Blue Dream: Maxarya Ray 2 Semi Recumbent w/high eff mid drive

[neptronix]

Okay, to test a theory.. ( front suspension is too wimpy and bobbing while pedaling and front tire PSI is too low )
I did:
+5 PSI in the front shock.
+10 PSI on the front tire.
Keep 75PSI in the rear.

The bike is a little faster than my 29er now and surprisingly the front NVH hasn't degraded much.
Diametermaxxing all the way is the way to go.
I would call it 'okay' along the NVH test course. So there is room to adjust PSI downward for more comfort.
It is also much faster when pedaling uphill.

Speed wise, the fastest recumbent i've ridden is a bikeE, and this is a hair behind that now.
Finally after 5 years of tweaking and tuning, i actually like the bike.

I'm kind of shocked at the degree to which the front end can affect the rolling resistance.
Looking forward to this faster and slightly bigger rear tire.

 

[neptronix]

Tire arrived really quick.

...and yeah, it is kinda flimsy and it feels like it has half the rubber thickness of the Kenda Drumlin Cargo.
But i have to satisfy the curiosity on how fast this bike can actually go with an optimal tire.

Too bad it has an unlisted spec here. 85 PSI min
Oh well, let's rock it @ 85 PSI and see what happens.



Looks like i have a meager 2mm of clearance between chain and tire when in my first gear.
The OS20 aka ~22" wheel upgrade is a necessity after this point!!



So how does it ride?



From a dead stop, i got up to and maintained 22mph on flat ground for a mile on pedal power. That's 1mph faster than i was able to do on the BikeE!
I used to struggle to maintain 16mph before!

After going down a hill and getting my speed up 32mph, when i transitioned to flat ground, i was able to keep going 30-31mph solid for half a mile until i hit a stoplight.

This thing is a thrill on pedal power and i can't imagine what a riot it would be with a motor!
This is on rims that are far too narrow, with a heavy tube, and the front tire still at 40 PSI.
So basically it's still unoptimized and i'm still getting awesome power.

The rear tire was surprisingly not sliding around along the gravel part of the test course.

What did we learn? the rear tire on a semi recumbent matters a hell of a lot.


NVH in the rear is verging on unacceptable at 85 PSI, but not as bad as i was expecting to to be.
For the crazy speed, it's practically worth the rattling.
I think i'm going to throw some stans in it and see if it can survive Utah's roads on some epic rides on pedal power.

These 1.6"-1.85" ~22" tires available for the larger rim are of the same high speed BMX type, and their weights indicate they're ~4mm of rubber kinda tires too.

Let's see how it goes to determine if i go crawling back to my 20 x 2.4" setup!

 

[Chalo]

Minimum tire pressures are almost always horse puckey. Minimum is dictated by axle weight, speed, rim width, rim to tire size ratio, and surface conditions. No tire manufacturer can know those things. Kenda has a habit of slapping "50-85 psi" on any 700C tire between 35mm and 50mm wide. There's no making sense of that except that they have the tooling to put it on whatever tire.

Respect the maximum rating, within reason. (Snafu used to rate their 20 x 2.1" freestyle tires at 130 psi, despite lots of 20" rims being totally incapable of that.) Ignore the minimum rating except as a point of reference.

 

[Chalo]

Also, front tire optimum pressure is a function of front tire axle weight. 40 psi might be about right for a lot of MWB recumbents. You only have to have enough pressure to cover the corners of the envelope (e.g. heavily loaded, hard braking, rough surface, downhill to uphill transition). And apart from those things, if the tire is fat and the rim is narrow, there's a minimum pressure to maintain lateral stability in the tire.