Mint Chocolate Chip-A bike built for the Crested Butte Chainless World Champs (Finished)

[squirreldh]

Not sure what to call this thing...
(Edit: I figured out a title/motif)

I competed in the Crested Butte Chainless World Championship last year in Crested Butte, CO. I competed on my JC Higgins and ended up placing fairly well, despite an incident causing a flat near the finish. Here is a video, not mine, of last years event:



And a link to the history of Crested Buttes Fat Tire Bike Week

http://cbbikeweek.com/history/

This year I am thinking of a build specifically for this event. No cranks, pegs on the rear axle for the feet instead, a "pan" of sorts to support my torso, and road bike drop bars for that aero tuck.

[Insert microsoft paint sketch here, yet to be drawn]

I have on hand a heavy cheap steel track frame, fork and headset:

The fork even has a semi aero teardrop shape to it!

Dug around my parts bin and located a set of formula track hubs, and some heavy deep dish rims:

Thats what i have for now. Need to get assembling and cleaning the headset and install the fork.
Then overhaul hubs, looking for some grease that lubricates well but doesnt have a lot of stiction, need little rolling resistance.
Calculate spoke lengths and see if i have them on hand.
Find a set of bars and stem.
Make some sort of support for my body.
And aero this thing out, thinking corrugated plastic, and maybe find some fairings from a childs electric motorcycle? We shall see...

 

[Fv2]

I find this interesting.

 

[squirreldh]

I got the headset installed and overhauled. Fork is in. Tossed the hubs in just to see them in there...

Also removed the bottom bracket. As there will be no drivetrain... and folks, please dont store your bikes outside in the rain. I know most here probably do not leave theirs outside but i like to throw some pics up anyways

Despite the moisture the BB was in okay shape under the greasy wet mess. Bearings still feel good. Going in the parts bin! And whats with crank up the volume? I want my bottom brackets silent!

 

[squirreldh]

While this rig may not have a drivetrain, I feel i may need brakes.

Last year gave me a good sense of what the course is like, they always run it down Kebler Pass into town. The only section that may or may not require braking is the last segment into the finish. For most of the run you are on pavement, with a section of dirt midway through, more pavement, then a fairly steep fire road down into a 90° turn on pavement into the finish. The whole course is about 7 miles long.

I have in mind two different brake setups and am unsure which to run.

First is a "Schwinn Approved" centerpull Dia Compe brake, i have a set, front and rear. These would provide more than ample braking power with fresh pads and would also be drag free going down the road.

I also have this old disc brake, I believe it is either an old tandem drag brake, or maybe a disc brake from a early 70s muscle bike? Anyways, I have had it in my stash for almost 3yrs without a bike to put it on. Being a threaded rotor is what leads me to believe it was meant for tandem drag brake use, and limited what I can install it on.

That last corner is the only one you may or may not need to brake for. So having a powerful brake may not be necessary. I do not want a brake that will be dragging and causing resistance on the way down. Although it is a descent down a mountain pass it really is not that steep.

I ask, as if I even have to, what does the RRB community think i should run for a brake?

Schwinn/DiaCompe
Or
Tandem/Muscle Bike disc

Pros for schwinns:
-Ease of setup
-Drag free
-Plenty of stopping power for intended use
-No mods required for rear hub

Cons:
-may not be aero enough
-need to do cable hangers (fr not really an issue, rr may be with body positioning
-cool factor low

Pros for disc:
-get to use a cool part that I have had for a few years
-may have just enough stopping power to regulate speed
-out of the way for aero-ness
-COOL, nuff said

Cons:
-may not be able to setup drag-free which is most important in this type of race
-may not have enough stopping power for last turn
-needs fine tuning on rear axle spacing and odd dishing of rim is possible, but not a huge issue

So what brake should I run?
Decision needs to be made before I build rear wheel

I will be using these Cane Creek SCR-5 brake levers with either setup:

Tires:

I plan on running a 28c-32c tire, dont want to go too big, yet dont want to go too small either. Need to make sure i have tire to brake clearance if going with the schwinn/diacompe set and smooth rolling resistance, and enough tread to corner on dirt and gravel at the finish.

I am thinking along the lines of the Panaracer Pasela in a 700c x 28c maybe? If available... have not researched sizes but I can toss them on my Trek 420 gravel bike afterwards so they would have more than one purpose, plus they are skinwall

 

[The Renaissance Man]

That disc brake is cool!

 

[LukeTheJoker]

Hard choice on the brakes...

 

[squirreldh]

I know. I really want to run that disc brake but am afraid I wont be able to set it up drag free, not without a bit of modification anyways. It looks like I need to clearance a chainstay to get it to sit flush with the dropout, then i may be able to get it aligned with the rotor properly. Wondering if I should go ahead with the wheelbuild then worry about the brake later, or try to fit it now...

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[GuitarlCarl]

Check out the old GRAVITY bike thread here...
Looks like a lot of fun to me...
I'd do the ball bearing mod to the hubs, and run some high pressure tires.

Carl.

 

[squirreldh]

Oh yeah! Thanks for the link! Wondered how long it was going to take before someone put two and two together and figured out this is pretty much a gravity bike. Will have to check out what the ball bearing mod entails, I do appreciate you tossing the link up there for ease of finding it

I have been doing a lot of thinking about weight vs resistance and how to reduce drag as much as possible. While aerodynamics dont play a huge factor in this race as the speeds are low, every bit helps in my opinion sobI am considering a faring of some sorts.

I spoke with someone I met out there last year who has more experience with the event than I, he said a few showed up on gravity bikes in the past, but being low and difficult to get moving at the start made them not competitive, you are only allowed one push with your foot at the start. I imagine he was speaking of the flipped bmx frame style with 20" wheels? I am planning a taller framed ride, 700c tires, narrow but not too skinny. We shall see how my ideas work, and I am sure I will be borrowing one or two from the GB thread!

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[GuitarlCarl]

I'm not sure if there is a real "how to" post anywhere about ball bearing mods. But basically you take all the bearings from the frames they are suspended in and run them loose in the hubs. You'll probably need a couple extra balls to take up the space, but when you're finished rolling resistance is much less. Guys here have been doing it to coaster hubs and report improved performance. I think it would help any hub.

Guitarl.

 

[squirreldh]

Ah, i see. The hubs I am using are already "loose ball" not caged bearing, but i am considering using a wheelset that is hanging at the local shop that uses sealed cartridge bearings. If i run into issues while testing with improper lubrication i can swap them out with a different cartridge and not worry about ruining the cones and races in the cheap Formula hubs I have. The front one feels notchy already, so that makes me a little worried about using it as it may just destroy the bearings inside really quickly. It may just have a pitted cone though, if I can swap that out with a good one then these hubs will be used.

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[RustyGold]

Looks like a blast!

Jason

 

[squirreldh]

So I went to the DMV yesterday to renew my liscense. That was a long experience, and it gave me time to read through the GB thread. I am loving the fact that a couple of my ideas may have already been attempted, like filling the frame tubes with sand, fairing from a pocket bike, etc. A few things are the norm for the top finishers, like running bmx pegs on the rear wheel, etc.. I also like how they had a limit to how much weight could be added to the bike. I plan on testing my ride down some local mtn roads with varying amounts of weight to see at which point it no longer helps me go faster, and starts slowing me down due to too much weight. Last year I wore a backpack with a 35lb sand bag in it, it helped but was very uncomfortable wearing it in a tucked position for such a long time. I weigh 135, and am competing against guys that are heavier than I, need all the help I can get!

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[1oldbikelover]

Good luck with your build, buddy and smoke 'em. You are a rocketsquirreldh!

 

[squirreldh]

Thanks 1oldbikelover! How is Ipswich? My brother went riding out in Willowdale over the weekend with my nephew, looks dry out there!

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[Georgeediii]

Not sure what the rules are but have you considered filling the frame tubing with lead?

 

[squirreldh]

That I have not! The rules are fairly open. No pedalling. Thats about it. Those with coaster brakes are required to tie the chain to the chainring so they can still brake. I am considering sand, as I have a bag of play sand with no purpose at the moment. I am wondering how it will affect the ride, if it will make the frame feel "dead" those tubes are hollow for a reason...

I need to weigh my higgins and see where it is at, maybe shoot for that as a goal for this ride, though I did have weight on my back which I would prefer to put on the bike... or maybe I should wear a scuba divers weight belt...

I think I need to get it assembled so I can start testing asap. Make these decisions after the tests.

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[squirreldh]

Picked up a couple items from work. Got a set of bars, a quill to threadless adaptor, and a set of aero bar elbow pads for my knee rests.

 

[squirreldh]

Got the bars, stem and adaptor installed, also tossed on the levers. Believe I decided on running the rim brake, as speeds arent too high, and ease of setup.

 

[squirreldh]

Rear wheel build time...