Halfords bodge up, help to sort it please!

Brent

I have recently got a carrea vulcan disc spec through the cycle to work scheme.
They built the bike for me and i picked it up, a mile down the road i released i couldnt shift the front cogs.
When i got home, i did some reading up on adjusting, i have had a go at this and when im on the inner cog front and larger cog back and try to adjust the derailleur using the screw i get it to a point where it shifts ok but the chain now rubs on the tyre.
Also when i try and adjust the hi screw while the cogs are on the smallest back and largest front the derailleur doesnt seem to want to move. The rear seems to work fine and changes perfectly. I have followed a guide step by step but i must be missing something?

What am i doing wrong? Im totaly new to this and would like to learn, but the one thing i refuse to do it to take it back to the numpties at halfords as i belive i have more knolage than my local halfords and i have only turned a few screws!!!

Edit: the derailer is about 2mm above the cogs and the correct angle from what i can see!

Thanks in advance!

nicklouse

TBH you shold take it back and demand that they sort it.

but as you ask.

Also when i try and adjust the hi screw while the cogs are on the smallest back and largest front the derailleur doesnt seem to want to move. The rear seems to work fine and changes perfectly. I have followed a guide step by step but i must be missing something?

which mech?

Brent

Front or do you mean the make?

If i cant do it by the weekend il take it down there and see what they say, just dont want them to mess it up even more, the guy who apparently built it (the one from the display was gone) couldnt even work a till correctly.

nicklouse

if adjusting the H screw is not moving the mech outwards you need more cable tension/length with the adjuster.. Or you need to adjust the clamping position.

Brent

ok so slacken off the cable tension bolt pull it tight, tighten the bolt and try the H screw again?

Any ideas why the chain rubs on the tyre when i get it to a point itl shift?

nicklouse

just go through the set up and see if it still rubs.

if it does, tyres too big/frame bent....

Brent

ok il have a look, the bikes completely standard, might just have a dodgy one!

Thanks again!

Anonymous

Take it back and stat there to watch them doing the work, then you'll know how to do it for yourself later

supersonic

Chain should never rub the tyre. Take it back.

tjm

when the chain rubs on the the tyre is it also rubbing on the front mech cage? If it is, the mech could be pushing the chain onto the tyre although I would then expect it to change off the inside of the smallest ring. If it is not (and it shouldn't if the mech is adjusted right) then there is something more serious than just adjustment.

Brent

ok is it safe to ride 3 miles to halfords tho? or should i fight and get it into my little hatch back car!

Edit: it rubs on the cage until i adjust till it doesnt then it rubs on the tyre.

supersonic

Never ride a bike you know has problems - you can make it worse and invalidate the warranty. Play safe, take it in the car - afterall, if they need to book it in the workshop, you need to get back!!!

Brent

ok no prob, is the front wheel easy to get off so i can get it in?

supersonic

Yep! Undo the QR release, and pull out. Make sure you reinstall it correctly though.

Sounds like you'd benefit from a good instruction book, like the one by Leonard Zinn - this small investment will have you making all your own adjustments in no time, and save on costly trips to the bike shop.

Brent

dont need to undo any brakes or anything?

Cheers il look that book up, give me anything to do on a car and i can do it without thinking, but a bike im having to use my head abit more and its alot of fine tuning and adjusting.
Suppose its just a new learning curve.

supersonic

Yeah, wheel with its disc just slides out.

Brent

ok, thanks for your help everyone, hopefully tomorrow i can update the topic with a sorted post!

iain1775

after you have the front wheel off - do NOT pull the front brake lever at all - the pads will squeeze together and the wheel will not easily fit back in until they are released again

Brent

ok thanks iain, would it be worth putting something the same thickness as the disc in there to keep the gap open?
Like a couple bits of cardboard? Just incase in the struggle of getting it into the car i pull the leaver?

tjm

a spacer of some sort is a good idea. Wood, plastic or metal is better than cardboard as cardboard can get crushed easily.

edit: I've not tried but you might find something like a penny or twopence piece is the right thickness?

iain1775

definately, you can actually buy bits of plastic just for that purpose, but cardboard or something a similar thickness should do the job just as well

If they do pull together you can prise apart gently with a flat screwdriver but this needs to be done carefully so not to damage the pads

supersonic

Its a mechanical disc - not a hydraulic. There is no need for this.

tjm

oops. Good point.

Brent

Right halfords wont see my bike till saturday!
I have played with the limit screws and tension in the cable and have the gears switching in one turn, but while on the innermost front cog the chain is still rubbing on the wheel!
So its still going in on saturday to see if they can see a problem, unless any one has any ideas at what i can look at/fix?

tjm

Is the wheel straight in the frame?
Does the frame look straight - view it from the back, the back wheel seat tube, head tube and front wheel should all be in line.
Is the bottom bracket properly in the frame and adjusted (if it is the adjustable type)

Depending on the bottom bracket it could have the axle the wrong way round. that would put the chainrings too close the the frame. With the chain in the middle gear at the back and the middle ring at the front the chain should be roughly straight.

These are all things a decent bike shop would check and advise on but I it depends how good your local halfords is as to whether they will find the problem.

If you don't have any joy at halfords it is worth going to a local bike shop. If you explain the situation most will check the bike for free and advise you what to do next.