Rear wheel rubbing

[Miffy]

Just a quick question to see if anyone can help..
The rear wheel on my friends bike seems to be rubbing, it looks as if the big cog is rubbing on the plastic bit that attaches to the wheel (sorry I don't know what the technical name for this is!) The brakes seem ok. Might this happen if the wheel isn't quite straight or could something else be happening? Its a trax bike from Halfords, she hasn't had it long so it'll be going back but it would be nice to have a clue as to what is going on... If its a problem that couldn't have been caused by normal use i'm imagining they would fix it FOC.. any help appreciated

 

[MattHB]

A pic would help, it's a bit hard picturing what you mean!

 

[PpPete]

Transparent(ish) plastic bit that attaches to the wheel ? Between the cogs and the spokes?
Sounds like a "dork-disk" to me. Probably come loose from the spokes. Pull it off, you may need to attack with pliers first, then bin it.
Serves no useful purpose on a properly set up bike.

 

[potsy]

Its a trax bike from Halfords

Serves no useful purpose on a properly set up bike.

Good one Pete

 

[Miffy]

Sorry my description probably isn't the best, don't think i'll be able to get a pic up tonight though. Basically when the bike is upside down and you spin the back wheel you can hear something rubbing and stopping the wheel. It isn't the brakes. When the chain is on the big cog you can see and hear that this is rubbing on the plastic bit that is between the cogs and the wheel, which obv. isn't normal, and when you move the chain down it still sounds as if something is rubbing! I'm afraid the changing an inner tube is the extent of my technical bike knowledge (though I am working on it!) so we'll be at the mercy of halfords!

 

[Miffy]

Sorry was writing that last reply as those were posted! yes it is that plasticy bit!

 

[YahudaMoon]

Dork dish. Not heard that one before. Pie plate ?

 

[screenman]

Does the noise go away when you keep pedaling the bike, as in keeping the sprockets rotating at the same speed as the wheel, as opposed to free wheeling?

 

[Miffy]

no you can still hear the rubbing noise when pedalling, along with a clunking noise!

 

[PpPete]

Clunking noise does not sound good.

Any close fitting mudguards on this thing ?
If it's not mudguard related (and after you've binned the dork-disc - aka pie plate) I'd whip the chain off and see if, by rotating wheel & pedals separately, you can identify the whereabouts of the clunk.

 

[screenman]

If you can hear the noise whilst pedaling it is unlikely to be the plastic shield as this will be spinning at the same speed as everything else. How much side to side play in the wheel? possible axle problem.

 

[Miffy]

Ok just went a had another good look/listen, the clunking noise obscures everything a bit when the pedals are turning but maybe its that I hear and not the rubbing, I can see that the plastic guard is bent inwards in places and i'm sure thats what the cog is rubbing against, so i'm assuming replacing or removing that would solve that problem. However.. the chain really is clunking along, only sounds smooth in certain gears, seems to be also rubbing along part of the front derailleur when in the small or large cog on the back, the gears are extremely hard to change and seem to shift pretty randomly all seems a bit of a mess really. I think maybe too much of a problem to be solved by ourselves unfortunately, wish I had a better understanding of the mechanics but anything other than simple adjustments may be beyond me! We are debating whether to take it back to Halfords or get it to the LBS to see if it is worth paying to sort it? Theres less than 100 miles been ridden on it, makes you wonder if it was fit for purpose

 

[Miffy]

If you can hear the noise whilst pedaling it is unlikely to be the plastic shield as this will be spinning at the same speed as everything else. How much side to side play in the wheel? possible axle problem.

Quite a bit

No mudguards either

 

[YahudaMoon]

Theres less than 100 miles been ridden on it, makes you wonder if it was fit for purpose

I have Just googled 'trax bike'. Maybe you have answered your own question ?

 

[Miffy]

Indeed. I got my specialised vita following advice on here and its been perfect, unfortunately my friend couldn't get anything in that price bracket but thought it would be ok for getting back to uni and stuff. perhaps not but i'd have thought even something basic should last longer than a month!