DiTBho

seriously, which is the lightest road bicycle steel fork ever made?
what is its weight? and with which type of steel alloyed?

Andrew R Stewart 

For what size wheel/tire, what steerer/.headset standard and what brake?

These types of questions remind me of a friend, of a shop that I use to work at. who decided his tandem frame and parts by their weights as a primary determinate. Simple to say that he had an awful working tandem in real life use. Andy

Nessism

I made a wonderfully lightweight (for steel) fork one time using True Temper blades and steerer tube. Henry James crown. I can't remember the exact model number for these parts, but the blades were very skinny down by the dropouts. I bent the fork for about 50mm of offset, and still remember how it would chatter on slow stops. I learned a lesson on that one...

unterhausen

It seems like some company is still making lightweight steel steerers in 1". The lightweight 1 1/8" true temper steerers used to be lighter than any 1" steerer.
There have been a lot of weight weenied steel forks.

I couldn't find any info about 953 or XCR fork blades. I was wondering if they were lighter than anything else available now. 853 blades are lighter than 921 blades.

DiTBho

28" wheel
tire of 24
Campagnolo Victory headset, 1" (It's not aluminum, it's steel)
Caliper RIM brake

Trakhak

28" wheel means 700c, we'll assume.

What does "tire of 14" mean? Typing error?

Kontact 

I recalled this article:

https://www.sheldonbrown.com/rinard/..._forktest.html

It was a test of contemporary road forks, comparing the weight and deflection of steel, aluminum and carbon forks with 1" threaded steerers. Of the three weighed steel forks in the test, the Tange Silhouette was markedly lighter at 590 grams - almost the weight of a Kestrel EMS carbon fork. Tange advertised this unicrown fork as being lighter than aluminum forks.

https://www.equusbicycle.com/bike/tan...ngecat1997.pdf

There could certainly be lighter steel forks, but I would bet the construction is going to have to be similar to the Silhouette. Given the fixed steerer size, going to thinner wall, oversized tubing may not necessarily yield a lighter fork as it does with frames.


It is interesting that the light steel fork was markedly more flexible than any of the crowned steel forks, which were more alike than any other forks in the test.

unterhausen

That's interesting that Tange built a lightweight unicrown fork. I was guessing the lightest fork was either made by them, or TrueTemper. People are still building road forks by brazing the blades directly to the steerer. The blades are just regular ones that are meant to use with crowns.

Kontact 

Do they braze on caps for the blade tops? Like on some Ti chain stays?

unterhausen

They close them off somehow. Also, some people use spacers out from the steerer.

t2p

interesting article and chart

Kinesis alloy fork sits in/around the middle … apparently that is good

bulgie 

The steel fork I made for my wife's Davidson road bike in about '89 weighed 450g, just under 1.0 lb. That was for 700c wheels, small frame (short steerer). I know it isn't the lightest though, because then later I made a still-lighter fork for a smaller rider, probably 650c wheels (I forget). That one used 7/8" chainstays as forkblades. Don't remember the weight but it was lighter. Bob Freeman of Elliott Bay Bicycles in Seattle sold it, so he may know what the fork weighed -- but I doubt it. I expect we'll never know that number.

I don't know anything about how well the lighter one rode or how long it lasted, but Laurie says that 450g fork rode great ("best ever") -- and she had her share of top-notch lightweight bikes to compare it with. She won medals at Districts and raced at Nationals, and always paid attention to bike handling. She rode it for over 15 years before the bike was retired. I don't know her mileage but it was more than I was riding! She tended to ride hard; her friends were racers and ex-racers who still liked to hammer. Rider weight about 120 lb. The fork is still fine, can still be ridden, but it doesn't fit her anymore due to too short a steerer. She's over 70 now and can't bend down so low for the bars, so she likes a much taller steerer. But I'd say the fork proved itself reliable.

Mark B

unterhausen

What blades did you use for that bike? Was the crown modified?

The Rene Herse crown for Toei Special blades is really light and makes me wonder why I would use something like the Pacenti Paris Brest crown, which is a brick
https://www.renehersecycles.com/shop...mm-fork-crown/

bulgie 

I don't remember for sure but the blades were probably either Excel or Prestige, the extra-light (0.8 mm) model no longer available. Excel were 0.7 I believe or maybe even 0.6. I still have a pair and they're scary-light. Some "super-steel" though, stronger than Prestige.

Whatever they were, I spun them slowly in the lathe (held by the small end of course) and ground them down thinner with a Dynafile, just moving the dynafile and paying attention to how much pressure I was putting on it and how long I was dwelling on any region. With the goal of thinning the wall only in the middle, away from the (eventual) HAZ at both ends. Sort of like double-butted in the final result. Since I had no good way to measure the resulting wall thickness down there halfway down the blade, I just went with weight as a proxy for wall thickness, and stopped when I reached my predetermined goal for lightening. I don't remember what that was now, but I'm sure I stopped well short of taking half the wall off. More likely I took off a quarter or less.

Sound risky? yes of course, and too time-consuming, so I would never do this for a paying customer. Laurie was into it though, I wasn't foisting this on her unawares. She said "hell yeah" when I proposed making the lightest fork I could. My justification for it was basically "why should she have to use the same blades I used for my own fork, when I weigh literally twice what she does? I'm 95% sure the resulting fork was more reliable for her, than my fork is for me.

The crown is a Saba, investment cast, very tiny. Then I lightened it by thinning it down from every direction, even milling a pocket down inside the blade socket. I don't know how much got turned into chips, probably not a huge amount since the crown is so minimalist already.



Builders who used them in the '80s include Glenn Erickson and Dave Moulton. Ooh here they are for sale cheap on ebay: https://www.ebay.com/itm/254458998579

Oh yeah I also thinned and lightened the dropouts, and used an un-butted steerer. Nothing else wacky about the steerer though, I didn't thin it or drill holes in it like on Merckx's hour-record bike...

Mark B

unterhausen

Merckx probably wishes he thought of sanding down the fork blades on his bike.

bulgie 

LOL
And round track blades are much easier to sand down. Much less hand-eye coordination needed. For oval, there's a tendency to grind too much off the major axis (front and back of the blade) and less off the sides, if you just hold the dynafile steady. So you have to vary the pressure on the dynafile in time with the rotation, to make yourself grind more off the sides, to keep it even. And know you're not going to be perfect at it, so account for the fact that there will be thicker and thinner places, where you didn't grind it exactly evenly. So leave a little more safety margin than you might have to in a perfect world.

It helps to grind at a 45° angle to the rotation axis (or any angle really, other than 90°). Switch sides now and then, from 45° left to 45° right, so the scratches cross each other -- then you can see when the first set of scratches just starts to disappear.

But why am I describing this crazy procedure that no one is ever going to do (if they're smart)?

zandoval 

A new light weight SLX steel fork for 700c?

Yep, they are out there, but its gonna be quite a sting in the wallet for sure...

bulgie 

Are you saying there's an SLX fork blade, as in different from SL? Does it have helical ribs on the inside wall? (I hope not, that would be dumb.)

In the past (like when I was a builder, last millennium) SLX main triangle tubes were very similar to SL, but slightly heavier. Blades were the same -- no different blade for SLX, same as SL

Am I behind on the newer offerings?

unterhausen

Only thing new I see from Columbus is disc blades, i.e., heavier.

zandoval 

Thanks bulgie... Few months ago I took a wrong turn on one of my local Ravel rides. I had to go down a steep torn up ravel road that had been destroyed by Motocross and heavy duty E-bikes. My front fork on my Peugeot P6 held up quite well. It all makes me think. A light weight fork is of course to be admired, but really, there are other areas I would to lighten.

For road bikes I think we need to take lessons from the Track Bike builders. They have probably shaved the weight down on forks to the barest minimum...

bulgie 

No, not in my experience. Of course "all" bike forks are plastic now, but I'm a vintage guy, so let's talk about steel forks. In those days, track forks were generally not one bit lighter than road forks. The only real differences were the blades were round not oval, and the crown height was usually lower with no mud- or fender-clearance, usually no brake hole. But the tubes and crown weren't any lighter and the dropouts were often heavier.

Two reasons why track forks were heavy:

1. There's almost no advantage to light weight on a track bike. With no hills, weight almost goes away as a factor in a race. You don't accelerate enough for the slower acceleration to be a factor, even in Match Sprint.
2. Most trackies wanted max stiffness. I was skeptical of the value of that, so I made my own track bike with light tubing, and even I had to admit, it was too flexible for me. I sold it to a skinny guy with no sprinting ability to speak of, and he loved it! Most people want 'em stiff though, even if it means heavier.

Round blades are more flexible in the fore-aft direction than oval, which makes them worse for hard braking and more prone to judder; also weaker in terms of front-end collision, or fatigue life on the road. The upside of round blades is more side-to-side stiffness, which is what track sprinters want.

Round track blades came in 22 mm and 24 mm, but the 22 mm ones generally weren't any lighter because they were thicker wall. Maybe Columbus Record had lighter blades, anyone know? Named after the tubeset made for Merckx's hour record bike. He didn't really need light-weight for an hour of steady output with only one acceleration at the beginning, but he didn't need stiffness either, so why not? They went nuts on the lightening, like leaving the hub dustcaps off so you could see the ball bearings. Major drillium all over including huge holes drilled in the handlebars. Nuts! If it made him faster, it would only have been the psyche factor, aka placebo.

unterhausen

They drilled holes in the steerer on Merckx's hour record bike. I never really understood it, he's probably lucky it made it to the end of the hour. It's funny that the tiniest bit of aero would have helped more than all that drilling. But we didn't believe in aero back then.

JohnDThompson 

According to my Columbus catalog, PL fork blades were 1.0mm thick, PS were 1.05mm, and Record were 0.9mm
https://drive.google.com/file/d/1-Ib...ew?usp=sharing

bulgie 

And 0.9 is the same as SL, so again, not really lighter than a road fork. Though the Record is probably 22 mm, correct? That would make it about 8% lighter than a 24 mm blade in the same thickness. Whether that is considered significant is up to each rider to decide -- I'd say no. Especially for a track bike where weight is less important.

DiTBho

ops, typo, meant 700x24c