tech advice

lighterman

Before I start I should let you know I'm a complete newbie to Road bikes and want to see if anyone has come across this before. I'm also bringing it back to shop to get is assessed.

I bought a new Audacio 200 last week and have gone on a few local rides around the area and I had said from day one that I had concerns about the brakes but thought they may need to be worked in. (Uneducated guess) Today I went for a longer ride.

When I was 17km approx into the ride I came to a steep hill. I picked up a good speed and started to pull the back brakes as i knew there was an approaching junction.

When i was pulling the lever it didn't have any great effect so I pulled the front levers aswell. I was still approaching the junction at speed and at this stage I was at full lock on the 2 levers. Then there was a loud bang like a shot gun bang which was the tyre and tube going.i travelled a small distance on the rim before I could jump off the moving bike to completely stop.

I've inspected the tyre and I can't find anything in the tyre to puncture it. Has anyone came across this before or heard of it before.

As I said I'm going to the shop tomorrow but it friend the crap out of me. Thanks for reading if you could read it all

07Lapierre

Sounds like the brake pads were rubbing the tyre and the wheel rim ( they should only make contact with the wheel rim).
If you pull the rear brake lever, and look at the brake blocks, they shouldn't make contact with the tyre.

http://www.youtube.com/watch?v=8merR9JxVbo&sns=em

darkvalley

What 07lapeirre says sounds right, but 2 questions occur to me on it. Surely if the pads are contacting the tyre it should still slow the bike down, even if not very efficiently? Should the brake pad contacting the tyre cause it to explode after the distance the op is talking about?

mirv

It sounds like you were mainly using the rear brake, and by your own words you had locked the rear wheel which may have skidded through and burst through either wearing out the tread or overheating the rim. It's probably less likely you skidded and burst the front wheel if you managed to jump off after hearing a bang.

Either that or the brakes were rubbing on the tyre from either bad alignment of the pads, or bad alignment of the wheels in the dropouts - did you remove the wheels when you took the bike home?

Go get it checked out by the shop that sold you the bike, and you might want to read up on how to brake while descending a hill - you should be pulling the both the front and rear brakes, but 80% of the stopping power comes from the front - perhaps you didn't pull the front brake early enough and your issues with the braking performance was due to your preference of the rear brake.

http://sheldonbrown.com/brakturn.html

lighterman

darkvalley wrote: »

What 07lapeirre says sounds right, but 2 questions occur to me on it. Surely if the pads are contacting the tyre it should still slow the bike down, even if not very efficiently? Should the brake pad contacting the tyre cause it to explode after the distance the op is talking about?

Just to clarify the back brakes did have an effect and maybe riding on a flat they would have stopped the bike but I had picked up some speed on a steep decline.

If I want so near the junction and the tyre hadn't popped I may have been able to bring the bike to a stop naturally instead of jumping off the bike.

That was the only section I really used the brakes as I was traveling on flat and incline for the majority of it.

When I was pulling the brakes it also felt and sounded like when driving a car and the pads are worn. Steel on steel I suppose

lighterman

mirv wrote: »

It sounds like you were mainly using the rear brake, and by your own words you had locked the rear wheel which may have skidded through and burst through either wearing out the tread or overheating the rim. It's probably less likely you skidded and burst the front wheel if you managed to jump off after hearing a bang.

Either that or the brakes were rubbing on the tyre from either bad alignment of the pads, or bad alignment of the wheels in the dropouts - did you remove the wheels when you took the bike home?

Go get it checked out by the shop that sold you the bike, and you might want to read up on how to brake while descending a hill - you should be pulling the both the front and rear brakes, but 80% of the stopping power comes from the front - perhaps you didn't pull the front brake early enough and your issues with the braking performance was due to your preference of the rear brake.

http://sheldonbrown.com/brakturn.html

It didn't feel like the wheel skidded but to be honest I was panicking so it could have been doing anything.

No didn't take the wheels off.i was able to fit it in.

Thanks for the advice. As I said I'm a newbie and haven't anyone to show me the ropes but to be honest andi may be wrong something just didn't feel right with them

mirv

I never said that the back brake doesn't work - it just tends to be about a quarter as powerful as the front brake just due to the physics of load transfer during braking.

Braking should be very quiet if pads are adjusted correctly with clean pads and rims. Should sound near silent, or like exhaling softly. Definitely not like a jet engine or like steel on steel grinding, and you shouldn't smell anything while braking either.

Which wheel did the bang happen to? Was there a worn through patch on the tread or any damage to the tyre sidewall?

lighterman

mirv wrote: »

I never said that the back brake doesn't work - it just tends to be about a quarter as powerful as the front brake just due to the physics of load transfer during braking.

Braking should be very quiet if pads are adjusted correctly with clean pads and rims. Should sound near silent, or like exhaling softly. Definitely not like a jet engine or like steel on steel grinding, and you shouldn't smell anything while braking either.

Which wheel did the bang happen to? Was there a worn through patch on the tread or any damage to the tyre sidewall?

Sorry you've confused about back brake not working. I know us didn't say that.

defo wasn't a quiet braking action. Probably should have got it checked but I just thought it needed to be worn in.

It was the back wheel. I didn't see any sort of damage to the tyre.

lighterman

By jaysus i'm having a run of it with this bike.Did 29 miles today and as i was finishing,just turned in to the yard in fact, the rear deraileur i think(the section that has 2 small reels coming off the main gear reel on the rear wheel) is now pointing up witha small piece of plastic broken off it. i can actually see inside it and and see lumps of grease. Has anyone seen this before.

Another trip back to the shop for me!!!!

happytramp

lighterman wrote: »

By jaysus i'm having a run of it with this bike.Did 29 miles today and as i was finishing,just turned in to the yard in fact, the rear deraileur i think(the section that has 2 small reels coming off the main gear reel on the rear wheel) is now pointing up witha small piece of plastic broken off it. i can actually see inside it and and see lumps of grease. Has anyone seen this before.

Another trip back to the shop for me!!!!

Wow. That does not sound good. Did it happen after you tried to change into an easier gear? Maybe it went to far and made contact with the wheel. If that's the case it's not your fault it's the person's who set it up.

lighterman

happytramp wrote: »

Wow. That does not sound good. Did it happen after you tried to change into an easier gear? Maybe it went to far and made contact with the wheel. If that's the case it's not your fault it's the person's who set it up.

The shop asked me if it received a bang or fall which it didnt.What i find strange is it didnt happen during the ride.I was changing in to an easier gear but i had been doing this throughout the ride

mirv

Sounds like someone made a tits of the low-limit adjustment on your rear mech. Did you ever figure out what the problem was with the braking?

lighterman

mirv wrote: »

Sounds like someone made a tits of the low-limit adjustment on your rear mech. Did you ever figure out what the problem was with the braking?

Sorry should have reported back here after posting but afraid not.

The shop said there may have been a film of residue on the blocks.

They said the blow out was one of them things and was unconnected.I queried it but still cost me the price of a new tube and tyre.

Is the current problem a big job to fix.Would they be able to fix whilst i wait.

happytramp

lighterman wrote: »

Is the current problem a big job to fix.Would they be able to fix whilst i wait.

Hard to say. Depends on how bad it is and how busy they are. Is putting up a picture of the damage too much hassle?

lighterman

Ill certainly try.Its far from a great picture though.I took it earlier today

Cee-Jay-Cee

If you need a new rear mech then its not really a 'wait while we do it' job and they'll need to keep the bike a few hours. If the bike didn't fall or receive a knock then insist on a new rear mech and not a repair to the current one and do not pay for it, the bike is under guarantee and things like that should not happen.

mirv

As you were coming into the yard, did you change gear without pedalling, then backpedal for a bit, and then pedal forwards?

lighterman

mirv wrote: »

As you were coming into the yard, did you change gear without pedalling, then backpedal for a bit, and then pedal forwards?

Nope. Just brought it in to a lower gear

ZiabR

That is a fair amount of damage alright. Trying to work out how something like that would happen. The rear mec looks completely twisted and facing the wrong way...

mirrormatrix

Looks completely f***ed. Must be that the limits weren't set right. Did the chain come off the top of the cassette (largest cog) into the wheel when it happened?

lighterman

mirrormatrix wrote: »

Looks completely f***ed. Must be that the limits weren't set right. Did the chain come off the top of the cassette (largest cog) into the wheel when it happened?[/quote

its stuck on the 3rd cog from the top. It's jammed solid so doubt it

lighterman

Well they've assessed the bike. They say all screws etc are as should be and can't offer any explanation why it happened.

They say the chain is ruined and will replace free of charge. They are charging for the derailleur which is €20. There was a small kink in the wheel which they've straightened out.

I'm starting to regret getting it now. 2 weeks old, 75 miles on it and has cost me €47 for 2 unexplained faults/incidents

Cee-Jay-Cee

lighterman wrote: »

Well they've assessed the bike. They say all screws etc are as should be and can't offer any explanation why it happened.

They say the chain is ruined and will replace free of charge. They are charging for the derailleur which is €20. There was a small kink in the wheel which they've straightened out.

I'm starting to regret getting it now. 2 weeks old, 75 miles on it and has cost me €47 for 2 unexplained faults/incidents

I'm guessing a kink in the chain caused the problem. I certainly wouldn't be paying for a new RD no matter how little it costs.

mackeminexile

best thing you can do is get on youtube and learn everything you can about maintenance of the bike and also riding skills. I was in the same position as you this time last year and I now service my own bike and I've completely upgraded everything apart from the frame myself. The shop I had bought from did a bad job setting it up too and in hindsight I should have learnt more before spending the dough. This forum is great for advice too. Good luck!