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citternmaker

Not meaning to delve too far into weight weenie territory here, but just out of curiosity... do any of y'all know how much 1970's era TdF frames and forks weigh? I put my early 70's 62cm frame/fork/headset on the scale today, and think the aftermarket fork might be skewing the results a bit...it all came out to about 7.2 Lbs (without the bottom bracket).

Thanks in advance for any thoughts y'all have on this....

verktyg

In the past very few frame weight claims had much real world relevence. There's quite a weight difference between a 50cm and a 64cm frame.

The bottom line is that a Reynolds/Columbus framed high performance bike from the 70s equipped with sewups should weigh between 21 to 23 Lbs. A bike with clinchers and alloy rims should be about 23 to 25 Lbs.

Up through the late 1970s most European production bikes made with Reynolds or Columbus tubing were built with medium to heavy gage tubes. These were still 5 to 7 Lbs. lighter than standard bottom of the line European models made with gas pipe tubing, steel rims, bars and so on.

Chas.

citternmaker

Chas,

Thanks as always for your insight! I wish I had weighed the 54 cm frame/fork before building it up, just for comparison's sake with the larger frame. In the built-up versions, both frames came pretty close to each other (within a pound or so).

Some of the frame/fork weights advertised on modern TIG-welded (low end) frames just seem...optimistic by comparison (and probably are understating the actual weight).

Still, at less than 22 Lbs, the 54cm TdF is much less to haul around than the 35+ Lb Sears/Puch I used to ride.

Thanks,

Ron
(who's re-learning how to repair tubular tires this evening...patches, needle and thread)

vanhelmont

Ron,

I was curious about weights, too, so I weighed some stuff one day. My 63 cm Super Corsa frame came out 4.9 lb, or 2.21 kg. I don't have an authentic fork, but a 90s Columbus Zona fork probably on the low weight end of steel forks, was 1.4 lb. The fork I'm using is a Raleigh Super Course fork, with the same crown as a TdF or SC fork would have, which weighed 1.8 lb. The proper fork would surely be between these, probably closer to the Super Course fork. I think a headset would be about .2 lb, maybe a bit more for a steel headset.
Then my frame/fork/headset combination should be about 4.9 + 1.8 + .2 = 6.9 lb, for whatever that's worth. Maybe your fork or headset is a bit heavier.

Dave

citternmaker

Thanks for the info Dave,

The replacement fork on my 62 cm frame is a (sort-of) Cinelli-esque unit made by SR/SAKAE. The headset is a replacement 1st-gen Dura Ace unit (aluminum), so I'd bet the SR fork has a cast crown or possibly heavier legs that are adding the extra little bit of weight.

verktyg

Some full sloping fork crowns are solid steel and can be quite heavy compared to the Wagner, Nervex or Bocama crowns that were used on Gitanes.

Bike tubing like Reynolds, Columbus, Super Vitus and other quality brands are made of Alloy Steels which are 25% to 100% stronger than the carbon steel used in the "gas pipe" tubing found on lower priced bikes.

The tinsel strength of Carbon Steel tubing used in bikes is around 45-55,000 PSI.

So called "High-Tensile" or "Manganese" Steels ranges from 70-78,000 PSI.

The Alloy Steels used in Reynolds, Columbus, Super Vitus, (and others including Chrome-Moly, Chromo, etc.) tubes have tensile strengths of 98-126,000 PSI.

Reynolds 753 tubing had a tensile strength up to 178,000 PSI. From the late 80s on Reynolds, Columbus and others made specialty tubing that had similar high tensile strengths.

In comparison, the Aluminum alloys used in bikes is 45-55,000 PSI, Titanium up to 100,000 PSI and Carbon Fiber Reinforced Composites, 100-300,000 PSI.

Alloy Steels are not only stronger than Carbon Steels but they have much higher resistance to fatigue. This allows for tubes made of Alloy Steels to have much thinner wall thicknesses resulting in lighter weight bike frames.

I did "post mortems" on the crashed frames that customers brought in for replacement or disposal.

For example, in the 1970s I saw cheap bikes from Japan and Taiwan made of tubing with a 3mm wall thickness in the main tubes - that's almost 1/8". These weighed in around 38-40 Lbs. In comparison, many of the less expensive European bikes from the Bike Boom era used tubing around 2mm wall thickness in the main tubes and weighed between 28 and 32 Lbs. with heavy steel components.

Gitane used thinner walled tubing on their less expensive models than many completive brands. I still have a down tube from a Gitane Gran Sport. I'll have to measure the wall thickness again.

It's not only the weight that makes a difference, but the thinner walled tubes make for a more flexible frame that absorbs road shock better. That's why heavy bikes have a "clunky", dead feel. There is a lot of mythology surrounding frame flexibility - most of it's BULL PUCKY!

The frame, wheels and tires are the suspension system of the bike isolating the rider from road shock and vibration. In the summer issue of Bicycle Quarterly they did a blind test with 3 identical custom built bikes - the only difference was that one frame was made with heavier gage main tubes.

http://www.vintagebicyclepress.com/currentissue.html

While the results were highly subjective the general consensus was that the more flexible frames were better riding and more efficient. They also introduced some engineering studies to back up their experiment.

I have to qualify this claim a little: bikes with too much lateral flexibility across the bottom bracket or head tube are exceptions to these findings. My first Gitane Super Corsa had a very light frame, about 21 Lbs. complete. It was a 60cm bike and either it was made from Reynolds 531 SL thin wall tubing or they used a seat tube for the down tube or both.

On a hard sprint I could flex the bottom bracket so much that the bike would "ghost shift". That is the shift cables would pull enough that both the front and rear dérailleurs would shift by themselves.

I traded the frame in for a 57cm Super Corsa frame that was more my size. The new frame was at least a 1/2 Lb. heavier but it didn't have the lateral flex problems.

One last thing, larger frames are going to me more flexible than smaller ones. A 64cm frame made of heavier gage Reynolds 531 tubing may be ideal but a 50cm frame made from the same wall thickness tubing is going to have a harsher ride. Also, riders weighing less than 150 Lbs. will rarely be able to flex a standard frame very much.

In my serious riding days, 30 some years ago, I weighed 175 Lbs. Today I weigh 225 Lbs. I have some bikes in my collection that I would have considered way too stiff back in the day that are now quite comfortable to ride.

All of this bike talk has got me all excited, I have to go for a ride... Twisted Evil

Chas.

citternmaker

Chas,

Even beore I weighed 185 Lbs, I saw the ghost shift issue on my 62 cm frame. The 54 cm frame is just about right for me...just flexible enough to absorb the shock, but not enough to get wacky on a steep climb.

Also, I finally got to do something yesterday that I've been wanting to do all Summer. I took the 54 cm TdF out on a particularly nasty section of chip-seal (one that usually buzzes my water bottle out of the cage on my Aluminum/Carbon bike). While the difference wasn't exactly like night and day, the TdF sure made riding on the chip-seal an much nicer experience. I'll definitely be using it on centuries with bad roads from now on.

The TdF's frame is certainly more compliant then the newer bike, and just for grins I also brought along a really stiff deep V section clincher front wheel to see if the better ride experience on the bad road was due to the frame. I was pretty surprised at the result -- the wheel change really didn't make that much difference (other than looking really ugly and out of place on the bike). The heavier/stiffer wheel made the TdF respond a little more sluggishly, but it didn't make that much more buzz appear in the ride. The ride quality of the clincher vs. the tubular was another matter, though....

Have a great ride! I'll be probably be going out again tomorrow -- I'd be going for a ride today, but I'm finishing a tire glue-up session instead.