Aluminum frame update from ALPHA Cycling Innovations

Unicycles and Equipment
1

Gentlemen (and ladies),

i recently recieved an email from Rod Wylie wondering what was up with the aluminum frames i spoke so much of back in the day. the “day” being late december…

well here’s the update:

since early january i’ve been studying my ass off. this is the first intense term i’ve had since i began my miserable yet soon to be over career as a mechanical engineering student. school has taken up way too much of my time and i’ve almost completely put the uni project on the backburner.
some professors have gladly given me some very valuable advice on the heat treating process i need to use after bending and before welding of the sheet aluminum that i plan to use for the frame. this was my only hangup and has now been solved.

in short, i’ve been fairly unproductive as far as manufacturing goes. my school term will be done in a few weeks (we only have eleven week terms in which we cram sixteen weeks of class time, hence the intensity) so i will be back at home where the magic can happen.

I talked quite a bit with Ben plotkin-Swing on the AOL instant messenger and he gave me his opinions on seat tube diameters and some other things. ben, if your reading this i appreciate it all and your still on the top of my list for testing/sponsorship…

the design for the 20" trials frame is designed totally around a profile hubset and a monty tire. the spacing of the legs is such that the inside of the frames legs will be about a sixteenth of an inch from the outside of the hub. i plan on including custom spacers to properly and cleanly maintain this spacing.
the fork legs stay a constant 3 inches apart from bearing holder to where they beign to follow the contour of the monty tire, and the frame will be 4.5 inches wide at it’s widest point, the top. the inside of the frame will follow the profile of the monty tire very closely with more than enough room for mud clearance and whatnot.
the top of the frame will slope down slightly from the seat tube to its outermost part in two flat sections, but will not be angled froward like the holme frame. this should provide adaquate placement of the foot for gliding and such, but was not a primary concern in the design.
the aluminum frame was figured on a CAD program to wiegh just under a pound, but i’ve since decided to make the first frames from 14 gauge rather than 16 guage aluminum, so they’ll wiegh in at a bit more.

at first i planned on only making a twenty inch frame and then later considering a 24" version. i’m now going to be producing both at the same time.
the twentyfour will be very similar to the above described 20, but will be disigned around a 3" gazz. it will have slightly more room for mud clearance being that it will most likely see more dirt than a twenty incher.
i’m planning on making a flush mount brake option on every 24 incher that can accept a four bolt magura set up with some spacers that will be included with the frame. if brakes are not run, there will be no protrusions and everything will still look pretty.

ben helped me decide to go with a 27.2 diameter seat tube on both frames. i was considering running a bit larger to fit a uni specific seat post that i also plan on offering.

the seat post will be aluminum with an angle adjustment similar to that on a thomson seatpost and a bit of forward and back adjustments. they will come with a top plate that will mount deirectly to a velo seat and i’ll probably end up making optional plates to fit schwinns and miyatas bolt patterns.

i’ve yet to throw the 24 into cad so i’m not sure of what it will wiegh, but stiffness around the brake area should be adequate. if the first run shows any flex i’ll have to go with an internal brake booster type plate. i’m guessing without any such plate it will probably a pound and a half at the most and be stiff as hell.

Since i will be doing all the manufacturing in my garage (excluding the laser cutting) custom seat tube diameters and lengths will be very easy for me to offer. a seat tube with a permanently mounted plate at custom angles should be fairly appealing for durability and weight savings, as well as give you that “i’ve got a custom uni designed around me, and you don’t” feeling that everyone loves.

Rod, i appreciate your interest and promise you and everyone else that these frames will be made available to you within the next few months.

since my computer access is low while i’m at school i haven’t been visiting the forums on a regular basis. if anyone wishes to contact me with questions please feel free to email me at:
Michealpritchett@hotmail.com
i will post any replies on the forum.

thank you to all that have shown interest and support. i’m looking forward to begining a career that will benefit those with similar passions to my own.

Mike Pritchett
almost CEO of ALPHA Cycling Innovations, INC.
michealpritchett@hotmail.com

2

You should really consider running a 30.0 inside diameter seat tube, as this is the upcoming standard mt. bike size, and it can easily be shimmed down to fit 27.2 or any other size one desires. You mine as well not make the same mistake as most other manufactures have in going with “obsolete” sizes (see: Hunter uni, semcycle, etc.), as you obviously have not in the rest of your design. It sounds awesome, put my order in!

3

indeed

that was my original thinking as well.
unfortuanatly mountain bike standards take wuite a while to make their way into the unicyling world.
the first ones will most likely be 27.2, but this could possibly change in the next few months.
i guess if i offered a 30.0 seatpost that will be better than anything out now…
maybe i could just include the 30 post with my frames and charge a bit more to cover the cost.
i don’t think anyone’s that attached to whatever post they’
re using to not want my uni frame because of that. in fact, i’d personally be more interested in that as a consumer…
thanks for the thought implant.

4

the seat post size of 27.2 will never be “obsolete”
(if i may be so bold)

5

Hey, nice to hear from you. Glad to hear that things are moving forward with the frames. Hope your school’s going well.

Ben

6

That sounds nice!
I’m also thinking that it would be a good idea to have some re-inforcement around the bottom of the main caps for grinding and pedal grabbing. Also, I think it would be an excellent idea to include the seatpost with your frame, and maybe an adapter as well. Keep us posted.

-Ryan

7

YES!!!
i presented this idea to Steve Howard shortly after he sent me one of his frames to torture.since SH frames are alluminum i was scared that just 1 missed grab would result in landing on the frame,cracking it right through.

i think a protective bearing cap for all bearing caps is a great idea.

8

rienforcements

The bearing holders will be a clamp similar to that on kris holms frame, but out of machined aluminum.
the top of the clamp will be very low profile and welded to the tapered rectangular fork legs. the bottom will be a bit thicker to take the abuse of slamming due to pedal grabs and grinding.
i was originally thinking of making them square on the bottom for grinding but realized that this may not be ideal when landing seat in front pedal grabs.
any input on that would be appreciated.

as far as missing and possibly ruining the frame, i think after properly treating the frame the aluminum should be very dent resistant.
being that the frames don’t support much as far as regular stresses go, i’m trying to use the thinnest material possible to keep weight down. as previously stated i was planning on using 16 guage, but decided to go with 14 because i feared the sixteen would dent to easily.
because i am bending the material i cannot use standard 6061-t6 aluminum. T6 is commonly used in the cycling industry and is the most ideal material next to 7000 series aluminum which is far to difficult and expensive to work with and usually fails earlier.
the t6 is the “temper” of the material or, in general, how hard it is. t6 aluminum will crack or tear when formed at the ninety degree angles in the design. luckily i can start with 6061 at zero temper. in this stage the material is highly formable and will be easy to turn into a unicycle.

after bending the sheets to create the tapered box legs and monocoque crown i need to temper the aluminum, then tig weld, grind, then heat treat, then shot peen everything, then anodize it all so it looks pretty and then finally, lazer engrave my fancy logo on each frame. it’s seems like alot to do, but is all needed to create the strongest lightest frame possible.

only highly abusive testing can tell, but i’m pretty confident the frame will live up to alot of direct impact.

9

Sounds great. Any idea on cost?

Thanks,
Andrew

10

cost

i think with materials and other peoples labor (not including the three to four hours of my own time estimated for the machining and preping of each frame) i’ve guessed my costs to be slightly over a hundred bucks a frame.
i had a connection for free laser cutting, but i think i lost that hook up. so each cut design will have a two to three hundred dollar set up charge plus a few bucks per slice. each frame will be made of two laser cut parts, so thats up to 1200 bones in fixed costs regardless of how many frames i make.

i really just want to make enough from this project to cover my costs and allow me to treat a few deserving riders to some free swag. any additional profit will likely go into development of a hub i have in mind, think ISIS standard (see all the best mtn bike crank arms), Chro-mo spindle, thin hub spacing, and uni specific machined 7075 aluminum crank arms…
oh no, i’ve said too much.

im guessing first run frames will go for around 250. i’m not sure how many of these i can sell, so i’ll probably toss them on ebay at first. then maybe i’ll get in touch with the folks at unicycle.com. only problem with that is that i would be adding a middle man which means my profits would go down or the price for you people would go up. both possibilities are bad. the upside to uni.com is that it would be free marketing in that everyone who would be interested in such a product would see it there, possibly increasing the number of frames sold and allowing me to sell them for less.

my primary career goal is to make a name for myself in the cycling industry and i can’t think of a better and hopefully more appreciative part of that industry than unicycling.

11

Re: cost

why do i need to be more appreciative? there is only glory though god…

12

Re: cost

Be careful with your design for an ISIS hub. Using the ISIS design does not guarantee a strong spindle. See Sheldon Brown’s experience with an FSA bottom bracket
<http://www.sheldonbrown.com/fsabb.html>
I beleive FSA has redesigned their BB after that.

13

true

Mr Childs,

I agree. although i believe good designing, engineering, and manufacturing can ensure one hell of a spindle. as nice as it would be to make a ridiculously light hub, similar to the one in your example, a hub/spindle has to be strong. unfortunately that means it also has to be heavy. proper research could yeild design and material optimizations making a hub with a better strength to wieght ratio possible.
and if not, i’ll just keep buying profiles. they seem to do the job quite well.
the isis thing just comes from it’s noticeably stiffer design and would allow the use of better mtn bike cranks as well as optimally designed uni specific crank arms that could be made out of aluminum rather than tubular chromoly, making them easier to manufacture and noteably lighter.

14

errr

errr,

i just re-read the FSA bottom bracket story after a cup of coffee and realized i read the part about it being light wrong…
so that part of my theory is shot.

but, as shown in the picture and noted by the author, the failure was obviously due to engineering error. stress risers=pain.

i’ve noticed this after cracking many a cheap trials fork at the point where the lower bearing race presses on. back in the day most forks had a sharp edge there that would serve as a high concentration area for stresses. after catastophic failure on about three forks over a few year period i realized this and have since avoided any bottom brackets, forks, pedal axles, and wheel axles with noticable shap edges.

15

I think you should consider making the bottom part of the bearing holder steel for grinding purposes. Ask any BMX guy and he’ll tell you, aluminum does not grind well, nor does it stand up to that kind of abuse for long. Steel is more slick, and lasts longer under those conditions. Have you thought of making a clip-on plastic bash gaurd to protect the bottom of the crank arms? I think someone should make one, I know my profiles are getting pretty banged up, and I fear one day they we be so dented that I have a hard time getting the bolts out. Just an idea.

16

both very good ideas. as a former bmxer i certainly realized and agree that steel slides much better. i had considered making the bottom caps out of chromo, but decided it would jsut add wieght. it’s actualy nice to know that people would be interested in steel caps, they would be cheaper and easier to make. that is certainly going be made an option for those who are into grinding. i will most likely offer the aluminum caps stock though.

as far as clip on things go…
on my trials bike, i have some clear hose that i cut a slit down, form it over my left crank arm (it just covers the bottom and about a quarter inch on each side) if you drill a few holes you can secure it with zip ties. the holes are so the zip ties are under the hose, that way they dont just tear whenj landed on.
this would work well except for grinding…
making a clip on or otherwise fastened gaurd would probably be successful. only problem being crank arm compatibilities. i guess most people will be using profiles for seriously abusive riding so that could be possible starting point.

i’m not too familiar with the molding of plastic. machining is somewhat of a pain and usually smells bad. not to mention the expense of all that wasted material it would take to make a hoolowed out clip on guard. i’ll keep it in mind though. seems like it’d be easier and cheaper to just amke yourself a custom guard, maybe you could sell a few and buy a bb gun or something. that’d be cool.

17

Hey Mike!

Thanks for responding to my inquiry. During the testing phase, will you encourage testers to share results? Would you schedule the feedback to occur after a certain time, or just leave it up to the testers to post whenever?

I look forward to your product with anticipation.