fork blade specifically designed for disc applications

[ryker]

Attachment 66638

You have very clean fender attachment with good clearance for the caliper. Nice work.

[e-RICHIE]

They are in backwards and the axle ends up a few mm's off center. Even if they were in the other way the axle would be off center. I'm not worried about this at all since there's plenty of bronze in there and the offset is minimal.

It's not about the braze material's contact patch, it's about good design, or once was.

[JohnnyChromatic]

It's not about the braze material's contact patch, it's about good design, or once was.

e-RICHIE,

Is this mostly an esthetic issue? I see how moving the axle away from the blade centerline would probably increase stress on the blade/dropout connection. And I appreciate that curving the blade straight into the axle can be estheticly pleasing. In this instance, I am not sure what you mean by "good design".

[e-RICHIE]

e-RICHIE,

Is this mostly an esthetic issue? I see how moving the axle away from the blade centerline would probably increase stress on the blade/dropout connection. And I appreciate that curving the blade straight into the axle can be estheticly pleasing. In this instance, I am not sure what you mean by "good design".

On one hand, you (the independent effbuilder...) have started the conversation by choosing to make a fork rather than buy one from Forks R Us. That's a plus, and you're lucky that industry has parts for you. The same can't be said for cats whose column sizes exceed 28.6mm. This conversation includes that you 1) can even make a fork in the first place when so many of your brethren can't, or won't and, 2) you've designed the fork to work with (sic) the frame you're being commissioned for. Part of that conversation includes a relationship between the fork rake, the front center, and the rest of the bicycle's dims. You choose the pipes, you curve the blades, you're committed to fulfilling dreams, and you have to make it all work. If in this example, the design calls for a 47mm rake, you curve the blades and trim the length so that the axle is at the 47mm mark. The curve and the radius it's bent over serve a purpose; to deliver the dropout someplace so that the 47mm dim is yielded. If the center point of the dropout (the place where a hub axle resides) falls behind the path that delivers it, then you've bent the blade more than you have to. It's akin (kinda') to putting 50mm rake into both blades, but then setting the fork fixture to 47mm so that 47mm is what the fork itself has when brazed. You'd still have a 47mm rake fork, but the blades would be leaning rearward from center. These parts all work in harmony, or should. On the other hand, if the issue here is that the plug dropouts, the blades at hand, and the ODs and IDs only allow a certain range of intercept before the male and female thingys no longer fit, then you are fucked. The ideal is to make them work, to show the parts who's boss, and NOT concede to the fact that the dropout only fits in a certain place of the blade when it's cut to length so that's where it has to get brazed. That's bad design, too. You want the blade to have a curve that's just the right amount so that the rake is as designed, and so that the hub axle at rest is in the path the runs through the blade's center line rather than in front or behind it.

You can get mediocrity at the LBS or from Ribble. Folks hire us because there is no such thing as a small detail. The confluence of the front axle and the blade whose path delivers a dropout into the correct spot shouldn't be compromised by having it anywhere other than centered.

[JohnnyChromatic]

On one hand, you (the independent effbuilder...) have started the conversation by choosing to make a fork rather than buy one from Forks R Us. That's a plus, and you're lucky that industry has parts for you. The same can't be said for cats whose column sizes exceed 28.6mm. This conversation includes that you 1) can even make a fork in the first place when so many of your brethren can't, or won't and, 2) you've designed the fork to work with (sic) the frame you're being commissioned for. Part of that conversation includes a relationship between the fork rake, the front center, and the rest of the bicycle's dims. You choose the pipes, you curve the blades, you're committed to fulfilling dreams, and you have to make it all work. If in this example, the design calls for a 47mm rake, you curve the blades and trim the length so that the axle is at the 47mm mark. The curve and the radius it's bent over serve a purpose; to deliver the dropout someplace so that the 47mm dim is yielded. If the center point of the dropout (the place where a hub axle resides) falls behind the path that delivers it, then you've bent the blade more than you have to. It's akin (kinda') to putting 50mm rake into both blades, but then setting the fork fixture to 47mm so that 47mm is what the fork itself has when brazed. You'd still have a 47mm rake fork, but the blades would be leaning rearward from center. These parts all work in harmony, or should. On the other hand, if the issue here is that the plug dropouts, the blades at hand, and the ODs and IDs only allow a certain range of intercept before the male and female thingys no longer fit, then you are fucked. The ideal is to make them work, to show the parts who's boss, and NOT concede to the fact that the dropout only fits in a certain place of the blade when it's cut to length so that's where it has to get brazed. That's bad design, too. You want the blade to have a curve that's just the right amount so that the rake is as designed, and so that the hub axle at rest is in the path the runs through the blade's center line rather than in front or behind it.

You can get mediocrity at the LBS or from Ribble. Folks hire us because there is no such thing as a small detail. The confluence of the front axle and the blade whose path delivers a dropout into the correct spot shouldn't be compromised by having it anywhere other than centered.

OK. I've seen plenty of forks designed such that the axle does not line up with the blade centers, mostly on mountain bikes. There are probably mechanical and esthetic reasons for those designs, with or without suspension. From an esthetics standpoint, I agree that axle to blade-center alignment is important. But I can also see how someone may want to make the alignment off by up to 1-2 mm in order to achieve a certain look. Other than having the desired rake, and to a lesser extent, maximizing the strenght to weight ratio, is there some other mechanical reason for aligning the axle to the blade center. I am thinking mostly in terms of tabbed dropouts. Plug and socket dropouts are obviously (to me anyways) much more demanding, alignment-wise.

More generally, it's clear that esthetics are a critical factor in the success, or lack thereof, of a custom frame builder. Is that all you're really saying?

As a newbie, I apologise if I am beating a dead horse or hijacking the thread.

[e-RICHIE]

OK. I've seen plenty of forks designed such that the axle does not line up with the blade centers, mostly on mountain bikes. There are probably mechanical and esthetic reasons for those designs, with or without suspension. From an esthetics standpoint, I agree that axle to blade-center alignment is important. But I can also see how someone may want to make the alignment off by up to 1-2 mm in order to achieve a certain look. Other than having the desired rake, and to a lesser extent, maximizing the strenght to weight ratio, is there some other mechanical reason for aligning the axle to the blade center. I am thinking mostly in terms of tabbed dropouts. Plug and socket dropouts are obviously (to me anyways) much more demanding, alignment-wise.

More generally, it's clear that esthetics are a critical factor in the success, or lack thereof, of a custom frame builder. Is that all you're really saying?

As a newbie, I apologise if I am beating a dead horse or hijacking the thread.

The aesthetics are a byproduct of sound design. When the center line of the blade, and the path taken from it to the axle, and the resting spot in the dropout where forces push the axle into a resting place all line up, that is sound design.

Regarding plug dropouts, fork blades, dims, interference fits, and IPAs, there is one rule: you don't settle for what's available. You make it all work for you, you have the vendor redesign the tools that yield the parts you really need, or you keep shopping. PS Smuttynose Finestkind atmo.

[e.Gellie]

Until that happens, could one not simply swap left for right and re-braze the eyelets?

On droputs like the Paragon DR1050 the eyelets would not need any modification as far as I can see. No lawyer lips though.

Attachment 66630

Mark, in my opinion yes that would be OK. It's all about the angle, the slot being angled forward of a line passing from the Brake-pad to the -Wheel-axle.

[e.Gellie]

They are in backwards and the axle ends up a few mm's off center. Even if they were in the other way the axle would be off center. I'm not worried about this at all since there's plenty of bronze in there and the offset is minimal.

Joel, so you removed and re-located the eyelets?? These look different, but I reckon the desired angle is not quite there. See my next post....
N disc fork L.jpg C pic.JPG

[e.Gellie]

The Paragon family of straight plug dropouts should check all the boxes. When installed on raked blades the opening will face slightly forward so that braking forces should pull the axle in and not out. They have lawyer lips. They are symmetric and available with 0, 1, or 2 eyelets. They can be welded or brazed. And they are made by Paragon so no questions about quality.
www.paragonmachineworks.com - DR2017SteelFrontDropoutPlugTypeNoEyelets

David, not in my opinion. This pic is of my test-mule fork: without a perfect fit of the quick-release-skewer head in the lawyer 'rim', it squirmed. Which felt horrible. The wheel didn't come out, but it clunked out of place under braking.

Here's another go in words ..."the slot needs to be angled forward of a line passing from the Brake-pad to Wheel-axle."

Raked or straight blades are not the specific issue. It's all about the angle relative to the "Brake-pad to Wheel-axle" line.

-----------

If the fork tip is angled forward of the "Brake-pad to Wheel-axle" line, wheel-axle tries to bury itself deeper into the slot under braking forces, and all is good. And so all the skewer must do is clamp the dropouts together enough that they don't spread and release the axle. Which I'd say is all they were originally designed for.

P straight tip.JPG

There is something on the web about what happens if the slot isn't forward. Something to do with a tandem. Not too hard to find. We are all trying to get our heads around this. Carefully considered ideas are vital.

[Rich Beaudoin]

Hard to see because qr obscures view, but I brazed these socket dropouts in 'backwards' so the slot is almost horizontal opening forward. The wheel doesn't move at all under hard braking. And it sits in line with the blade too. image.jpg

[GEBLA]

Good Morning from the old world,

I designed my fork ends for disc brake in a way, that the axle sits a few millimeters in front of the blade. The reason ist that the brake caliper sits closer to the blade this way, which leads to a smaller disc brake adapter, lower leverage and therefore lower forces. The design is also stiffer, which is better to avoid squealing. Having made more than 100 disc forks over the past years, there has not been a single complaint.

I also find it important that the disc brake adapter is connected to the fork end in some way (or is a single piece). The brake moments are high and should not be translated through the blade only. Very often you can see pics of people taking huge risks by using simple disc brake adapters that create sharp corners and stiffness variations where the moments are highest. Good luck to the rider is all that can be said in those cases...


GEBLA120207.jpg

GEBLA120208.jpg

Greetings,
Georg

[David Tollefson]

Could one not also put the brake caliper on the OTHER fork leg, forward of the blade? Changes the force angle enough that reversing the dropouts is unnecessary.

[Will Neide]

Could one not also put the brake caliper on the OTHER fork leg, forward of the blade? Changes the force angle enough that reversing the dropouts is unnecessary.

I think Cotic does this.

Aesthetically it's not my cup of tea. I'd be interested to hear what the mechanical or functional advantages are though.

[Clockwork]

Joel, so you removed and re-located the eyelets?? These look different, but I reckon the desired angle is not quite there. See my next post....
N disc fork L.jpg C pic.JPG

I didn't. The dropout must have changed from the time that Nova pic was taken.

[Eric Estlund]

The drop out in the inset photo is a Long Shen LE101-1 . Nova calls it their NOV-DROP-106. I bought a set the week they released this stuff and reported back to them that the fit up, while functional, was sub optimal.

They are now suggesting what they call NOV_102M_DSK, which has a larger diameter plug. I believe (don't know) that this is a LiowKo product.

I have had a similar conversation with Reynolds that produces a similar blade- there really isn't a market available plug and play drop out yet.

[blasdelf]

I also find it important that the disc brake adapter is connected to the fork end in some way (or is a single piece)

It's a very good idea to integrate it, but making an IS tab as a single piece with the dropout turns out to be a pain.

On the rear the inside face of an IS tab is in plane with the dropout, but a front hub has the rotor 5mm further outboard than the rear.

The spec has the front tab offset by 4mm to accommodate that. Shimano gets the last millimeter by having the front caliper adapter be thinner on the mating side, Avid doesn't bother.


I used these prototype dropouts on my bike that Alex Wetmore designed for high-offset curved forks, it takes a 180 adapter for a 160 rotor to keep it low profile:



It uses Keith Anderson's TITO inserts which get it 1mm of offset, but as we discovered that's not enough to function -- Alex milled recesses out of a caliper adapter to fit on his, but on mine we just cut the dropout off and reattached it with an offset.


Our next attempt at an integrated disc dropout is probably going to be post mount, which has the centerline of the bolts 1mm inboard of the dropout face. That makes it more practical to machine, since you can start with 3/8" plate and relieve just the dropout area from the inside.

[steve garro]

my name is Fred Blasdel, if you couldn't figure that out without this signature you should take an internet class at your senior center.

The google results are fucking hilarious!

"Look at her, she's been screwing every guy she meets! Yeah, she's gettin down with her bad self."

- Garro.

[blasdelf]

apparently the senior center in Warwick doesn't have wifi

[e-RICHIE]

apparently the senior center in Warwick doesn't have wifi

Don't go there Fred.

[Jussi Kettunen]

Anyone using Reynolds 631 or 853 raked 27.5x20x1.1 blades?

Before purchasing them I'm trying to figure out if it's possible to build ~395-400mm AC fork with them with right fork crown, they're quite short at 370mm.