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lofter

ok heres a question for all out there , when did they switch "as in what year about" to the straightened out forks on bikes in general ?

heres a pic i found looking around and combing thru gitane bikes as i do almost everyday. what year did they go to those kind of forks?

i really like this bike by the way. if it would have had yellow decals , oh man heaven ! heres the link that i found it at
www.leboncoin.fr/sports_hobbies/133691527.htm?ca=7_s

ive never seen a gitane with those type forks . ive seen them on other bikes , but this is when i wasnt really into cycling anymore and im lost on this one . any help, comments ,thoughts ,expert knowledge Rolling Eyes

?

Wisey

I'm guessing in the mid 90's when straight forks became popular. There were very popular with the manufacturers as it cut large amounts of time from the production process.

I just checked the catalogues. 1994 a straight fork was introduced on some models. From 1995 onwards, it looks like most of the top end models had a straight fork. This seems to have been the trend until carbon and aluminium forks were introduced in 98 - 2000.

Gtane

Lofter,

That's a good question. It's amazing how these thing just pass us by yet when we go back to consider we then realise how significant they were.

Regards the Pro ranks, the image that sticks in my mind is Tony Rominger's straight forked Colnago in the early 1990s. However, this is only off the top of the head info. It might be worth going back in time, sometime, to see when they first appeared to firmly establish the timeline.

Through very quick research I found that Colnago offered the C35 with straight forks in 1989 - http://tinyurl.com/272hso6

Wisey, I would agree with you that is was about the mid 1990s when they became mainstream.

Tim

lofter

they just never appealed to me . i thought they looked dumb at the time . i dont know if they were more aero dynamic or what . i guess im really old school Wink

Wisey

There was a buzz at the time on frame rigidity. The tubing manufacturers hadn't come up with anything new for a while. Reynolds had their 3 flagships being 531, 653 and 753. Columbus had SL, and SLX primarily, but they did some other stuff like the Gilco shaped tubes for the Colnago Master series.

In order to get a marketing edge, some frame companies started to find an edge through frame design. Colnago started lowering the top tube (aka head tube and seat tube extensions) on their larger models. Straight forks was another gimmick. This continued until the tubing manufacturers started to produce the start of the oversize tube sets like Columbus EL and MAX. Reynolds had their first generation 631OS. Then it all went lugless tig welded, then it went aluminium, then carbon tubes glued into alu lugs, then monocoque carbon, then that was too expensive to manufacture so it shifted to modular carbon construction which is where we are now. I wonder what the next trend will be?

One day there will be a "new" trend where they use the thin walled hi-tech alloy tubes that are silver brazed into special investment cast lugs. These frames will be marketed as providing the ideal balance between weight, rigidity, ride comfort, and longevity. It will be a break through and everyone will want one......... Twisted Evil

Lofter, you're not old school. You're just old Wink

. Personally, I always preferred curved forks on a steel bike as well. Perhaps I'm just old too.

logarto

Ernesto Colnago makes a big deal about this in some recent sales collateral, to the effect that he claims to have "discovered" after 70 years of bike manufacture that raked forks were functionally useless. Probably circa 1994 or so?

I like a good load of marketing manure as much as the next guy, but it occurred to me at the time that the straight fork was probably the earliest design concept from the velocipede days and that raked probably came along a little later.

I think that if the roads were reduced to their condition of 1948 the framebuilding gods would "discover" the principal of rake all over again too. Probably overnight too? What Jacques Anquetil called a racing bike wouldn't even be considered sport touring today.

Oddly enough most of the people that I've turned onto old French bikes really love the soft front end. Even people whose "good" bike is a Merlin or a Cervelo. IMO nobody would dare design a carbon fork today that jumps back and forth over the bumps like an early 1980s Gitane or Motobecane does. Their lawyers wouldn't let them, (apologies to Stephan.)

And once again Yoshi Konno was there ten years ahead of everyone else by incorporating a substantial portion of the rake into the fork crown as an offset forward.

lofter

you know , i really have never ridden one myself . how did they ride , handle , plus +'s, minus' ? anybody got some info?

verktyg

verktyg

Sometimes my novellas wont go through so I have to break them up...

To answer lofter's questions, the bike fits me great and is a heck of a climber. It has a very short wheelbase and corners very well. That's all due to the basic frame geometry not the straight fork blades.

When I first got the frame I was concerned that the forks would have a harsh ride. The answer was - yes and no.

Depending of the wall thickness of the tubing, the diameter and taper of the tubes and the amount of fork rake, forks can spring back and forth front to rear. Some can also bounce up and down.

These fork blades are made of thin wall tubing. On a relatively flat smooth surface they absorb a reasonable amount of road shock via front to rear flexing. But... of rough road surfaces, there's very little up and down flexing.

It hit a small pothole the first time I had it out on a fast group ride. We came up to a stop light at the bottom of a long fast hill. I was doing everything just to stop the bike, not seeing the pothole. It knocked my Silca pump and water bottle loose and rattled my teeth.

The same pothole on a decent bike (Gitane) would have been just a bump!

Wisey

Gtane

logarto

[quote="logarto"]What Jacques Anquetil called a racing bike wouldn't even be considered sport touring today.

[quote]

I was thinking of my 1973 Olmo when I wrote that; it had such generous rake and wheelbase that, competing against the shorter late 1970s Colnagos and Masis and Marinonis I tried to avoid L-shaped criterium courses where I couldn't expect to take all the corners on the outside of the pack.

But a more accessable example of how bad the roads actually were from the frame designers' point of view back then would be when one of the real glossy pro cycling magazines had a look at Tom Simpson's bike a year or so ago.

Before they ever turned it upside down an old time team mechanic had told them that it would probably have a broom handle stuck far up into the steering tube from underneath. Naturally the writer had to see for themself (as would I,) and upon examination there it was.

I don't think they were doing this for their health, err actually I DO think they were doing it for their health!

Some team wrench must have started this practice in the early 1960s after a few steering tubes had come apart in the heat of battle. When your fork blades jump back and forth like a leaf spring the stress will naturally migrate up to this part of the steering assembly. The broomstick at least gives the rider a fighting chance to reduce speed and dismount. Fork crowns were also fhe first place where investment casting was used, again the lower steering tube is sitting there getting pummeled and fatigued. This was thought to be a drawback of the original Cinelli full sloping fork crown, it was too strong for the pieces that were getting brazed into it.

I've broken exactly one crankarm in 30 plus years of riding pro bikes, I was extremely fortunate as to the circumstances and results. Even though I was home and laughing about it within ten minutes this made me re-evaluate every single bit of older alloy equipment on all of my bikes. Since then I've become partial to steel quill stems like the Ritchey and Salsa.

But I would think a seperated steering tube would make a broken crankarm or stem seem like child's play by comparison?

That's probably why Columbus applied their helical reinfocements to this round tube first, as manifested by my Olmo?

FWIW Reynolds never followed suit, but Columbus subsequently deployed the same helical reinforcements to the down and seat tubes (SLX) and ultimately to all the round tubes (TSX.)

verktyg

I'm not sure if I've ever seen a steering tube that was broken at the fork crown (that wasn't severely crashed). What I have seen is braze failures between the crown and steerer.

These failures tend to come on slowly and are the result of a poor quality braze job. The front brake bolt will usually keep the forks from searating from the steerer.

Back in the 60s and 70s both Peugeot and Motobecane were infamous for using a piece of straight gage low quality pipe for steerers. They used a split sleeve brazed inside the bottom of the steerer as reinforcement.

Note also that both of those makers were big proponents of using a wood dowel pin inside the bottom of the steerer!

Here's a Peugeot U0-8 fork. You can clearly see the split sleeve. Also notice the seams in the back of the fork blades. They were made of sheet metal rolled into the fork blade shape and brazed rather than from tubing

Braze failures weren't limited to lower quality French bikes. Here's fork from a sacred Cinelli that was poorly brazed and failed! Embarassed

Gitane on the other hand used better quality butted steerers made by Nervor during that era.

repairtec