of getting clogged by mud?

smacl

Not a cyclocross person, but I would have thought if there was enough slack for a chain tensioner with all the gears still available, you could increase the chain tension simlpy by removing a link or two. I wonder is it there to raise the chain level off the ground? I've only ever seen tensioners on single speed bikes.

Alek

I have increased the tension already on the mech and shortened the chain, yet I've dropped a chain this morning going down a small rooty hill.

I assume it is used in MTB bikes to protect the chain from going down or sideways - and this is what I need it for. Contact with the ground alone wouldn't do much harm to a chain. Much worse for a mech or chainring

dave2pvd

That will stop your chain jumping off from below the chainring(s). You need one above also. Bash guards alone won't work.

My setup:

Alek

How does it work to prevent the chain unwrapping from the bottom? Somehow I can't imagine it technically.

dave2pvd

The chain is less less likely to leave from the bottom. If it does, it's not a big deal: keep pedaling.

It also helps when you follow Shimano's instructions re chain length.

Alek

I've tried to install an equivalent DIY solution yesterday, and gave up - there does not seem to be a lot of room on a CX frame... I've shortened the chain even further, applied more tension to the deraileur and now I hope for the best The chain does not bounce much now, even when dropping the the bike from some height.

lennymc

narrow wide chainrings are supposed to be good

Alek

I'm on a tight budget recently so keeping the cost of upgrades as close to 0 as possible.... Especially after getting a new tubeless wheelset for CX :P :P

rollingscone

Alek wrote: »

I'm on a tight budget recently so keeping the cost of upgrades as close to 0 as possible.... Especially after getting a new tubeless wheelset for CX :P :P

What happened to getting lightweight road wheels?

Alek

I decided to go for the same set as I already have, mostly for convenience. They are good, stiff, medium weight wheels (1800g), fully tubeless (no holes in the rim bed) and just in case I can swap parts between them. And cost only 270e, while DTSwiss R23 DB would be over 400e, being less than 200g lighter and not as robust.

dave2pvd

Alek, the thing that will make you faster in CX than any equipment upgrade is not dropping your chain. You won't get away with the arrangement you have now as it does not capture the chain from popping straight up off the top of the chainring.

If your bike has a round downtube, there are several options. In a futile attempt to save money, I think I tried every single one of them on my pitbike. Had I known, I would have just gone ahead and bought the Paul's Components catcher at the beginning.

Lusk_Doyle

lennymc wrote: »

narrow wide chainrings are supposed to be good

Does not compute?

Alek

you won't get away with the arrangement you have now as it does not capture the chain from popping straight up off the top of the chainring.

I have actually managed to botch a mini chain keeper mounted above the chainring - something alike the one below, just with much smaller rings. Kindof Hopefully it will not allow the chain to raise enough above the chainring teeth to disengage.

lennymc

Lusk_Doyle wrote: »

Does not compute?

one tooth narrow one tooth wide. All the rage in the 1* community. Along with clutch derailleurs. I do know of someone running an xt (i think) clutch derailleur with a narrow wide chainring and standard road shifters.
edit - Pauls components are highly regarded as being very good.

Lusk_Doyle

lennymc wrote: »

one tooth narrow one tooth wide. All the rage in the 1* community. Along with clutch derailleurs. I do know of someone running an xt (i think) clutch derailleur with a narrow wide chainring and standard road shifters.
edit - Pauls components are highly regarded as being very good.

I see...I think I so anyway!

lennymc

Lusk_Doyle wrote: »

I see...I think I so anyway!

http://www.pinkbike.com/news/Race-Face-Narrow-Wide-Chainring-Tested-2013.html

Lusk_Doyle

lennymc wrote: »

http://www.pinkbike.com/news/Race-Face-Narrow-Wide-Chainring-Tested-2013.html

Ok. I'm up to speed with all the new fangled technology now. I'll stick with my compact setup on the cx bike and see how it goes for now.

lennymc

you on a cx bike. That should be funny.

Lusk_Doyle

lennymc wrote: »

you on a cx bike. That should be funny.

Find out tomorrow.

lennymc

Unfortunately I will miss tomorrow.

Lusk_Doyle

lennymc wrote: »

Unfortunately I will miss tomorrow.

It will still happen though.

comete

lennymc wrote: »

one tooth narrow one tooth wide. All the rage in the 1* community. Along with clutch derailleurs. I do know of someone running an xt (i think) clutch derailleur with a narrow wide chainring and standard road shifters.
edit - Pauls components are highly regarded as being very good.

Think I know the fella, absolute top bloke. His is an older xt rear mech, without a clutch I think, but he has the tension wound up and as few links as possible in the chain, hasn't dropped a chain yet but racing might be a different story.