Blue Dream: Maxarya Ray 2 Semi Recumbent w/high eff mid drive
- Thread starter neptronix
- Start date
There was no valve stem nut. I think that might help a little bit but not enough. The tear could still happen. The bike has very powerful braking also, so the likelihood the tire/tube/strip can move on the rim is very high.
I think my 18mm internal width rim with a 50mm wide ( 2.0" ) tire isn't helping things; the crazy thing is the stock tire diameter was 2.2", this makes for a floppy front wheel which may have contributed to the slippage, IDK.
I think my 18mm internal width rim with a 50mm wide ( 2.0" ) tire isn't helping things; the crazy thing is the stock tire diameter was 2.2", this makes for a floppy front wheel which may have contributed to the slippage, IDK.
Chalo
100 TW
No.
When the tire crawls around the rim, it can't bring the valve with it. Nutting the valve stem in place doesn't change that. It would probably make it fail slightly earlier.
Makes sense!
Looking over the bike..
The rear did nothing to help break my fall; it's much narrower than the pedals. So, my body took up the slack in the rear.
Looks like the pedals and the handlebar both helped me take the fall. Thank heavens for that 128mm wide bottom bracket i installed, otherwise my knees would have gotten smacked.
Thinking about it, we have something at the top and bottom of the front of the bike protruding to help take the fall...
But nothing in the rear.
Here's a solution that would prevent >90% of body to ground contact while falling to the side.
General idea: have a 1-2 inch buffer between my body and the road.
..in the case of a crash, if you hold the handlebars straight and keep your knees in, there should be zero body to ground contact.
Handlebar extender for the top of the seat:
Bar ends:
Once i'm healed up i'd like to build these safety mechanisms and do a test crash...
..because what's cooler than a fast recumbent bike? one you can dump at high speed and walk away from totally unscathed.
Nonetheless i am still really happy at how recumbent bikes crash & how easy it would be to add some effective safety to them for some 90% of types of crashes..
It's going to be hard to ride my upright bike knowing how much nicer a recumbent crash is.
Then again, some of this thinking translates to an upright bike too..
The rear did nothing to help break my fall; it's much narrower than the pedals. So, my body took up the slack in the rear.
Looks like the pedals and the handlebar both helped me take the fall. Thank heavens for that 128mm wide bottom bracket i installed, otherwise my knees would have gotten smacked.
Thinking about it, we have something at the top and bottom of the front of the bike protruding to help take the fall...
But nothing in the rear.
Here's a solution that would prevent >90% of body to ground contact while falling to the side.
General idea: have a 1-2 inch buffer between my body and the road.
- Keep this handlebar width, it's more than adequate, but put bar ends on it.. this bar also helps orient it along the road so it can do it's thing as a primary "crumple zone" even if we don't have the handlebar perfectly aligned.
- Bolt some drop grips to the bottom of the seat, this should create a 4 inch protrusion ( handlebars are still 3 inches wider but that's okay ). Alternatively if i can find some thin plastic boxes for storage, these can be my side-bumper.
- 2 inch of plastic pipe bolted to the end of the cranks.
- Handlebar extender with plastic pipe going through it.
..in the case of a crash, if you hold the handlebars straight and keep your knees in, there should be zero body to ground contact.
Handlebar extender for the top of the seat:
Bar ends:
Once i'm healed up i'd like to build these safety mechanisms and do a test crash...
..because what's cooler than a fast recumbent bike? one you can dump at high speed and walk away from totally unscathed.
Nonetheless i am still really happy at how recumbent bikes crash & how easy it would be to add some effective safety to them for some 90% of types of crashes..
It's going to be hard to ride my upright bike knowing how much nicer a recumbent crash is.
Then again, some of this thinking translates to an upright bike too..
Proper tire inflation is highly recommended. But to inhibit tires rotating on the rims, I use automotive V-belt dressing on the tire's bead seats...
I guess if you want to be the test pilot on a hot build some armoring up would be a good idea. Motorcycle gear and a full face helmet might work. Building a "cage" might be good, or bad depending on the crash scenario.
I avoid falling as much as possible, but have gone down a time or two on my Huffy Oslo while bar hopping. Not a good idea.
I avoid falling as much as possible, but have gone down a time or two on my Huffy Oslo while bar hopping. Not a good idea.
Interesting idea!
I think a rather thick & grippy 20" x 1.75" BMX tire could help increase the PSI, the Schwalbe i had was so thin and hard and not rubber like..
Yeah i'm thinking this is the appropriate safety gear:
Hey, shit happens! it would be cool to be not have to worry about when it does
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Nice demonstration of all 4 corners of a motorcycle being fitted with some form of crash protection.
So funny how this is so similar to my idea.
Many motorcycle crash bar systems have 2 or 3 points and seem to be effective.
I did a ton of research about crash bars on motorcycles. They seem to be primarily designed with preserving the motorcycle itself, not protecting the rider. However, i see that they protect the rider some.
My idea is to never have my knee hit the ground. But going sideways, your legs are going to naturally want to drop down since they can't grip anything. No length of bar can help you there - you basically need a rollcage.
Maybe pedals with straps is the key to keeping the leg on the bike pointed straight during the fall. The only part you need to worry about is your ass. Unlike an upright bike seat, you can't leverage your thighs against it to stay on. The answer to that is probably to put the rollcage aspect of things around the butt. Buttcage.
Maybe this buttcage can be a platform for some very thin panniers in addition to providing the ability to keep the butt in the seat when we've gone sideways. The only thing the rider needs to do is tuck their knees in and hold the handlebars straight in the event of a crash to prevent road rash.
In this 3 point configuration, shoulder protection depends on you keeping the handlebar relatively straight. A fourth point at the top of the seat could provide some forgiveness.. maybe it's worth it!
It sounds like a good plot to greatly increase safety, am i missing anything?
So funny how this is so similar to my idea.
Many motorcycle crash bar systems have 2 or 3 points and seem to be effective.
I did a ton of research about crash bars on motorcycles. They seem to be primarily designed with preserving the motorcycle itself, not protecting the rider. However, i see that they protect the rider some.
My idea is to never have my knee hit the ground. But going sideways, your legs are going to naturally want to drop down since they can't grip anything. No length of bar can help you there - you basically need a rollcage.
Maybe pedals with straps is the key to keeping the leg on the bike pointed straight during the fall. The only part you need to worry about is your ass. Unlike an upright bike seat, you can't leverage your thighs against it to stay on. The answer to that is probably to put the rollcage aspect of things around the butt. Buttcage.
Maybe this buttcage can be a platform for some very thin panniers in addition to providing the ability to keep the butt in the seat when we've gone sideways. The only thing the rider needs to do is tuck their knees in and hold the handlebars straight in the event of a crash to prevent road rash.
In this 3 point configuration, shoulder protection depends on you keeping the handlebar relatively straight. A fourth point at the top of the seat could provide some forgiveness.. maybe it's worth it!
It sounds like a good plot to greatly increase safety, am i missing anything?
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PaPaSteve
1 kW
Streamlined bodies offer significant crash protection
and
improved range
Coroplast is low cost, quiet, reasonably aero efficient and prevents road rash.
Carbon fiber, Kevlar, core construction is higher cost, more effort to build but offers better efficiency and protection.
and
improved range
Coroplast is low cost, quiet, reasonably aero efficient and prevents road rash.
Carbon fiber, Kevlar, core construction is higher cost, more effort to build but offers better efficiency and protection.
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tigcross
100 W
Hey Netronix, I'm glad to hear that your crash was not too bad, and I agree that if the seat and bars were wider you might have been able to adopt a "keep hands and feet inside the vehicle" approach and come out with even less damage.
your experience highlights something that I have believed for quite some time, which is that most off-the-shelf recumbents are unsuitable platforms for electrification. They often do not allow for suspension forks or wide tires and typically run less than optimal components. I wonder, would you choose the Maxaraya again if you were to start this project right now?
your experience highlights something that I have believed for quite some time, which is that most off-the-shelf recumbents are unsuitable platforms for electrification. They often do not allow for suspension forks or wide tires and typically run less than optimal components. I wonder, would you choose the Maxaraya again if you were to start this project right now?
Love that one in the center. Thanks for the inspiration!
I've been calculating like a madman.
18 x 2.4 = 1495mm dia
20 x 1.5 = 1490mm dia
My calculations prior were totally wrong & based on circumference instead of diameter.
Let's start from scratch on the angle correction.
10mm front spacer is removed.
Frontend gain from suspension fork: approx 15mm considering large sag
Front: from 2.2" stock road tire to 1.5" grippy BMX tire
0.7 inch / 2 = .35 inch or 8.89mm
Total front height vs stock: +6.11mm
Rear: from 2.2" stock to 2.6" cargo bike tire
0.4 inches = 10.16mm / 2 = 5.08mm
Total rear height vs stock: +5.08mm
The bike is now 1mm higher in the front vs stock, but the lower PSI front tire subtracts from that, so we've got a miniscule gain.
The bike also gets a drag racer look
Recumbent fans, how do you feel about 1.5 wide front tires? too narrow for 35mph?
I've been calculating like a madman.
18 x 2.4 = 1495mm dia
20 x 1.5 = 1490mm dia
My calculations prior were totally wrong & based on circumference instead of diameter.
Let's start from scratch on the angle correction.
10mm front spacer is removed.
Frontend gain from suspension fork: approx 15mm considering large sag
Front: from 2.2" stock road tire to 1.5" grippy BMX tire
0.7 inch / 2 = .35 inch or 8.89mm
Total front height vs stock: +6.11mm
Rear: from 2.2" stock to 2.6" cargo bike tire
0.4 inches = 10.16mm / 2 = 5.08mm
Total rear height vs stock: +5.08mm
The bike is now 1mm higher in the front vs stock, but the lower PSI front tire subtracts from that, so we've got a miniscule gain.
The bike also gets a drag racer look
Recumbent fans, how do you feel about 1.5 wide front tires? too narrow for 35mph?
tigcross
100 W
I think that 1.5 is way too skinny for safety. I'm running 16 X 2.75 Moped tires and feel much better about high speed than when I was running 2.00 BMX tires. I would do everything in your power to avoid running low pressure on the front tire as it makes for unpredictable handling.
Thanks for chiming in, i really like what you're doin' over there.
If i could do it again i'd build my own from scratch, a good CLWB with rear suspension is hard to come by & most of them have nightmarish shapes preventing the mounting of all sorts of things.
The Maxarya is the bike, i settled for, main complaints are:
- cranks could be 2 inches forward and higher, allowing the rider to go forward & have better weight balance
- this change coincidentally would allow the front end to be at less a steep angle & therefore front suspension would be able to articulate better.
- the bike would be a little faster as a result of this change thanks to the aerodynamic help for the legs
- there should be some rear overhang like the cannondale so that cargo can be mounted. All stock cargo mounting options are compromised
Hm, well, 18 x 2.4" is within 5mm of the diameter of 20 x 1.5". So maybe the half step is a bad idea.
What kind of speeds are you talkin?
Example of the cannondale tail that's missing on the maxarya:
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PaPaSteve
1 kW
A general tire pressure rule is : 10 to 15 percent sag.
Say the tire profile measures 20mm so when in use case conditions then the sag measures 2 to 3mm.
Use case is when you are on the bike so you will need a buddy to do the measure.
Axle center to ground unloaded verse loaded conditions.
During my racing days I spent many hours doing laps in small parking lots or outside basket ball courts learning the traction limits of tires.
Say the tire profile measures 20mm so when in use case conditions then the sag measures 2 to 3mm.
Use case is when you are on the bike so you will need a buddy to do the measure.
Axle center to ground unloaded verse loaded conditions.
During my racing days I spent many hours doing laps in small parking lots or outside basket ball courts learning the traction limits of tires.
tigcross
100 W
I think that an 18inch rim might be just the ticket, as you can get them in robust configurations. Of course, you will be setting yourself up for less tire selection but there's bound to be something that will work.
Yes, unless the use is a pure racing vehicle, storage space should be one of the first things that a bike designer thinks about.
Yes, unless the use is a pure racing vehicle, storage space should be one of the first things that a bike designer thinks about.
of course, I would never break the British Columbia e-bike regulated top speed for an ebike of 32 km/h, but when testing on private roads the Electrom's top speed on the flat is 70 km/h, which works out to 43 mp/h. In downhill testing, I have had it up to 88 km/h (yes, I have heard Doc Brown's Back To The Future 88km/h quote) the cool thing about heavy hub motors is that the faster you go, the more stable they become as they act like gyroscopes. Here's a short clip of riding it off-road at decent speeds.
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Thanks for the demonstration.. that's quite capable!
I feel very lucky, found a wheel with 3/8" axles; this axle measures 9.5mm diameter which is an exact fit to my front fork's slightly oversized dropouts. I get 2x the wheel - fork contact this way so losing QR is not a negative.
Will run with a BMX 18 x 2.3" on it. The rim should take a 2.5" maximum which i think is enough wiggle room to get adequate traction.
36 spokes is overkill, but with some work, this could be an 18 spoke wheel. The Cannondale front 16" has 16 spokes, and that bike sits you +2 inches up front, so i think 18 spokes would be equivalent strength.
Brakes? i'll use vbrakes with a box 2 brake post extender to make the calipers fit/align.
I think that:
- Dropping the front 1.4 inches/35mm
- Using the odd tooth chainring hack to adjust the pedals forward 8mm ( then i can move the seat forward that amount )
- And wheels with ~200g less unsprung weight
..should have a noticeable impact on the front juddering & allow me to go up some PSI and get away with it.
..at a bare minimum i should see a small improvement to cornering.
Parts ordered.. fingers crossed!
I feel very lucky, found a wheel with 3/8" axles; this axle measures 9.5mm diameter which is an exact fit to my front fork's slightly oversized dropouts. I get 2x the wheel - fork contact this way so losing QR is not a negative.
Will run with a BMX 18 x 2.3" on it. The rim should take a 2.5" maximum which i think is enough wiggle room to get adequate traction.
36 spokes is overkill, but with some work, this could be an 18 spoke wheel. The Cannondale front 16" has 16 spokes, and that bike sits you +2 inches up front, so i think 18 spokes would be equivalent strength.
Brakes? i'll use vbrakes with a box 2 brake post extender to make the calipers fit/align.
I think that:
- Dropping the front 1.4 inches/35mm
- Using the odd tooth chainring hack to adjust the pedals forward 8mm ( then i can move the seat forward that amount )
- And wheels with ~200g less unsprung weight
..should have a noticeable impact on the front juddering & allow me to go up some PSI and get away with it.
..at a bare minimum i should see a small improvement to cornering.
Parts ordered.. fingers crossed!
Been doin' more of the big think..
How about instead of protection on the side of the seat, i make a bar i can tense a thigh on to hang on the bike while it's sideways.. a bar of sufficient strength would be less than half the weight.. we just have to accept that the bar might move and dump me off the bike within a few seconds.. this might be OK because by the time i have 3 points scraping the ground, the bike has decelerated quite a bit before we have ass to ground contact.
Seems like the least weight/aesthetic compromising option.. the only problem is if you end up flying forward somehow, it's gonna slam you in the nuts.
Well, i'm still healing up this road rash so i got plenty of time to iterate..
How about instead of protection on the side of the seat, i make a bar i can tense a thigh on to hang on the bike while it's sideways.. a bar of sufficient strength would be less than half the weight.. we just have to accept that the bar might move and dump me off the bike within a few seconds.. this might be OK because by the time i have 3 points scraping the ground, the bike has decelerated quite a bit before we have ass to ground contact.
Seems like the least weight/aesthetic compromising option.. the only problem is if you end up flying forward somehow, it's gonna slam you in the nuts.
Well, i'm still healing up this road rash so i got plenty of time to iterate..
Engineers don't "cross fingers"... because it jams up typing on the calculator.
tigcross
100 W
that looks like the right wheel for sure, and I think a solid axle is fine in this case. I would suggest leaving it as a 36-spoke as the weight of 18 spokes is pretty minor when you have electric assist.
What hack is this?
hypersphere
10 mW
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.
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.
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!
I think it would be hard to go flying on this bike, versus an upright.
Maybe the bar could be curved in such a way that it acts as a ramp and isn't a nut smasher anymore, instead it will direct the body towards the handlebars, which will help break the momentum as they fold in half.
If we have a fairing up front then maybe we get some additional protection from flying forward.. hopefully that big plastic bubble is helping break the fall / i hit it before i hit the handlebar tube.
leelorr
100 W
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...
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...
