Doug Fattic 

I'll repeat what I wrote earlier that the emphasis on using horizontal dropouts is primarily based on framebuilder efficiency. It is much harder to use vertical dropouts and get a wheel to be right in the center of both the chain stays and seat stays with the limited equipment classic era artisans used. Before during and after I learned how to build frames in Yorkshire in the mid 70's I visited many non-production builders in Europe (including the Taylor Bros). Ellis Briggs where I learned had the best equipment I was aware of but had nothing except spending time to make verticals at a perfect length. Because frames sold in that era for less than $150 a builder didn't have time to fuss.

One option that Shimano came out with (in the late 70's I'd guess) was a semi-vertical dropout with little bitty screw adjusters. Shimano undoubtedly realized the problem and as a result came up with their EF dropouts. This discussion comes up fairly often on the Classic Rendezvous list and most posts come from the buyer promoting the advantages of verticals instead of the disadvantages they require of the maker and as a result the subject thread don't acknowledge the real problem. When the Japanese;started importing their frames they made them with precise fixturing so for them it didn't matter which type of dropout was used.

Here is a picture of a bicycle frame I made in 1980 with Shimano EF semi-vertical dropouts.


Shimano EF semi-vertical dropouts on a custom frame I made in 1980

DiabloScott

1. Vertical dropouts were invented by a grumpy old guy who hated seeing fixed gear conversions.
2. Horizontal dropouts work fine with internal cam QRs, not so much with internal cams.
3. Track ends are not dropouts.
4. There is one other type found on the best classic bikes:

El Chaba

And then there is the best of both worlds……

jolly_codger

A big thank you for the responses; I knew I'd learn something! I won't say I like horizontal dropouts, but at least I can appreciate all of the history behind them. Of course, the first time the axle slips forward on the drive side in reaction to the serious watts I put down () I will have something more colorful to say about them.
John

79pmooney

There's one more though it is really just an offshoot of the horizontal dropout. The "L" shaped horizontal dropout. Opens to the front like a horizontal, then a hard 90 degree turn down. I've heard it was done in the 1930s though I've never seen one or a picture. A framebuilder in the Bay Area, Richmond I believe, built some in the '90s or '00s. I saw one of his at Alpenrose Velodrome set up road fix gear. Jessica J, the TiCycles of my photo has an L shaped cut from plate titanium. All the advantages of horizontal dropouts plus the easy in and out of vertical dropouts and like vertical dropouts, you can run a huge tire that nearly touches the seat tube and still pull the wheel out easily inflated hard.

martl

that thing is a major pita if you want to take out the wheel...
btw Gios used adjustable dropouts on their "compact" frames to allow wheelbase adjustment. whether or not that affected handling in a significant way is another matter but it was a thing.

P!N20

Do you mean something like this?

smontanaro 

I've seen mention of this tool (these tools?) before, have never seen what they look like. Anybody got a picture handy? I came across this blog post which has what I takes to be a picture of the Campy tool, but it's not obvious to me how it would be registered to the frame to keep everything aligned properly. I see the groves for the teeth. Shouldn't it tire into the bottom bracket shell somehow?

​​​​​

JohnDThompson 

I believe that this is the official Campagnolo "Cambio Corsa" dropout tool:

guy153

Agree with everyone who said it was because frames weren't always built that well so it gave you a bit of "wiggle room". I have also seen it claimed that people used to run a fixed gear for winter training to save getting mud all over their derailleurs. Doesn't sound super-plausible to me just on the face of it.

T-Mar

Shimano introduced SIS commercially for the 1985 model year. At that time the vast majority of European pro teams were still using horizontal dropouts. The only exceptions that I recall were were the Vitus based PY10FC of the Peugeot team, the Vitus 979 of the Skil-Sem team and the Alans of the Teka and Varta - Café de Columbia teams.

If you examine 1985 race photos, advertisement and catalogues, you'll find that the the bicycles supplied to the following teams were equipped with horizontal dropouts: La View Claire (Hinault), Panasonic - Raleigh, Lotto (Eddy Merckx), Kelme (Eddy Merckx), Hitachi (Splendor), Sommontana (Bianchi), Carrera (Battaglin), Renault - Elf (Gitane), Ariostea (De Rosa), Malvor (Bottecchia), Gis - Trentino (Moser), Kwantum - Decosol (Colnago), Del Tongo - Colnago, Safir - Van De Ven (Colnago), Atala - Camapgnolo, La Redoute (Motobecane), Fagor (Zeus), Zor (Zeus), Alpilatte (Olmo), Gin - MG (Orbea), Reynolds (Pinarello).

The only major European based pro teams using bicycles with vertical dropouts were those with aluminum or carbon frame frames. The vast majority were still using steel frames with horizontal dropouts. If you look at the bicycle industry in 1985, vertical dropouts were used primarily on non-ferrous frames, grand touring bicycles and ATBs. Yes, there were some exceptions, but the industry as a whole, and road racing in particular, was still overwhelmingly steel frames with horizontal dropouts. Indexing would become the prime factor in reversing that situation.

T-Mar

When I started racing in the eraly 1970s, it was still very popular to use fixed gears for early season training. However, the reason had nothing to do with derailleur contamination, as you were still doing more frequent bearing overhauls and chain cleaning. The reason was to force the legs to be constantly moving, to reintroduce muscle memory for pedaling and get your spin back.

Edit: Back then, n+1 and specialized bicles were rare, except for the well off, so for most amateur racers their competition bicycle was general purpose. About the only fairly common concession, was an extra set of wheels, for training.

smontanaro 

I have one bike with SIS (7sp, Regina America 1992 group), my Univega Super Speciale, made by Miyata I believe. I don't think I've messed with indexed shifting since an Accushift experiment about 10 years ago. Adjusting this bike's hearing it took maybe ten minutes, and I've not touched it since. Strava tells me I've logged over 900 miles on the bike since then. If I can manage to keep indexed shifting running on a bike with horizontal dropouts, you'd think pro team mechanics wouldn't have much trouble. I agree with T-Mar that SIS was unlikely to have been a major driver in the switch to vertical dropouts.

Edit: ​​​​​​T-Mar said the opposite. Keep that in mind. His response to my reply is below.

smd4

I'm good with any excuse to use micro-adjusters on a bike--like the screw adjusters in horizontal dropouts.

T-Mar

But I said just the opposite. Indexing was a big factor in drivng the introduction of vertical dropouts. It eliminated the ability to play around with the axle position, which was one parameter that could contribute to a deterioration of shifting performance.

smontanaro 

My bad. I misunderstood.

zukahn1 

Probably because one could accidentally pop the rear wheel out under hard/emergency breaking if the if everything isn't fully tight.

79pmooney

Yes. (Mine's cleaner, much longer; nearly 2", the 90 degree turn (not more as in the photo) goes into a slot like a vertical dropout. No backward pull required to remove the wheel. You could put in too big a tire, then inflate it hard so the wheel is solidly jammed and you'd still be above to pull it out. Your photo may well be the dropout the Portland fix gear guru told me about when he saw mine. This one is close the dropout I saw at the velodrome in size though that one had an entry like mine.

Now this one also has a vertical dropout forward, That I have never seen before. I'd love to know that that is all about. Looks like it could be a derailleur mount but is so, why would it open down and not just be a secure hole?

79pmooney

[QUOTE=guy153;22491866... I have also seen it claimed that people used to run a fixed gear for winter training to save getting mud all over their derailleurs. Doesn't sound super-plausible to me just on the face of it.[/QUOTE]

Fact. Many of us rode fix gear in the winter. 1970s in Boston, the guru racing, John Allis, the first to race in Europe in the very early '70, swore by winter fix gear training, did it forever and was famous as being hard as nails. I didn't remove the derailleur from my racing bike, I set my other bike up fix gear at the advice of several of my club's veterans. (Winters there were salt, not mud. Not a place you wanted to take your race bike. Few if us removed derailleurs but it we lived in a salt free area, we might well have. I remember hearing of it. And on ice, derailleur-free bikes have another advantage. When you lay the bike down to the drive side on that ice, the bike still works and you can ride it home.)

DiabloScott

It's a skill. Not difficult, but your fingers will get some chain grease on em.


You would think so... you'd be wrong. You'd have to totally bugger up the wheel install to get something to go wrong. Klein invented these things because they're a little lighter and they allow for a shorter wheelbase, but the hub/dropout interface is at least as secure as forward vertical dropouts.

imakecircles

I love horizontal dropouts, to me they are the epitome of design tweaks over the life of a longstanding product resulting in multiple benefits.

They aren't really horizontal, but the angle of them has evolved to be tangential to the rear brake pad mounting bolt. This minimizes as much as possible the amount of both angle and reach adjustment needed at the brake pads when moving the wheel through the range of the dropout.

The additional benefit of their long evolution is that the ride characteristics promoted by the position of the wheel within the dropout are complementary. If I have smaller, lighter tires on the bike and move the wheel to its most forward position, the wheelbase will be shorter, which generally will promote a quicker handling ride. Again, due to the angle of the dropout, this position also results in the rear end of the bike moving up several mm, both raising the bottom bracket and effectively steepening the head and seat tube angles - all characteristics that will make the bike respond faster to inputs.

Conversely, if I wanted to soften the ride, the first things to do would be to mount bigger tires on the bike and move the wheels back, which will increase the wheelbase, lower the rear of the bike (assuming same size tires front and back), slacken the head and seat angles, and provide for a bit more clearance around the rear brake and behind the seat tube. If keeping similar sized tires, this position also allows for more room for fenders for converting a bike to winter training. Again, changing all of these attributes simultaneously is complementary to the desired result.

79pmooney

Interesting take. My ti fix gear with its long dropout has the angle set at 11 degrees which is roughly half a regular dropout to 1) keep the BB height change to a minimum and 2) keep the brake pad on a somewhat deep Velocity Aero rim. (When I slide the wheel all the way forward the pads are completely down on the aero and off the brake tracks. I don't sweat it because how much hard braking to you do riding a 42-24? And with that tiny gear, leg braking is very effective! To hit the more than sedate but hardly radical speed of 25 mph, I have to pedal 177 RPM; not a place I spend a great deal of time.)

The big part of my choice of dropout angle is to avoid lowering the BB any more than I absolutely need to because it is when I am using those tiny cogs that I am doing mountain descents with corners. Striking a pedal there would not be fun. After 20,000 miles, that bike is still the most fun bike I have ever ridden and there isn't one decision from the seattube back that I would tweak at all. It's all a compromise, yes, but a really good one. (I'd push the front wheel 5mm forward to get fender toe clearance.)

JaccoW

One reason why I don't like them (besides broken or stuck screws) is that it gets really annoying if you have to fully deflate the tyre to even stand a chance at removing the rear wheel if you use anything resembling comfortable tyres.

That issue gets extra bad when using fenders on bikes like my Batavus Randonneur with its fenders. 35mm with fenders easily fits but those dropouts probably only work with 22mm strings of rubber.

But then again, I was born in the late 80's when both cars, electronics and bicycles started having tighter tolerances.

MCHunt

Rearward dropout take too long to change the wheel in race situations. I raced Kleins for two years and can tell you from experience of trying to chase back to the group that it is inferior to forward facing horizontal dropouts for races. It's probably fine otherwise, but it still makes it hard to get the wheel out to change a flat.

gugie 

The Bike Butcher of Portland often gets requests to replace horizontal dropouts with verticals.

He has yet to get a request to replace verticals with horizontals.

Vertical positives far outweigh negatives for the majority of usages. YMMV.