rekmeyata

Steel lugs had some problems prior to the mid '70s, but even those were far and few between. Since the mid 70's they perfected that design pretty good, there may have been some isolated incidents, but not much to jump and down about.

There is a reason why all steel bikes back in the day were warranted for life, while CF bikes today are warranted for 3 to 5 years.

Why Carbon Fiber Bikes Are Failing (outsideonline.com)

(2) Throwback Thursday: Why you should be riding steel and not carbon | Road Bike, Cycling Forums (roadbikereview.com)

Bike frame materials compared: alloy vs carbon vs steel vs titanium - BikeRadar


I'm not slamming CF, just pointing out that there are issues that can cause a major and sudden catastrophic failure. Look, I have a Lynskey TI bike, it uses a CF fork, so I'm not against CF. However, since I knew this stuff when I bought the bike, I opted to go with a tandem rated CF fork, a Enve 2.0, I only weigh 173, so this fork is designed for that weight and up to 240 pounds, PLUS another person! I opted to go with an over-engineered fork.

You can go to any bike shop and walk up to any CF bike on display and take your finger and thumb and squeeze the middle of the top tube and you will feel it give slightly, not reassuring! Additionally, because CF is so weak you have to use a torque wrench for anything you need to tighten on it, and you better make sure you have the correct torque specs, over tightening something could cause that part to fail; there is no room for error with a CF bike. You can't even clamp a bike repair stand clamp to a CF tube, it has to be clamped at the seat post.

This guy is extremely knowledgeable in this stuff, this is highly educational, pay attention: (39) Carbon Fiber Bikes - Are They Strong Enough? (ft. Raoul Luescher) - YouTube

If you like, you can watch his other videos, very informative stuff.

PeteHski

It appears that you are actually. Except for the CF fork on your own ti bike. How convenient.

PeteHski

70 psi is actually on the high side for a 32 mm wide tyre unless you are very heavy. Try using one of the online tyre pressure calculators to get a better starting point. I use the SRAM or Silca pressure calculators. At my weight of around 80 kg I run pressures of 60-65 psi with 30 mm wide tyres. For 32 mm I would run even lower.

Guys running 100 psi on 25 mm tyres have no advantage unless your roads are super smooth and even then it is not significant. On rougher roads you will have the advantage, especially on a long ride where fatigue is a major factor.

Maelochs

As for tire pressure, I recommend testing. Everybody rides differently .... I weigh an eighth of a ton but I ride "light" in that I rise up over obstacles, big cracks, train tracks, and such, so that my legs, not the bike, absorbs the impact. That is how I get away with 24- and 28-spoke wheels despite my weight.

With new tires wheels, or a bike, I generally start my tires stiff (so if I press with a thumb there is very little give,) and then let out air ride after ride (or just don't pump them so hard) until I like the feel .... if the tires--particularly the rear--feel like the wheel is shifting sideways over the contact patch, I know I need more air,. if I get a pinch flat and didn't hit some obstacle I didn't see, then I know I need more air.

32-mm at 70 psi for me would be worthless. I know because I have 32s on my Cannondale and I run 90 optimally. 70 and I would be crashing or walking ... but if you weigh less, or have different wheels, or different personal preferences ... you might be fine at 65, who knows? Only you can say what works for you, and only through experimentation can you learn.

I recommend against extremes .... drop a few psi per ride, not 20--but do experiment. As was noted above, hard tires only really help at the track. On the road, a little give is a good thing.

Iride01 

Tell the people that were riding them when the lugs failed that it's not something to jump up and down about. That's what all the fear mongers do for CF bikes. They jump up and down about every little thing that goes on with CF. But yet the steel bike failures and aluminum bike failures you claim aren't much to jump up and down about

All bikes have had some issues no matter what material they are made from CF isn't any different in that respect. It's much of the early design mistakes that keep getting put forth by fear mongers that CF is bad. And along the way there have been and will be other design mistakes or manufacturing mistakes as were those lug failures.

Carbon Fiber bike frames also enjoy a lifetime warranty too. Just like some steel frames only have a 3-5 year warranty. Depends entirely on the manufacturer or brand of bike and the tier level a model of bike belongs too.

Lombard

Carbon fiber frames are like anything else. There are good ones and there are bad ones. Granted that metals won't shatter to pieces, but they can still fail in a way that makes you kiss the pavement.

It is in fact possible to make a carbon fiber frame that is way stronger than any alloy frame. Note that jets are made of carbon fiber and planes aren't falling out of the sky. Trouble is most people buying a carbon fiber bike want the lightest weight there is and don't want to pay a fortune for it. And as the saying goes, light, cheap, durable.......pick two.

rekmeyata

No I'm not, just showing some videos, which I know you didn't watch any of them or you would not have said what you said.

Maelochs

I hear that there are still people claiming that only some materials are suitable for bike frames .... and the Earth is still flat, right?

rekmeyata

I find it amazing how many smart arse cyclists there are on these forums. Another igiot who didn't bother to comprehend what I said or look at all the videos, just mouthing off.

Maelochs

At least you feel at home here, eh?

Eric F 

Please help me understand how CF material can suffer catastrophic internal damage without any external evidence.

I have a 20+yo CF MTB, that is pretty beat up, and I still ride pretty regularly. I have a CF road bike (bought used) that I spent a good amount of time doing 30+mph on today..and many other days. I have another CF MTB (bought used) that I have ridden hard in some extreme conditions for over a year with no sign of any issues. I also have a CF gravel bike (bought used) that has been pushed hard for some pretty long and tough rides. Which one should I expect to assplode first?

Eric F 

Checking just 2 of the biggest names, both Trek and Specialized have lifetime warranties on their frames, regardless of material. This is really easy to verify. Please stop making things up.


Or, I can go to my garage, and squeeze to top tubes of 5 different CF bikes. Zero give on any of them. Please provide specific makes and models of bikes where you personally experienced what you describe.

Trakhak

The first time I came across the claim that someone had squeezed a top tube and felt the tube give, it was in the '70s, with a Reynolds 753 steel frame.

As for carbon requiring the bike to be clamped in a stand by the seatpost, the only frames I've seen that were damaged by being clamped in a bike stand were two steel bikes, where customers had wheeled their bikes in and clamped them in the stand by the seat tube, not realizing that the clamp was currently adjusted to clamp the seatpost. The seat tubes ended up optimized for crosswind aerodynamics.

A little-known fact about steel frames: different steel tube sets have different recommended weight limits. The Columbus SL tube set, for example, was recommended for racers up to approximately 180 lbs, and KL was recommended only for record attempts and was therefore considered too fragile for other forms of racing. Similarly, the lightest Reynolds tube sets were intended for light riders and record attempts.

The new higher-strength steel tube sets enable frame builders to sell frames that are lighter than the frames built with the older steels, but higher strength equals greater brittleness in steel. Luckily, the riders who are wealthy enough to afford to buy bikes built with those new high-strength steels tend to be older (and to have their racing days well behind them) and are thus unlikely to ride the bikes hard enough to put them to the test.

Lombard

I can't say I have ever been able to make a bike tube give by squeezing it. Total BS.

It is a good idea to use the seatpost to clamp ANY bike in a stand. Tubing, regardless of material can be damaged by clamping force in a bike stand. Besides, I'd rather trash a seatpost than a bike frame.

Rogerogeroge

I had a Trek Madone 7 series with what they called Kamtail tubing. It was very easy to deflect the flat side of the tubing, but not the sides. Like someone else said, thin walled chromoly frames from decades ago could also be pinched.

rekmeyata

AGAiN, watch the videos

Eric F 

No. It’s pointless. CF has too long a history as a proven material for bicycle frames and parts for you to convince me otherwise. Additionally, the credibility of your arguments is already shattered with your BS about squeezy tubes and warranties. It’s regurgitated nonsense that has been circling for years.

BlazingPedals

IMHO it's never a bad idea to buy used for your first bike. You're likely to get ideas of what you want to change after riding for a month or two, and by buying used you'll still have a budget to work with; be it for upgrades on that bike or buying a second one (n+1, baby!) Have a friend that knows what he's looking at help you..

rekmeyata

yup, sure do

rekmeyata

Those videos are not all anti-CF, in fact, one of them comes from a guy who makes CF stuff for bikes, so you decide who you're going to believe, yourself or someone who is in the business, go to that video and read the comments, he is well known in the field.

You darn right know, unless you're weak, you can take your thumb and index finger and squeeze a top or down tube on a CF bike and it will give in slightly, try it to your bike. 4 to 6 NM on a torque wrench setting for mounting stuff on a CF frame or handlebar is not that much pressure, and that is the standard they tell you for mounting stuff, that is a fact that you would know if you wrench on your CF bike. My grandson who is 16 didn't believe a person could squeeze those tubes either, so I took him to a bike shop and had him walk around to several bike and do it, to his amazement he could feel them give a tiny bit, I told him to do the same thing with several aluminum bikes they had in the shop, he couldn't do with those.

Your refusal to watch those videos is because you refuse to learn anything, not even from professionals in the field.

Trakhak

Just pressed my thumb down on the flat top of my coffee table. I could swear I felt the veneered half-inch-thick particle board compress. I'm stronger than I realized.

Eric F 

At this point, you’re right. I’m not willing to “learn”. I’ve been down this road, on this forum, more times than I can remember. Zero times has it changed my conclusion about the application of CF for bike frames and parts.

There is no perfect material for bike frames. All materials can break, especially when subjected to high-speed impact. I’ve ridden and raced on steel, aluminum, titanium, and CF bikes. My preference is CF.

Eric F 

I did. I just went out to my garage and squeezed multiple tubes on all 5 of my CF-framed bikes, which include some that are 20+yo, and some that are <5yo, with large cross-section, shaped tubes. Every one had the same result - zero deflection under a good hard thumb squeeze.

I suppose there might be some frames out there that might deflect under this test, but it’s hardly a universal thing for all CF frames.

PeteHski

I said it "appears" like you are slamming CF frame in your post. Two of the videos you posted are titled "Why carbon bikes are failing" and "Why you should be riding steel and not carbon". Then the rest of your post is a fear mongering rant about the risk of catastrophic failure, why you felt the need to specify a "tandem rated" CF fork and tubing that you can crush in your hand.

But it would appear that I was mistaken and you are not really slamming CF at all. I can see now that you are just attempting to educate us as to why we should all be riding metal frames with perhaps "tandem rated" CF forks if we are feeling brave.

Edit: I just read your first 2 links. The first raised a few sensible points, the second one about why we should choose steel was as lame AF. But the reference to diesel engines was funny with the benefit of a decade's hindsight.

big john

A/I infiltrating again?