Style and Fork Inspiration

[Andrew R Stewart]

So I need some more help. I'll be building a couple of touring bikes in a year or so for me and the wife. I've done this before and have most of the short comings of the previous frames figured out. This time I'll use larger diameter tubing and a 1.125" steerer. The frame will likely be filleted given the geometry and tubing.

I like to have all the frame joints match in style. A lugged frame gets a socket style (lugged) crown. A filleted frame gets a crown with internal plugs.

So my question is does any one know of a crown with a 1.125" steerer that has clearance for 32+mm tires and uses internal plugs (for that smooth lugless look)?

Or other suggestions? Andy.

[Amaro Bikes]

Hi Andy

Here you have Peter's list, and there're at least a couple of them matching your needs
http://ceeway.com/NEWPARTSPAGES/Cast...k%20Crowns.htm

Cheers

[Andrew R Stewart]

Aimar- Thanks but I already have checked out Ceeway's selections. The problem is that I want it all. Wider then 40/41mm tire clearance, substantial crown cross section between the steerer and blades, 1.125" steerer and the plug style blade joints.

The J04 and SCA both have too little tire clearance and narrow crown cross section. The LC20 has WAT too little clearance. The others are either a socketed blade joint or for the wrong blade/steerer. But i do have a pending order (waiting for tool to be restocked) and might add two of either the SCA (but it doesn't indicate the steerer diameter) or the J04 any way.

I have made a couple of bikes with crowns having the slim cross section (shoulders) before and felt that they were a bit flexible. For the non touring bikes they were this was not bad. But i've watched my front axle move back and forth what seems like a couple of cm's under braking forces when using a crown like the LC27. Going to a stiffer steerer (1.125") will help some but i wonder how much flex is in the crown.

I have a year to dwell on this... Andy.

[Will Neide]

Why not make your own lugs to accomodate the odd angles or do a bilaminate design to give you a consistant look with a lugged fork?

[blasdelf]

but i wonder how much flex is in the crown

Nearly all of it, look at where they yield when crashed. People fuss over the curve of the blades, but forks just don't flex much there unless you use really small tubing.


I don't think the plug crown you're looking for exists. There are some candidates from the early 90s MTB boom, but I don't remember any being a perfect match, and it's not like you'd find one unbuilt anyway…

Your best bet for the smooth style you seek is to get creative with unicrown construction

[echelon_john]

I'd vote for unicrown too. Mostly because every time you type it, it autocorrects to unicorn, and who doesn't love unicorns?

But seriously, I think taking the time to do a unicrown (it did it again!) fork with nicely raked blades would make a really nice look with a filleted frame.

[Jim N]

How's about a plate crown? They are easy to make and to my eye match a filleted frame.

[timto]

i was in your same situation for an upcoming bike I'm making. I went unicrown to best match the fillet of the main frame. I think the smooth shoulders , good clearance and raked blades will look good. I'm not equipped/experienced to rake blades but had Joel of clockwork do the honors...






Clockwork Bikes photo stream Uni-crown Blade Raking--60mm | Flickr - Photo Sharing!

[Chauncey Matthews]

Unicrowns are fun to make for a change of pace, but they always remind me of cheap mass produced bikes, ymmv.
In the past I've cut the seat tube sleeve to match the crown shape...it does a nice job of bringing the bike together and really opens up a lot of crown possibilities.
Here's a bad pic from a few years ago to show what I mean: Matthews Custom Cycles: Two posts in one day!

[afwalker]

Maybe find some old Tange unicrown blades? Nice blade at least.
But perhaps a Panceti crown. Not socketed, but a nice classic look brazed and wide enough for fenders.
BikeLugs.com
or even the mtb lug.
cheers
andy walker

[Andrew R Stewart]

Thanks all- Good ideas and thoughts.

Velo Wilco- i do hope to make my own lugs sometime but not yet. Not until I have my lathe up and an idea for the shore lines. Bilams never turned me on.

Blasdelf- Once we are at odds, :) Of the many forks I've seen bent from impacts very few had bent crowns and most of these were stamped steel units (IIRC). Many more steerers and blades with distortions have come past my eyes (including 3 of my frames). Maybe unicrowns are an answer.

Jim- I never felt plate crowns matcfilletedlleted frame. I think this is a recent thing. Probably because they are easy (so to speak) to do, like fillets.

E John and Timto- As said above, unicrowns meet all my requirements except my comfort zone. The issue of bending the top section and how much steerer height they take up have been the quI'veons i've had.

Chauncey- Yes, I like to tie in different parts of the frame stylisticly. We'll see if this needs to be a focus to make the crown match the frame.

Andy- The Pancenti crown is a plate crown with sockets, as far as I'm concerned. See above. That said i do have two on my shelf already.

So as you all might be saying, I am looking for a solution that might not be available. Glad I have a lot of time. Andy.

[blasdelf]

Blasdelf- Once we are at odds, :) Of the many forks I've seen bent from impacts very few had bent crowns and most of these were stamped steel units (IIRC). Many more steerers and blades with distortions have come past my eyes (including 3 of my frames). Maybe unicrowns are an answer.

I've seen a bunch with the common Long Shen crowns, including on a bike I crashed into a curb myself with a LC44 :(

When it happens there's also usually a hump in the steerer around the butt, and the blades have some mangling of their own, but when you look carefully the goofy new angles of the blades mostly start at the sockets

You also mostly see carbon forks failing right at the crown race, and if you think about it canti chatter on rough surfaces can only result from fork flex above the canti posts

[Andrew R Stewart]

blasdelf- Agree with carbon fork failures. The crown is the focus of the stresses after all and not all carbon forks have the engineering or production QC that the best brands claim to have. My understanding of canti chatter with carbon forks is that it is mostly a steerer flex thing. If the blades were a large component of chatter then the crown mounted hangers wouldn't fix the problem (like they do fix it). I've done the crown hanger replacement a number of times with very good results.

Whether steel cast crowns will bend in an accident is less my concern. But accidents are a worst case scenario. I think my goal of a stiffer crown is still a good one. Andy.

[timto]

Thanks all- Good ideas and thoughts.

E John and Timto- As said above, unicrowns meet all my requirements except my comfort zone. The issue of bending the top section and how much steerer height they take up have been the quI'veons i've had.

Update to this - Joel finished my fork. I'm pretty stoked how it turned out. Regarding height - yes it's tall 403 atc. This is taller than I had imagined. I think he used some nova blades for this and he has some pics that show clearance with a 32 cx tire. It's pretty generous. I like how he raked the blades too. OVerall i'm still very happy I went this route and will build the frame to match.

FWIW

[Will Neide]

Regarding height - yes it's tall 403 atc. This is taller than I had imagined.

I had a CX fork with an atc similar to that and it wasn't an issue. I'm generally not a fan of unicrown forks for aesthetic reasons, but that fork just looks "right." Very nice!