Thane Orbitrek elliptical, right side view
I was not looking for an elliptical trainer, as I am not really heavily into cardio, but one popped up curbside, so I brought it home. The Thane Orbitrek elliptical trainer needed a lot of work in order to function. Thankfully it all turned out well and I now have another option for cardio to add to rope skipping and a stationary bike.
Though it was intact, the two side covers were broken. More importantly the chain was missing, and the front and rear sprockets were not standard bicycle sizes. A quick search for replacement parts from Thane Canada revealed that they only do warranty work, and even then very sparingly. It was an unfortunate design choice for Thane to not use standard bicycle sprockets and chain, as this would have been much easier for me.
The benefits of an Elliptical cardio machine
An elliptical machine can give you a great cardio workout. While it is still weight bearing, unlike a bicycle, the elliptical is much easier on your joints as there are no jarring movements. You can also use your upper body to work out, but compared to strength training, this would be pretty minimal. Most of your workout will be lower body and core. The elliptical movement is somewhat similar to running, but with much less stress on joints. It is supposedly good for recovery from injury.
Tools/Parts Required
-angle grinder, welder
-large bicycle sprocket, small bicycle sprocket
-bicycle chain, chain breaker
-jigsaw, files
-drill, drill bits
Sprocket replacement
The two sprockets, the larger 8″ rear sprocket and really small 1.5″ front sprocket, were not standard bicycle sizes, with very small but more plentiful teeth. I could not find a replacement chain from the manufacturer.
Interestingly the large rear sprocket used a standard bicycle single piece hub, so I was able to easily remove it. The large sprocket, which has very small teeth, not standard bicycle sprocket teeth, was welded on, so I needed to grind off the welds with an angle grinder, install a similar sized bicycle sprocket, and then weld it on in its place. I chose to reuse the single piece bicycle crank. A similar sized single piece bicycle crank I had also worked, but a 3 sprocket front derailleur gear set and crank also fit. I did not try a more modern 2 piece crankset, but I think it would also work. Using a multi-sprocket front crank may have some issues with width.
Thane Orbitrek elliptical, old rear chainring, welds needed to be ground off, Photo 04 by Don Tai
Thane Orbitrek elliptical, old rear chainring, Photo 05 by Don Tai
Thane Orbitrek elliptical, old rear chainring, note the closely spaced teeth, Photo 06 by Don Tai
Thane Orbitrek elliptical, new rear chainring, welded, Photo 07 by Don Tai
The very small front sprocket, the one attached to the large wheel, was problematic. The front sprocket was not threaded onto the axle, so I could not remove it. As well, the usually threaded metal sprocket was moulded into the ABS rear wheel. Since I could not remove the front sprocket I decided to weld an additional small sprocket right on top of the original sprocket, and hope for the best. The new small sprocket came from a 14″ kid’s bicycle. The ABS wheel had to be taken apart in order to protect the ABS from being melted. There was a metal band strip in the middle of the wheel, where the friction strap goes, that had to be disassembled.
Thane Orbitrek elliptical, welded front chainring, Photo 03 by Don Tai
I ground the paint and grease off the original small sprocket, as well as the newer small sprocket. I found a bicycle seat post that fit the hub so I could, as best i can, ensure the new sprocket was centered. I then used thin wire to clamp down the position of the new sprocket so it would not move during welding. The welding grounding clamp had to be used on the newer small sprocket because the original sprocket would be hidden and the hub and wheel are ABS and therefore non-conductive.
I was concerned that the SMAW (shielded metal arc welding) stick welding process of melting metal at 6k C would also melt and damage the ABS hub and wheel, so took great precautions reduce the welding heat to a minimum. During welding I dabbed two welds on opposite sides, cracked the slag off and then let the welds cool to the touch. I also used a very thin welding rod, 1/16″ 6013 at 40 amps, in order to reduce the heat. This is tricky because with such low amps striking an arc is more difficult, and especially so with a new rod. I heated up the new rod on a piece of scrap metal by successfully striking an arc, before trying to weld the sprockets. While this took a long time, I was able to complete the welding while not melting the ABS hub and wheel. I hope I have enough penetration into the original small sprocket, as rewelding this would be quite difficult.
Adding the new bicycle chain was very easy, but then found out that the original chainstay was designed too low. I had to cut and grind down the original chainstay on the chain side, bend it up and reweld it at a higher position. This was not too difficult.
I then tried to reassembled the ABS wheel and its metal inner track. Since the new sprocket is larger than the original one, the hole in the ABS wheel cover would not fit, so I had to use a jigsaw to enlarge the opening. I was then able to reassemble the wheel and metal strip.
Wheel alignment problematic
It took a while to fiddle with the wheel hub, the speed sensor and the axle bolts. The speed sensor, which plugs into a display that tells you some statistics about your workout, would want to move, which would pull on its wire. This would be bad. The speed sensor connects to the speed display, which when tested actually still works. When the wheel is out of alignment with the large sprocket, the chain would come off. Front wheel alignment was quite time consuming and tricky.
Thane Orbitrek elliptical, replaced chain drive, note the chainstay needed moving up higher to provide chain clearance, Photo 01 by Don Tai
Moving the footplates
As a home elliptical machine, it is short in length. Compact in size is good for storage and not taking up precious real estate in your home, but not for use as an elliptical. This is because the shorter the length the higher the distance from the top of the stroke to the bottom of the stroke. Such a height difference makes the elliptical very uncomfortable to use. While I could cut and lengthen the frame, for now I decided to move the footplates 18cm forward. I would reuse the front hole as the new rear hole, and drill a new front hole. This worked out pretty well, after I measured properly.
Thane Orbitrek elliptical, moved footplate forward, Photo 02 by Don Tai
Greasing all joints
Once I got the elliptical to move well, I had to take all the parts apart, grease al the joints and reassemble.
Thane Orbitrek elliptical, reassembled, side view, Photo 08 by Don Tai
Thane Orbitrek elliptical, right side view
Result
24 Sept 22: I’ve been using this elliptical for a couple of weeks now and it does give you a good workout and elevates your heart rate. I only do 10 minutes of low intensity zone 2 cardio, but I do sweat. The foot pads work at somewhat of a steep angle and my feet seem to slip forward and then need adjustment. It is not too bad though.
You really need to coordinate your arms and legs to get a fluid motion with this machine. The flywheel is quite light and therefore has very little momentum. Your feet are a little wider than walking or running, which again is unnatural and needs getting used to. It is a learned skill and this takes some time. Still, I find it acceptable. The whole movement is very gentle on your joints.
The small computer monitor has a scan mode with time, speed, distance and calories, but I just put it into dedicated time mode, without scanning through all the options. I welded up an additional stand that puts the monitor higher up, so I can see it more easily.