Repair Guide – NordicTrack C7ZL Upright Exercise Bike

If you need to manual for this then head here –

These bikes are really good quality, not far off gym spec and far better than the awful unbranded items you get out of Argos etc.

I was given this free as a project. It was described as working but with a dodgy resistance adjustment. The way these work is similar to a spin bike, with a pad pushed against the flywheel to change resistance. In a spin bike it’s normally a fabric/cloth material, on this bike it’s a couple of magnets that slow the flywheel. Unlike a spin bike where adjustment is manual and adjusted with a big knob (fnar) it has an actuator that moves the resistance pad (magnets) which can either be controlled with a dial on the control panel or select one of the variable workouts that do all the adjustment for you. I presumed this actuator might be the issue as it’s moving part that is hard to service without taking the whole machine apart.

Magnets for resistance attached to the actuator by the metal arm.

First check – when I got it out the car the rubber drive belt had obviously been shaken a little loose and popped out the side. It was worn as hell so I pulled it off and ordered a new one from

“NordicTrack C7ZL Upright Exercise Bike Drive Belt NTEVEX 78009.1” for £24 delivered. A little pricey considering you can get a drive belt for a car for less but the old unit was definitely  ruined and I couldn’t find cheaper elsewhere.

If the drive belt is outside the bike it may be a subtle hint of the problem.

The strip down process is detailed in the manual above. I found it easier to use a crank puller to pull the crank arms and pedals as one to save time, then it’s just lots of screws to split the two halves.

There isn’t that much to these bikes, just a sturdy frame, the belt driving the flywheel and the resistance pad and actuator. I tested the resistance adjustment and it all worked fine so (spin the adjustment dial on the control panel and watch the actuator turn and the magnets move towards the flywheel).

Bearing Change – Whilst pedalling (using the old knackered drive belt as a test) it made an alarming noise at irregular intervals.

Having a poke around and the crank bearing on the non-pulley side was fine, but it wasn’t possible to see the one on the other side as hidden behind the pulley. It felt a little hard to turn at times and there seemed to be play so I assumed the bearing had worn giving play and likely also adding to the wear on the belt.

Circlip shown outside of groove. You need to push those two holes away from each other to open the circlip and allow it to move free.

To remove the crank (the shaft the pedal crank arms attach to) you need to knock it from the free end but first the circlip/snap ring needs removing. If you don’t have proper circlip removers you can manage it with two small screwdrivers but it’s a bit fiddly. The ring is sat in a grove so you need to use the tool to open the ring and slide forward and off the crank arm. Then the crank just needs knocking through. The bearings should be tight in the frame but looser on the shaft of the crank. To avoid knackering the tapered end of the crank I’d recommend putting the crank arm back on and hitting that with a block of wood instead.

Once out I could check both bearings and as expected it had a completely worn crank bearing on the pulley end.

You shouldn’t be able to see the ball bearings inside the bearing, it should be sealed like the one above. This one is toast.

Figured it was worth replacing both bearings at same time. The part you need is in imperial dimensions and a R12-ZZ Shielded Deep Groove Ball Bearing 3/4×1.5/8×7/16 inch. I purchased two from for £9.77 delivered.

Original two bearings on top and two new ones below.

To put the bearings back in you either need to use a bearing puller or line them up with the hole and with a block of wood to protect it, slowly tap the bearings back in. They should fit flush or slightly recessed from edge of the frame. Once in, push the crank back through and you should see the small groove on the end of the crank to allow you to reinstall the circlip/snap ring. If you can’t see the groove then either the crank needs pushing in further or the bearings need seating further into the frame. Once done you should have a freely rotating pulley and pedals. Job one sorted.

Drive Belt – you’ll need to undo the bolts on the flywheel to allow you to thread the belt around the flywheel shaft and then slip over the pulley.

The manual above gives advice on how to adjust the belt but I found the drawing is incorrect as it shows the upper section of the belt being pulled down by the idler but in fact the idler pushes up on the bottom section of the belt to provide the correct tension.

Section from manual and I believe incorrect belt arrangement.
Correct belt arrangement, bottom section passes over the idler. Photo is with a spare belt, not the correct item.

Once done I put the crank arms and pedals back on and tried a test ride before putting side panels back on. Assuming all done correctly you should feel very little resistance and smooth operation on lowest resistance, and need to stand on the pedals to keep moving on the highest setting.

Another random internet example of same type of tension arrangement and again bottom of belt passes over the idler.

All done! These bikes were close to £600 new and by spending £35 and a couple of hours work I’ve replaced the main wear components and returned the bike to as new condition. Resale value on one of these is circa £150-£200 so there’s clear profit if I was intending to sell on, but I will probably keep as an exercise bike that will last many many years.

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