Bicycle Mechanics - Specialized Hotrock 16 coaster brake rattle

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samundsen
05-24-04, 11:29 PM
I just bought a brand new Specialized Hotrock 16 for my 4.5 year old son. As soon as we got home and he started riding I heard a very distinct rattle inside the coaster brake. This can also be heard by just lifting the bike and giving it a small bounce.

I took it back to the store (Bike Barn, north of Houston), and they confirmed it came from within the coaster brake. The rattle does not occur if the brake is engaged. Other Hotrocks in the store had the same rattle when given the bounce test on the floor.

The tech in the store told me it was nothing to worry about, just the play in the coaster brake. Tonight I've done some Googling, and it appears that these brakes should have a liberal amount of grease inside, which to me indicates there shouldn't be any room for rattles.

Any good suggestions? I'm tempted to take it back and ask them to take the thing appart and make sure it is properly greased. Unfortunately, the Hotrock was the only bike there that appealed to my speed freak of a son. The only other brand, the Trek Jet 16, just didn't cut it.

Sverre


BikerRyan
05-25-04, 06:44 PM
If the rattle is coming from the coaster brake pads inside the hub grease may work for a few stops but it will soon wear off and the rattle will be back. You see, inside a coaster hub there are these curved "pads" made of metal. They ride around a cone shaped piece that moves left and right inside the hub. When the gear is pedaled backwards, the cone moves left and it forces the "pads" to touch the inside of the hub shell which in turn slows the bike. Greasing the pads would work for a stop or two but the grease would likely just rub off the pad surfaces and the click would be back in no time.

Good Luck,
-Ryan

DieselDan
05-25-04, 08:45 PM
A type-E Shimano coaster brake hub that rattles? Have the LBS adjust the cone on the drive side, as the cone may be too tight aganist the bearing. If that doesn't fix it, as you can't get the rattle to go away without the wheel wobbling, then the bearings need to be repacked. Those hubs are made in large quanities, and sometimes a batch gets through that wasn't greased throughly.


samundsen
05-27-04, 02:22 PM
Well, I took it back to the LBS today and had them take another look at it. They decided to order a whole new wheel from Specialized. Fine with me, even though it's going to take a couple of weeks.