Trainer Bump

[Chislenko]

Wheel on fluid trainer, rear tyre exploded the other day. It was an old Marathon 700 x 28 which came off an old bike. It had done a fair mileage so no quarms.

Anyway, selected another old tyre from the garage wall, a 700 x 23 Mavic. The problem I am now having is a discernable "bump" on every revolution right at the point where the valve is.

Have took the tyre and tube back off, made sure they are in fine with no kinks and it is seated fine.

Is this something that just happens with a thinner tyre on a turbo or does anybody have any real world experience similar?

Obviously with it being a fluid trainer there is no adjustment to be made on the trainer itself.

Thanks in advance.

 

[CXRAndy]

You need to deflate the tyre and push the valve further into the tyre. If this doesn't work replace inner tube for smaller size to eliminate valve bulge

 

[Chislenko]

You need to deflate the tyre and push the valve further into the tyre. If this doesn't work replace inner tube for smaller size to eliminate valve bulge

Thanks Andy, will give it a go. The new tube I fitted is a "one size fits all" as opposed to in the "olden days" tubes were quite specific 20-23 or was it 18-23?

 

[CXRAndy]

Thanks Andy, will give it a go. The new tube I fitted is a "one size fits all" as opposed to in the "olden days" tubes were quite specific 20-23 or was it 18-23?

Also check tyre rim bead is seated evenly all around the rim

 

[ColinJ]

Hmm, I have that problem on my turbo bike. I had assumed that the rear wheel was not round enough but it makes much more sense that the tyre (or the way it is mounted) is the cause of the problem.

 

[Chislenko]

Hmm, I have that problem on my turbo bike. I had assumed that the rear wheel was not round enough but it makes much more sense that the tyre (or the way it is mounted) is the cause of the problem.

Have you just learnt to live with it Colin? I only tried it out for a few minutes after fitting a new tyre and tube and it was driving me nuts!

I do have some bigger spare tyres in the garage 28 & 32 but I had the 23 and Elite (the turbo manufacturer) suggests 23 to be the optimal tyre for their turbo. I will have a look at it during the week.

I think there is something in what Andy says though as the tube I have fitted is "up to 28" so maybe a true 23 only (or less) tube might be the answer.

 

[ColinJ]

Have you just learnt to live with it Colin? I only tried it out for a few minutes after fitting a new tyre and tube and it was driving me nuts!

Yes - but only by staying off the turbo trainer... It was driving me nuts too!

I drowned out the sound by listening to music on headphones but I could still feel the thumping!

 

[ColinJ]

I tried reducing the severity of the thumps by reducing the pressure in the tyre and winding the roller slightly further away, but then the tyre kept slipping on the roller.

I probably*** won't want to set up the turbo for another couple of months but I might take a look at the tyre before then.



*** Cue apocalyptic early winter!!!

 

[ColinJ]

I just took a look...

The tyre was soft because it hasn't been used for over a year but I noticed a big dent in it where it had been left pressed against the roller. I am wondering if that might be what causes the problem?

It would make sense to release the roller tensioner when not actually using the turbo trainer.

I have a turbo tyre which I can swap in when I start to use the tt again. I will soon see if that makes a difference.

I am busy for the next couple of weeks. I will investigate further after that.

 

[Chislenko]

@CXRAndy

Brilliant piece of advice Andy re deflating and pushing the valve in. It has cured the problem which is a good job as I don't have any thinner tubes in the garage.

Thanks very much.