Turbo Trainer - Broken or bad setup?

[wm]

I have a turbo trainer that I brought secondhand. A Gist Magnetic one if that makes any difference. Although I have had it about a year it hasn't got much use until recently given the snow. I did the first two sessions without any problems. The problem came the third time, when it was much colder (I use it in an unheated, poorly weather sealed garage). I was riding and the resistance of the unit would change (more and less resistance) without any adjustment to the lever to change it. I compensated by changing gears as needed but it was a bit of a pain to be honest. I then tried to ride again, on a different bike last night but it did the same thing with varying resistance, it also produced a nasty burning smell which might have just been dirt on the tyre getting hot and burning.

Is this maybe a sign that the bearings on the turbo are worn or is this something to do with my setup. I have never ridden on another turbo so don't know if its just a knackered machine. Any experience of this much appreciated.

[ANTONISH]

Tyres get hot on a turbo and maybe that is causing the smell.. I don't know what the electrical/electronic control system is on your turbo but cold and condensation may give a problem. Can you leave in a warm dry place for a few hours and then try it?

[wm]

The variation in resistance is mechanical I believe. I think its just a magnet that is moved closer or further from the flywheel with a cable on a lever. It's just a gear cable basically so can't see that that would change the resistance. I will try bringing it indoors to warm up, although I will have to take it outside again to ride.

[ANTONISH]

Have you tried withdrawing the inner cable and lubricating it? - I assume it's a Bowden cable.

[enigmatic]

How long did you ride it before giving up? In cold weather mine (similar type) can take at least ten minutes before everything settles down and moves smoothly.

[wm]

Thanks for the replies. I brought it inside for 24hrs before riding it for 10 mins. It was still smelling and changing wildly in resistance. I am thinking that I need to strip it down and see what the problem is as I am fairly sure it most be something more than the temperature with this trail. The problem is being able to keep warm enough in the garage while I strip it down.

I also need to find a lassies Allan key (12mm?) which I know I don't have.

[Steve Kish]

I was riding and the resistance of the unit would change (more and less resistance) without any adjustment to the lever to change it. I compensated by changing gears as needed but it was a bit of a pain to be honest.

Perfect criterium training ....

[gilesjuk]

Are you sure the tyre wasn't slipping?

[wm]

gilesjuk I think if anything I have too much pressureon the tyre. The thing stow almost instantly when you stop pedalling. I think it's describes as a very short run down time. I have no idea if that's normal but I adjusted it that way to make sure I didn't get tyre slip.

[wm]

Having taken the turbo apart it was clear on of the bearings is ceased. Have now got some new ones from the LBS. Now just to remove the old ones and fit the new ones. Anyone with any good tips for removing the bearings much appreciated.

[Edwards]

A photo would help. They way they are normally done on vehicles is to use a drift and hammer. The drift is pushed all the way through to the inside of the bearing outer race. It is then hit out one tap then the opposite side. Try to tap and not belt it out.
That is unless the inner race is tight on the shaft then you will probably need a puller. I doubt if is is this type.

[wm]

Thanks Keith. Yes its held on the outer race. [img]photo-8.jpg[/img]

The problem I am having with this one is that I can't get to the back of the bearing. There is a loose collar between the two bearings which doesn't allow access to even the inner race with a drift. The bearing pertrudes slightly and I have tried clamping this in the vice and moving the remainder of the flywheel. This didn't work though as there isn't enough to get a great grip. I also tried the same thing after heating the flywheel over the gas hob.

Any further thoughts? I must be missing something.

[Edwards]

Looking at the photo and assuming the bearing shown is still in the flywheel.
Try just drifting the axle that is in the bearing out this should remove one bearing and give access to the other.
If you already have one bearing out.
Try putting a tube inside in contact with the collar. Then with the flywheel supported drift the tube and push the whole bearing out of the flywheel.
If the flywheel is one piece this makes it easier. If not you will have to use a socket or something else (vice) that is only in contact with the flywheel and does on grip the bearing.

[s1965c]

Try prising the metal shield off of the bearing and re-lubing it with some lithium grease, preferably before belting it with a hammer.

[Nik123]

Hello, I wonder if anyone could help me before I damage my hearing too badly or my neighbours assault me! I have a Cycleops Mag Plus turbo trainer which makes an extremely loud vibrating noise above 22mph. I have placed duck tape on the inside of the resistance unit cover which helped for a while but no longer, I have placed the bike on a mat, I have experimented with different tyre pressures and different tightnesses of the nut on the turbo trainer which brings the trainer into contact with the tyre. The noise is rarely the same two sessions running but it is always too much . I wear ear defenders but I would prefer not to and this doesn't help my neighbours! Is there a way of greasing or oiling it? I would be very grateful for any advice (and so would my neighbours)!