How to fix a wobbling excercise bike

Hi, I’m John. I’m an engineer by trade and also an expert in fitness machines.

This is an upright bike and I’ve almost finished building it.

I’m just going to test it out before I put the final covers on a bit of trim just to make sure everything’s okay. Let’s see what we’ve got.

No, there’s something definitely wrong with this bike. I can feel all sorts of movement coming to the frame, definitely not right at all.

We’ll stop there, let’s take a look and see what the likeliest causes are: well, everything seems nice and tight up here, just check with my spanner: check my column: that’s tight, seat fairly tight.

It’s not sitting levelled on the floor for some reason, I think that’s given us the problem in this particular case. Now I know that the floor in the workshop here is nice and levelled so we need to tip the bike over, let’s see what’s going on.

I’m just going to lay it on its side there, it will be perfectly safe and that we can see underneath that we’ve got two fixing screws here: this is for the rear leg and we’ve got two fixing screws here. I’m going to check in with the spanner that came with the bike, see whether they’re tight maybe I didn’t do them up tight enough.

Well, there’s a problem. I don’t think I did them up at all. I think I probably did the finger tight but I’ve not tighten those up, let’s do those.

I suspect the back ones are probably the same, let’s just check. So there were fixing bolts that need to be nice and tight otherwise these legs are going to cause a wobble and while I’m here we’ve also got the feet, we’ve got four feet on this bike, one in each corner. These are actually adjustable.

If I remove this foot from here you’ll see what I mean, there we are, so we’ve got a rubber pad that sits on the floor and then there’s the shaft which comes out there and a nut, this is a locking nut so these are designed to be adjustable.

They go into the screw hole there and if I screw them in, or screw them out, I can adjust the height of the foot so I need to just have a look and make sure these are all levelled. Let’s put those the same, just put those in. On the front there I can see that with this particular one there’s a good two fingers worth of gap between there and on here.

This is all the way and I can’t even get one finger in there, so obviously what I need to do is tighten the nut up so it looks about the same as that one.

If I want to make a fine adjustment I can just adjust this foot here, let’s just do that, just unscrew that ever so slightly.

That’s better, that’s perfect, let’s double check, back on the bike, feet in the feet straps, these machines have got foot straps (I’m going to use them because if I don’t I’m worried that my these might actually start knocking on the side of the frame). I feel it is a lot better.