L
Luke
Guest
Several months ago I did a Google search on the subject of running fixed gear cogs without
lockrings. There are quite a few threads - some quite contentious - on the subject.
I planned to lace up a wheel using an old Phil BMX hub and install it on my FG messenger bike. After
the wheel was completed, the hub's threads' were lightly greased and the cog was tightened as hard
as possible with a chain whip and installed on the bike. The front of the bike was then wedged in a
corner and I bounced on the cranks as an added measure. The cog didn't budge.
I run a 48t chainring with the 15t cog (bit of a masher here) and weigh in at 175 lbs. I considered
adding a BB lockring - as was recommended by some of the previous posters on the subject - but
*didn't think* it was necessary.
And there the matter stood. The setup performed flawlessly for several months, 8 hours a day, 5 days
a week - until a week ago that is. I was riding along at approximately 20 km/h, slowly
de-accelerating by lightly back pedallng when I heard a "pop" and found myself freewheeling. Since
the FG has brakes it wasn't a problem stopping.
I was surprised the cog would unscrew with such little force. Even though on numerous earlier
occasions I had locked the rear wheel by forceful back pedalling, the cog had never once unscrewed.
So why had it now? Maybe the continual vibrations and jarrings of daily use had more of an loosening
effect than anticipated? I'm wondering about how much of a role temperature plays. On the day, or
rather evening, the cog unscrewed the temperature (in Toronto) was -18 degrees Celsius. It was cold!
The Dura Ace cog is steel and the Phil hub body aluminum. Perhaps the two metals' differing rates of
temperature related contraction and expansion factored into the result.
A BB lockring - loctite secured - has now found it's way onto the hub. Of course it's not a true
locking but I'm hoping it's enough to keep the cog tight.
Luke
lockrings. There are quite a few threads - some quite contentious - on the subject.
I planned to lace up a wheel using an old Phil BMX hub and install it on my FG messenger bike. After
the wheel was completed, the hub's threads' were lightly greased and the cog was tightened as hard
as possible with a chain whip and installed on the bike. The front of the bike was then wedged in a
corner and I bounced on the cranks as an added measure. The cog didn't budge.
I run a 48t chainring with the 15t cog (bit of a masher here) and weigh in at 175 lbs. I considered
adding a BB lockring - as was recommended by some of the previous posters on the subject - but
*didn't think* it was necessary.
And there the matter stood. The setup performed flawlessly for several months, 8 hours a day, 5 days
a week - until a week ago that is. I was riding along at approximately 20 km/h, slowly
de-accelerating by lightly back pedallng when I heard a "pop" and found myself freewheeling. Since
the FG has brakes it wasn't a problem stopping.
I was surprised the cog would unscrew with such little force. Even though on numerous earlier
occasions I had locked the rear wheel by forceful back pedalling, the cog had never once unscrewed.
So why had it now? Maybe the continual vibrations and jarrings of daily use had more of an loosening
effect than anticipated? I'm wondering about how much of a role temperature plays. On the day, or
rather evening, the cog unscrewed the temperature (in Toronto) was -18 degrees Celsius. It was cold!
The Dura Ace cog is steel and the Phil hub body aluminum. Perhaps the two metals' differing rates of
temperature related contraction and expansion factored into the result.
A BB lockring - loctite secured - has now found it's way onto the hub. Of course it's not a true
locking but I'm hoping it's enough to keep the cog tight.
Luke