Fixing a Pro-Form Tour De France exercise bike with broken lift motor
Another random how-to in hope it will help someone save an expensive piece of kit. This all relates to Ver1 of the Tour De France, model PFEVEX71316.0 but looks like many of them use the same lift motor which was the problem.
About the bike – “ProForm TDF Indoor Cycle Trainers replicate outdoor riding experiences like no other exercise bikes can. To imitate the feel of road bikes, the new ProForm Tour de France 1.0 for 2016 has configurable gears, a freewheel clutch and a three-piece crank. It supports uphill and downhill training with an automated 15% incline and 15% decline, and its workout programs help make rides especially true to life. Built-in coaching programs facilitate interval training and use incline/decline settings from French tour segments. Additionally riders using the iFit app can get full-color interactive street views for Google Maps routes.” Or in simple terms it goes up and down and has gears to better simulate a real bike.
Issue – This was being sold cheap as the lift mechanism had broken. When the incline is adjusted it started a cycle of going up a bit and down a bit on a constant loop and generally being a bit annoying. My plan when I picked it was to bin the mechanism, replace with a solid shaft and just use as a normal bike. BUT when I started to fiddle, I realised that unlike normal spin bikes that have a resistance dial/buttons to adjust the effort level needed, this used the incline buttons to adjust both the bike lift motor and the electromagnetic resistance motor that adjust resistance. As such I had to use the incline buttons and associated annoying up and down or end up with a really easy effort level forever. Not ideal.
Plans – Came up with a couple of options:
- Replace the lift mechanism – Part number 381160 Model LMA60305-A – looked around on internet and struggled to find a price. Pro-forma have a parts website but no prices or anything useful, just a number to call. I could find similar parts for anything from £200 to £450! The motors I found all had power cable and a feedback cable so indicated some form of position measurement or counting of rotations to know where it was on it’s linear stroke.
- Replace with a solid shaft (or simply disconnect the cables if the motor itself was solid) and see if it would still simply adjust the resistance and the software would just ignore the lack of motor or feedback without throwing up errors or refusing to work. I measured the full stroke of the motor and it was approx. 26cm at shortest and 35cm at longest. So a 30cm length of bar or box section with some hole either end would work.
- Try and fix the lift mechanism.
Strip the side panels off – This video https://www.youtube.com/watch?v=wKQaDYKE-aE shows the process well
Lift motor inspection –
- Once covers off, it became clear the motor function (or linear actuator really) was fine but the plastic casing had exploded for want of a better word. The bearing was loose, and a small circuit board was hanging on a wire.
- The small circuit board was some sort of measurement device that counted rotations of the shaft based on a small metal insert in the plastic collar. Presume some form of inductance or similar.
- I tested the unit by holding the circuit board close to the plastic collar and operating the bike incline buttons. It all seemed to work as expected, with the bike rising slightly, then stopping. No annoying beeps, no bouncing up and down. So if I could find a way to repair the plastic housing and hold the circuit board in correct place it might be repairable.
- Now to remove the lift motor and have a look.
Lift motor removal –
- Disconnect cabling first. Take photos. In my case there was a + and – connection direct to motor. Also a white cable from unit with a connection close to the unit to pull apart. The loose circuit board that counted the rotations was on a multiway ribbon cable. I traced this back and it plugged directly into the main controller board between the pedals. This required cutting a cable tie on the seat post stem that held all other main cabling.
- Disconnect other cable ties – there is one that holds the flexible gasket section to the motor and another on the cabling to keep it away from the mechanism.
- Bottom of motor actuator is bolted into the base plate, hidden under the plastic cover just below the flexible gasket sections. The plastic cover pulls up. Need two 14mm spanners for the nut and bolt.
- Top is held by a metal pin that is bolted into the frame by an Allen key bolt either end. Remove the bolts and then drive the pin out with a hammer and drift.
- Motor is now loose. Either fit a new one, or try and fix it.
Lift motor repair–
- The seller had kindly given the sections of casing that had exploded, or all that he could fine.
- I could piece it back together with a slot available for the counting circuit board.
- Why had it failed? Fiddling showed that whilst the unit is normally under compression so very strong, if the unit is placed in tension the bearing is only held in place by the plastic casing. If you were to lift the entire bike up from the saddle, as you might well do to tip it onto it’s front wheels, the weight of the frame is hanging off the plastic casing. This seems a poor design and I suspect the lift motor is a generic part used for many applications where it would never be in tension like this so would normally be OK. Not in this instance. Likely this also means any replacement lift motor would be of the same design and inherent weakness.
- To fix I glued the sections I had back together with two-part resin for strength, making sure the small circuit board was inserted.
- The metal tube on the rear of the plastic housing is bolted by four long bolts. I decided to use a metal plate to reinforce the glued side, and extend the bolt holes through the unit to sandwich the plastic casing between two metal plates. This way if you lift the bike weight is now transferred from the rotating shaft, through these bolts and directly to the metal casing of the actuator and bike frame, not all hanging off a plastic casing (hopefully photos show this better!)
- After some tinkering I went with a very thick machine washer that fitted over the strut, drilled two holes that lined up with the now extended bolt holes and then installed two long bolts to sandwich it all together. I used locktight and double nuts to ensure it didn’t work loose.
- Reverse of removal, found it easier to attached the top first, then bottom, then connect cables.
- Plug the mains power in, turn it on and hope.
- The unit powered up and lift motor spun to lower the bike to lowest position then stopped ready.
- Fiddling with buttons and it all worked exactly as it should. Each 0.5% include increase have a small rise, no annoying bleeds, nothing else.