you could just make longer horizontal dropouts.

The reason is simple. Track ends where in use long before shortened chainstays made dropouts impractical. Dropouts came into being to accomodate derailers. Since track bikes don't have to worry about that there was no necessity to switch. Therefore track bikes kept track ends while geared bikes got dropouts. Everything else is just an added bonus.

could we be more incorrect?
 

Although 'flip-flops' have been around for a very very long time, before Derailleurs enabled changing gears.
Racers in the classics ( Le Tour, Giro ) would stop dismount and 'flip' wheeel depending on going UP or Down grades. Changing the number of teeth on the cog would require changing number of links in the chain. Yes, there is some degree of play when changing size of cog but beyond two teeth in either direction ( up or down in number of ) you will be adding or removing links.

I think the original question asked why trackends open to the rear instead of to the front.

On my bike, the rear wheel sits so close to the seat tube I could not move it forward enough to get it off the bike if I had forward opening trackends.

Same here. Plus they are super hot, but don't ask me why I think that. I just do.

Do you have to use a chainbreaker to take your wheel off? Deflate the tire? If so, maybe you should add a link or two.

Thankyou Ken. That, in my view, is precisely the reason.

My track ends open to the rear.
I don't have to do anything special to remove my rear wheel.

In my earlier post, regarding forward/rearward opening track ends, I said on my bike I could not move my wheel far enough forward to remove it, chain or no chain, if I had forward opening track ends.
The chain has nothing to do with it.

Remember the original question?

Why do track ends open to the rear and not to the front?

The answer: because track bikes have short chain stays, and the wheel normally sits so close to the seat post that one cannot move the wheel forewards far enough to remove it with forward opening track ends.
In fact, with forward opening track ends, one could not get the wheel on in the first place.

Chain breaker?
All of my chains have master links.

I have a different length chain for every chainwheel and cog combination I could run, and that way I can put the axle in the middle of the track ends, just about where the seat stays join the track ends.

has everyone forgot about tugs beig a factor in here to keep the chain at proper tension and make it even harder to steal your rear wheel

Chain tugs may get the chain to proper tension, but the axle nuts are what keep the tension.

Also, though I don't know if it was an intended effect of horizontal dropouts, they do give the ability to fine tune the handling of the bike. By putting the wheel all the way back in the dropouts, you lower the bb slightly and extend the wheelbase to give a smoother, more stable ride. By putting it further forward, you raise the bb and shorten the wheelbase a bit, thus giving a more responsive, quicker handling bike.

If your "wheel sits so close to the seat tube [that you can] not move it forward enough to get it off the bike if [you] had forward opening trackends" (by which I assume you mean horizontal dropouts?), that implies to me that your chain is keeping it there, which implies to me that you don't have enough forward play in your ends to loosen the chain enough to get your wheel off without deflating the tire and busting out ye olde chainbreaker (or in your case, whatever irritating little tool you use to deal with irritating little master links).

You have to remove the chain from that pesky little cog before that wheel is coming out of the frame, right?

Yes.

I do.

The answer (in my humble opinion): tradition, aesthetics, and the consequent simplicity of being able to quickly and properly tension a chain when brake pad alignment is a non-issue or when you want to change gearings w/o carrying a bunch of extra links around. Mostly aesthetics and tradition, though.

See, this is what I was asking about. W/R/T rear wheel clearance, I would be very surprised if there was much of a difference between a pista and a road, tri or crit frame with "aggressive" geometry.

Let's pick something pretty for an example:
http://www.classicrendezvous.com/ima...s/Gios_73L.jpg

As you can see, that's a pretty snug fit.

http://www.colonelsbikes.com/pics2/bianchi_pista.jpg

And here's your bike, with the wheel as far forward in the ends as possible. Not much different. With the axle centered, the difference would be negligible.

Soooooooooooo... I respectfully disagree with your assertion that rear wheel clearance has anything to do with it.

you can use chain tensioners with track ends. makes life a lot easier. and your wheel won't come off if your axle bolts come loose.

Look at the Bianchi, above.

If the track ends opened to the front, how would you move the axle forward to get the axle out of the track end?

It doesn't matter whether we discuss a multi-geared bike or a fixed-gear bike.
Given a forward-opening horizontal track end, the seat tube does not allow one to move the axle forward enough to clear the track end.

The chain has nothing to do with it.

Forget about the chain.

Just look at the frame.

No chain.

No cog.

Just an axle, a wheel, a seatpost and a horizontal trackend.

It the track end opens to the front, one could not even put the wheel/axle on the bike.
Unless, of course, one made the chainstays longer, just for putting the wheel/axle on the bike.
Why make the chainstays longer when one can just turn the trackend around, so it opens to the rear?

The chain has nothing to do with it.

Did I mention that the chain has nothing to do with it? :)

=====

Regarding chains, on fixed gear bikes, I have only used chains made for that purpose, and they come already broken, with a master link.
I use a chain breaker to shorten the chain to the length I want, and then thereafter I simply use the master link to disassemble and reassemble the chain.
A master link doesn't need any tools.
A fingernail will do it...though...I use a little screwdriver to save wear and terar on my fingernails.

rustang was right that dutret would be right.. everything else is just a bonus...

...like how sexy they are

mctano: your "not much difference" in the track and road bikes you posted has a frambuilder crying somewhere right now

as i read it, the original question was why track bikes have track end as opposed to horizontal dropouts (the ones on your 70s raleigh, or whatever) not forward facing track ends. it's a little silly to argue in regards to "forward facing track ends" as such a thing does not even exist.

Horizontal dropouts?

I actually had a brand new 1974 Raleigh Grand Prix in 1974. :)
I rode that bike in Portland for a year, before it got stolen.
What a heartache.
That sweetheart cost me $650 in 1974 dollars.
I passed cars on the freeway going downhill on Canyon Drive with that bike.

I don't remember "horizontal dropouts."

In fact, the phrase horizontal dropouts doesn't make sense, to me.
Does trons have a picture of this critter?

I just reread the original question.

I think the poster means forward-angled dropouts, the kind that let you use a rear brake.

Cynikal had it right:

you know, horizontal dropouts http://www.sheldonbrown.com/gloss_dr-z.html

You're saying there's a huge difference with regards to rear wheel clearance between those two bikes? If so, I don't really see it.

m.

I don't think I have any idea what you're talking about. The OP asked about the relative merits of horizontal drops vs track ends; you seem to be talking about a third entity the likes of which I have not seen.

Just throwing it out there:
To me, I see the appeal of track-ends for mountain bikes, ie: they seem to be a much stronger structure. I love SS mountainbiking, and a strong trackend that allows me to tension my chain without any extra parts is very nice.
Also, I don't know how much of a difference it makes, but from my experience, it would seem that a trackend would be easier to achieve proper tension with, because you are pulling the axle straight backwards, rather than backwards and upwards.
Just a thought.

Derailers can be easly put on rear facing track ends with just a little modifing---surely campy could figure this out if derailers were the only reason.
http://i99.photobucket.com/albums/l2...ntley30001.jpg
I modified this derailer to add gears to an old rear facing roadster frame
I still beleave track bikes are working bikes and speed and ease of using rear facing track ends are the reason.Flip the wheel,pull the wheel/chain tight and fix the nuts and back in the race(so to speak)simpler.

you're right. i think you are totally missing what ken is saying.

bike frames with track geometry require track ends, to make it possible to remove the wheel. bikes that have horizontal dropouts have longer chainstays to allow clearance for you to slide the wheel forwards in order to remove it. also, horizontal dropouts are not exactly parallel to the ground, they actually slope down towards the front of the bike slightly. regardless... if you look at bikes from different eras you'll notice how geometry and frame design has changed for specific types of riding. modern road bikes have vertical dropouts now that allow the rear wheel to be very close to the seat tube but still easily removable because the axle simply drops out, no sliding necessary. older frames, and i've noticed this even in track specific frames, have generally longer wheels bases; the front wheel has plenty of clearance and the chainstays are longer, lots of room for wheels to be taken out.

track ends really just make it easy to remove the wheel when dealing with tight frame geometry, and because they are parallel to the ground you're not changing the height of the bb or anything, even if in reality the change is relatively small.

are you people serious? you DONT see a big difference between the clearance of the rear tire to the seat tube here?

the Gios has like an inch of clearance, while you can barely see light through the bianchi...

the bottom line is the same reason why most (esspecialy high end) tri bikes have rear entries... as well as why we now use micro-drops... or vertical drops... tire/wheel clearance to the seat tube....

tri bikes are set up geometricly similar to track bikes in alot of ways... for uber handling at all costs, as well as lower aerodynamic drag (a longer gap between the rear wheel and seat tube will create place for air passing by the bike to build up) and if you look at a quintana roo frame... rear entry drops/track ends are in place... with a derailuer hanging below the slot... and yes they are horrible to change wheels on... but there is no way in the wheel could come out the front in any way, since the seat tube is actualy heavily notched for the tire...

vertical drops allow a similar (but not as drastic) geometery to be had... because the wheel doesnt have to go forward to come out, it can be placed very close to the seat tube... however because it cant go forward or back, we all know we cant adjust chain tension this way... making them useless on SS and FG bikes...

i bring this up because someone is likely to point out the fuji aloha tri frame doesnt have rear entry/track ends... but it does have vertical drops, and doesnt have as drasticaly notched seat tube as a tri bike with rear entry/track frames...

so ladies and gents... the best reason for track ends is to allow tighter geometery... which sheldon brown also mentions in his article... describing why true track bikes are not ideal for street use in his opinion
-pete

I can't believe people are making this so complicated. If you have a road frame which has limited clearance, that would make me ask the question, why DOESN'T this have dropouts that open to the back (track ends). Why wouldn't you want to be able to remove the wheel more easily? Not hard to put a derailleur hanger on a track end, I think.

Road bikes have evolved to vertical dropouts partly because tight clearances made wheel removal a hassle (constant niggle on my Gazelle, I can tell you). You can't do that with a track bike because you need to be able to move the wheel for chain tension. Therefore, track ends. Easy removal, easy tensioning. Track bikes just got there a lot sooner than road bikes.

You can put the hanger there but the issue isn't the hanger it's getting the wheel in with the chain threaded through a derailer. Track bikes didn't "get there first" all bikes where there then a better solution was created for bikes with derailers. And finally an even better solution was created for bikes with modern derailers.

The clearence issue is silly. There is no reason to have dropouts(or trackends) that come so far forward that you can't fit a wheel in them. That space is unusable anyway. If you make a bike with low clearence you just use shorter dropouts or move them further back and not use the back part. If you can't get the wheel out you can't use that part of the dropout anyway so who cares.

Vertical dropouts are about easy wheel changes, no adjustments, no slipping and the fact that modern derailers work well without fine adjustment of the wheel position. Rolling a 23mm tire against the seatube of a frame never meant to use such a large tire in order to get the wheel in isn't a major consideration.