Morph III Independent Seat Tilt Study

During our recent visit to George Reynolds shop to view the progress on Morph III, Rory McCarthy and I discussed the current approach to seat tilt correction. When the bike morphs up, the seat tilts forward. This is more pronounced on Morph III because it morphs through a larger range, and because we expect to start with the seat in the fully tilted-forward position. On Morph II, we have the seat fixed in one position because the tilt mechanism was very difficult to change. This leaves the seat tilted back even when you morph down, which hurts ergonomics significantly.
 
This presentation looks at how an independently-tilting seat might work. The current design integrates the seat and rear morphing frame. To adjust seat tilt, you essentially pull the wheels further under you, and that tilts the whole rear frame, including the seat.

Morph II vs Morph III Side View Drawings with Dimensions Along With Some Shop Photos

Here is a comparison of the dimensions of both designs. I sampled two dimensions that we measured in the shop: Morph II wheelbase, and Morph III wheelbase. Both match the drawings exactly!

Morph III in upright mode. Wheelbase is about 3" longer than Morph II. Height is about an inch higher. Inches count here, especially in tight places, so we'll have to see how it feels. We may be able to shorten the red main tube and pull a couple inches back in length and wheelbase.

Morph III in the shop, upright mode. Not that the seat is still in the position used in low rider.

We added a wooden block to bring the seat back to a more level position.

Morph III in low rider position. Wheelbase is about 2.5" longer. Seat height is dropped by a little over three inches. However, we have been riding Morph II only with the front seat tilted back, which adds at least an inch to seat height. So Morph III will be significantly lower.

Morph III in the shop, in low rider position, January 13, 2009

Morph II in low rider mode. Note the 5.1 inches of trail shown. That turned out to be a problem and we modified the forks to bring this trail to near zero in low rider mode.

Morph III in low rider, with some additional dimensions.

George on Morph II. Note that seat is still tilted up, even in low rider postion. This is because the two red struts that were supposed to adjust the angle were very difficult to secure, so we left them in one position.

Morph III in high rider. Note overall lenght of 61.42 is about 2.5" longer than Morph II in high rider.

Note head tube angle of about 50 degrees.

Front view of Morph II in low rider.

Front view of Morph II in high rider mode.

Combining The MWF Website with Individual Blogs for Each Project, and Twitter Tags (Repost)

The slide show below shows how we're integrating an Apple iWeb site for our main website, along with individual blogs for each project. Also, each project will have a specific twitter tag. All tweets will go out on Move With Freedom's twitter handle: @mwfree. This is a repost of the Powerpoint with the font changed to Ariel, which hopefully fixes problems with the display of the Powerpoint.

APRIL 7, 2007: A BOUNCING FOUR-BAR CRACKS A WELD

During this test, there was no locking mechanism in the down position. (Although the Morph 2 design includes an up and and a down locking mechanism. We only built the up lock, which is safer to operate.) 

With almost 200 pounds of upward force coming from the gas springs when you are in the low rider position, we figured the down lock had to be perfect. If it ever released, you’d get quite a shock as the unweighted Morph sprang to the upright position.

So we left off the down lock and rode without it. This had the fun effect of allowing me to bounce while riding, somewhere in between up and down.

But take a look at the side view of the mechanism. There is a very large mechanical advantage applied to the gas spring. I think that both of them total 600 pounds for a 180 lb rider.

This means as you bounce along, your long lever arm over the attach point of the gas spring means you can apply a huge force to the to of the member. And that’s just where it cracked!
Crack in upper morphing arm.
Bill Warner on the Morph 2 prototype.

The final version of Morph 2 included some serious extra welding at the area of high stress. We haven't seen any problems so far. Nevertheless, the high forces here are something to keep in mind.