EZ-1 Geometry Experiments      Text by Mark Stonich

I'm modifying an EZ-1 to accept a pedaled sidecar. While there is still disagreement about the value of trail on 2 wheelers, most serious builders understand that more than a little is trouble on multi track vehicles. The fork has modified dropouts giving just ½ inch of trail

The added rake, and switching to some of my cranks, (which are selling like hotcakes, by the way.) allowed me to move the BB shell forward 3”. And a new front derailleur tube was needed. This was done to improve weight distribution and reduce tiller.

Jim Black and Carl Gulbronson are looking into the possibility of having a separate run of factory modified EZ-1s built, specifically for use in their Quadribents . I suggested that they use similar geometry for their EZ-Quads, and that the reduced trail would also improve steering when the bikes were separated for use as singles.

We decided to get some opinions of various configurations at the next MnHPVA meeting.



1. Carl brought a stock EZ-1 Lite,
with about 2" of trail (dark blue).
2. I brought the modified EZ-1 SC (red)

3. Jim brought an EZ-1 SC with fork and 20" front wheel from an EZ Sport.
This bike had approx 3" of trail.

Those that tried out the bikes included 3 or 4 people who had never been on a recumbent before, about 8 recumbent riders and 3 or 4 EZ-1 owners.

Not surprisingly, #3 had a wheelflop problem. Comments were so negative that the newbies wouldn't try it.

The experienced 'benters all seemed to prefer #2 to #1. But comments were of the "Ya, I guess I like the red one better" sort.

The other results were somewhat surprising;
I expected that due to the reduced tiller and wheelflop, and with weight distribution that would require smaller balancing corrections, the newbies would love #2. It turned out that they all seemed to prefer whichever they rode 2nd. I guess that they were somewhat freaked by their first ride.

I also thought that, due to the acclimation factor, the EZ-1 owners might prefer the stock bike. However, they were the most enthusiastic about the improvements on the modified one. "How much to do mine?" And my favorite; "Why couldn't Gardner figure this out?" I think they were so attuned to the bike, they could focus completely on the differences.

The add-on bits were carved from 3/16" cold rolled 1018 steel plate. I used a TIG weld until I got near the area where there was brass in the fork, the switched over to brazing. The increased offset is whatever it took to get trail down to 0.5". Note that the axle went up as it went forward. This is so that the axle is the same distance from the center of the brake slot as it had been before. Loss of ground clearance was not an issue as the cranks are now 155mm instead of 170mm.

Material below the yellow line could be removed with no loss of strength.


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