Big Wheel Build

[62Higgins]

Until now all my "builds" have been nothing more than bolt on goodies and sometimes paint...

Today the mighty Rigid cordless reciprocating saw joined the build team.

The headtube will be cut between the top and down tubes, leaving a 3 1/2" long headtube, which will get a 1" threadless headset. None of the toptube pictured will be included in the build.

The juncture of the chainstays and the original big wheel frame are still in the head scratching phase. I need to get some measurements (twice) before I cut (once) things apart.

Since there is only one brake on what we hope to be a guided downhill missile, we will install linear pull brakes with some quality pads on this 20" wheel/fork combo. 20" Maxxis Hookworm tire for speed and grip.

 

[62Higgins]

Now that I have some pix up I have some questions for you guys.

This big wheel that I bought has about a 63 degree headtube angle on it. That seems a little too chopperish for high speeds to me, what do you guys think? I was thinking more like a MTB or roadbike head angle for a speed demon. Somewhere between 70 and 73 degrees?

And the really great part of this build is that I need two of them built...how else can my son and I race? :mrgreen:

 

[stretch]

well i dont think the angle of the headtube is that bad.. looks pretty safe. the only thing is.. your building a bike to go downhill, and your only going to have a front brake. i think that might insue some flipping over. :shock: i think you sould maybe look for some baby buggy wheels to replace those plastic ones, that way you can have rear brakes.

 

[Wildcat]

I think your center of gravity will be so low, you'll be locking up the front wheel without flipping, but you might still need some extra braking. Maybe a lever on the rear like they had on horse drawn wagons, plain friction right on the wheel.

 

[62Higgins]

I am not really worried about the brake issue and here is why. Check out the first two videos:

http://www.extremebigwheels.com/Videoclips.html

 

[62Higgins]

The rear wheels will get replaced with some 8" inflatable jobs with bearings or possibly go kart wheels with slicks, but they require 5/8" bore to affix and this thing came with 1/2", so it needs a mod or two.

 

[bmxerpete]

You want the slower head tube angle for blasting down hills. The steeper angle would get pretty twitchy at high speed, definitely not fun. Look at serious downhill bikes- they look almost like choppers.
With the low center of gravity you're going to have I don't think you'll have to worry too much about flipping it with the front brakes. Use a good V brake or good cantis with BIG pads, like the Odyssey 1x4's.

Looks like a fun project.

 

[OUTLAW]

that hookworm tire will not get you alot of speed. find an animal tire. lot better on speed. you need to go to the gravity site and start reading what we are using on our gravity bikes if ya want to go fast.

Outlaw

 

[thatismytruck]

where are you going to put your feet?

See if you can get two of these wheelsets:
http://www.huffybikes.com/greenmachine/ ... tails.html
It's not a fixed pedal/wheel like on a baby trike. you can coast and keep your feet on the pedals. Boy has one. I can't wait until he out grows it. I'm soo making a giant trike for me ... I mean him.

 

[62Higgins]

bmxerpete and Outlaw - Thanks, that's the kind of feedback I am looking for.

Thatismytruck - Freestyle pegs on the front wheel...like the Colorado guys have in their video(s).