This weekend at Jingle Cross I destroyed a derailleur Friday night and a hanger Saturday. Lots of other people had the same problem. Many riders had repeat failures while others had no issues. What causes this specifically, many theories were tossed around. What can be done to prevent. The course was grass at first but turned to mud and grass shortly. There was also a section of pea gravel after a muddy area.
This is something that I have seen a lot of on courses where there is a lot of grass or leaves/pine needles and mud. The vegetation binds with the mud and keeps building at an exponential rate until things explode. The best thing that I know is to pit often and spray everything down repeatedly with Pam or another spray. You really have to hit basically the entire back end of your bike...
Thanks, great suggestions..But, why does this not happen to Mt. bikers? What is it about the cyclocross drive train? This makes for an expensive weekend and most do not have pit bikes or people to man them.
Perhaps a mud shedding device before the chain enters the jocky pullys?
The most common issue I've seen this season here in New England and Mid-Atlantic is guys trying to shift for that extra gear beyond the 25/27/28/whatever-is-your-highest-gear-that-doesn't-really-exist. The derailleur built up with mud catches a spoke and BOOM everything is in pieces. The clearance between the derailleur and the spokes isn't very much to begin with and once you reduce that even further with a frantic shift on a mud clogged derailleur you're asking for catastrophe.
The solution is the PAM one if you don't have a pit bike. Davide Frattini (he won the hole shot at Mercer) uses it extensively on his bikes as he doesn't always have a pit guy there, but always has his two bikes. He gets a little build up on the bikes, but not as bad as non-PAMed bikes.
yes, thanks. On day two I was worried about my derailleur and when I felt it being sucked into the spokes I resolved to keep it out of my lowest gear, after that I had no more incedents. Next muddy race ( in addition to the pam) I think I will set the limit screw to keep me from going into my 27 and perhaps put a 39 chainring in place of my 42.
Pam, a well lubed drive train, a properly adjusted drive train, and proper mud/grass portaging technique. I saw way too many racers pushing their bikes at Jingle Cross. You want to keep your bike out of the muck - grass, mud, clay, leaf mess - as much as possible. Pushing your bike through that stuff causes an even bigger build up of excess matter - pick it up and shoulder it through the really sticky, messy stuff - I am thinking all the grass at the top of the hill on Saturday after coming up the steep sloppy peanut buttery run up on Mt. Krumpit.
As far as post race clean up with PAM. It's really no different than any other post race cleaning. Do no use PAM on your chain and don't get it on the braking surface of your wheels. Otherwise a good coating on the downtube, behind the bottom bracket , under the fork crown, and on the backside of the seat tube and seatstays will keep the muck off for a little while. The PAM trick doesn't work all that great in sticky/clayish mud with lots of grass, it works much better on Mud with more moisture and less organic matter.
The night before I head off to a race I wipe my frames down with Armor All wipes, Pledge, or Bike Lust. It puts a nice coating on the frame that make it much easier to clean and as a bonus you roll up to the line with a nice shiny bike.
You got it right Mike. I was standing at the base of the descent on Saturday and many, many riders reached the bottom and promptly found their derailleur broken off when they started to apply power. Mud+grass+more mud is pretty effective for making that happen.
I raced both Saturday and Sunday with no derailleur problems, but I did see alot of people carrying their bikes back with broken ders and hangers. I dont know if this actually helped or not but anytime I came to standing water I'd hit it as hard as I could and try to cleanout some of the mud. However Im just a Cat 4 racer so I have really no idea. LOL