I have built a custom coker frame and several muni and trials frames and it really helps to have a wheel first to build a frame to. To get it straight and centered and to get the brake mounts if any in the right place build your wheel first. you can get close enough for ordering materials by knowing the size of wheel half of 36" is 18" then give yourself some extra for the crown. If you are building a custom frame I wouldn’t use the stock seatpost size which is 22.2mm or 7/8" I would use 25.4 or 1" or 27.2mm. If you havent built a frame before I would recomend useing cromoly steel which is much easier to work with and is plenty strong. If you already have someone who fabricates with Ti like a relative or good friend great but otherwise it’s going to be a very expensive frame.
A frame with a rounded crown is best for a Coker. You don’t need a flat crown. A rounded crown is narrower. Flat crowns tend to be wider and can end up rubbing your upper thigh as you ride. It’s a factor for some people, particularly those with shorter or fatter legs.
The Hunter 36" frame is a nice design for a Coker frame. Rounded crown and the frame is stiff. I wonder how well that frame design would work in titanium?
Pay particular attention to the bearing holders on the frame. You want quality bearing holders that hold the bearing securely. The cheap stamped metal bearing holders, like on the stock Coker frame, can (and will) wiggle on the bearings which translates into noticeable frame flex and wiggliness. You want machined bearing holders similar in style to the bearing holders on the KH unicycles or the Hunter unicycles.
And make it to fit the extra wide Unicycle.com hub rather than the standard width unicycle hubs. The wider hub makes for a stronger and stiffer wheel.
The stock Coker frame uses a 22.2 mm seatpost. I would suggest using something with a larger diameter. 25.4mm or 27.2mm are good sizes and there are regular unicycle seatposts available in those sizes. Larger diameter seatposts clamp more securely (less likely to twist or slip). Make sure the neck of the frame fits the seatpost without any slop. It may be difficult to find tubing with the right ID for the seatpost.
Think about whether you want to accommodate a extra wide hub (which lots of people prefer) or not. The stock coker does not have this, which supposedly results in more wheel flex (but, for some, the ability to ride faster).
Just be carefull with those demented fram demensions. I would suggest
using regular DIMENSION
> This is a request to you Coker owners:
> I want to build a titanium Coker frame, but I don’t want to buy a
> standard Coker frame first, so…
> Could you please let me know the current critical dimensions of the
> standard Coker frame?
> * inside distance between forks, both at the crown and at the bearing
> holders… if it’s different
> * space between inside bottom of crown and top of tyre/tire
> * length of seatpost tube
> *how long the total amount of tubung is so I can buy a long enough
> Oh, yeah… what’s the inside diameter of a standard Coker’s seatpost
> Also, if you have any pet peeves about features of the Coker frame that
> should be improved/changed/fixed… I’d like to hear that. too!
> Uniman is in Issue #‘8’ (http://tinyurl.com/oq8yk)
> mycellnumberareacode>(503) 989 5360, turned off
> sparrowhawk wrote:
> > ive been dreaming for years of the prediction made by the gods written
> > on the scrolls of Korteweg that i will be in a signature on a odd
> > invention made by man himself…oh you can dream…you can
> > dream
> Ducttape’s Profile: http://www.unicyclist.com/profile/12006
> View this thread: http://www.unicyclist.com/thread/53665
It’s not so much the material cost it’s the dificulty working with titanium it’s not something you can usualy do yourself unless you have access to a shop that works with Titanium. There have been other threads about titanium unicycles where you could get more specific details but it requires an oxegen free environment to weld it and it is very dificult to cut, bend, drill, or work in any other way. That’s why things made from it are so expensive.
I found a guy who will give me a quote on a custom Titanium Unicycle fame, but I need to get his a drawing and measurements… would someone be able to come up with a CAD drawing of a Unicycle frame similar to a hunter cycle frame… with the measurements… thank you…