Yet another reason to avoid carbon frames

[pedals2slowly]

What certification and qualified assurances are you referring to, and from whom?

Does the manufacturer have an UCAS accredited IS0 9001 certificate - normally paraded by holders on their website.
However cyclists (customers) probably don't know about ISO9001 so cycle manufacturers either don't publish the fact or haven't got it.

Ideally someone like Reynolds would have their own qualification process and only sell bicycle frame material to accredited frame builders

[fastpedaller]

I'm not necessarily impressed by holders of ISO 9001 and similar, I'd prefer to see the results of their product in the field over several years (but of course that's only my personal opinion). An example of a company that lauded it's ISO 9001 approval (apologies it's car related ) ......... I was supplied a pair of car seats which had adjustable runners to enable the seats to be moved backwards/forwards. Problem was that when the seats were mounted on the runners it was impossible to move the operating lever upwards because the seat cushion prevented it, so the seat position wasn't adjustable at all
Their 'explanation' was that the 'original' seat runner was made by a company that went bust, so these were a replacement item. When I asked if they had actually done the obvious and fitted one of the new runners onto the seat to test it (rather than just assuming it 'worked' because they were told it would) they became defensive and stated"we are an ISO 9001 company'
I asked them how they'd react if the ISO governance were informed of their performance, so they rectified the matter (grumbling all the way that I was getting 'a more expensive pair of runners'). I was not impressed.

[pedals2slowly]

I'm not necessarily impressed by holders of ISO 9001 and similar

Very sensible, there are plenty of ISO9001 companies who talk the talk but don't walk the walk, and plenty of duff ISO9001 certs.
But ISO9001 is the starting point whereby a company would have to prove it has sources the correct certified material, have mill traceability for metals and I assume similar for carbon fibre, also show it's production processes were consistent, customer complaints adequately dealt with and continuous improvement proven.

[MartinC]

......Steel and carbon fibre are two different choices, that's all.

Ah, so you did understand my post after all!

[Manc33]

Carbon framed road bikes take some of the harshness of the road away, that alone would probably be my main reason for carbon since road bikes tend to have skinny, rock hard tyres.

It's not just about the frame being lighter and stiffer, to me that's a side issue that happens to be true.

I was quite surprised when I built up a carbon road bike, at how much better it was at absorbing bumps in the road, compared to the aluminium Triban 3 I had been using. That Triban 3 was better again than the really old Reynolds 531 bike I had used a few times, the thing was a complete boneshaker, albeit probably a very desirable bike... 50 years ago!

If a carbon frame is coupled with carbon handlebars, a lot of the road vibration is reduced dramatically while the frame itself dramatically reduces the harshness of the ride. One instance I will always remember on that carbon road bike was going over a bit of road rough enough to lift my rear wheel slightly and it made a "boing" noise.

[djnotts]

Carbon framed road bikes take some of the harshness of the road away, that alone would probably be my main reason for carbon since road bikes tend to have skinny, rock hard tyres.

It's not just about the frame being lighter and stiffer, to me that's a side issue that happens to be true.
...........

If a carbon frame is coupled with carbon handlebars, a lot of the road vibration is reduced dramatically while the frame itself dramatically reduces the harshness of the ride. One instance I will always remember on that carbon road bike was going over a bit of road rough enough to lift my rear wheel slightly and it made a "boing" noise.

Absolutely! I reckon in comfort terms carbon + 23mm tyres equals Ti + 25 and steel + 28 - 32 depending on quality (Columbus SLX or 531C IME).

[alexnharvey]

Carbon framed road bikes take some of the harshness of the road away, that alone would probably be my main reason for carbon since road bikes tend to have skinny, rock hard tyres.

It's not just about the frame being lighter and stiffer, to me that's a side issue that happens to be true.
...........

If a carbon frame is coupled with carbon handlebars, a lot of the road vibration is reduced dramatically while the frame itself dramatically reduces the harshness of the ride. One instance I will always remember on that carbon road bike was going over a bit of road rough enough to lift my rear wheel slightly and it made a "boing" noise.

Absolutely! I reckon in comfort terms carbon + 23mm tyres equals Ti + 25 and steel + 28 - 32 depending on quality (Columbus SLX or 531C IME).

The variance within each group is bigger than the differences between the
groups.

[MartinC]

.....The variance within each group is bigger than the differences between the
groups.

Yes, this, and other threads, is rife with people creating generalisations from their own personal circumstances. The variances due to design and manufacture will outweigh those due to material.

[cyclop]

Kind of related to this thread....met a friend for our usual weekly run out,Brampton,Cumbria,with the intention of doing Hartside pass,Alston,Brampton.Whilst idly casting an eye over my pals Trek OCLV carbon,a bike at least 20yrs old,I noticed some flaking gelcoat on the rear of the fork.I picked a few flakes off and found a serious crack,in fact I could bend the fork to open the crack up.He aborted his ride,of course but wondered about the cause.On last weeks ride,there was a terrible clatter from his bike which sounded serious.He had ,in fact,picked up a lump of asphalt which clattered into the fork,most likely causing the damage(hot day,tarmac sticky).........A salutary lesson here to inspect a bike for damage after such a trauma,particularly carbon.

[bgnukem]

Absolutely! I reckon in comfort terms carbon + 23mm tyres equals Ti + 25 and steel + 28 - 32 depending on quality (Columbus SLX or 531C IME).

Too many other variables. Carbon can be laid up to be stiff or flexible in different dimensions, tailoring the properties for the application with the number of plies and the angle of the fibres in the plies w.r.t. the 'tube' axes.

The stiffness of metallic materials is pretty much fixed as the Young's moduli of different steels tend not to vary by much (maybe 10% at most) and similar applies for Al alloys of different types/strengths, so the frame stiffness is varied mainly by varying tube diameters and wall thicknesses and frame angles, chainstay length and seatpost length play a part . I've owned/ridden horribly harsh steel frames and very comfy ones.

Ali frames gained a reputation for harshness in the '70s and '80s as they were built to minimise flex (hence fatigue), but newer frames have more complex tube shapes and butting and tailored stiffness. A current ali frame is typically much more shock absorbent than those made 20-30y ago. My (basic, oversized) Ribble 7005 frame is built on old school lines and is much stiffer than my Giant Rapid, which has profiled tubes of various cross-sectional areas and skinny rear stays.

[djnotts]

Absolutely! I reckon in comfort terms carbon + 23mm tyres equals Ti + 25 and steel + 28 - 32 depending on quality (Columbus SLX or 531C IME).

Too many other variables.
........

I was to some extent allowing for variables and comparing bike "type" with like. I entirely agree that in particular geometry especially angles and wheel base important factors. But other things being (as) equal (as possible) I stand by my admittedly, inevitably, subjective conclusions drawn from dozens of bicycles.

[mumbojumbo]

Why would anyone WANT a bike that lasts for years? I just get bored. By carbon touring what I really mean is big tyres and mudguards! A grand a year depreciation is neither here nor there.

The bike is less crucial than the route chosen and the environment.Buying a bike you realize will disintegrate seems wasteful,poor Economics,and costly with no resale value.If you find a bike you like stay with it.

[djnotts]

Why would anyone WANT a bike that lasts for years? I just get bored. By carbon touring what I really mean is big tyres and mudguards! A grand a year depreciation is neither here nor there.

The bike is less crucial than the route chosen and the environment.Buying a bike you realize will disintegrate seems wasteful,poor Economics,and costly with no resale value.If you find a bike you like stay with it.

Carbon bikes do not disintegrate! I can chose the route but not the weather. Buying only second hand greatly reduces depreciation. And in any case my health means absolutely no point in worrying whether a bike is going to last 1 year or 2!

[hamster]

I'm not necessarily impressed by holders of ISO 9001 and similar

Very sensible, there are plenty of ISO9001 companies who talk the talk but don't walk the walk, and plenty of duff ISO9001 certs.
But ISO9001 is the starting point whereby a company would have to prove it has sources the correct certified material, have mill traceability for metals and I assume similar for carbon fibre, also show it's production processes were consistent, customer complaints adequately dealt with and continuous improvement proven.

ISO 9001 is that you have a quality system and follow it. What you specify in that system is not covered.
SO if you specify that faults are covered with masking tape and resprayed, then that fits ISO9001, provided you comply.

Product quality and performance are another area altogether. Typically if the company hides behind ISO9001 it's a charlatan.

[MartinC]

..... I entirely agree that in particular geometry especially angles and wheel base important factors....

The stiffness of the tubes will have a bigger effect. The weight of the rider and the size of the frame are part of this too. Tyre characteristics don't just depend on the nominal width either. Wheels, position, steerer design, bars, stem and seatpost/saddle all affect comfort too.

There are just too many variables for your original proposition for it to be valid generically. In the real world all other things are very rarely equal. Personal experience is quite a powerful influencer but one needs to avoid falling into syllogism - my black bike is better than my red bike therefore all black bikes are better than red bikes.

I've been cycling a long time and I have a fair idea of what works for me and after a lifetime working in technology I'm happy trying out new things. I've learnt that there's no progress without change but not all change is progress. I've also learnt to be very wary of being prescriptive about what will work for others. Cycling is a wonderfully diverse activity and the variation in the objectives and physiology of participants varies immensely. Carbon frames are a great boon for some. Those who point out the drawbacks aren't anti, they're just trying to enable us all to make informed choices.