Galah 460-7 -finished (seat and paint added)

[Benj]

the first dually.
460-because that's how long the swingarm is (I'm interested to try another one with an ultra short swingarm to see how that feels)
7-because that's how much travel it has (3:1 shock ratio on a 2.35 shock)
Galah-because someone said we had to have a name (and we ride like galahs)

Geometry:
(in the middle shock position)
Cockpit (CP):420mm
(cockpit: horizontal distance between bb and top center of head tube-the most sensible way of measuring DH, jump and trials bikes)
'Chainstay':-15.5' static, 16.5'-17' sagged (given the rearward axle path it seemed most sensible to design around the sagged height)
BB: 14.2 (static)
Head angle (66 deg)

I havent weighed it. It ain't no intense but it's not bad-similar or perhaps slightly lighter than my D8

I've only been for a quick ride locally but early indications are very promising. looking forward to Buller (and hoping its still there)

Yes, I know it doesn't have a seat-it was a bitch to fit one in with the high pivot (hence balfa/appalache's funky down tube) and I wanted to keep the construction simple. I'm hoping to sqeeze in a bolt on seat tower at some point.
And obviously I need to get some rollers.

 

[Renegade]

Seat.. what the?

 

[Guiver]

Ekkk... way to pinch your nuts, hope you can get that Seat bolt sorted.

 

[---Matt---]

Now...despite the fact that this bike looks odd with the lack of a seat, it does actually ride really well! There is very little flex in the rear end (due to the widely spaced 4 pivot bearings). The effective chain length very slightly extends over the travel which gives the bike excellent pedalling characteristics.
OMG!!! It pedals like a hardtail... [/sarcasm]
And while it is on the slightly heavy side, even without a seat tower, it doesn't feel to sluggish to maneuver and the head angle and BB height feel just right. It's also nice having the range of adjustments with the shock placement.
I'm definately looking forward to having a decent ride on a DH track later this week!

I think that is an excellent achievement, especially for a first go!

---Matt---

 

[Red Rocket]

Woah! That came out really cleanly. Well done! I agree on the comments about the need for a seat - but its good to hear you have something in the pipeline.

Congratulations on your first frame job. Look foward to future installments.

 

[sheepy]

my god it's a dual suspension trials bike

looks nice though! good work

 

[juzzo]

my god it's a dual suspension trials bike

looks nice though! good work

haha thats what i thought it looked like nice bike mate

 

[Shorty40]

Dodgy photchop I know, but what about a Norco style seat mount ?

Supported off the main frame and enough room to clear the shock system.

 

[---Matt---]

That looks pretty good... only it'd be nice to be a bolt on version, D8 style. That'd give better access to the shock adjustment. Also, having the possibility of being alu would be nice for the weight savings

---Matt---

 

[leitch]

looks like a great effort! i like the thinking in using a high pivot point etc. would it be possible to see a photo of it with someone sitting on it or something so we can see what it looks like when "sagged"?

EDIT: someone standing on it, i mean

 

[---Matt---]

EDIT: someone standing on it, i mean

hehe... I think something else would be sagging besides the bike after you sat on it

---Matt---

 

[dazz]

Awesome work!

Nice job with the TIG, you obviously know what your doing. How about a write up including methods used, problems encounted during manufacture. Your own 'How To' guide to frame building, Benj style. ?
I know I'd love to read all about it.

You've inspired me to get back to work on design no. 4,359,476 revision F.

Did you get the frame tubing from Airport metals?
BB shell -
Head tube -
Seat tube -

An idea for testing purposes: just tape some foam from an old couch cushion or similar over the shock & top of the swing-arm, it won't look pretty but will prevent the unthinkable from happening.

 

[S.]

Very nice. How high above the BB is the pivot?

 

[mountain_man(1)]

Dodgy photchop I know, but what about a Norco style seat mount ?

Supported off the main frame and enough room to clear the shock system.

thinkin the same thing.
looks money great work and the welds look top notch. I think it might be pretty race-able if you spent on a light race setup for it. GEt some testing going and write us are review and an updated proto. NICk

 

[Gekigengar]

now paint it ....

make it some funky colours too and design your own logo so it looks factory made

 

[Tristan23]

Oath dude. That's legend. Who needs a seat in DH anyway?

And then, when you get a bit closed in you can use it for trials..possibly.

Im loving it. Action shots would be sweet.

Enjoy.

 

[AngoXC]

That is seriously one awesome build.
Just one question...what is the advantage of having the chain routed up via the pivot point before if comes down to the front ring?

 

[MrPlow]

That is seriously one awesome build.
Just one question...what is the advantage of having the chain routed up via the pivot point before if comes down to the front ring?

Imagine how much the chain would grow otherwise with such a high pivot

Very nice work there mate. Interested to see how it handles square edge bumps.
Would it make sense to run another roller to get the return side of the chain a little higher too?

S.:
What is your take on the pivot location?

 

[Benj]

Awesome work!

Nice job with the TIG, you obviously know what your doing. How about a write up including methods used, problems encounted during manufacture. Your own 'How To' guide to frame building, Benj style. ?
I know I'd love to read all about it.

You've inspired me to get back to work on design no. 4,359,476 revision F.

Did you get the frame tubing from Airport metals?
BB shell -
Head tube -
Seat tube -

An idea for testing purposes: just tape some foam from an old couch cushion or similar over the shock & top of the swing-arm, it won't look pretty but will prevent the unthinkable from happening.

BB shell was from British International (sydney) but you can also get them from Greenspeed in Melb too. Next time we'll be getting 83mm BB's instead of the 68mm used here (imported from Nova Cycles in the USA)!
Headtube was from the USA. We couldn't get the right size tubing here in Aus.
The seat tube was also from Greenspeed in Melbourne. It's the only place we could find that had it.

Very nice. How high above the BB is the pivot?

The pivot is 187mm above the BB. The pivot location was designed so that the wheel path was 66 degrees at 2" sag (to match the fork).

now paint it ....

make it some funky colours too and design your own logo so it looks factory made

I might...

Would it make sense to run another roller to get the return side of the chain a little higher too?

The chainguide does a good job of this. There's no need for any more rollers. Pedalling seems to be really good so far.

 

[treggs]

The pivot is 187mm above the BB. The pivot location was designed so that the wheel path was 66 degrees at 2" sag (to match the fork).

Interesting idea. Obviously having the rear wheel move away from objects is a good idea, but at the same angle as the forks? In theory it sounds like a good idea. How does it go in practice?

10/10 for effort