[S.K.C.]

HaveFaith - you are the man!

Nice write up, and definitely mad props for going through with this!

I've always wanted to do something like this myself, but never had the time. Lot of blood, sweat, and tears must have gone into that rig.

As a privateer racer/builder it takes balls to go for it like this and see it all the way through.

Well done!

:beerjam:

P.S. - I really dig the design of the frame... kinda reminds me of something.

 

[FOXROX]

i think this is what the mtn. cycle swing arm is for! if someone made that you wouldn't need that gigantic bearing

but then again you would want a bike that doesn't feel like total crap

 

[HaveFaith]

It uses roller ball bearings included with the gearbox. They are high quality sealed units.

 

[HaveFaith]

A few more of Pat's pics from the weekend. Namely of my elbow. Didnt realize it was so deep till I got to the finish and my forearm of my jersey was cherry red. Looks like a cigar burn here. D'oh!

Thanks for the support guys. Means a lot. Hopefully we can show enough interest in these types of bikes to get some reaction in the industry? Its bound to happen sometime soon...

Next up, refine this thing!

Some background info on the g-boxx: http://www.g-boxx.com and http://www.g-boxx.org

 

[zspecial]

Been waiting for a while for finished pics, looks great!

The seat looks to be mounted directly to the seat tube? I guess this is a way to keep weight down?

Also I hope the chain doesn't wear a hole in the Gboxx for your right crank arms' sake....

 

[karpi]

wow! I also wish I could pull something like that! Man, the bike design in my eyes is almost perfect! You got the main weight (thus the center of gravity) smack in the middle which should make for such good handling! a few questions though, whats is the size on that rear shock? what travel does the frame get? and what is the leverage ratio? When I said almost perfect, it's because I see the chainstay to be on the longside (personal opinion), but you could correct me, how long is the chainstay? amd what's up with the seat tube? haha looks really interesting, should lower weight right? Props again, so rad! I'd love a frame like that! specially with gboxx

 

[Eren]

looks awesome and great write up

i want one

 

[PatBranch]

Been waiting for a while for finished pics, looks great!

The seat looks to be mounted directly to the seat tube? I guess this is a way to keep weight down?

Also I hope the chain doesn't wear a hole in the Gboxx for your right crank arms' sake....

It does keep the weight down. He used thompson post pieces to mount the seat.

 

[big cal]

fan-fricken-tastic, well done. I'm amazed that you managed to get such a pro looking bike up and running so quickly, congratulations!

 

[Damo]

Seeing that bike come to life on this forum has been absolutely great. The finished product looks awesome and its great to hear it rides well too.

 

[Trekrules]

That bike is 1 sick piece off art.Looks great

 

[rbx]

brilliant design and dedication!

 

[blacksim549]

Siiiickk!!

I want one!!

 

[ire]

nice bike and great write up!

 

[zahgurim]

Awesome bikey!

I want to build my own, too. It's good to see threads like this.

 

[beaverbiker]

rad bike. nice work man. it looks like it came together well.

 

[rbx]

hey havefaith

How does the bike pedal compared to other you've tried?

(On paper gearbox bike should not pedal as good as for example sunday's because of their low anti-squat)

 

[Bikael Molton]

best post ever.

where's the geo #s on the frame?

 

[HaveFaith]

Hey everyone, I appreciate all the positive remarks. I will address the few questions/comments that have been floating around.

It has 7.25" of travel through a 9.5x3" stroke shock. Avg leverage ratio of 2.4:1.

The chainstays are 17.38" long, and I must say this thing is pretty easy to pick up the front end and manual. I was pre-manualing the rollers on the SO DH course without any trouble at all.

The chain does ride on the crank boss for now, but Ive placed a zip tie around that portion so now the chain is only riding on that. Its actually pretty smooth. This will be addressed later with either a slider surface there or a small idler (which would help with tensioning as well).

The pedaling is pretty damn good. While it does not have quite the extreme anti-squat characteristics of the sunday, it stands and sprints well. It does squat a bit when seated and pedaling (body bobbing as well as pedaling) but it wasn't noticeable when I was riding in earnest. The thing to remember is that with a concentric output, your squat characteristics remain fairly consistent through the travel, instead of having a broad range of effects. Its definitely better than a standard single pivot (which is what I normally ride). Keep the questions coming!

 

[CBJ]

Great looking bike and love the integrated post like the Scott light weight fully.

 

[rbx]

Did you get your g-boxx step file from g-boxx.org? i have the old file with squared edges

 

[HaveFaith]

Did you get your g-boxx step file from g-boxx.org? i have the old file with squared edges

I did, and it definitely ended up being really conservative to the g-boxx2 size. There is a lot of clearance to the shock and chainstay cross-brace.

The spacing between bearings on the g-boxx and bike centerline is a little tricky. I would definitely contact them before you start to weld to make sure you have it right. Some conflicting info floating around between drawings and models etc...

 

[Total Heckler]

Wow man. So impressive.

I think once you have everything dialed, sell the design to the highest bidding bike company and laugh your way all the way to the bank as well as move the sport significantly forward technology wise. =]

Good work man. +rep

 

[no skid marks]

Let us know when it gets below 40lbs

 

[hardcore poser]

hey man, sweet ride.
i met you out at sea otter, how'd you do?
hopefully i'll be making a gear box as part of my senior project next fall.

 

[Percy]

Looks fantastic dude, bloody well done.

 

[bikemonkey]

the bike looks super sweet, and you finished it in no time.

 

[HaveFaith]

hey man, sweet ride.
i met you out at sea otter, how'd you do?
hopefully i'll be making a gear box as part of my senior project next fall.

Unfortunately I fell in my race run pretty hard, in a fast section. oster_oops:

The bike is alright though, and we are moving on with testing!

 

[syc7090]

wow. your accomplishments are nothing short of spectacular. the fact that you took the initiative to turn an idea into reality is greatly admirable. congratulations.

 

[HaveFaith]

wow. your accomplishments are nothing short of spectacular. the fact that you took the initiative to turn an idea into reality is greatly admirable. congratulations.

Thanks, I really appreciate that! These weekend holds some back to back testing runs. Going to get a good feel for it, see if the geo needs any tweaks and keep getting the setup dialed.

Also, I clear-coated the 4130. Looks nice and shiny!

 

[MrPlow]

i cant believe you built that so quick! congrats mate. great!!

 

[MMcG]

This was one helluva cool thread to follow. Great work!!!

 

[HaveFaith]

I have some updates coming down the pipes. Been riding and testing the thing and we've got some further ideas to dial it in. Stay tuned...

 

[Total Heckler]

I have some updates coming down the pipes. Been riding and testing the thing and we've got some further ideas to dial it in. Stay tuned...

Cant wait.

 

[dirtdigger]

I have some updates coming down the pipes. Been riding and testing the thing and we've got some further ideas to dial it in. Stay tuned...

sounds good,there would be a number of ideas i have to tweak that design, heres a few

- rotate gbox output shaft/pivot back and up to get chain line closer to center of gravity and to shorten the swing arm and use less chain.

- lower the toptube for coolness

- increase the tube size of the chain stays just so it looks more in proportion

and a how strong is the gbox cases? will it handle the load of being in between the rocker pivot and lower shock mount?

 

[GPERKINS]

mad props on the bike, it takes a guy like you to step up the sport in a positive way. What program did you do all the designing on? where can I buy and download it at?

Thanks,

Austin

 

[MobileChernobyl]

^
http://www.freebyte.com/cad/cad.htm
Heres a list of some CAD freeware 2D and 3D you can download. I've heard alot of good things with Rhino.

One of the easiest to learn and most powerful/most widely used 3d drafting programs is Solidworks. You can get a Student version of that for like $80 from some colleges and online. My suggestion unless your rollin in extra cash is to find a very computer literate person and tip him off you might need a full free version of it... i'll let you figure it out for yourself tho haha, the full version cost close to a grand, but is VERY powerful, doing FEA tests on full assemblys (only as accurate as the constraints you put in however).

 

[BALOG]

Waiting for the updates guys.... no news???

 

[Bulldog]

I jumped in on the link from the first post - the buildup and updates. Did I miss the weight?

And this looks eerily similar to that pencil drawing of a rumored (or fake) '09 Specialized gearbox bike! As cool as it is to read this thread, you gotta protect your investments against the big guys.

Whatever happens - FANTASTIC JOB! Looks great and you accomplished it crazy fast! Huge props to you!

 

[Rick205]

Fantastic looking project and a great outcome, the bike looks really good.

I dont think there is much that can be done to protect about this design being used by someone else, as it is essentially a single pivot, so correct me if im wrong not much to patent.

Looks like a well designed, well built frame though, what sets you apart at the moment is you have built it and are riding it, i am yet to see the 'big boys' and their offerings....