Oh yeah. Linkage rocks too. Like Bikecad, you can drag stuff around, dump it out to DXF, then crack on with proper work.

Brant – what do you use for the CAD side of things?

Brant – what do you use for the CAD side of things?

I generally twiddle in bikecad, dump to DXF twiddle in some awful 2D cad package called CADINTOSH that I have, then pass to taiwan with lots of scribbles.

Jack in Taiwan (or Mr ****) then 3d it in Solidworks and we do alts that way.

Works for me.

“The empire concept is really nice.”
If you are interested in cast aluminium (such as the Empire) then geogfischer.com might be able to help. They may have been of assistance to Empire.
KTM motorbikes were of some inspiration to Empire.
Although the Empire frame looks horrendous, nice sharp edges next to your knees etc.

If I was going to go to all teh bother of designing my own frame I would go for a linkaged front end – probably a single wishbone / mcpherson strut type Should have some real advantages in an MTB – softer springing and damping possible without diving on the brakes, rising rate with coil springs, rigidity.

If I was going to go to all teh bother of designing my own frame I would go for a linkaged front end – probably a single wishbone / mcpherson strut type Should have some real advantages in an MTB – softer springing and damping possible without diving on the brakes, rising rate with coil springs, rigidity.

Heavier, travel limit, more complicated, undesirable axle path…

I think the op should step it up a notch and try to design/build a full sus out of aluminium 🙂 that’s a whole new world of complexity! A note on linkage, take all the supplied data for existing bikes with a pinch of salt. They are usually produced from a side on photo meaning pivot points etc are not 100% correct. It only take a couple of mm here and there to drastically alter the graphs for leverage ratio etc.

Brant, thanks for the little autobiographical chat at the bristol show the other week, was interesting and entertaining!

For cast aluminium frames,
http://www.eisenbibliothek.ch/public/topstory/neu/top_story_georg_fischer_wins_the_race.pdf

Although hollow sections are normally used for lightness,
http://reynoldstechnology.biz/assets/pdf/rtl_steel_alloys_extract.pdf

For suspension,
http://www.tz350.net/book_reviews2.htm
Motorcycle Handling and Chassis Design, the art and science
By Tony Foale.

Brant, thanks for the little autobiographical chat at the bristol show the other week, was interesting and entertaining!

Cheers. Let a few cats out of bags there.

It only take a couple of mm here and there to drastically alter the graphs for leverage ratio etc

Indeed. There was a graph on the Whyte site a few years ago comparing axle paths for their design against a few others… guess who had the ‘job’ of producing that?…. 😉

http://blog.makezine.com/MAKE_1172.jpg