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

[neptronix]

What hack is this?

The bike has an eccentric BB up front to tension the front chain, with it positioned downwards currently. The difference between it being pointed forward ( what we want ) and pointed downwards is -1 tooth on the chainring.

So i could theoretically move forward half an inch... which ain't much.. but anything helps.

Side note, i'm 6 foot tall with proportionally longer legs than most people.. i ride a bike designed for someone slightly taller than me .. i'm difficult to fit to a bike. Most people won't have crazy fitment issues like the ones i'm experiencing

First off, I appreciate you sharing your journey with this bike. I hope you recover fully.
I've been considering something like this and am glad you are figuring out the problems I might someday hit... uh, maybe not the best word choice.

Thanks! my knee is finally fully scabbed up today, thank heavens.
I'm glad this thread is helpful even though it's been non stop frustration and tinkering, lol..
I'm hoping at the end i have a pretty good recipe for one of the few remaining rear suspension CLWB models that is still sold.

Drunk people survive car accidents at higher rates than the people they hit because they're so relaxed. I think if you're planning to be tensed up then you're more likely to get seriously hurt!

Yeah i've heard that.. but i think it might be more relevant to how car crashes work.

From my experiences, the most likely scenario for these bikes in crashes is to go sideways. Not tensing up and hanging on means i would need somewhat of a rollcage, which i want to avoid for these reasons:

- it's much heavier
- it makes the bike look less like a bike and more like offroad equipment w/o a license plate, IE cop magnet
- all my mounting points for such a thing are very difficult to utilize and very weak
- there's no way to get adequate coverage of someone who is not tensed up and hanging on while the bike goes horizontal w/o a much bigger rollcage.

The alternate route for protecting a slack human body is a full bike aerodynamic fairing.. then you're falling and sliding on cloroplast.. which should hold up! but.. that route is very involved and i'm not ready to go there yet.

Here's how i plan to test my minimalist safety contraption:

Phase 1: build the center bar, attempt to mount the bike sideways & hold the position for at least 5 seconds. ( i might have to build some hip flexor strength first, let's see )
Phase 2: 3x varied 10mph crashes on sand or muddy grass wearing lots & lots of protection.
Phase 3: 25mph crash ( to test if i can react quick enough ) wearing even more gear on sand/mud.

We call the experimental minimalist safety system a success when i can crash w/o physical damage while not wearing gear!

 

[neptronix]

Where did you buy your Maxarya?
Now that you have figured how to electrify one I am taking a more serious at getting one. I am finding it tough to find a dealer that actually sells them...

Went to their website and bought it. There's almost no dealers. Small company.

My advice:
Don't buy the locbuster, it's flimsy and screws up the angle of the handlebars even worse.
Do buy a large hand file to take meat off the cranks and add a kid's 20" suspension fork because the frontend it comes with is extremely rickety, loud, and chattery on pedal power. I found it unbearable out of the box.
Buy the biggest frame you can fit.
I don't recommend the lower end model with the spring rear shock. The rear spring sucks. Air suspension on the rear will provide a massive improvement.

 

[Zambam]

Thanks! my knee is finally fully scabbed up today, thank heavens.

If you had long pants and sleeves on, it probably would have lessened the damage by a lot. I had a fall on my first ebike ever (Ecotric Dolphin w fat tires) @ around 15 mph when a bicyclist passed me on my left and turned in front of me. I swerved right to avoid hitting him, lost control and fell on my right side. I had helmet, jacket, long pants on. After cursing, got up, checked myself and bike out and all was ok. At the moment of impact, I saw stars and a brief blackout sensation. My helmet did not hit anything, there were no scratches on it. I think it was blood rushing to my head from the sudden deceleration which caused that blackout sensation. Did you have a brief blackout when you landed?

The next day, I noticed a small red spot on my right knee and elbow where the skin had been rubbed away. There were no holes in my pants or jacket. The clothing rubbing against the skin apparently took some of it off.

Edit: I never wear shorts (do not own any), even on the hottest days.

 

[neptronix]

.. i'm a big fan of shorts all year, so i build in a 1 inch additional safety margin.

I've had a short blackout when i went flying at 20mph 12 years ago! And thank heavens i was wearing a helmet.

This time was too slow to have any of that happen.

Falling to the side is also common on uprights and some of these ideas could apply there too.

 

[Zambam]

Maybe I was going faster than 15. We were going downhill beating a red light.

Falling from low on a recumbent probably makes a difference too compared to high on an upright. What would you say the difference is (in inches)?

 

[neptronix]

Falling from low on a recumbent probably makes a difference too compared to high on an upright. What would you say the difference is (in inches)?

I measured this for you, with suspension sag.
Semi recumbent bike with a slightly lifted rear: 26 inches off the ground
The MTB i sit on is 39 inches off the ground.

The cannondale Bent and bikeE were both lower vs the Maxarya sitting by a few inches on stock tires.

I feel like i flopped onto the ground instead of fell.

 

[Zambam]

I measured this for you, with suspension sag.
Semi recumbent bike with a slightly lifted rear: 26 inches off the ground
The MTB i sit on is 39 inches off the ground.

The cannondale Bent and bikeE were both lower vs the Maxarya sitting by a few inches on stock tires.

I feel like i flopped onto the ground instead of fell.

So the lower seat height of the recumbent did help a lot to lessen the impact. Maybe I want to find one to convert to mid drive. What's the smallest and lightest recumbent out there, new or used?

 

[neptronix]

So the lower seat height of the recumbent did help a lot to lessen the impact.

Totally, and the nature of the fall was different, more like a plop to the side... an upright bike will throw you off.. a recumbent will slide you off.

Sooo much more of your body is supported by the recumbent!

Keep in mind my fall was at maybe 5-10mph, so i've yet to experience a big one.
Another interesting safety factor is that the front wheel doesn't really get upset when you hit odd shaped things or mis-steer. You have a massive margin of error for mis-piloting the bike or hitting things & being able to counter-correct out of it.

Maxarya might have the cheapest model that has rear suspension right now.

Suspensionless, we've got some deals here from the company that took over RANS: https://phoenixbikewrx.com/
You also have these guys close to you, and they sell used bikes sometimes i think: https://bicycleman.com/

 

[Zambam]

Here's an audio-visual of the bike:

I grabbed this screenshot of your shifter from your video. I have a SRAM 8 spd shifter similar to your's that I had to replace when I broke it trying to replace the cable (parts went flying). On mine 1 is the lowest (biggest cog). Is your's the same? Why are the gear numbering laid out differently in direction of twist?

 

[neptronix]

The sta-tru 18" wheel came here..
It has 28 spokes instead of 36. It's a meager 2mm wider. What's advertised as a 1.5" rim is actually 25.5mm outer, so 1".
I can feel all kinds of resistance in the wheel at the bearings.
Axle is .2mm shy of 3/8" and isn't a better fit.

Very disappointing. Will see if the bike shop can do something about the bearings.
I ordered a 2.0" tire as that's the largest size that could reasonably fit on that rim. If i like how it rides, i'll get a wheel built and fit that nice Haro 18" x 2.3" tire to a 32-40mm internal width rim.

I reversed the position of the freewheel and maxarya chainring holder, then moved the mid drive inward a notch. I now realize i had the chainring holders in the wrong order. The freewheel chainring holder has more inward offset, and the maxarya one has more outward offset.

Because of this, i'm able to switch from 6mm spacers to 2mm spacers on both sides, and the chainline is much more straight than before. Major win.

A bonus: my big chainring now lines up to the middle of the gears, instead of lining up with the second to smallest gear. I have a regular, ideal bike chainline now too

I will probably upsize the main drive gear once my motor is getting full power. Looks like we max out at 60T; not bad!

52T

60T

Now waiting on parts and my knee skin to heal, can't wait to get 'er back on the road.

 

[99t4]

Maybe the bar could be curved in such a way that it acts as a ramp and isn't a nut smasher anymore...

Can you wrap it in foam, padding it and making it more comfortable during an impact?

 

[neptronix]

I could do that! that would be another level of comfymaxxing!

 

[neptronix]

Simulating a 2.0" tire while i'm waiting for one.



Fork angle is looking much improved. Looks like the extreme end of a downhill bike's fork angle. Not bad, considering we haven't removed the 10mm spacer yet.

I think we can reasonably achieve stock geometry or slightly better.

Aesthetically, i feel like the huge front chainring contrasts poorly to the smaller front wheel. Finding a way to get back to stock gear size ( 36T > 22T ) in the front would help.

 

[neptronix]

Okay, tried a 18 x 2.0 wheel + tire.



Front suspension is worse, juddering is worse, steering has went from confident to twitchy. Total disaster.
Lowered the 18" front tire from 30psi to 25psi, juddering improved from critical to bad, but suspension is still worse.

I would not trust this steering for the high speeds i intend to travel. The change is pretty dramatic.
I notice this fork that has 25.4mm stanchions has a ton of stiction in it. It seems like it's completely inactive when it comes to handling these annoyingly uneven road surfaces. It just helps on bumps. Well, it's a cheap fork, so..

Wheel diameter has a larger than expected impact on bump compliance. In the 18", going over a 1 inch curb is turning into an event.

On the other hand, with 18"s, i can go with a bit taller fork. A 18 x 2.5" tire with a 40mm internal rim would have >2x the rim - strip - tube contact, thus it would handle lower pressure.

v-- stock size
tire size circumference radius drop
20 x 2.2 = 1625mm 258.6mm 0mm
20 x 2.0 = 1593mm 253.5mm -5.1mm
18 x 3.0 = 1592mm 253mm -5.6mm
20 x 1.75= 1553mm 247.2mm -11.4mm
18 x 2.7 = 1544mm 245.7mm -12.9mm
18 x 2.5 = 1512mm 240mm -15.8mm <-- with fork sag, should be equal to OE front height
18 x 2.3 = 1481mm 235.7mm -22.9mm
18 x 2.0 = 1433mm 231.5mm -27.1mm

I found a suntour air fork that's 80mm. That's 30mm axle to crown taller than my crappy spinner fork, but it has 28mm stanchions. Letting some air out should make the difference smaller.

I've enquired about the width, it might be just narrow enough that i can run a 136mm bottom bracket and clear it. The Suntour XCM JR L i bought was just a little too wide.

Left: Suntour air
Right: Suntour XCM JR L ( model i have )

Eyeballing it, i'd say the air model is 4mm narrower. This should absolutely clear a 136mm bottom bracket.. and i have more room for spacers now that the chainline is closer to correct. Could work!



I'm off to ride the bike with a slightly lowered rear suspension, higher PSI front suspension and a 2.3" at 25psi to see if leveling it out more helps.

 

[neptronix]

Well, i'll be damned.
The 2.3" on 25psi with a little more pressure in the air fork & a reduction in rear spring tension is close to a win.

The juddering situation changed from, on a 1-10 scale, from 6.5 to a 4 ( not ideal but not awful ).
Cornering is still sharp.

This tire is only a tiny bit larger. I wonder if the difference is in the compound. But a $55 Haro rides a LOT better than a $25 Kenda.

The bike rode through some gravel a lot more confidently but still not great. Kind of confirms what mr. electrom was saying. More width = more better.



Steering wise, the twitchiness did improve, on a 1 to 10 scale, it went from a 6 to a 4.5.

Bump compliance is much better. I think the extra volume of the tire is participating in that.

I think a 2.5" tire on a super wide rim + a better fork = 5-15% improvement in the front, which is exactly what i need.
Can't wait for payday & emails back from fork suppliers about fork width.

 

[Chalo]

Based on my experience, even a little more fork offset will do a lot more good than messing with tires. In terms of stability, the best thing you can do to your front wheel is make it heavier at the circumference. That gives more gyro-precession force when the bike is tilted.

But the thing that turned my front load cargo bike (with 20" front wheel) from a headshaker into something much more manageable was changing the fork from a 32mm offset BMX fork to a nominally 44mm offset recumbent fork.

I understand that the weight distribution, head angle, and a lot of other things distinguish my cargo bike from your recumbent, but when I see that fork offset on that head angle, I think, "no that's not right".

 

[neptronix]

On the money, i think.

I looked at fork offsets. My current one is 39.5mm. The suntour is 40mm, and some wider 20" forks that have no chance of ever fitting go all the way up to... 45mm.

The stock aluminum skeletal punishment device fork has 50mm offset.

Do you think somehow shoehorning on a fork with 45mm offset would make enough of a difference vs the much more common 40mm?

Was your change a 'night and day'?

 

[Chalo]

Do you think somehow shoehorning on a fork with 45mm offset would make enough of a difference vs the much more common 40mm?

Was your change a 'night and day'?

My bike was ridable, but it would headshake when I let go of the bars, even with nothing loaded in the cargo box. The more weight I carried, the lower the speed at which it would shake, and the more it did so even with both hands on the grips.



Adding 12mm of fork offset without using a longer fork was enough to erase the headshake entirely.

 

[Papa]

My bike was ridable, but it would headshake when I let go of the bars, even with nothing loaded in the cargo box. The more weight I carried, the lower the speed at which it would shake, and the more it did so even with both hands on the grips.

View attachment 359706

Adding 12mm of fork offset without using a longer fork was enough to erase the headshake entirely.

View attachment 359707

Shimmy or Speed Wobble by Jobst Brandt

Article by Jobst Brandt about front-end oscillation of bicycles

www.sheldonbrown.com

"Bicycle shimmy is the lateral oscillation of the head tube about the road contact point of the front wheel and depends largely on frame geometry and the elasticity of the top and down tubes. It is driven by gyroscopic forces of the front wheel, making it largely speed dependent. It cannot be fixed by adjustments because it is inherent to the geometry and elasticity of the bicycle frame. The longer the frame and the higher the saddle, the greater the tendency to shimmy, other things being equal. Weight distribution also has no effect on shimmy although where that weight contacts the frame does."

 

[Chalo]

Shimmy or Speed Wobble by Jobst Brandt

Article by Jobst Brandt about front-end oscillation of bicycles

www.sheldonbrown.com

"Bicycle shimmy is the lateral oscillation of the head tube about the road contact point of the front wheel and depends largely on frame geometry and the elasticity of the top and down tubes. It is driven by gyroscopic forces of the front wheel, making it largely speed dependent. It cannot be fixed by adjustments because it is inherent to the geometry and elasticity of the bicycle frame. The longer the frame and the higher the saddle, the greater the tendency to shimmy, other things being equal. Weight distribution also has no effect on shimmy although where that weight contacts the frame does."

I had quite a few conversations with the late Jobst and others about this topic, and I have done a relative lot of experimenting and observation. In my observation, he left out a couple of major factors.

One is wheel lateral stiffness. I've cured a few wiggly bikes just by using stiffer wheels that what they came with. That was after suffering a shimmy severe enough to taco the rear wheel of a 27" wheeled bike, which alerted me to the fact that the wheels were springing back and forth too.

And another is steering trail. There are only a couple of annoying problems with excessive trail as I've seen it. First and most noticeable is the tendency for a bike with excessive trail to flop the front end hard to one side or the other at a standstill or at low speeds. But if there's too much trail it can also serve as too strong a level lever for the steering to self-correct with, so the correction overshoots the center and the process oscillates between one side and the other. Frame stiffness isn't really a major factor in this.

My big cargo bike has one of the stiffest, if not the stiffest frame I've ever ridden. The fork itself (both of them) is both short and substantially reinforced in the lower end of the steer tube where lateral flex would concentrate. So in its case, I think shimmy is pretty much a self-stoking movement in the front steering and not an elastic phenomenon.

 

[neptronix]

Interesting to hear about the challenges of your application.
I see how a large rake benefits it a lot.

Any shimmy i've had seems directly related to the front tire. It was worse with a 21mm external width 20" rim with a 2.2 tire on it.

Based on my searches, this is about as wide as a 18" rim gets. I think this will be allright for a 2.5".

 

[99t4]

Rainbow Bridge!
​

 

[neptronix]

Looks like i'm going to have to go full Karen to get a simple spec:

 

[LewTwo]

LOL ... I have seen "kids" that easily double my 135 pounds.

 

[neptronix]

..finally got him to cough it out.
Ok good.. i have a XCM springer here already, so i can do a test fit with a 137mm bottom bracket.

137mm bb ordered!