Info on rear dropouts
09-11-07, 04:50 PM
#1
Senior Member
Thread Starter
Info on rear dropouts
Just took alook at the Campagnolo dropouts on the second Mondia purchased last week. They aren't the horizontal style. More vertical. Can someone enlighten me on this style? Why use it vs. horizontal?
09-11-07, 05:38 PM
#2
Senior Member
Join Date: Nov 2004
Posts: 23,223
Mentioned: 654 Post(s)
Tagged: 1 Thread(s)
Quoted: 4722 Post(s)
Likes: 0
Liked 3,036 Times
in
1,874 Posts
1. The rear wheel cannot be pulled forward under hard accelerations, if the skewer is not properly tightened. With horizontal dropouts, if the wheel is pulled foward, the tire will rub on the left chainstay and quickly bring you to a stop. This is a minor inconvenience, unless you are racing, in which case, you just lost.
2. When the wheel is placed in the frame, it will automatically centers the tire between the chainstays. This is very important for wheel changes during races. However it requires proper dishing of the rear wheel and closer manufacturing tolerances for chainstay length and rear triangle alignment.
3. The rear wheel will track directly behind and in line with the front, subject to the last sentence in the above paragraph. In horizontal dropouts, if the there are dishing or alignment issues, the wheel can be canted sideways to compensate for a non-centered tire. The rear wheel will then sit an angle to the front and causes premature rear tire wear. The axle also does not sit square with the dropout causing bending stresses and premature axle failure. In extreme cases, handing will be affected.
3. The distance of the axle relative to the derailleur mounting bolt is fixed at its optimum position to ensure proper chain wrap and gap. This is critical for proper operation of modern indexed derailleurs.
4. It fixes the wheelbase and chainstay length, preventing cyclists from experimenting with the designer's geometry.
2. When the wheel is placed in the frame, it will automatically centers the tire between the chainstays. This is very important for wheel changes during races. However it requires proper dishing of the rear wheel and closer manufacturing tolerances for chainstay length and rear triangle alignment.
3. The rear wheel will track directly behind and in line with the front, subject to the last sentence in the above paragraph. In horizontal dropouts, if the there are dishing or alignment issues, the wheel can be canted sideways to compensate for a non-centered tire. The rear wheel will then sit an angle to the front and causes premature rear tire wear. The axle also does not sit square with the dropout causing bending stresses and premature axle failure. In extreme cases, handing will be affected.
3. The distance of the axle relative to the derailleur mounting bolt is fixed at its optimum position to ensure proper chain wrap and gap. This is critical for proper operation of modern indexed derailleurs.
4. It fixes the wheelbase and chainstay length, preventing cyclists from experimenting with the designer's geometry.
09-11-07, 06:48 PM
#3
Senior Member
Thread Starter
Wow! Outstanding answer, T-Mar. Thanks. Could those dropouts have influenced the previous owner to convert this Super Mondia to a hybrid configuration? Has a Sugino triple up front and a Campi Nuovo Record long cage RD. Standard Araya 27" alloy rims, Campi LF hubs. Whadda ya think? Thanks again.
