Project Shredmaster 2020 - Selfmade Gearbox Frame 41

This is awesome.

What’s the geo on that? Better be forward thinking

I added the geo chart!

Looks pretty decent depending how tall you are

1,92 m, aka 6,4 feet in my case!

Omg your taller then me. Why so short

Stunning bike!! 😵 when are you doing an all mountain version with this gearbox?
https://images.app.goo.gl/RqhBCht1K1Kg4mWq5
🤗

The DH-Frame gets optimized first. We'll see what comes next

Geezus fucking tapdancing christ, self made??? This looks production ready!!

High pivot 29er with a gear box. Holy shit.
This is everything a DH bike needs. I bet it murders!

I want to hear the big guys defend not using gear boxes now. Bravo.

Sick looking bike. Got any action shots?

No Shots, just one crappy Vid of the first Testrun.
Everythings is closed to covid/weather here right now :/

https://youtu.be/rlbcTm_YaTQ

Is it aluminum?

Yes!

That's amazing. The bike just looks ridiculously clean and tidy for a home project. Who welded it? As I understand it, welding aluminum frame tubes is significantly harder than welding steel. I guess the biggest benefit is that machine time goes way down for making all the bits and bobs out of aluminum instead of steel. I have a friend who made a steel gearbox downhill bike and it seems like he spent a whole year on the mill making junctions and braces and pivot locations.

The welding (and heat treatment) was done by Ingo Müller.
He is also welding the Kavenz Bikes for example. I'd say he's pretty good

Welp, no other do it yourself bike with top this. Pack it up folks.

HECK. YES!

Perfect. Would be a dream to build a bike like this. Any recs for how to get started?

Get Linkage Design (https://www.bikechecker.com/) and Design your suspension and geometry.
Then find someone who knows how to translate that into CAD

The double idler set up is interesting.

It's a tensioner for the gearbox. Gives it a really nice tidy symmetrical look.

Gearbox GT Fury

Checks all the boxes! Nice to see HPP, gearbox and durability over weight - all put together into such a neat package.

Very cool! Looks well thought out, well put together & solid - if not a tad heavy. Bet it's an absolute blast to ride 👍

Yeah, we went save, especially on the chain- & seatstays in terms of wall thickness.

But i'm pretty happy with the overall weight of 17,9 Kgs.

There is no Carbon on the bike (except the handlebar), the rims are amongst the strongest on the market, the tires are true DH-Casings and no air shock.

First ride was quite a blast

Under 40 pounds... jeesh people need to do some push ups. Would take that over some brittle plastic any day. Rad looking bike dude!

I like it! It reminds me of the Raaw Madonna! But may I ask what the point is of a pinion gearbox on a Dh bike? Those things have something like 600% of range? Do you put a dropper on it and pedal it uphills too?

Thx!

It's the 6-Gear Version with 295% range. Pretty much the same Range as a SRAM DH 7-Gear Setup.

The reason for the Gearbox was first of all less unsprung weight on the rear wheel (about 450g),
which makes the suspension more active and supple / plush. Which is the whole point of a DH-Bike suspension i'd say.

The weight also sits perfectly low in the frame and makes the bike feel super planted and stable (low center of gravity).

No derailleur to rip off, super low maintainance, always perfect chainline, no cassette to clog with mud, etc. is also quite nice


I do not intend to pedal it uphill ever, or any other bike ^^

Sounds like it rips. How does it handle pedaling and shifting under load?

About as well as Eagle does if you try shift it under full load. Shifting is best done a pinion in the deadspot of pedal stroke - timing becomes natural pretty quick.

Haha yeah I get what you mean! Pedalling sucks did you buy the tubes off the shelf and weld it yourself or did you get someone to do it? I heard Aluminium is tricky to weld?

We bought the tubes all over the place, wherever we would get them :D

Welding was done by a professional welder, including heat treatment afterwards. Because yeah, you need to know what you are doing, when welding aluminium, and i dont

Where did you get the tubes if it's not a secret? And do you know Ingo or did you just contact him out of the blue? When you say Linkage, how did you do dimensioning of the tubes and stuff to make sure the bike holds up?

We didnt know Ingo personally, we just conacted him

Tubes came from: Zonenschein, Wowbike and Huahsines.

About dimensioning, well Peter has an engineering backround and we got recommendations from Kavenz bikes and others. And then we mostly added a bit on top

Peter? Is this a team effort?

Yes it is! He's one of my mates, i went to school with.

He did the CAD drawing, i did the linkage design & geo.

Bike of the Day December 9, 2020!

Awesome!

Soo cool!