Mountain Bike Reviews Forum banner
1 - 12 of 12 Posts

·
mmm
Joined
·
947 Posts
Discussion Starter · #1 ·
How do I prevent this? (pictures below) My maiden voyage resulted in my chain coming off my crank as I biked off a street curb causing me to flip over my handlebars while spraining my knee. It was pretty funny as I look back.

With a little more knowledge and a bruised ego I've since then did my best to align my chainring/cog combo and shortened the chain by two extra links. Is there anything else I can do to prevent future mishaps? Thanks.
 

Attachments

·
Hit The Road Cyclery
Joined
·
920 Posts
Yeah, get a flat SS specific chainring. The shift "gates" and profiled teeth on a middle ring from a triple crankset are intended to help the chain jump off, you'll never keep it on with that ring.
 

·
Premium Member
Joined
·
48,161 Posts
-Anomie- said:
Yeah, get a flat SS specific chainring. The shift "gates" and profiled teeth on a middle ring from a triple crankset are intended to help the chain jump off, you'll never keep it on with that ring.
I do not call straight cut rings and cogs SS-specific because they were made and used on gearies for many years. I use straight cut rings on my 2x9 Coiler.

The ramped and pinned stuff is "gearie-specific".
 

·
mmm
Joined
·
947 Posts
Discussion Starter · #9 ·
Ratt said:
Can you take a picture of the chainline from the rear, wondering how far off you are if you are off at all.
Here are pictures POST-fall. It looked a little off so I respaced the rear cog to the left one spacer. Since then I've also shortened the chain 2 links and flipped the chainring around.
 

Attachments

·
viva la v-brakes!
Joined
·
2,435 Posts
a little off still

Looks to me like your chainline is still off a hair, the rear cog should be 1 - 2 mm futher in towards the wheel, based on your last photo.

I'm wondering if you've ridden this since you've made the tweaks to the chainline and reversed the chain ring. We're trying to build my wife's old bike up cheaply, and I'm hoping to get away with a ramped and pinned front chainring. Any luck?
 

·
mmm
Joined
·
947 Posts
Discussion Starter · #11 ·
FishMan473 said:
Looks to me like your chainline is still off a hair, the rear cog should be 1 - 2 mm futher in towards the wheel, based on your last photo.

I'm wondering if you've ridden this since you've made the tweaks to the chainline and reversed the chain ring. We're trying to build my wife's old bike up cheaply, and I'm hoping to get away with a ramped and pinned front chainring. Any luck?
It's been ridden around the street but nothing too serious. I'm still waiting for my knee to heel.
:eek: Goodluck with your conversion.
 

·
Flyin Canine
Joined
·
2,258 Posts
If it happened when you jumped off the curb I would say maybe the xt rear derailluer is not keeping the chain tight enough to keep the chain from jumping off the ring. Bad chain line may be only part of the problem here. Rear derailluers are used to getting help from the front derailuer cage to keep this from happening. If you're not fully commited to singlespeed yet, try putting your front derailluer back on and setting the limit screws so that it keeps the chain from falling to the side. That way even if the chain flops around it will be more likely to fall back onto the chainring than off it. It you want to spend a littl money then get a surly singleator or something similar and scrap the xt derailluer. The singleator provides more spring tension and should do a better job.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top