Building a new fork; need input
 

Hey all,
I have an early 90's Specialized Allez, lugged steel frame with the awful, in my opinion, aluminum direct drive fork. I love the ride of the frame, but the fork is stiff and uncomfortable with dull input feel. I want to build a lugged steel fork for this frame. Here's my question; if I build the new fork with the same spec's as the aluminum fork, will it perform the same? In other words, I'm thinking of using the alum fork as a copy to set my fork jig to build the steel fork.
What do y'all think?
Jay

No. The steel fork will feel different. How you describe that difference we might learn...


I will make a comment about this- " I have an early 90's Specialized Allez, lugged steel frame with the awful, in my opinion, aluminum direct drive fork. I love the ride of the frame, but the fork is stiff and uncomfortable with dull input feel."


Those forks were generally considered to be rather more flexible then steel ones. Main reason is they use nearly the same dimensions (steerer diameter) but with a material 1/3 as stiff as steel. I suspect what you're trying to describe is the lack stiffness.


Your frame is well designed and is, depending on the version, nice to really well done. The AL forks, on the other hand, took away from the crispness of handling IMO. Andy.

Id say comfort goal, go with an old 50s short radius J bend, at the small diameter, tip

being an adaptation to the rougher roads back then, would be better, than ...


the larger radius over the whole blade length ,Italian style, where the stiffer racing bike fork "looked better" more 'modern'

because the tip would flex more , and absorb, some roughness ...





....

I thought that regardless of the blade curve style(or lack of such as a straight blade) forks with the same rake will ride pretty much the same(given similar wall thickness and diameter). Comments??

thanks, Brian

It takes longer tubes to make a fork with the "French flick", so you get the benefit of that extra length bending when you go over bumps. Forks made in that style sometimes used blades that tapered down quite a lot to increase the effect (and save weight). Check out this 1950 Rene Herse:

http://www.reneherse.com/images/DSCN00097.JPG
(from Rene Herse project is about the Rene Herse velo de cyclotourisme, also Camille Daudon Alex Singer Narcisse Barra Maury Dujardin Goeland.)

I suspect that the rake of the Direct Drive fork is about 1/3 that of the Herse's fork. That's a lot more dimension to have the tight radius actually start to curve towards horizontal. BTW I suspect that the Herse's head angle is slacker, further making the fork tips more horizontal. No way the Specialized would end up with such an extended forward fork tip and retain the handling nature it was designed with.


IMO if you mimic the dimensions of the Direct Drive fork the handling that's due to geometry will be the same. But not all handling is geometry controlled, there's a rider too. So I would expect no handed riding to be pretty much the same but with hands on the flex difference (between AL and steel) comes into play. The steel fork will likely feel stiffer when out of the saddle, using your upper body a lot and over bumps. It will add around a half pound of weight.


Back in that era one way to "up grade" your steel racing bike was to swap out the steel fork for an Al one. I knew quite a few riders who did this as well as sold a handful number of Al forks in my LBS. Most all liked the lesser weight, the smoother ride over bumps but noted that there was a certain snap that was lost in the handling/cornering aspect.


If I had this bike and really liked how it felt handling wise, I would consider doing the same. Making a steel fork with identical dimensions. Andy.