SkinGriz

I know nothing about road bikes other than what can be casually observed by someone who grew up riding BMX bikes.

This question has probably been asked...

Why were all the top tubes on old road bikes parallel with the ground?
Am I misunderstanding something or over generalizing?

Thank you.

alo

With a lot of modern bikes, the top of the seat post is kept low so short people can ride them. Tall people can use a long seat post and ride the same bike. So manufacturers make bikes to fit a wider range of people, instead of having a wide range of frame sizes. In the past there were a wider range of frame sizes. This might not be true for all manufacturers.

In the old days, there were boys bikes with high bars and girls step through bikes. Step through is ideal for girls wearing skirts or dresses. In Asia it is still common for girls to ride bikes to school or work. Having a low bar, means the same bike can be used for boys and girls, instead of having two different frames.

Having a lower bar makes it easier to get on and off.

A horizontal bar may have a very tiny aerodynamic advantage.

merziac

Old school vs new school, new frames with sloping top tubes fit more people with less sizes, all of a sudden, 3+ fistfulls of seatpost is ok.

Win, win for bike companies, smaller frames, less material, new tech = $$$$$.

Rolla

BITD, bikes were made in many more sizes than current ones are; some manufacturers offered frames in 1cm size increments. Since you would size a bike based on the standover height, the top tube could be parallel to the ground and still give you plenty of crotch clearance. In many cases, the seat tube measurement would be the same as the top tube, so you ended up with a 54cm X 54cm frame, for example.

Nowadays, frames are increasingly sized like T-shirts: S, M, L, XL. To make that work, manufacturers have to slope the top tube to achieve standover clearance for a much wider range of rider inseam lengths. So you get bikes with a 51cm seat tube and a 55cm top tube, and you use the seatpost and stem to dial in the cockpit.

Some claim that a compact frame with a sloping top tube is lighter and stiffer, but material and design are also factors there.

SurferRosa

Modern consumers do not value classic beauty.

repechage

Turn of the previous century, 1899-1900
plenty of up sloping top tubes
blame the racers later
some bikes even came with adjustable bars via serrated joint halves.

Trakhak

Blame racers for what?

Bike frames were initially brazed/welded without lugs, using tubing that had to be carefully mitered to fit together at the tube ends. The use of lugs was then introduced as a cost-cutting measure to eliminate the need for the time-consuming mitering step (or at least to reduce the need for precise mitering).

Building bikes with a horizontal top tube and parallel head and seat tubes helped reduce the range of lugs a bike manufacturer would have to keep in stock. In fact, for the vast majority of bikes (i.e., for the utility bikes used for transportation rather than for sport riding or racing), one set of lugs would suffice for all sizes, with longer or shorter head tubes and seat tubes used for taller or shorter riders and tubes of unvarying length used for the top and down tubes. Further simplifying production, utility bikes were usually manufactured in at most two or three frame sizes.

Drop bar racing bikes were of necessity manufactured with smaller increments between frame sizes and with varying lug angles and tubing lengths, but the practice of maintaining a horizontal top tube eliminated at least that variable. Standardization!

Oh, and BMX bikes, which came along much, much later, were cheap to manufacture without lugs because, although precise mitering of the tubes was required, the bikes were usually built in only one size, which meant that manufacturers needed only one complete set of mitered tubes in inventory.

nlerner

Back in the day, we liked the occasional collision of a steel level top tube and our junk.

SkinGriz

On a BMX bike the pedaling that matters is done when standing up. Maybe that might self correct size issues a bit.

On a road bike, it seems size of the frame would be important.
I have longish legs, arms, broad shoulders and a relatively shorter torso.
If I was to ride a road bike for distance, might need to get fitted for a bike.

beicster 

Kids these days are soft

ClydeClydeson

Mentioned above, when frames were primarily constructed with lugs, all the tubes needed to have similar angular relationships to each other. It was an economic decision made by bike manufacturers ~100 years ago so they didn't need dozens of different lug designs. TIG welding, and frame materials other than small diameter steel tubes made lugged construction obsolete.

SkinGriz

To make that work- were there also many steering tube lengths and fork stem lengths?

ClydeClydeson

Yes there were. Even aftermarket forks were available in many steerer tube lengths with standard threading for a headset. Shops generally had a die set for threading forks, but this was generally saved for a last resort when you couldn't find a fork to fit. I don't know if the manufacturers made the forks with pre-cut and -threaded steerers or if they made one length and cut and threaded to fit.

Threadless headsets was touted as a way to make your bike lighter but I'll bet the fact that it allowed manufacturers to simplify inventory was the real reason they adopted it.

cyccommute 

Except there aren’t fewer sizes. Trek’s 1983 catalog lists road bikes in 19”, 21”, 22.5”, 24”, and 25,5” sizes. Occasionally, there may have been a 22” frame in the mix. Today, Trek road bikes come in 44cm, 47cm, 50cm, 52cm, 54cm, 56cm, 58cm, 60cm, and 62cm sizes. The 44cm is listed In women’s sizes but is available to everyone. That’s 9 sizes vs 5 from “back in the good old days”.

From the standpoint of someone who has fought long and hard in the “Size Wars”, I can tell you that it’s a whole lot better now than it was back when people told my 5’ tall wife that a 19” frame was “close enough”. A 44cm is probably too tall for her but it’s far closer. And, if you think that close is “close enough” go out and ride around on a frame that is 7 to 9cm (3” to 4”) taller than what you usually ride.

A lot of the reason that 3 fists full of seatpost is possible is that the material used to make the seatposts are so much better. Mountain biking changed the way that we use bicycles significantly. An SR Laprade seatpost from 1984 just wasn’t up to the stresses demanded by bicycles that had to be smaller for obvious reasons. The walls on the old Laprade post was almost thick enough to qualify the post as a billet rather than a tube. Even then, they didn’t hold up to the bending stresses put on them. I’ve even bent steel seatposts. New materials allowed the posts to be thinner, lighter, and stronger than those old posts.

Yes, but not for the reasons you think. Smaller triangles on the frame as stiffer and the ride is more responsive. It’s more enjoyable to ride a stiff frame than it is to ride a noodly frame. Less material also means less weight. Less weight means the bike is more fun to ride. New technology also makes the bike easier to use and, again, more fun to ride.

Friction shifting is a royal pain. As a kid, I was told by every other kid who was riding a multi gear bike “don’t shift” because friction shifting clatters and clunks and sounds like the bike is going to break. When I got my own multi gear bike years later, I did learn to shift fairly well but I completely understood the problem. Unless you are bold and aggressive, shifting with friction makes a whole lot of noise.Today, I click and the bike shifts. I don’t have to worry about trimming the shift. I don’t have to constantly adjust. I don’t have to do anything other than enjoy the ride and shift when and where I want to shift.

Yes, new bikes cost a lot but the price isn’t nearly as bad as many people think it is. Sure there are $20,000 super bikes but the less expensive “regular” bike is a great value for a good machine that works better, for less, then bikes from “back in the day”. People seldom take inflation into account when considering costs. I paid $500 for a Miyata Ridge Runner in 1984. It was the top of the line mountain bike in the Miyata line because it was the only thing in the line. In 2021 dollars, that’s $1300. $1300 today buys a hell of a lot better bike! A Specialized Rockhopper Expert cost $1250, has an air shock and a much lighter frame than the Ridge Runner. It’s also a much more capable mountain bike machine.

All that stuff you pooh, pooh may make the companies more money but it also makes for a more accessible and more enjoyable bicycle experience for the riders.

merziac

If you say so.

repechage

The Racers led the fashion. They gravitated to level top tubes to lower drag, wind resistance.
Lugs came later.
Some design attributes really took a long time to vanish, the very slack seat tube remained long after it was nullified by the "7" seatpost that allowed the saddle to move closer to the bottom bracket in forward displacement.
A large percentage of utility or pleasure bike riders did not need a level top tube, but that is what they got.
The "type forming" of a typical bike had never stayed constant since the early 1900's, level top tubes did endure for a long time, lots of other things changed.

pcb 

IME, modern compact road frames were an attempt to use marketspeak to justify a smaller run of frame sizes. After a year or two it became apparent that mfrs needed more than just 3 or 4 frame sizes regardless of top tube angle. At that point it was too late to abandon the marketspeak justification for the new/improved design, so they kept on keeping on with the marketspeak and just as many different frame sizes. I'm talking about the modern inception of this design, now 20yrs ago.

To be fair, in our current world of exploring gravel/sketchy surfaces at speed, and many of us enthusiasts aging, it's not a bad thing to have a frame with generous standover clearance that can still get handlebars up into our aged comfort zone.

I speak only for myself, though. And I stubbornly insist on the Swinging Leg Mount, so a sloped top tube doesn't make it any easier for me to get on/off the bike. I'm sure that will change as my hip sockets disintegrate further.

repechage

Interesting perspective I think has a bunch of holes, but a more basic question, this is the Classic and Vintage section of Bikeforums, why are you here?

cyccommute 

Some. Most after market threaded forks were threaded far down the tube (and had a key way cut for the tabbed washer) and then cut to length. During manufacturing, the threads are usually cut to the size of the frame. I see this a lot of used forks where a fork for a 49cm bike is threaded differently from a 60cm fork. Just the top of the fork is thread for each which means using the 60cm fork on a 49cm frame would mean not just cutting off the fork but also threading a lot of it and grinding in a key way. Cutting threads on a fork is not all that easy to do by hand, either. It’s a lot of work to thread on 7 or 8 cm of thread.

The reason for OEM forks having different threading is that the fork was generally painted to match the frame so they didn’t really need to thread all that much of the steer tube. It’s cheaper to thread only a little bit of fork than a whole lot.

I know it’s popular to engage in conspiratorial thinking but it’s often wrong. Threadless isn’t to make the bike lighter, it’s to make the headset more durable. In the days of early mountain biking and threaded headset, the extra pounding that the headset endured was hard on headsets. The greater magnitude and duration of the vibration during mountain biking caused the threaded headsets to loosen. It was easy to ruin a headset on a single mountain bike outing because it’s not all that easy to field repair a loose threaded headset. During the late 80s and early 90s, there was an extensive cottage industry of threaded headset locking top nuts around to “solve” this problem. They were mostly useless and expensive.

I often replaced headsets several times a year in those early days. A headset press was actually one of the first “real” bike tools I bought and it has been very well used over the last 30 years. I also spent a lot of money on replacement headsets over those years. And before you go saying “but you just didn’t know how to do it properly”, I assure you that I was not the only one having the problem. It was a very common complaint...see the note about locking top nuts above.

The development of the threadless headset was a miracle! I went from constant replacement of headsets due to damage to zero replacements due to damage. I replace them no for upgrades but I haven’t had to replace one for any other reason in more than 25 years. I have Chris King headsets that are in excess of 20 years old. If I replace a King now, it’s because I want a different color headset...not because it is damaged.

Threadless is also superior when it comes to service and adjustment. A threaded headset adjustment is a hit and miss affair. It’s usually too tight or too loose and finding the “just right point” requires lots of iterations to get it right. For a threaded headset, the orders of operation are, tighten the top race and the top nut, check the bearing adjustment, (probably) loosen the top nut, reposition the top race, and repeat as needed. It’s also an operation that is difficult to perform outside of a repair stand but the check of the bearing load is difficult to assess in the stand. So add multiple steps of removing the bike from the stand and putting it back in. It requires multiple dedicated wrenches to do that adjustment as well.

Compare that to a threadless headset. Loosen the stem, tighten the top cap just a little, check the bearings, adjust if need, and tighten the stem. All done with a single 5mm Allen wrench. It can even be done in the field if necessary, although field adjustment is seldom required.

I teach a mechanics class at my local co-op. On headset night, I have the students disassemble headsets, completely remove them (cups and crown race), install into the frame, reassemble, and adjust the headset. I do threaded and threadless side-by-side and make each student do each one. I try to make them do the threaded first and then the threadless. To a person, doing the side-by-side, they all realize how much easier the threadless is than the threaded. I’ve taught a couple of hundred students by now and not a single one has preferred the threaded.

Finally, I tell my students a story about how quick and easy threadless is. I got a new suspension fork in the mail and want to use it for the next day’s ride. The Colbert Report came on at 2130 MDT here in Denver. The interview part of the show started at 2150. I grabbed my fork; took it out to the garage; removed the wheel; dropped the old fork; stripped off the brakes; pulled the crown race; installed the race and brakes; installed the fork, stem, and top cap; adjusted the bearing load; tightened the stem; and hung the bike back up on the wall. When I came back in, the 10 o’clock news was just starting. That’s 10 minutes to do a fork swap. I know I couldn’t do it that fast with a threaded headset.

Threadless...like much else in bicycling...may be better for the manufacturer but it is also better for the consumer.

cyccommute 

Why are you here? Classic and vintage covers a lot of bicycling. Sloping top tubes aren’t new as you, yourself, pointed out. Their modern usage goes backs to the early 90s. Other improvements in technology fit squarely in the “classic” and “vintage” categories. Suntour had an index shift system in 1969...that’s way older than what most people here post as vintage or classic. Shimano introduced the Positron system in 1977...again, older than most vintage bikes posted here. SIS (Shimano Integrated Shifting) was introduced in 1984. STI (Shimano Total Integration) is from 1990. Both are well within the category of classic and vintage. Threadless headsets are from the same era. Jim Rader was showing his threadless headset to anyone who would listen at the 1990 mountain bike World Cups in Durango in that year.

In fact most every innovation over the last 30 years have come from mountain bikes. One could say that the “classic” part of mountain biking is from 1990 to present. Very little new technology has come out of road cycling.

Since I’m on a tear, why am I here? Because I appreciate bicycles. I appreciate bicycle history. My bikes aren’t as old as some but I don’t have that many new bikes. My newest bike is a 2010 Cannondale T1. That, by its self, is a classic. It’s one of the last Cannondale touring bikes made in the US and almost one of the last touring bikes they make, period. My other bikes are late 90s or early 2000s mountain bikes. Those can also be considered vintage or classic. Two of them are fine examples of late 90s small shop titanium mountain bikes...Moots and Dean. Two of them are examples of one of the best bicycle suspension systems ever invented...the Specialized Brain.

Further, I’m not a huge fan of most modern bikes. I’m not against technology but the technology has to make things better without making it too complicated with respect to bicycles. Threadless headsets, suspension forks, better materials, index shifting, and clipless pedals are all examples of good technology that I adopted early. I won’t ever own a 29er (one of the dumbest “innovations” in bicycling ever). I have zero use for 1x and wide range 2x in gearing. I have nothing but malice for hydraulic brakes. Mechanical discs are okay but if a bike doesn’t have discs, I know enough about braking that I don’t need them. Electronic shifting? Nope. Never going to happen.

Go ahead and point out the holes. I’ve been riding...and buying...bikes for 40 years and I’ve never noticed a decrease in the number of sizes of frames available. Just the opposite in fact.

cyccommute 

I haven’t done a complete survey of every bicycle manufacturer since the beginning of time, but your assumption is flawed. Trek has consistently offered 5 to 9 frame sizes since the 80s. The earliest years have fewer frame sizes then the later years. Cannondale in 1984 offered 4 frame sizes in road bikes. Today, they offer 6. They don’t use a radical slope but they offer more frame sizes. The Specialized Allez was offered in 6 sizes in 1991. Today they offer 7 road bike sizes with a fairly good slope to the top tube. I’ve bought a lot of Specialized mountain bikes over the years and not one has been selected from only 3 or 4 frame sizes.

cbrstar

This is speculation but I also think with the invention of threadless headsets. It's cheaper for bicycle manufacturers to move the headtube up instead of adding extra fork steer tube length and spacers. IMHO The reason for that nice flat bar with vintage road bikes is basic geometry. The straighter a triangle the stronger and less flexible it is. But with stiffer materials like aluminum and the aide of computer design they can make the frame even stiffer with a much more offset triangle.

Personally I love the lines of the classic road bike much more then the new ones.

mstateglfr 

Some fuel to add to this thread.

- Level top tubes due to lugs for the most part. You would have had to stock a ton more lugs with various angles if top tubes sloped since it would have been a different slope for each frame size.
- Sloping top tubes help increase stack height without resorting to questionable kludges and to be quite frank- many people on here could benefit from an increased stack height on their road bikes. I consider myself to be included in that slight insult.
- Threadless headsets solved a dangerous issue in mountain biking and there is no downside to them so they caught on.
- Frames come in tons of sizes, even with sloping top tubes. That was true in the 90s, true in the 00s, true in the 10s, and true in the 20s. Im sure one could find bike shop brands with fewer sizes at various points in the last 3 decades, but I sure can find a lot of brands and models with more sizes now than 30-40 years ago.

gugie 

Someone once told me that lugs are like strikeouts - they're fascist. ;-)

Fillet brazing and TIG welding opens up the design possibilities, but I do like the look of a vintage, lugged frame.

nlerner

So where do lugged mixties fit in this paradigm?