DISC BRAKE HELP

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DISC BRAKE HELP

Postby croat4ever » Tue Oct 02, 2007 10:49 am

Hi guys,
i got the TEKTRO brake system on my bike and i was just wandering is it normal if i cant get my back brakes to lock up?Also why would that be the case if i cant lock them up if it isnt normal...?

Thanks
Hope to hear your responses
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by BNA » Tue Oct 02, 2007 11:24 am

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Postby Bnej » Tue Oct 02, 2007 11:24 am

If you can't get your brakes to lock it is NOT normal, it is dangerous to ride with brakes that cannot effectively stop the wheel! If you can pull the lever all the way to the bar then they are not properly set up.

With cable disc brakes, you need to wind the inside pad out so it is only just clear of the rotor, then adjust the outside pad and cable tension so it is also just clear. When you pull the lever it should flex the rotor very slightly into the inside pad and further pull on the lever will grab the disc harder.

If you are not confident setting up your brakes yourself then take it to a bike shop and ask them to help you.

If you look around on the web you might be able to find a service manual for the brakes you have, which would show specifically which parts you need to adjust.
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Postby croat4ever » Tue Oct 02, 2007 11:30 am

liek i can stop in time,like straight away but they are just not locking up and i have adjusted the lever....
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Postby Mulger bill » Tue Oct 02, 2007 11:30 am

G'Day Croat

I'm pretty sure you run cable discs, it sounds like it could be a cable stretch issue.

Your bike is still very new, maybe try the dealer?

If you want to do it yourself...
First up you should be able to download a manual that'll show you what's what, then check out sheldonbrown.com or park tools.com for lots of handy maintenance tips. Have a go and let us know.

Shaun
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Postby Bnej » Tue Oct 02, 2007 12:13 pm

croat4ever wrote:liek i can stop in time,like straight away but they are just not locking up and i have adjusted the lever....


It's not weather you can stop in normal circumstances or flat ground, it's when you're on a downhill and you find yourself still picking up speed with the lever pulled all the way to the bar. If you can pull the lever all the way to the bar, then it's not braking as hard as it could be.

If you're on road you mainly need the front brake, off road you definitely need both.

If you look at the rotor when you put the rear brake on, does it move much before it contacts the inner pad?
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Postby croat4ever » Tue Oct 02, 2007 1:05 pm

ill get back to your question later but i mean my brake stops perfectly and everythign it just never locks up,but it does have that stoppping power to make me stop goign down a hill,anyway ill go now and have a look at it and ride it a bit....
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Postby MountGower » Tue Oct 02, 2007 1:10 pm

Error. This post can no longer be displayed.
Last edited by MountGower on Tue Feb 15, 2011 8:20 pm, edited 2 times in total.
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Postby Bnej » Tue Oct 02, 2007 1:12 pm

You don't have oil or some other contaminant on the pads or rotor? If you hold the lever as hard as you can, the wheel shouldn't turn.

If you are concerned and can't work it out yourself get the shop to look at it.
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Postby Kalgrm » Tue Oct 02, 2007 1:51 pm

Croat4Ever,

Can you describe exactly what happens when you pull the lever? Does it go all the way to the bar? Does it come up solid but still not lock up? If it doesn't lock, they are not set up properly: there is no escape from that fact.

It could be oil on the brakes as Bnej said (good call Bnej), but it could also be a "feature" of Tecktro levers - they have a system where the amount of cable movement when you squeeze the levers can be varied. If you have a little knob on the levers it could be that you have the pull set inappropriately and it needs adjusting there. If you can post a pic of your lever and your callipers it might help us help you.

MountGower, he would also need a new wheel-set to fit V brakes (disc rims don't have a braking surface) and he may not have the V-brake lugs on the frame and forks. Maybe it's also just as good to have discs and know how to use them ..... ;)

Cheers,
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Postby croat4ever » Tue Oct 02, 2007 2:23 pm

just came back form my ride...the results are in:P
when i tried to skid on the grass the brakes sort of skidded liek it was just grabbing...if that helps...whether the bike shop put some lub o nit and it just has to settle in but i am not sure i will get some pics up now....
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Postby Bnej » Tue Oct 02, 2007 2:28 pm

MountGower wrote:Time after time I see people with disc brakes too scared to use them, sliding through corners with their back wheel locked and the complete loss of steering that goes with them. Better to have V brakes and know how to use them than to have discs and be too scared to use them.

They are a constant maintenance hassle. As if virtually pulling the bike down, cleaning and reassembling it after a morning out isn't bad enough. How much more of a pain in the arse to have to worry about these things aswell.


There are plenty of advantages to disc brakes. Some are indeed more fiddly, but not that much more. When they're properly set up you get a nice light touch, easily modulated braking action. They can get hotter without degrading performance as much, and you can't puncture your tube by overheating your rim. The rotor is generally out of the crud more too.

That said, many bikes have poor quality disc brakes now just for the bling factor - Giant are especially guilty of this, as they don't make any bike above the entry level with V brakes.
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Postby croat4ever » Tue Oct 02, 2007 2:31 pm

hw od oyu add photos???do oyu need to have oyur own ftp site??[/img]
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Postby Kalgrm » Tue Oct 02, 2007 2:32 pm

There should not be any lube on your brakes. And it should not "sort of lock up on the grass" - it should be quite definite. The reason people put disc brakes on MTBs is the supreme stopping power they exhibit - there is no maybe about it. Your brakes are not functioning correctly.

Cheers,
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Postby Kalgrm » Tue Oct 02, 2007 2:34 pm

croat4ever wrote:hw od oyu add photos???do oyu need to have oyur own ftp site??[/img]

Email them to me and I'll sort it out for you: graeme.hird at gmail dot com. You do need a place to drop them on the net.
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Postby croat4ever » Tue Oct 02, 2007 2:34 pm

i know they arent functioning properly but they were fine 2 weeks ago and i got it serviced and they changed my brake levers to go softer and from the non everythign went down hill...
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Postby Kalgrm » Tue Oct 02, 2007 2:56 pm

Here are the photos of the brakes:

Image

Image

Image

The levers aren't Tektro, so the knob I was referring to is not there. Can you send us a close-up of the gap between the pads and the rotor please? It might be hard to capture with your camera. When the callipers are set up properly, there should only be enough room for one or two sheets of paper to slip through the gap. If there is more than that, the LBS has not done the job properly.

What they may have done to satisfy your request is to wind the knob on the brake lever (1st photo) back so that it supplies lots of slack in the cable. If that's the case, it's an easy fix - just wind that knob back out until you're happy with the feel of the brakes. This may well be what they have done, since both the knobs controlling cable slack (on the lever and the calliper) are in the extreme slack position.

Cheers,
Graeme
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Postby croat4ever » Tue Oct 02, 2007 7:26 pm

yeh its like 2-3 sheets of paper on the width...i might go otmorrow to bike shop and ask them....what do i say?do isay i cant skid or what??if i say i skid they'll say thats why its broken....?
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Postby Mulger bill » Fri Oct 05, 2007 12:30 am

So how'd it go Croat?

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Postby croat4ever » Fri Oct 05, 2007 12:41 am

hey yeh didnt end up going,i looked at it and was just playing with the lever aand teh screws adjustign the pad and it seems i fixed it,either by chance or i knew what i was doing :P but ill go soem other time to the bike shop to get it tuned...
thansk for askign anyways....
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