Sloping Top Tube Vintage Road Bikes
 

It seems the sloping top tube didn't become popular on road bikes until the early 90's. There seems to be scant few pre-90's vintage road bikes which use the sloping top tube design. Any member want to show their vintage road bike with a sloping top tube? I have a Sekine Toledo which doesn't slope but there is another version of the exact same frame, and from the same era, which does - weird.

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Meral of France is one manufactuer who offered them routinely at least a generation prior to the date you mention.

The forum has had a number of threads on cycles from this producer.

https://cycles-meral.fr


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If it’s vintage with a sloping top tube it generally means the rear wheel has been removed...:rolleyes:

Mongoose nickel motomag. :) Nobody talks about it, but that's where sloping top tubes started. For that matter that's where the concept of 'wheelsets' started.

Sloping top tubes didn't even really migrate to mountain bikes until about 1990. Kona was an early proponent. As far as sloping top tube in vintage road bikes, there simply weren't any.

Fred DeLong's touring bike, circa late '60s. Strangely, with a Unicantor or somesuch on it. A custom job, it is essentially a Paramount.
https://live.staticflickr.com/65535/...898c49a9_k.jpg
Above photo from https://restoringvintagebicycles.com...f-fred-delong/

more at :https://www.facebook.com/media/set/?...1&l=a8ee5e8619

Cool. I knew when I typed that that someone would find some one off exception somewhere. I hadn't seen that Fred DeLong bike before. Pretty neat.

It wouldn't surprise me if there were a couple other custom frames out there with sloping top tubes, but these would have been like a one in a million thing.

I believe Serotta built the Super Tourer in the early '80s with a sloping top tube.

I got Fred's book as a Christmas gift in '74 and found the idea of a sloping top tube quite astounding. I have always wondered just how much that bike may have influenced the later builders. There is also the idea of simultaneous invention, though, where two people, faced with similar needs, will come up with a similar solution.

Fred seems to have wanted a properly sized frame for his height (he was quite tall) but also wanted easy on and off and stand-over. Later, mountain bike builders recognized the need to stand over the bike when the terrain below the bike night be quite uneven. The sloping top tube is a common solution.

Someone recently posted this same example of a Jack Taylor "Rough Stuff," c. 1979. I found the photo on Flickr from a user named Andrew:, so that's where credit is due.

And though not really what the thread is about, many early safety bicycles used sloping top tubes.

-Gregory


https://cimg6.ibsrv.net/gimg/bikefor...24590e03de.jpg

That is one of the coolest bikes we have ever seen here. ;)

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does anyone recognise the accretion seen on the rear mech in this photo? :foo:

one might at first think mud but the cycle appears to be otherwise clean...


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One of the early adopters was Rocky Mtn with their Blizzard in 87. A grail bike for me.
https://cimg4.ibsrv.net/gimg/bikefor...f9d561d2ee.jpg

My content is not vintage but 'tweener years'.
For vintage sloping = read - Mixte. and all the step-thru derivations.

Around '98 I heard the term - upslope. Slight rise in the top tube.
Not sure when Giant or someone else first did the CF compact frame design w/ mtb seatposts of carbon.

Upslope.
Perhaps a bit more standover?
Don't know if it was for a taller head tube?
Certainly not to stiffen the rear triangle.

On my custom steel bike, ordered in 2003 (delivered 2004), we targeted a taller head tube and achieved it with a couple of cm of upslope and slight extension, without raising the standover by a similar amount. Subtlety in design to solve a given concern.

https://cimg7.ibsrv.net/gimg/bikefor...98520aaa05.jpg
Frame by Jon Tallerico - central California. Mixed Columbus tubing, lugged construction with mods for 1 1/8 headtube, Columbus SuperMuscle fork, Campy10 mixed, FSA compact crank, Deda stem & bars. Now running tubular wheelset and different saddle.


Any way, i've not seen vintage production drop handlebar, classic steel lightweight bicycles with sloping geometry. Middleweights - all bets are off. Aluminium frames got shaped and sloped for aero and stiffness reasons, but i also heard it said that increasing the welding perimeter made Al frames more dependable (stronger?).

Except for the smallest frames sloping top tubes aren't really needed. They like brifters and carbon frames for all are just products the bicycle companies decided we needed. If your bike is properly sized you don't need a sloping anything. As I see it telling people they need a sloping TT gives the seller the advantage of only making 4 instead of 6 or 7 frame sizes.

Fred did all sorts of things that were practical but were things that only he did. I think that, in that picture, there is a sew-up on the rear and a clincher on the front. His granny gear is good for 2mph at 1000rpm.

In later pictures I think there is a different RD on the bike, or at least the object is removed. I always thought, given that he rode everywhere and anywhere, that it was some sort of protective covering so that the mechanism would not get filled with dirt. The photo in the book is no clearer. There is another picture in the book, but it is smaller and even less clear.

Since I own a copy of the book that I could scan, I felt comfortable posting that picture with accreditation. There are photos on the Facebook site that you could look at. I don't feel comfortable reproducing them here, even with accreditation, as they are the property of the bike's current owner.

One real advantage on his frame is a more upright riding position while having to utilize the short-quilled stems of the day. No Technomics or threadless riser stems back in those days.

One of the reasons sloping tubes were not done before mountain bikes became popular is that standard Campy or Shimano seat posts were not that long. I remember when I made custom frames in the 70's and early 80's for tall people was that the seat tube had to be long enough so that a proper amount of seat post was still inserted into the seat tube. You will notice on Fred DeLong's frame his seat tube extends beyond the top tube for this reason. Non-framebuilders may not realize that placing a top tube in the middle of a seat tube is a problem because the wall thickness of the seat tube is so thin in the middle. Of course it is possible to put a reinforcing sleeve where the top tube joins but that is an extra time consuming step.

- perhaps many consumers like STI shifting more than downtube or bar end and instead of companies decided we need STI, they offered it as an option on some models, received feedback, and further refined their lineup to reach the largest possible audience.
I know, thats crazy talk.
- apply the crazy approach to business mentioned above to carbon frames too. Heck, add carbon components and titanuim frames while we are at it.
Either bike companies decided we needed that and forced it on us, or they offered it in some models bit not all, and reviewed feedback to further refine their offerings to try and sell as many bikes to consumers as possible.
- there are many reasons(results/benefits) that have come from sloping top tube bikes. For MTB- crotch clearance should be an obvious benefit that removes any disagreement from the design.
For road- sloping top tubes can create a stiffer frame while giving some compliance due to a longer seatpost. It can also benefit tall and shorter riders, even when a bike is properly fit since it allows for stack heights to vary a lot more than traditional diamond frames. Its odd that you discount the flexibility a taller stack height gives a user- fewer spacers are needed which is critical for steerer tubes now.

Consumers drive the economic relationship and brands continually refine to make their products attractive to consumers. This reality doesn't always fit the narrative of us in this forum who often wax poetically about the soul of a bike being tied to a craftsman and friction shifting connecting you to the bike as one.

I think the Giant TCR was one of the first sloping top tube road bikes:

https://cimg9.ibsrv.net/gimg/bikefor...e12a652d6f.png

A major benefit of sloping top tubes is that not as many frame sizes are needed. This is helpful to both shops and manufacturers for pretty obvious business reasons.

^^^ That is flippin awesome. ;)

The compact geometry with a slopping top tube occurred in 1997 when Giant sponsored the ONCE team. Mike Burrows was hired as their consultant. By having a compact geometry, smaller frame triangles are stiffer and lighter. It also allowed for fewer frame size. At that point in time road bikes were available from 48 to 62 cm in 2 cm increments.

Chesini Innovation
https://cimg7.ibsrv.net/gimg/bikefor...3160c42dc9.jpg

I think you guys saying it was the Giant TCR that was the first one are correct. By that time sloping top tubes and aheadsets were standard for mountain bikes, and it really was only a matter of time before some company tried the same format for with road bikes. Since Giant mostly made mountain bikes at the time, it makes sense. I'm slightly surprised the UCI didn't ban it, but it is still a double triangle.

WRT the OP's Sekine, IIRC a couple manufacturers used sloping top tubes in the smallest sizes purely as a practical way to be able to fit 700c wheels on a 19" frame without excessively weakening the front of the bike. I believe that is the case here.

That Fred DeLong bike strikes me as oddly prescient. Obviously there were some other outliers, but these to me look less like the modern format, and more like a semi dropped top tube compromise between full 'ladies' bike and normal diamond frame.

Dropped top tube were also common during the original bike boom at the turn of the (20th) century. For that matter one might call American cruiser type bikes semi dropped top tube. These date from the 20s and 30s, through the 50s, and frankly into the present