How do vintage steel frames compare to modern ones?

Question

I got myself a nice vintage Koga Miyata road-speed from 1978 and am planning to converting most parts of it while keeping the frameset intact.

The bike rides really nice and have no issues but it got me thinking how these old hand-made frames compare to new ones.

From the Koga catalog I was able to find the exact model which contains some details on the steel metal used (translated version ahead):

Specifically it says "High-Tensile steel tubing". It also says "frame is made of Tange seamless manganese steel tubes".

I'm curious what does the "1024" mean in this context and how does this compare with modern steel frames. For instance I've read that high-tensile steel is probably the cheapest of the steel frames nowadays and that something like chromoly is of higher quality.

But wondering whether such comparison applies only to modern high-tensile; whereas instead perhaps these older frames have certain craft-ship that we don't do anymore.

Would be nice to get some general idea on the quality of the frame if anybody has such knowledge. Thanks!

Answer 1

The ad copy is saying that the frame has some of Tange's 531-esque product of the time, i.e. a steel with manganese and molybdenum alloying elements. It's either all Tange, or some Tange and some 1024/hi-ten tubes, or Tange frame/1024 fork, or some mix thereof. None of that would be unusual. The proud "1024" logo is there to play to the notion of the buying public being impressed by assurances that the frame is made of something nicer than straight melted Chevies, where some care and QC went into producing the material for its tubes. High-tensile steels do in fact have good properties for making bikes compared to cheaper alternatives, which bikes were also once made of. Today it's true that something like 4130, which is much better yet, is rightfully viewed as more of a baseline for a "real" bike, but it and similar nice-but-not-extravagant steels didn't have that position in the 70s.

A rule of talking about comparing steels as they're used in bike frames in different historical eras is other than for some very specific intents and purposes, there's not a conversation unless you're also talking about wall thickness. A question you could ask is whether the transition from the lug to the TIG era brought with it any changes in wall thicknesses typically used along with 1020-ish steels, since TIG processes are more sensitive to distortion and will run faster and cheaper if thicknesses are increased, even if it's unnecessary on a strength level and takes away from light weight and ride quality. Some contemporary steel bikes suffer greatly from this, including 1020-ish ones and even many basic chromoly (4130, Reynolds 520, etc) ones.

Midrange and nicer Japanese bikes from this era are usually very well-made regardless of the material, and so it is true that 1020 type materials on a bike like the one in question were likely handled with more respect than usually found globally today. (This is not to say there's no variance today, and you'd also likely be comparing a mostly TIG versus a mostly brazed bike so some elements become apples-to-oranges). It is critical though to point out that that's more characteristic of Japanese bikes above a certain quality tier than it is of bike-boom era high-ten bikes in general. As a whole, many 70s and 80s hi-ten bikes had terrible production quality (gappy brazing, rough lug finishing, etc) that barely passed in use.

Answer 2

From my understanding, the 1024 High Tensile Steel forms the fork blades (aka tines) and maybe the crown. Meanwhile, the frame is made of Tange steel, which is itself considered a rival to Reynolds' butted tubes of a similar vintage.

This fork suggests its steerer is made with Tange steel and 1024 high-tensile steel.

And here's a fork showing the same decal

Upshot - two different metals used in different parts of the bike, and labelled accordingly.

Answer 3

Don't expect too much from this one. Koga-Miyata is known as a quality brand, but looking at the full catalog, it's clear that this particular model is the lowest tier in the road bike series. The "pro race" and "race" models are CrMo, which is already one or two steps down from the modern high strength steels, the medium level is advertised as manganese alloyed steel and as far as I can tell, this one is more or less the same "hi-ten" tube as current affordable steel bikes.

The good and bad parts of vintage bikes apply to this one too: Quill stem with all its problems, and adjustability if you can't find the right height, flexible frame compared to current bikes, better tire clearance than 90s and 2000s bikes but still not great, good parts compatibility unless it has one of the weird thread standards, etc.

Answer 4

Here is a link to the complete 1878 Koga Miyata catalogue.

The Road-Speed is the least expensive bike in the line.
In its day it was a very well-constructed frame for it's price range made by a company known for quality.

How do vintage steel frames compare to modern ones

It's like asking how vintage cars compare to modern ones.
The answer is - it depends on which vintage bikes you compare to which newer bikes.

The inference is to compare the Road-Speed to modern bikes. This narrows it down some but which modern bikes? What characteristics are we comparing? Ride, construction, durability are three characteristics that come to mind. These things can be debated back and forth.

I would offer that the real question is - does this bike meet your needs?

Answer 5

But wondering whether such comparison applies only to modern high-tensile; whereas instead perhaps these older frames have certain craft-ship that we don't do anymore.

Unfortunately, old frames are mis-designed.

The steerer tube of the fork is almost always 1" in these old frames. That has always been marginal, even with steel. With aluminum it would fail immediately.

Furthermore, you can't find 1" threadless stems. Therefore, you are restricted to quill stems, which are really problematic (well you could buy 1" quill to 1+1/8" threadless stem adapter but that has all of the problems of quill except the possibility to slightly adjust handlebar height without a hammer if the adapter has enough adjustment range in the stem clamping area). The stem flexes too much, and can get stuck to the steerer tube. Every adjustment requires a hammer, and sometimes even a hammer isn't enough. Also, you can't adjust the headset without one very large headset adjustment wrench and one huge and heavy adjustable wrench -- with threadless, you can adjust the headset with small Allen wrenches.

Finding 1" threadless forks is very hard, too. So you are restricted to 1" threaded forks and 1" quill stems.

If selecting a frame from new frame options, you will always have an option for disc brakes or V brakes too, which you lack with old frames that are caliper brakes only.