Race vs "normal" mtb frame

[arendoog]

HeHey E

Gaan jy weer J2C doen? Ek is nog onseker. As ek gaan sal ek solo gaan. Sal lekker wees om iemand te ken.

Nog onseker .My gesin is lus vir vakansie daai tyd .Defnitief die moeite werd en logistiek vanaf Gauteng is super maklik .Ons moet dalk n Epic saam doen ??

[Butterbean]

I am eagerly waiting for this to go further.....

 

Like most of my dates in high school...

[TALUS]

Nog onseker .My gesin is lus vir vakansie daai tyd .Defnitief die moeite werd en logistiek vanaf Gauteng is super maklik .Ons moet dalk n Epic saam doen ??

Ek is nie in daai league nie - eendag as ek groot is

[Eldron]

Ok lets try and add some rationale to this debate.

 

I used to be a "steel on SSer" kinda guy. Then I was offered a Niner CYA Carbon at a reasonable price so I bought it.

 

Previously I rode the Niner MCR with tensioner and SIR - both 853 frames. All bikes had rigid forks.

 

Steel is lovely for SS - nice and whippy and comfy. I thought the carbon would be harsh and unforgiving but I'm loving the frame - even more than my RDO and that is supposed to ave some "give" in it. In this case I would place the CYA over the MRC and SIR in terms of ride comfort and feel.

 

Bottom line - in general steel is more whippy and forgiving than carbon and alu but it's frame dependant.

 

In terms of carbon's strength for SS I don't agree that it's a time bomb waiting to happen. Sure you pedal slower on a SSer sometimes but the force you put into a bike is limited by gravity and how much you weigh. If you pedal harder than you weigh your arse lifts off the saddle. You can't pedal harder than your weight (with the exception of the slight increase when you're standing up and dropping your weight a few cm).

 

Carbon frames opening to the point where the wheel sits loose in the drop out? This is the first time I've heard of it.

 

Carbon fibre "rubbing" failuire mechanism? Ok I've never heard of that. I aint the worlds leading authority on carbon fibre but I've never heard of that. I always thought that placing the fibre in resin would eliminate that failure mode. I'm keen to learn more if anyone knows more?

[Jewbacca]

Ok.. So an 'engineer' would be rolling around? Really? And what do you think I do oh pearl of wisdom?

 

Look, epoxy and weave in carbon can be manipulated and woven to distribute flex in certain ways and accept some lag. The problem is most carbon geared frames arent designed for the severe amount of CONSTANT lateral flex.

 

On a geared bike you are out of the saddle seldom and you flip between your ratios for an even distribution of power/effort. On a SS you are out the saddle pulling the handlebars just to get you pedal stroke through 360. Wide or wriggly bars on a SS are commonplace as this allows more pull through the arms at less effort on those punchy climbs where you cadence slows down to nothing.

 

NINER make the AIR, cool. I had one and I broke it. Not from a crash or from an accident. The chainstay cracked in a puff of disaster on a big ass hill. Not all will do this I am sure as most people probably dont ride their SS in every race, over the Alps, across South Africa etc.... But a Mountain bike cant be wrapped in cardboard surely, even if it is 'my preciousssssss' carbon.

 

So like I said, enjoy what you will, ride what you want to. But when the BB starts emitting a sound similar to kindling at the birth of a new fire or your chainstay decides to crack, dont say you havent been warned.

 

Eldron, carbon is definitely frame specific as it will be influenced by how the weave was patterned before the epoxy was pulled through. But like most of you should know, carbon frames/forks have a limited time/km warranty which is due to the material and the stress being put through the frame. Couple this with the rigours of pulling/fighting the bike up hills constantly and it accellerated the process.

 

So basically due to the nature of the materials, Hooks' Law sits at a far lower level with carbon than steel and flex is essential to stop fatigue and the stays becoming brittle over time.

 

If you can see what im talking about, cool. If you cant then the answer is orange, I will forever be wrong in your eyes and wont justify this any further.

 

Yes, we are all entitled to our opinions but rule of thumb (funny if anyone remember the opening scene to Boondock Saints) says that experience is often the best teacher and if you look at most SS merchants, they ride steel. It is not coincidence, we could argue this for 600 years but just go ride, go explore, go and try out your carbon track frame etc and after 6 or 7 years come back to this topic.

 

Yes, like the brake threads and the riding style threads we can all log on and belittle or argue with people but just be aware that their OPINION and their input is often the culmination of years of experimentation and trial.

 

Engineers rolling around laughing? I scorn you without really taking offence.............

[rouxtjie]

Staal, die beste materiaal.

[Andyr249]

I am not an engineer but surely the increased forces when you pull on the handlebars on a SS compared to pulling on the handlebars on a geared bike would not be so different as to cause frame failure?

[rouxtjie]

I am not an engineer but surely the increased forces when you pull on the handlebars on a SS compared to pulling on the handlebars on a geared bike would not be so different as to cause frame failure?

Sure but if you are riding your geared bike like a singlespeed you are doing it wrong....when things get really steep like the concrete slabs at van gaalens as an example, your pull almost becomes part of your stroke, gives you the ability to turn the crank over and maintain cadence for the next pedal stroke....with gears, you just use your shifter. singlespeedguy has a point

[Eldron]

Yes, we are all entitled to our opinions but rule of thumb (funny if anyone remember the opening scene to Boondock Saints) says that experience is often the best teacher and if you look at most SS merchants, they ride steel. It is not coincidence, we could argue this for 600 years but just go ride, go explore, go and try out your carbon track frame etc and after 6 or 7 years come back to this topic.

 

In theory I agree - steel is a better material for SS than carbon (in terms of lifespan).

 

In practice I haven't ever owned a bike for more than 18 months so the lifespan of the frame in of little or no consequence to me :-)

 

That is the issue with anecdotal evidence like we have - I once broke 4 steel bikes in 6 months, I've also snapped alu and carbon (ok the carbon was replaced because the clear coat was cracking - the frame was fine). So in my experience steel is the worst performing frame materials.

 

I had a Singular Swift in steel. Man I hated that thing. Cumbersome and awkward were it's strongest attributes. Steel is not the only answer.

 

Topping all that of course is this: buy the bike that stirs your soul. XCO, Marathon and Road racing can be logical but SSing is a whimsical side of cycling that makes no sense (we like steel because it's all whippy and comfortable then we remove the suspension from the front).

 

What was this debate about again?

[Eldron]

Eldron, carbon is definitely frame specific as it will be influenced by how the weave was patterned before the epoxy was pulled through. But like most of you should know, carbon frames/forks have a limited time/km warranty which is due to the material and the stress being put through the frame. Couple this with the rigours of pulling/fighting the bike up hills constantly and it accellerated the process.

 

So basically due to the nature of the materials, Hooks' Law sits at a far lower level with carbon than steel and flex is essential to stop fatigue and the stays becoming brittle over time.

 

There is one area where you're off track. You're comparing the properties of the materials. This is all good and well until you consider failure mechanisms. Frames hardly ever fail mid tube - they crack/break at stress raisers.

 

In alu and steel these are found (almost without exception) at a junction - a weld, a water bottle boss, a hole for the cable to go internal etc. These stress raisers have compromised fatigue life because:

 

- the metal structure has been reduced to random by the welding process

- there is a point/burr/angle etc that has been created by the insertion of a boss/drill.

 

The steel frames I've broken have broken:

3 x top tube where the frame was drilled to allow internal tubing.

2 x BB where the chainstay and BB were welded

1 x chainstay/seat tube junction

 

The alu bike I broke was the top tube - seat tube junction.

 

Eldron's Friday pearl of wisdom - properties of materials are important - failure mechanism is more important.

[Andyr249]

Sure but if you are riding your geared bike like a singlespeed you are doing it wrong....when things get really steep like the concrete slabs at van gaalens as an example, your pull almost becomes part of your stroke, gives you the ability to turn the crank over and maintain cadence for the next pedal stroke....with gears, you just use your shifter. singlespeedguy has a point

 

I hear you but I still can't imagine the the force of the pull will be outside the frame tolerances and cause failures on the frame? Unless of course your name starts with "Chuck" and ends with "Norris".

Surely the force difference will be small enough to be still covered by the frame limits whether it be a SS or geared frame?

[rouxtjie]

I hear you but I still can't imagine the the force of the pull will be outside the frame tolerances and cause failures on the frame? Unless of course your name starts with "Chuck" and ends with "Norris".

Surely the force difference will be small enough to be still covered by the frame limits whether it be a SS or geared frame?

Yea and agree....I cant see my "pull" breaking the bike..I don't even lift brother

[arendoog]

We are talking hard working SS frames here .Riding 3 towers with SS and all the training before .I have litterary worn out my carbon frame,s rear dropouts and changed to steel before they broke completely

[rouxtjie]

We are talking hard working SS frames here .Riding 3 towers with SS and all the training before .I have litterary worn out my carbon frame,s rear dropouts and changed to steel before they broke completely

My steel donkey loved the towers...my teeth not so much.

[arendoog]

Ek is nie in daai league nie - eendag as ek groot is

Haai k .Jy onderskat jouself .Sit een uur by jou rytyd van W2W se eerste stage en jy het n moeilike epic stage .Niks moeliker nie ,net verder Edited November 8, 2013 by Blitzer

[arendoog]

Ok lets try and add some rationale to this debate.

 

I used to be a "steel on SSer" kinda guy. Then I was offered a Niner CYA Carbon at a reasonable price so I bought it.

 

Previously I rode the Niner MCR with tensioner and SIR - both 853 frames. All bikes had rigid forks.

 

Steel is lovely for SS - nice and whippy and comfy. I thought the carbon would be harsh and unforgiving but I'm loving the frame - even more than my RDO and that is supposed to ave some "give" in it. In this case I would place the CYA over the MRC and SIR in terms of ride comfort and feel.

 

Bottom line - in general steel is more whippy and forgiving than carbon and alu but it's frame dependant.

 

In terms of carbon's strength for SS I don't agree that it's a time bomb waiting to happen. Sure you pedal slower on a SSer sometimes but the force you put into a bike is limited by gravity and how much you weigh. If you pedal harder than you weigh your arse lifts off the saddle. You can't pedal harder than your weight (with the exception of the slight increase when you're standing up and dropping your weight a few cm).

 

Carbon frames opening to the point where the wheel sits loose in the drop out? This is the first time I've heard of it.

 

Carbon fibre "rubbing" failuire mechanism? Ok I've never heard of that. I aint the worlds leading authority on carbon fibre but I've never heard of that. I always thought that placing the fibre in resin would eliminate that failure mode. I'm keen to learn more if anyone knows more?

just to put things in perspective .I am 6'4 and weigh 100kg .My first gear ratio was 40x15 .I am running 36 x18 now for all purpose riding .34x18 is the lowest i will go but have not used it .I have no problem stretching a new bmx chain over a weekend .I would rather not put a 10k niner frame under those pressures unnessasary