carbon fiber bicycle

Hmq8

Regular
what is advantages and disadvantage of carbo fiber bicycle ?
what brand famous of carbon fiber ?
what is price ?
i think to change my bike to carbon because light weight which is half weight of my bicycle weight 13.5 mountain .
 

Hacienda71

Mancunian in self imposed exile in leafy Cheshire
Advantages: Carbon Fibre is strong, lightweight, relatively cheap and easy to form into complex shapes.
Disadvantages: Not great on impact damage, failures can be sudden/don't always manifest themselves in a visible way.
Misconceptions: Carbon fibre is fragile, carbon fibre is always lighter than other materials, carbon fibre always produces a stiff frame.
Brands: Most well known brands have carbon framed bikes in their ranges.
Price: can vary massively dependent on brand. A lot of frames are pretty generic made in trusted Chinese factories. Very few are bespoke and made by the well known manufacturer.
I have just passed 50,000 km on my road frame it is a generic Chinese frame from a known Chinese brand. It cost about £350 to £400 iirc. I have raced it, crashed it mutliple times and it is still going strong. It weighs about 7.5kg when built up with reasonable components. Anecdotally I would say you don't need to spend a fotrtune to get a good, lightweight bike if you don't get too hung up about brand names.
 
Last edited:

Ajax Bay

Veteran
Location
East Devon
If you are riding a mountain bike (MTB) and want to ride on the roads, buy a cheap second hand road bike (probably aluminium) and ride it. That will allow you to be informed better if you decide to procure a carbon framed bike. If you want to change your MTB for a carbon framed MTB then see @Hacienda71 's post above. Ask yourself WHY you want to make this change: is it just weight you're trying to reduce. How heavy is the rider?
 

MichaelW2

Veteran
There are several ways to construct carbon fibre, some inherently stronger than others and some more costly.
The design of the structure must take account of the strength and weakness of the matetial which is not always the case with carbon.
Brand names are a protection against noname manufacturing but brand name frames can fail and noname ones can soldier on.
 

cougie uk

Senior Member
It's not my bike, they are photos from Facebook.

Everything breaks sometimes. I could post pics of my CF bikes unbroken after several years but what's the point. For all we know that bike was hit by a truck.

CF is a perfectly good material but the OP doesn't need it.
 

Hacienda71

Mancunian in self imposed exile in leafy Cheshire
If we are going to post random pictures off the internet of frame failures with no context, then I thought I better do ones with steel, aluminium and titanium. I havent found a broken bamboo one yet, so may be that is the way to go....:whistle: ;) The one frame failure I had was on an aluminiun Ribble frame from the noughties, it cracked just above the BB shell. Again anecdotal but it shows that any frame can fail.
1605201728092.png


1605201782429.png


1605202347566.png

1605202398657.png
 

straas

Veteran
Just as a thought - is it likely that an impact that would shear CF, would just lead to a plastic deformation in steel?

The plastic deformation would then fail over time rather than at the time of collision, potentially causing greater injury?
 

MichaelW2

Veteran
Just as a thought - is it likely that an impact that would shear CF, would just lead to a plastic deformation in steel?

The plastic deformation would then fail over time rather than at the time of collision, potentially causing greater injury?
I rode my bike at about 5-7mph onto the back of a car . The forks bent but did not break. If the forks were stronger, the headtube would have been bent in at the downtube.
There have been sudden breakages of steel forks but generally you get a warning.
 

Ajax Bay

Veteran
Location
East Devon
Just as a thought - is it likely that an impact that would shear CF, would just lead to a plastic deformation in steel?
The plastic deformation would then fail over time rather than at the time of collision, potentially causing greater injury?
If there was plastic deformation (the tube/fork bent ;)) then the rider would feel there was something wrong, even if it wasn't obvious at a glance. If a fork blade then likely the wheel would at best rub and at worst not be able to turn.
A metallurgist can come along and confirm or correct, but steel which is bent is no more likely to fail than unbent steel, provided it's not bent to and fro, plasticly. Consider that it's reasonable practice to bend the rear triangle of a steel frame to increase the OLN distance (eg from 126mm to 130mm). Is that 'reset' frame more likely to failure, within decades or 100,000 miles say? ((My answer is 'no'.)
 
Last edited:

straas

Veteran
I'm not sure a metallurgist would be much help to you! :laugh:

Surely plastic deformation results in weakening and increased fatigue? I deal with a different material, but the concepts should be similar - but I could be completely wrong. I'm wrong quite often actually!
 
Top Bottom