straight blade fork-pros and cons
#1
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straight blade fork-pros and cons
i have the oppurtunity to buy a straight blade fork for my Pinarello.What are the advantages and disadvantaqges to straight blade?Is it less comfortable?Less or more nimble?You see it's chrome and columbus and would go great with my Pinny that came without a fork.
#2
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I think they look terribly ugly, that's all I need to know...
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Ernesto Colnago came up with it as a marketing tactic back in the 1980's, if I recall right.
The truth is that it's cheaper and faster to buy unbent blades and stick them in a crown without bending them. All Colnago had to do was design a crown with the necessary forward angle to the blade sockets to achieve this.
Does it do anything? Negligible. It's all about style - and I've yet to see anything look good with straight blade forks. Your mileage may vary.
-Kurt
The truth is that it's cheaper and faster to buy unbent blades and stick them in a crown without bending them. All Colnago had to do was design a crown with the necessary forward angle to the blade sockets to achieve this.
Does it do anything? Negligible. It's all about style - and I've yet to see anything look good with straight blade forks. Your mileage may vary.
-Kurt
#6
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What I heard was that on a machine that reproduced road vibration they tried different forks to find a way to make a smoother ride, they say this was the result, a straight fork. The thinking is that the bend in the blades adds a vibration in the frame after the fork hits a bump, more vibration. The straight fork just takes the bump and transmits it through the frame, less vibration. So you don't feel so beatup after 100 miles.
#8
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What I heard was that on a machine that reproduced road vibration they tried different forks to find a way to make a smoother ride, they say this was the result, a straight fork. The thinking is that the bend in the blades adds a vibration in the frame after the fork hits a bump, more vibration. The straight fork just takes the bump and transmits it through the frame, less vibration. So you don't feel so beatup after 100 miles.
#9
It's a nice touch at some frames - colnago's, late incarnations of the Gazelle mondial - but not necessary a pretty thing on most bikes. It seems a lot of current road bikes have them for the purported advantages that they have. but like so many things in the bike world like frame materials, angled TT's etcetera a lot of judgement is clouded by fashion, tradition and marketing buzz. I'd like to see those research reports mentioned before a verdict is passed, and maybe one of the guys over at frame builders can chime in with some insight from a builders perspective.
#11
Pros vs cons is squarely an individual opinion from an aesthetics standpoint as far as I can tell. Its been said here they sorta came to light as no extra time would have to be spent bending thousands and thousands of forks. mr colnago said handling is better and less road chatter with the straight fork but this is all marketing gibberish like that "vertically compliant" jargon you hear all the time these days. I personally love the way they look however, but I like forks that are curved too, only if they have just a little bit, especially when they start curving close to the hub, rather than around the center of the fork.
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I think it kills the look of a lugged steel frame, a graceful curved fork is more pleasing to my eyes, looks all around better to me. I don't think there is much performance difference between the two though as long as they are both well made, straight and not boat anchors. Now, if we are talking about the difference between steel and carbon forks, I gots me some real opinions on that.
#16
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I like them but I think it depends on the bike. they certainly look at home on the 'peacock' Colnagos. I would love to put a chrome one on something but I think the frame has to be pretty ornate. while a chrome fork will dress up most any bike, like a older Trek 650 or Pinarello I think if the frame is plain single color the straight blade looks out of place
I do have a XXXXX XXXXXX frame I need a fork for, so I am thinking a cheapish straight blade XXXXXXX fork is in order for that.
I read somewhere where Ernie claimed they preformed as well or better than a standard curved blade fork. since the rake was in the crown it actually allowed the whole blade to flex to absord road shock. fact or bull who knows. one thing is for sure if Eduardo Bianchi had thought it up all my bikes would certainly have straight froks LOL
I do have a XXXXX XXXXXX frame I need a fork for, so I am thinking a cheapish straight blade XXXXXXX fork is in order for that.
I read somewhere where Ernie claimed they preformed as well or better than a standard curved blade fork. since the rake was in the crown it actually allowed the whole blade to flex to absord road shock. fact or bull who knows. one thing is for sure if Eduardo Bianchi had thought it up all my bikes would certainly have straight froks LOL
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Last edited by Bianchigirll; 08-30-11 at 08:56 AM.
#17
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While I doubt they make any difference other than ease of construction, I do think it was a brilliant idea after all these years, and I kind of like them. But not for a vintage bike. Those old rakes are beautiful to my eye.
#18
Sorta, but what problem did curved forks provide a solution for? Which makes me wonder why they ever started building bikes with curved forks instead of straight blade forks to begin with. Logically, it seems like the first bikes would use a straight fork for ease and curved forks would be introduced later as an innovation to dampen road buzz. I think it boils down to nothing more than preference.
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In theory, the curve would absorb some of the shock to the blades where the straight fork would direct it all to the crown joint. But honestly, I doubt it matters. The brillance for me is using straight tubes, just like the rest of a bike frame. Once you see it, you wonder why it took so long for someone to see it.
#20
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To my eye I don't like straight bladed forks. I saw an otherwise nice Gunnar a few says ago with straight blades and I couldn't help but think that the bike had been aesthetically compromised as a result.
I also am not crazy about unicrown forks. My Trek 520 and my wife's Linus Mixte both have them and the aesthetic is "off" as a result. I've thought about replacing the fork on my wife's bike and would probably do the same with my Trek were it not for the fact I'll probably be selling it in the future since the frame is too small for me. Anyway...
I also am not crazy about unicrown forks. My Trek 520 and my wife's Linus Mixte both have them and the aesthetic is "off" as a result. I've thought about replacing the fork on my wife's bike and would probably do the same with my Trek were it not for the fact I'll probably be selling it in the future since the frame is too small for me. Anyway...
#21
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Wow,great response!Seems there is no consensus on function,performance, with maybe a slight feeling that it would be less comfy.Those who dislike on aesthetic grounds are many and strongly opposed on that ground.However there is a minority who like the aesthetics especially on a Colnago.I personally like the looks and if i succeed in gertting in touch with the seller I'm going to go for it and I'll post on it later.
#22
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Wow,great response!Seems there is no consensus on function,performance, with maybe a slight feeling that it would be less comfy.Those who dislike on aesthetic grounds are many and strongly opposed on that ground.However there is a minority who like the aesthetics especially on a Colnago.I personally like the looks and if i succeed in gertting in touch with the seller I'm going to go for it and I'll post on it later.
I think if it is about function and you like the aesthetic, then go for it. I'll be interested to see the result, but be ready for the onslaught from the folks here when you do. At least you're not proposing putting that fork on a English 3-Speed!!
#23
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I think straight blades are ugly. But nobody asked me, except maybe you did by starting this thread.
From a mechanical standpoint, when the wheel hits a bump it transmits an acceleration-derived force vertically only. In theory the longer the fork length between hub and HT the more material there is to absorb the deflection. Also when part of the blade is nearly perpendicular to the movement it can transmit force only via its bending resistance at that portion of the fork. By these arguments a curved fork should ride softer than a straight one. Whether it also vibrates sympathetically is a different question that involves masses, especially the mass of the wheel.
Most importantly though, it isn't at all clear whether those nominal mechanical differences are enough to be felt by the rider. It would depend on the rider's mass and strength, possibly the riding style, the condition of the roads, the tire size and pressure, etc. Very likely some could feel it and most couldn't.
But since they are so ugly and the effect on ride is probably so slight, why bother?
From a mechanical standpoint, when the wheel hits a bump it transmits an acceleration-derived force vertically only. In theory the longer the fork length between hub and HT the more material there is to absorb the deflection. Also when part of the blade is nearly perpendicular to the movement it can transmit force only via its bending resistance at that portion of the fork. By these arguments a curved fork should ride softer than a straight one. Whether it also vibrates sympathetically is a different question that involves masses, especially the mass of the wheel.
Most importantly though, it isn't at all clear whether those nominal mechanical differences are enough to be felt by the rider. It would depend on the rider's mass and strength, possibly the riding style, the condition of the roads, the tire size and pressure, etc. Very likely some could feel it and most couldn't.
But since they are so ugly and the effect on ride is probably so slight, why bother?
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#24
A strait blade fork using an offset crown restricts the framebuilder to just one pre-set fork rake, as determined by the angle of the offset cast into the crown. For a given style of offset fork crown there is usually only a single offset available to a small scale framebuilder from the supplier, not a bunch of fine graduations of available offsets. This may not be as big of a problem for a big factory building the exact same bike hundreds of times over if they can specify the offset as needed. But even then, different sizes of the same model likely should get slightly different rake for optimal handeling as the headtube angle is usually somewhat different for lage and small frames. If you still need to bend the "strait" blades to fine tune the rake, that sort of defeats the purpose of the cost savings of using strait blades.
By using a fork crown without offset and instead bending the blades, a builder can better fine tune the steering characteristics to suit the bike design, not compromize the design of the bike to fit the available castings. Bending fork blades to shape is suprizingly easy. I probably spent less than $20 on materials to construct a fork blade bending form and making the bends is really rather easy to do. I suspect that the one possible benefit of strait blades is that a builder might be able to get away using lighter tubing since it will not become weakened by the bending.
By using a fork crown without offset and instead bending the blades, a builder can better fine tune the steering characteristics to suit the bike design, not compromize the design of the bike to fit the available castings. Bending fork blades to shape is suprizingly easy. I probably spent less than $20 on materials to construct a fork blade bending form and making the bends is really rather easy to do. I suspect that the one possible benefit of strait blades is that a builder might be able to get away using lighter tubing since it will not become weakened by the bending.
#25
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