Maxarya Ray 2 Semi Recumbent w/high efficiency mid drive

[BalorNG]

I'm not an expert but i've been studying what experts have to say for months now and think i have a hang of it.

The rim shape makes complete sense since the tire looks like it would complete the shape.
This guy's fairing starts at beyond his width and creates additional frontal area near his shoulders and other areas.
The bottom part is a disaster. This was not properly measured before creation.

Despite these design disadvantages the fairing works well enough to increase speed, but was too impractically shaped.

So a badly designed but well built tail box does work.
..just like a kamm tail works on a car.

Well, if you think you can do better - go for it. Since your position is very un-aero to beging with, and unless you simply add a triangular tailbox with side converging at 45 deg (hope not!), it will work of course... just don't expect more than a few percent at right combination of speed and wind.

Kamm tail 'works' exactly because it is a 'lesser evil' - it allows to maintain a reasonable fairing length given proper convergence angle. Streamliners can get away with much 'stubbier' tail with steeper convergeance - because they are designed for certain patterns of air flow, guaranteed to be 'just turbulent enough' not to delaminate, but not TOO turbulent to prevent pressure recovery.

'Interrupted body aerodynamics', dealing with detached and reattached flows is a herculean task that stumps supercomputers, unfortunately... you'll have to experiement.

 

[neptronix]

I should have a bottom bracket in my mailbox on monday. Then i can ride the thing, When i can ride it, i can determine the optimum angle for the handlebars and then start experimenting with a few different front fairing shapes made out of cardboard. Whichever one provides the most benefit will be made out of ABS and Lexan for durability.

Then i'll repeat the same process on the tailbox. Make 3 shapes, pick the one that reduces my whr/mi the most, and construct it out of ABS.

No need to go crazy here. I can do that on the cannondale

 

[neptronix]

Just some news..

The wider bottom bracket didn't work out. Still have way too much metal to shave off the pedals. I need a 130mm wide bottom bracket at a minimum for clearance. Not happy with that. Such wideness will probably piss off my legs.

I could buy some 175mm pedals and re-thread them for about 165mm since maxarya only offers these specially threaded cranks at 170mm and 152mm. It would be better to have a narrow pedal stroke than one that's too wide.

I could have an unsuspended chromoly front fork made ( $$$ ) and pair it with a lightweight moto tire at slightly lower pressure to take this extreme harshness out of the front end.

The eccentric bottom bracket on the cannondale gives me the same pedal offset as the expensive eccentric BB i wanted to use, so i want to experiment with that first and see if my pedal clearance gets improved enough.


Another issue with the bike is that the headtube has no built in tensioning method against the frame. This was a problem when assembling the bike because the frontend was always a bit loose. I ordered a 6ft long M6 x 1.00 threaded rod from mcmaster-carr, and will come up with some solution based on that.

I still feel perpetually defeated by frames with 20" wheels and not having something that has full suspension that works with my long legs. I have gone through about 4 bikes that were a 'miss' in the last 4 years. If this is also a miss, the next step is building my own frame now that i have the space to do so.

 

[neptronix]

Decided to order a 127mm wide bottom bracket and say fuckit and bench grind the inner crank material.. wish me luck, lol

 

[qwerkus]

Decided to order a 127mm wide bottom bracket and say fuckit and bench grind the inner crank material.. wish me luck, lol

Well: good luck! Here a teaser about my next post - inspired by your awesome work!

 

[neptronix]

Hah, well i hope you learned and apply something useful from my fails so far and aren't going down the same dark path :lol:

 

[qwerkus]

Hah, well i hope you learned and apply something useful from my fails so far and aren't going down the same dark path :lol:

Nah, where is the fun in that? I'm happily going to make a thousand mistakes; first one was probably to get the bike without trying it first...

 

[neptronix]

Well honestly good luck riding a used or new recumbent bike unless you're real lucky to be next to a seller.

In my entire state we have one store... which only sells trikes.
A store that *might* have 2 wheelers is 800 miles away.

Kinda tough, you just have to buy and try out here :O

 

[neptronix]

Good news..

Shaving ~4mm off the inner part of the pedals worked excellently..
Full clearance of the fork at all angles of rotation.. with a little to spare





Have i weakened the pedals, yes, a bit.. does it matter? no; they'll never be stood on on this bike, nor cranked super hard thanks to the mid drive. In fact, i only removed a little bit of thread from one side. It should be plenty strong.

There are lots of other geometry/seat mount modifications to do.. but with this biggest issue tackled, i'm a lot more positive about this project turning out well.

 

[www.recumbents.com]

LOL, I have a couple crank arms that looks like that because I needed clearance to too. MTB cranks are way overbuilt for recumbent use.

 

[maiz]

Good news..

Shaving ~4mm off the inner part of the pedals worked excellently..
Full clearance of the fork at all angles of rotation.. with a little to spare

View attachment 297146

View attachment 297147

Have i weakened the pedals, yes, a bit.. does it matter? no; they'll never be stood on on this bike, nor cranked super hard thanks to the mid drive. In fact, i only removed a little bit of thread from one side. It should be plenty strong.

There are lots of other geometry/seat mount modifications to do.. but with this biggest issue tackled, i'm a lot more positive about this project turning out well.

Any updates?

 

[neptronix]

No updates, my entire ebike building setup is packed into a storage unit until next year

 

[maiz]

No updates, my entire ebike building setup is packed into a storage unit until next year

Bummer. Such a unique recumbent. Considering it for a build myself.

 

[neptronix]

So i finally have some space to wrench on some stuff.

I have the bike partially together, and there were some existing issues left to tackle

- The front end couldn't be properly tensioned with the new suspension fork & locbuster removal without some help from maxarya.
Now fixed,

- Removal of the locbuster leaves the handlebars not tall enough and i had to order their taller BMX like handlebar:

Ordered!

- I ordered a Monarch R rear shock from a third party because maxarya was out of stock... and had - supposedly, the right hardware fitted to it by a bike shop. The mounting points were off by by 1-2mm. Decided to revert to the crappy spring the bike came with for the time being.

This leaves the frontend ~30mm taller than stock. I'll deal with it for now. I think the proper cure down the line is to go to a 18" wheel, instead of raise the rear to counter-compensate, because the rider sits and inch or two higher vs the cannondale, and i don't want to compromise the center of gravity any further.

More updates on this later.

 

[neptronix]

Coming back together from parts!

In going from the default not so tall handlebar, to the tall handlebar, and also moving the seat to it's upright position, i can now finally reach the handlebar enough, which was a problem before.



It's possible i could put in a 5 inch section of cut fork tube and replace this upper tube that comes with the Ray 2 with a long regular stem. This would move the handlebars down 5 inches and towards me 1-1.5 inch, which should be adequate.

v-- here is how the bike was configured as stock vs how i had the cannondale set up.



It's quite a shame that the bottom bracket is so far forward on this bike, plus we have a different angle as well. Makes it pretty hard to fit a long legged person. If you are more of a short leg, long torso kinda dude, your body would like it a lot more.

I'm calling the handlebar solution good enough for now.


OK.. remaining problems with getting it on the road? since the swap from a 110mm BB to 127mm BB on front, we now have a chainline problem. I think a good answer is to add the lightest.bike mid drive in the middle BB on this bike, because it has a 122mm BB, aligning the chain to within ~2.5mm.

This means losing the 3 speed gear shifter, but this is fine because we get an advantage of being able to run the motor at higher speed than the cranks.

For now, i will add spacers to the chainring so that every thing lines up. I want to work out the fitment issues and ride it as an acoustic bike first.

 

[Cowardlyduck]

Somehow missed this thread till now despite it being right up my alley of electric MTB bents. Love your work Nep!
I'm especially interested in that special mono shock fork. One's suitable for 16" wheels or with disc brake mounts are incredibly hard to come by and the one I have on my AT is impossible to find now.

I have way to many projects to consider building another Emtb recumbent any time soon, but if I were able, I would seriously consider copying your work here Nep!

Cheers

 

[neptronix]

Thanks pardner!

Yeah bikee's are great on one hand, unfortunate on another due to the really small wheel. I really considered getting a long wheelbase version after seeing yours, but with my super crappy roads X the speed i need to travel at, 16" wheels make me extremely nervous.

it's too bad there aren't a lot of these types of bikes being made today, and we have more of a selection.
I don't have enough miles on the Maxarya to give a verdict on it yet, thankfully you missed the dull part of the thread

.. chainring spacers on the way!

 

[maiz]

Thanks pardner!

Yeah bikee's are great on one hand, unfortunate on another due to the really small wheel. I really considered getting a long wheelbase version after seeing yours, but with my super crappy roads X the speed i need to travel at, 16" wheels make me extremely nervous.

it's too bad there aren't a lot of these types of bikes being made today, and we have more of a selection.
I don't have enough miles on the Maxarya to give a verdict on it yet, thankfully you missed the dull part of the thread

.. chainring spacers on the way!

Did you already evaluate the revel propulsion motor?

 

[neptronix]

I think i did a long time ago, and ruled it out for some reason or another.
It was probably because of Q Factor.

I probably looked at it last in 2020.

Also looks like they're sold out?

 

[maiz]

I think i did a long time ago, and ruled it out for some reason or another.
It was probably because of Q Factor.

I probably looked at it last in 2020.

Also looks like they're sold out?

Right I couldn't remember what their q factor was or if it was symmetrical etc. No word yet on next batch?

 

[neptronix]

Appears to be dead, kind of a bummer - it'd be nice to have another mid drive choice if the lightest doesn't work out.

PaulD's lightweight mid drive development

Edit: apparently he's doing another batch.

 

[neptronix]

Good news. The front suspension modification is done, and the cables have been reworked. The bike is ready to ride.

I replaced the front 113mm wide bottom bracket with a ~128mm wide BB, and the mid BB went from 110mm to 123mm.
I put some spacers between the front chainring and the crank, the result is the front chain only has 4-5mm of offset. With some work ( new mid drive gear holder w/different offset ) this could be adjusted out and become perfectly straight.

The big middle chainring had to go from being in the outer position to the inner position to account for the large offset. This effectively removes my 3 speed cluster, but that's okay; the bike will have a minimum of 1200W of power.


The front suspension fork and 10mm spacer added 1 inch of height compared to the stock fork.
I have a 2.0" tire up front and a 2.25" out back. The rear looks like it could accommodate a 2.5", but i want the bike lower, not taller.

+0.75 inches up front becomes 0.5"-0.25" when you sit on the bike and the front suspension sags a little. Not bad and probably not very noticeable on the road.



I think that if i swap the 165mm rear spring for a 150mm rear shock, and get a 18" disc wheel built for the front, and modify the seat to sit me 0.5 inches lower, all these things could get within 0.5 inches of within the cannondale's seated height and i would end up with the proper cannondale successor, just without the fantastic rear suspension.


Now here's the heartbreaking part, it looks like Maxarya quit the bike business lately and is now just doing CAD work or whatever.. so this i'm on my third discontinued semi recumbent now.

^-- turns out i'm wrong about this, disregard

Seriously, if this bike doesn't work out, i'm so over buying semi recumbents. The ones with full suspension are all small production numbers and discontinued. I'll design and build my own out of steel using my Cannondale frame ( still have it! ) and the Ray 2 frame as a design reference if it comes down to it.



I've sent an email to maxarya asking if it's possible to get a frame and seat so that i can at least have spares. Let's see what happens.

It's raining/snowing for the next 3 days so the prospect of a ride to test out the new configuration is pending.

 

[neptronix]

According to my email, i have the lightest mid drive parts that let me run the drive on the bike coming my way.

Cool!

I'm thinking it belongs on the front to act as ballast to distribute the weight better.. and also give me the ability to gear it for 40mph. Sounds like good times to me!

 

[neptronix]

Okay, just came back from a quick ride!

The crank bolt sticking in the pedals is smacking ever so slightly and needs a millimeter shaved off.

Cornering isn't very good. I think the taller front end has a negative effect. I think i need that 18" wheel now.

The suspension was really great. I can tell that front air shock is helping the bike float over broken pavement. Massive difference over the loud and rickety aluminum front end.

Will give it a re-tune and re-ride in a sec.

 

[maiz]

Okay, just came back from a quick ride!

The crank bolt sticking in the pedals is smacking ever so slightly and needs a millimeter shaved off.

Cornering isn't very good. I think the taller front end has a negative effect. I think i need that 18" wheel now.

The suspension was really great. I can tell that front air shock is helping the bike float over broken pavement. Massive difference over the loud and rickety aluminum front end.

Will give it a re-tune and re-ride in a sec.

Do you have the large frame or the medium frame?