Any reason for the style of rear dropouts

Hi,

To some of you this may seem like a stupid question, but maybe you can help me anyway.
See, I am quite unsure why track dropouts have ended up like they have. What is wrong with the old style of horizontal dropouts? I mean I can understand the difference in road and track geometry, just not the style of dropout...

http://www.sheldonbrown.com/gloss_dr-z.html

"Track Ends" . They're not really dropouts.

Make it easier to get wheel in and out and adjust position. With horizontal droputs you have to push the wheel forwards to get it out, which can involved it getting wedged in / up against the frame.

So the rear wheel has no chance of falling out under the extreme torque they are subjected to with such high gearings as found on the track.

If you have no rear brake, then track ends are the simplest, easiest solution.

As soon as you add in considerations like a rear brake and mudguards, then horizontal dropouts are infinitely superior. Especially for brakes where the angle of the dropout aligns with the brake pad so that moving the axle position doesn't result in a need to realign the pad to the rim.

So horses for courses.

If you have no rear brake, then track ends are the simplest, easiest solution.

As soon as you add in considerations like a rear brake and mudguards, then horizontal dropouts are infinitely superior. Especially for brakes where the angle of the dropout aligns with the brake pad so that moving the axle position doesn't result in a need to realign the pad to the rim.

So horses for courses.

Bang a sensible answer! Depends on the use of the bike. the preferance for trackends at the moment is partly fashion..

If you have no rear brake, then track ends are the simplest, easiest solution.

As soon as you add in considerations like a rear brake and mudguards, then horizontal dropouts are infinitely superior. Especially for brakes where the angle of the dropout aligns with the brake pad so that moving the axle position doesn't result in a need to realign the pad to the rim.

So horses for courses.

how are they simpler than horiz drops?

because on a bike with tight clearances getting the wheel out forward is a lot harder than backwards.

i thought that may have been it.

It's also easier to fit a tensioner to keep the wheel in the same place under high torque riding with a track end than a horizontal drop out. And if the wheel does slip it can't pull out of the dropout on a track end so that's arguably slightly safer.

This is my first message so they won't let me post this as a new thread and this seemed like the most appropriate existing one.

How do I go about getting the back wheel out of a track ends (ie horiz. back facing drop outs)? If I loosen the nuts the wheel is still held in place by the chain tension.

derail the chain.

you should be able to push the wheel forward slightly to give enough slack to push the chain off the chainring, (rather than the sprocket on the hub) then turn the cranks a bit and voila! chain is off.

The other reason is that a track end lets you get the wheel closer to the seat tube for a shorter wheelbase, which qgives quicker handling and is more aerodynamic. The latter reason is why some TT bikes still use short trackends instead of vertical dropouts.

I've never really thought the "wheel slipping out of the dropout" argument stacks up. If your awesome power does move the wheel then it will jam on the chainstay, especially on a track bike with round chainstays (insetad of oval) and tight clearances. You'd have to set the wheel up pretty stupidly in a horizontal dropout to let it pull out completely.

Hence my use of the term 'arguably'. :^)

derail the chain.

you should be able to push the wheel forward slightly to give enough slack to push the chain off the chainring, (rather than the sprocket on the hub) then turn the cranks a bit and voila! chain is off.

I am obliged to you both.

has anyone ever tried to file their rear dropouts..?
I changed my rear wheel and the axle its thick for the dropouts. Probably 2 mm thicker...
Any advice??

file a 2 flats on the wheel axle, some were made this way.

110mm NJS frame?

Which hubs?

has anyone ever tried to file their rear dropouts..?
I changed my rear wheel and the axle its thick for the dropouts. Probably 2 mm thicker...
Any advice??

I've done it on my old Hercules which had the same problem - It's pretty easy. I used a good 2nd cut file. Just take your time to make sure you file both sides evenly. Probably took about 20 mins. I thought about filing flats on the hub axles but decided that doing the dropouts seemed like the better bet in the long run for swapping wheels etc.

If you have to file your frame's dropouts down, it's probably something very old designed for a Sturmey-Archer hub. If the frame's a lightweight, it's a pity to do this, IMO.
But if you are going to file do the bottom of the dropout, otherwise you might have alignment issues.

for the umpteenth time.
ALWAYS file the AXLE first.

+1

The hub is a Formula 120 mm, and the frame is an old Armstrong 531..
I thought of filing the axles, but it seemed to me more difficult to file both sides at the same area..
Probably I'll go with filing the frame and see how it goes... fingers crossed!

Thank you guys!!

If you have to file your frame's dropouts down, it's probably something very old designed for a Sturmey-Archer hub. If the frame's a lightweight, it's a pity to do this, IMO.
But if you are going to file do the bottom of the dropout, otherwise you might have alignment issues.

I've done it on my old Hercules which had the same problem - It's pretty easy. I used a good 2nd cut file. Just take your time to make sure you file both sides evenly. Probably took about 20 mins. I thought about filing flats on the hub axles but decided that doing the dropouts seemed like the better bet in the long run for swapping wheels etc.

thanks guys for the tips!