Electrathon America Forum

WayneTech Welding · Newbie

Rims for areocoupe

electrathon · administrator

You likely are running the plastic wheels. They will fold almost sideways on the rear when cornering. The moped wheels are alluminum and a far stronger. Mike Hodgert uses a lot of them on his cars since they are very durable. Another option is to go to a heavy duty 48 spoked BMX wheel.

Kyle Keenan · Veteran Member

We ran an Aerocoupe with a Skyway graphite rear wheel. While racing, a bearing "gernaded" itself and we ended up having to borrow a wheel.

We then changed to a Alex DM-24 rim with a Joytech hub. This can be found online for aroud $45 and has held up strong during three races and several test days. We are now using this combo on our new car as well.

We are still looking for a decent disc brake front hub set-up, so if anyone has any leads, that'd be awesome!

churd · Member

Kyle Keenan wrote:
We are still looking for a decent disc brake front hub set-up, so if anyone has any leads, that'd be awesome!

We bought a very inexpensive set from our local bike shop, for about $45 per wheel. We have been using them for about three years, and they have held up great. As soon as I get a chance, I'll find out the make and model number.

Kyle Keenan · Veteran Member

Yes! That'd be awesome! Thank you very much!

jeff Blackman · teacher

ft.wheels

churd · Member

RE: Rims for areocoupe

cory991 · Newbie

The bad thing with disc brakes are that they drag a little bit causing a loss of energy

churd · Member

If they are adjusted properly, they shouldn't drag at all, and they give the added bonus of weighing a lot less than the drums.

I do agree though, it's a lot more work adjusting them properly, and if used, the tolerances in manufacturing the supports for them are much higher.
This makes it even tougher, as my students do not have a full machine shop at their disposal, and it becomes quite challenging to manufacture spindles & brake supports with high tolerances so that they do not drag at all.

ECC · Newbie

Is there a specific type of wheel that can be used with drum brakes? I'm trying to research what the best tire/braking system would be for our 3-wheeled car

Zaine Stapleton · Senior Member

Willamette High School uses the Tomos Moped wheels for the front steering wheels on almost all of their cars. Mike Hodgert might be able to help you out if you have questions. I've got disc brakes on mine so I can't help you out there.

Brockport Electrathon · Newbie

I would stay away from skyway wheels! We had one come apart while the car was in motion.

Don't Buyt Skyway Wheels

-- Edited by Brockport Electrathon on Monday 14th of November 2011 03:42:11 PM

electrathon · administrator

Is that one of the plastic wheels? I have seen them fold over nearly sideways durring cornering. Three wheeled cars have a tremendous amount of side stress durring cornering.

Aaron

Kirk Swaney · Veteren Racer

The warnings are true about plastic wheels, but some are strong too. Remember, the vehicle loading on them are can vary also. A high center of gravity can even give spoke wheels grief. There are different materials used in different plastic wheels, even from the same manufacturer. So do be careful what you buy with the plastics. For example, plastic wheels made for a garden cart are often very soft and best to avoid, even though they look the same and you would think they're rugged.

For rear drive wheels, I recommend spoke or alloy. Here's an example of a strong spoked rear drive wheel with good strength to weight ratio that also accepts a standard freewheel sprocket adapter (if that's important to you).

And here is a strong alloy mag drive wheel system with 12mm axle and integrated drum brake if that is important, but no easy freewheel solution.

Kirk Swaney · Veteren Racer

The warnings are true about plastic wheels, but some are strong too. Remember, the vehicle loading on them are can vary also. A high center of gravity can even give spoke wheels grief. There are different materials used in different plastic wheels, even from the same manufacturer. So do be careful what you buy with the plastics. For example, a team I was on, bought plastic wheels with big bearings, made for a garden cart. We found them to bevery soft and best to avoid, even though they look the same thought they would be rugged.

For rear drive wheels, I recommend spoke or alloy. Here's an example of a strong spoked rear drive wheel with good strength-to-weight ratio that also accepts a standard freewheel sprocket adapter (if that's important to you).

And here is a strong alloy mag drive wheel system with 12mm axle and integrated drum brake if that is important, but no easy freewheel solution.

TotallyLost · Veteran Member

electrathon wrote:
You likely are running the plastic wheels. They will fold almost sideways on the rear when cornering. The moped wheels are alluminum and a far stronger. Mike Hodgert uses a lot of them on his cars since they are very durable. Another option is to go to a heavy duty 48 spoked BMX wheel.

I have dozen "plastic" 20" BMX wheels I use for a number of projects. I can prop them against a step and jump on them, and they barely deflect ... I'm nearly 200lbs.

I tried that with a spoked 20" BMX wheel, and it dished, then folded immediately.

Everyone needs to do there own sourcing, and testing. Broad statements like this are completely non-productive, and clearly encourage prople to make stupid mistakes, and avoid superior solutions.

If you can dish your wheel by by a 200 lb person jumping on it ... you probably needed another solution anyway.

Zaine Stapleton · Senior Member

Keep in mind that Aaron said they fold over when going around a corner when in motion. Not when stationary.

TotallyLost · Veteran Member

Zaine Stapleton wrote:
Keep in mind that Aaron said they fold over when going around a corner when in motion. Not when stationary.

The point is that some "plastic" wheels are strong, and some "spoked" wheels are strong.

And that some of each do not belong on Trikes, that do not lean --- YMMV

The older "plastic" Mongoose BMX wheels I have easily support a 250-300lb static/dynamic side load -- I can stand and bounce on them supported on opposite sides of the rim. I can however break those wheels with a sharp impact load (and I have), well in excess of that. But tires do not have that much dynamic friction to the pavement, without skidding/breaking loose.

Thus, impacting them against a curb sideways in a skid, will break them, .... but the same is also likely to fold over a double wall spoked rim too. I've also broken 13" alloy wheels on my Corvair autocrossing by nailing a concrete parking block after spinning out, where a normal factory steel rim would have just bent.

The "plastic" wheels on a typical childs first bike I had, easily fold over with about an 80lb side load. Those clearly would be bad news on a trike that weighs in at 300lbs.

My point, is that generic statements should be avoided. It would be wrong to say all metal spoked wheels fail, just because certain ones do. Just as it's wrong to say all plastic wheels fail, just because certain ones do.

meangreen · teacher / board member

It's been my experience that the plastic wheels seem to have a "life expectancy". When I was teaching, we had two Blue Sky Aerocoupes that came with plastic wheels. We never broke a rear wheel, but we broke four fronts. They all broke without warning while cornering. All the plastic wheels I've seen do flex some. Apparently they fatigue from the constant flexing and eventually fail. I replaced them with Weinmann 48-spoke BMX wheels with alloy rims. We did have a few broken spokes after that, but those are repairable.

TotallyLost · Veteran Member

meangreen wrote:
. All the plastic wheels I've seen do flex some. Apparently they fatigue from the constant flexing and eventually fail. I replaced them with Weinmann 48-spoke BMX wheels with alloy rims. We did have a few broken spokes after that, but those are repairable.

Again, this should be a subject of careful analysis, testing, and responsible life management with regular inspection. Some plastics, and nearly all aluminum alloys will fatigue as well. Certain fiber filled plastics, and various plastics with nylon like composite are unlikely to fatigue with an unexpected failure.

I've broken one set of aluminum alloy rims on my moutain bike from fatigue too. That was a very dramatic failure as well, and would have been just as "interesting" on the front of a trike in a race. The alloy rim separated with a clean fatigue fracture around the joint pins, along with a spoke failure that spiralled it, caught in the front fork, and left me head first over the handle bars.

In retrospect, I've bent a few steel bike rims, but they have never "just failed".

Even carbon fiber will fail after being stressed past the yeild point with a sharp impact. Knowing that, means replacing it after being excessively stressed is responsible management, and allows the material to be used in areas that steel would never fail the same way ... a tradeoff that allows lower weight with higher strength.

One should treat this kind of safety, as climbers do. After you take the max falls on a dynamic rope ... it's time to retire it, even when it still looks new. Careful analysis, testing, and responsbile life management is probably a good thing for alloy wheels, and even plastic composite wheels.

Otherwise, just stick with heavy steel rims, that are unlikely to fatigue.

TotallyLost · Veteran Member

meangreen wrote:
When I was teaching, we had two Blue Sky Aerocoupes that came with plastic wheels. We never broke a rear wheel, but we broke four fronts. They all broke without warning while cornering.

BTW ... I agree, that if multiple Aerocoupe plastic wheels have failed this way, testing suggests strongly that those wheels will continue to fail that way, and those wheels should not be used.

TotallyLost · Veteran Member

TotallyLost wrote:
I've broken one set of aluminum alloy rims on my moutain bike from fatigue too. That was a very dramatic failure as well, and would have been just as "interesting" on the front of a trike in a race. The alloy rim separated with a clean fatigue fracture around the joint pins, along with a spoke failure that spiralled it, caught in the front fork, and left me head first over the handle bars.

BTW ... I'm not the only person that's had failed "pinned" alloy bike wheels ... see: http://www.bikeforums.net/archive/index.php/t-106097.html

There are similar problems with welded alloy wheels that were not properly heat treated to remove the stresses from welding. Even when the welds are done right, problems with residual stresses from extrusion, machining, and forming have left spots that later fatigued. There have been multiple lawsuits over bicycle frame and rim weld failures that resulted in injury.

Regular inspection is ALWAYS your friend. And knowing what to expect and look for is important. Especially when wheels are used on the front of trikes, in an application that most wheels and spokes where not designed to regularly handle the high side loading forces.

Designing a leaning system, puts the wheel loads into the plane that the wheels are designed to properly handle.

FYI:

http://www.icelord.net/bike/thebicyclewheel.pdf

http://pardo.net/bike/pic/fail-009/000.html

http://www.metallurgist.com/html/vitae.html