A solution to NOT drill your track forks and have a normal front brake nonetheless

Hi,

after buying a sweet track frame+forks from daveray some time ago, I was really unable to drill the forks as it felt like rape. At the same time, I definitely need a front brake so I started to think about a solution.
Clip-on's were just not satisfying (too heavy, too bulky, too expensive, limited choice)

So this a first sketch of my solution, please let me know what you think of it:

Description: you take a piece of stainless steel, about 60x10x4 mm, bend it, file two slots in there and drill two holes. Then you add to it a normal 1" ahead star nut +bolt. And a normal nut (+washer, or a locking nut).
Then you take your favourite front brake and cut the bolt to around 10mm. Add threading with a thread cutter if needed. Mount everything into the hole at the bottom of the steerer and done.

Issues:
Some people (like me) have a very tight clearance between forks and tyre. Due to the slots, the clearance needed is already reduced to 3mm in my design. If it has to be less, the slots could be deeper (2mm) or the stainless steel could be replaced with titan alloy to maybe achieve 1.5mm.

Image: see below, a quick first rendering of piece + bolt + ahead double star nut

jetski

http://www.lfgss.com/picture.php?albumid=1518&pictureid=8918

Good idea. Wouldn't work on the bike I have due to a wafer thin clearance, but nice design that would work for most forks.

Hmm.
That is a lot of pressure on a single plate of metal, my worry would be bending that or getting too much flex out of the brake by not having a wide enough surface area to bolt ratio (if that makes sense)...

it's not directly pressure but more like tensile stress (wheel moves forward and is stopped by the brake). Especially if you move the hole a bit lower towards the tyre, the tensile load is almost a linear pull.

Also, the piece could be a lot wider than 10mm (for example 20mm or more).

When the brake contacts the front wheel it will pull this mount forward - I doubt the SFN would resist that force sufficiently, I see the whole mount being constantly pulled forward and down.

EDIT, but I like the idea - and your render.

. . . Especially if you move the hole a bit lower towards the tyre . . .

The hole would need to move up as the mount is further forward than a normal hole - and the further you get away from the fork the wheel rises (until it's apex).

Great idea. I'm seriously impressed !

Someone did that to a BMW gangsta so they can run road brake, think it work rather well.

here's another idea - what about drum brake?

When the brake contacts the front wheel it will pull this mount forward - I doubt the SFN would resist that force sufficiently, I see the whole mount being constantly pulled forward and down.

EDIT, but I like the idea - and your render.

Not sure, it's something that needs to be TESTED ;-)
From my experience, ahead starnuts are f*ckin' tough and get even tougher when you pull them (that's the idea behind them), - AND - you could actually use 2 or 3 of them in a row.

The hole would need to move up as the mount is further forward than a normal hole - and the further you get away from the fork the wheel rises (until it's apex).

if the steerer angle was 0, then yes, otherwise it should not rise?

ed: That's interesting and similar to my idea above, but I would not trust a normal quill mechanism as much as a starnut, as the starnut concept is based on getting stronger when pulled, while the quill force stays the same.

What is good about this idea is that the quill reaches so deep into the steerer, and that you keep the strong connection between caliper and quill. But few people will have such a long steerer that you can fit a quill from top and bottom at the same time (and the clearance issue is not resolved here, of course).

In my design, both of these issues can be improved by choosing a thicker piece of metal, for example 60 x 20 x 8, and the thickness of 8mm filed down by 6mm to have 2mm at the slots, and using two double starnuts in a row with a long bolt. This way, the piece will sit deeper in the steerer tube and also 'lean' on the steerer tube at the outside. And, the calipers will have a 8mm deep hole + nut to sit in.

Another solution would be simply buying another fork, steel fork are ten a penny after all.

Good idea. Wouldn't work on the bike I have due to a wafer thin clearance, but nice design that would work for most forks.

Actually I might have a similar situation, BUT ... there might be a way to change my design to almost zero clearance, by making use of the fact that the tightest point between forks and tyre is often only a thin line between the very top of the tyre and the forks (as a wafer thin clearance all around the tyre down to the rim is very rare?)

Another solution would be simply buying another fork, steel fork are ten a penny after all.

That is quite cheap.

I've got something similar which works.

Designed by a mate who designs for a living.

thats pretty cool, I assume the wedge tightens from below?

I've got something similar which works.
Designed by a mate who designs for a living.

Same here. :-)

His way to use a tyre-like rounded piece instead of flat is what I meant when I said I'd like to make use of the fact that the tightest point is at the top of the tyre.

I am wondering why your mate has it reaching out so far if you know what I mean? You could have it a lot more compact I think. The short 'stem' is good, but I guess this combined with a starnut might be better?

Are you actually using this one? What's your everyday experience with it?

(and who's your mate? :-)

Surely you could make a headset mount that replaces the crown race, like you see on some racks.

Some cool ideas on this thread

Not sure, it's something that needs to be TESTED ;-)
From my experience, ahead starnuts are f*ckin' tough and get even tougher when you pull them (that's the idea behind them), - AND - you could actually use 2 or 3 of them in a row.

I suspect the forces on the SFN/s would not be in their strongest direction (vertical pull).

2 or 3 would help like you say - also testing might show that they really are strong enough, I like the whole idea, but I would be tempted to avoid the SFNs - and use something with much more contact area with the inside of the steerer.

if the steerer angle was 0, then yes, otherwise it should not rise?

Whoops, sorry, good point, of course I am wrong here - the steerer / head tube angle is not likely going to be 0° !! Sorry not thinking when I posted that.

Quite a nice idea. Just needs a bit of fine tuning. I think a wedge type thing would work better and it also means the whole thing can be removed easily. Getting star nuts out are proper arseaches.

I've got something similar which works.

Designed by a mate who designs for a living.

can i get a picture of the fork that's on?

Truly great thinking... and also what Oz says, those SFN's can be little bastards...

Might need to be made of steel for strength..??? (at least the hanger part)

the star fangled nut isn't going to be rigid enough i wouldn't think.

this

is a refined design of your idea. which would work much better i would think.

btw, DMczone, you never cease to surprise me with the things you know/have.

the star fangled nut isn't going to be rigid enough i wouldn't think.

this
is a refined design of your idea. which would work much better i would think.

btw, DMczone, you never cease to surprise me with the things you know/have.

Truly great thinking... and also what Oz says, those SFN's can be little bastards...

I suspect the forces on the SFN/s would not be in their strongest direction (vertical pull).

2 or 3 would help like you say - also testing might show that they really are strong enough, I like the whole idea, but I would be tempted to avoid the SFNs - and use something with much more contact area with the inside of the steerer.

I know that you really love your quills, especially as we are not in a mtb forum here, but they are old technology. There is a fundamental difference in what quills and ahead sets are used for, it's not interchangeable: the quill concept is characterized by providing a *height-adjustable *locking mechanism.
This is not needed/wanted in a brake mount. Please keep in mind why the starnut was invented and how it works. When ahead sets came up, you were in need to replace the torque that is provided by a very large screw on a normal headset, to basically clamp the whole steering set.
That's definitely a higher force than the quill force that does not clamp anything, but just tightens itself into a tube.
A starnut actually 'cuts' slightly into the tube and can't be moved back even without tensioning it, let alone when there's tensioning applied.
A quill just lives on its friction and won't get stronger when pulled and might have the danger of being slowly moved out of its hole due to frequent sudden brake force shakings.
**
What's correct** is that the force applied onto the hanger piece itself needs to be adequately redirected into a linear pulling force on the starnut to avoid a non-linear pull.
This can be done by having a little stem-like piece as in dmczone's image, but then adding two double-starnuts in a row. This way, you got it all. Including full tensioning of the piece against the forks.

A word about quick mounting/demounting: think about when you would need that, I can only think of two situations: a) change from track to street and back or b) change from brakeless to law-complying.
With the starnuts already in there, a setup change would be even smoother than a quill. And if you ever want to completely remove the starnuts: yeah well, then take a suitable steel tube and hammer 'em out through the top. Takes 10 seconds.

jetski

A star nut isn't the best of both worlds...an expanding wedge is, and i don't mean a quill style wedge.

The types used for carbon steerers make the most sense as they expand evenly all the way round unlike a stem style wedge quill, but they also allow tensioning against the base of the fork like a star nut whilst still allowing complete removal without resorting to hammers and scoring the inside of the steerer.