Hunter Info

To anyone who can help me:

Are all the bars on a hunter unicycle frame hollow? I’m trying to build a hunter frame and I need to know tube diameters and thicknesses.

Budd White

Only Rick Hunter can build a Hunter frame. You mean to say that you want to build a Hunter copy or look-alike. :smiley:

I believe that, yes, they are hollow. Otherwise the frame would weigh a ton. However, how can you make a copy without having one to copy?

For unicycles with handles, the future design of frames will probably be based on a triangle (instead of a line). This concept started with the Hunter and Telford frames, but does not address the stress problems and extra weight we keep adding up in the seat/seatpost area.

The three points of the triangle frame design would be the wheel axle, the seat tube, and the area where the seat handle would be. This was an idea that popped into my head yesterday (January 12, 2004), and I think may be the direction for high-end frames in the future. I think this will especially be true for high-end road unis, like custom Cokers.

Of course you can copy a Hunter frame without having one in front of you. It will just be a less accurate copy. But if the person asking doesn’t even know if frame tubes are hollow or solid, they have a lot else to learn before making their final frame.

Wow!

I can’t wait for my JF24! Will they be powdercoated?

I’ll get to work on those as soon as I finish updating my web site… :roll_eyes:

Re: Hunter Info

And is there any specific reason you haven’t called Rick? Go to the link below and be done. He’s really nice, and when I asked he even offered to send me some bearing bearing housings. I don’t reccomend trying, though, you better be a damn good welder, I know he brazes his stuff. But seriously, just drop him a line.
Look no more

Hunter uses regular bicycle tubing for the unicycle frame. The tubing for the legs on the unicycle are the same as used for the seat stay on the Hunter bikes. The tubes are hollow.

You might be able to get the tubing from a local bicycle frame builder.

Re: Re: Hunter Info

So Rick mailed you bearing housings for your unicycle?

It’s not that i dont know alot about the hunter unicyle. I have only saw pictures of it but I have made scale drawings of it. I don’t have a hunter frame to look off of because they are so dam expensive.

I’m going to use Cr-Mo tubing to build this uni. The welding is no problem because my father is an awsome welder. I just need to worry about bending the fork tubes perfectly.

It’s not that i’m copying the Hunter frame, I’m goint to try to improve it also.

If you have any suggestions, please reply

Budd White

Re: Re: Re: Hunter Info

There’s nothing wrong with copying like that, Budd. It’s the way people learn a new skill. Writers, painters, actors, and frame builders do it. The first unicycle I built was essentially a copy of one I bought from unicycle.com. I’ve improved a lot since then, but it was a really good way to start.

When you talk of “improving” the Hunter, you should consider carefully what you are trying to improve and how you will demonstrate clearly that you have improved it. To do this, you have to be able to demonstrate the inadequacy of the original frame for certain tasks (what you are trying to fix). Simply adding tubing or changing an angle changes the frame, but doesn’t necessarily improve it.

Making a copy of a frame, then demonstrating side-by-side that they are identical, would be a huge, fantastic first step for an apprentice frame builder.

These comments are valid for any aspect of unicycle construction, or even engineering in general.

To improve the frame I plan on welding a cross bar between the two forks, at the point where the brake attachments are located. I hope that this will prevent the frame from bowing when the brakes are applied hard. If I don’t end up putting brakes on my first replica, it will just be a straight replica with no cross bars.

Budd White

How do you know that the frame bows? To what extent does it bow with what kind of brake pressure? What range of brake pressures are relevant to the riding you are thinking of? What amount of bowing is acceptable? How much do you expect a crossbar to improve the amount of bowing? How much does the crossbar actually improve the amount of bowing?

These are the kinds of questions, the answers to which will put strong oooomph behind any claims that your new design is better.

Otherwise, you have only increased the complexity of the frame, making it harder to manufacture, and heavier as well.

That’s true, but how will I know if I don’t try?

A 5’ doble bar arc’s 0.22 inches after 50 pounds is applied. Over time the frame can bow.

Budd White

I’m not trying to discourage you, Budd. Go for it. I’m really interested to hear about your progress!

Instead of copying an existing design, why not use it as a base for something different? The Telford, for example, is an elegant and great-looking frame, doing the same job.

To try something new, address the handle area in front of the seat. Instead of supporting the handle from the front of the seat (putting stress on the seat base), or from the seat post (stressing that area), it might be possible to end up with an overall lighter unicycle if the handle is considered as a part of the frame.

The main questions is, I guess, how to make the handle adjustable like a seat. How’s that for a starting point?

(Sorry, hit the enter by mistake :astonished: )

On that same line of thought,
If you’ve never actually seen a Hunter frame, let alone ridden one, why do you assume it needs improvement?
I’ve got two Hunters and a third on the way. They are great frames and as far as bowing at the brake bosses, my MUni’s set up with Maguras are capable of stopping the wheel with way more power than I will ever use or need.

(I believe the Vortex frame has a connection at the brake boss location from the front leg to the back leg.)

Some have posted here in the past about the Hunter frames and how they don’t make sense from an engineering standpoint. But in actual use, riding, which is really what matters, it is a great handling and extremely durable frame. It seems that “improvements” may not be the right word, maybe just something “different”. I also happen to love the looks of it.

Have fun with the project and please don’t misinterpet my post. It is not an attack, just a take from one who has logged many miles on Hunters.

  • Frank :astonished:

I suppose I should weigh in here as I’m having Rick build me a frame with a link between the fork blades at the brake boss.

Why did I request this? Braking power was never a consideration, nor was strength of the frame a concern.
When the brakes are applied they push in on the rim which bows out the frame, however the frame bow is very small compared to the travel of the brake so it really has no effect on braking force. All it does is cause the lever to feel a bit spongey, which isn’t all that bad in my experience because it can make it easier to judge how much force you are applying at the rim. And since the bowing is almost certainly below the elastic limit the frame won’t take a permanent set. (At least, not from just braking. Hitting a truck while braking might cause some permanent deformations…)

The rim applies a traction force to the brake (and vice versa) that also causes the fork to bow slightly, however this is also negligable unless the brake sticks and unsticks which could, theoretically, cause a vibration at low speeds. I wasn’t too worried about this either because the effect can’t really happen at any speed where I would want to use the brake.

However, since the traction and inward forces are applied off-axis with respect to the fork they also apply a twisting force (a torque) to the fork. This is the effect that I was worried about. “Worry” is really too strong a word here; clearly people have brakes on Hunters that work, so perhaps “curious” is a better word.

This twisting force causes a slight misalignment of the shoe against the rim. A twist of even one or two degrees dramatically changes the pattern of pressure between the brake pad and the rim. If the brake shoes are perfectly aligned with zero brake pressure, then when forces are applied the shoes twist out of alignment, which dramatically reduces the force, so the shoes spring back into alignment, the forces build up again and the cycle repeats. This is what causes the infamous “brake squeal” on poorly aligned bicycles.

Savey bike mechanics “toe in” the brake shoes so that applying the brake brings the shoes into perfect alignment to maximize the braking effect and eliminate the squeal. On some bikes I had to toe the brakes in as much as 5 to 7 degrees to get the bike to stop squealing.

Now, on my Hunter Coker will I ever apply the brakes hard enough to make them squeal? Doubtful. However, I’m a belts AND suspenders kind of guy. The fork stays are so long, and the tubing so narrow that I figured there was a possibility of squeal, and also figured that the brakes would be more predictable if I did something to control the alignment of the pads. (Note that a “brake booster” does exactly the same thing - control twist - but from the other end of the brake bosses.) This extra tube radically stiffens the fork tube against torsion, and it’s not that big a deal to add, so I figured it would be cheap insurance. I don’t like brake boosters and didn’t want to have to add one later to fix a problem that is more elegantly solved with this extra link.

Did I think it would be cool to have a unique Hunter? Yeah, a bit.

Did I think it would help other Unicyclists to recognize my oddball Coker if it ever got stolen? Definately! This is the real reason I added it. DC is full of fixed-gear fanatics who a) don’t make much money, and b) would love to have something as funky as a Hunter Coker. (It’s one of the main reasons I got a Hunter - it can be posively locked.)

I have noticed that the Airfoil rim abrades in a ripply way, which is consistent with the catch-release concept. I noticed it with the Magura brake on my standard Coker frame with one normal brake post.

Unlike normal road brakes, Magura brakes are specifically designed to be used with zero toe-in and work fine that way. However, to improve modulation for a unicycle, where a light touch can bring much good, it’s good to toe them in a little and angle them some as well.

Cyberbellum, what you say makes sense and I have no doubt that Rick will make you a great frame that you will love. On my Hunter36, I do toe the brakes in a little bit and don’t have a problem with squealing. In normal use, you never crank hard on the brake, but every once and a while, like a panic stop on a steep downhill, I sometimes use it hard. I have noticed the ripply pattern that U-Turn mentioned on my rim as it has seen LOTS of braking in its short life. Doesn’t seem to be a problem yet though.

Have fun with your new machine when he finishes it!

—Nathan

Interesting.

Are the ripples aligned with the spokes or independent? Spoke tension bows out the sides of the rim (either at the spoke holes or between them, I can’t recall) so the brakes wear down the high spots giving a ripply pattern on most wheels. Given the extreme tension of the spokes in your ultimate wheel the rim may be deforming in an unusual way.

If it really was catching and releasing you would notice a squeal or chatter as you braked. Does this occur?

The Maguras use magnets to hold the brake pads in place. This isn’t a solid mount, so perhaps the shoes are squirming around a bit as the brakes are applied.