Tuesday, July 13, 2010

Full-carbon, aluminium + carbon fork and aluminium + carbon fork and rear end. And steel. I've tried 'em all. And the difference is?

I'm tempted to say 'not worth arguing over', but my last steel bike was a beauty: custom higher bottom bracket height for crits, Campag all over it, fast wheels. Bought it in 1989, resprayed it in 1995 (to fend off the rust). Replaced the groupset with Mavic gear off my 1990 Look KG76 Carbon Kevlar (which took on 105 instead). Retired it for good in 1999 (rust again). Frankly, steel is a pain to maintain.

I sweat a lot, and I don't mind riding in the rain. I always clean, lube and rust-protect my steel bikes (including my Saronni-Colnago track bike, which almost never sees rain and has survived with scars and 2 re-sprays) but inevitably they rust. And I don't see (or feel) any advantage over other materials. So steel is just off the shopping list, at least for me. However my kids have cheap and cheerful steel bikes, and training wheels!

I should however say that my '85 Colnago Mexico was a great steel road bike. Smooth, effortless and hardly rusted at all. It was a great road bike but not handy at all in crits, so I got rid of it before I scratched it. As far as I know it's still intact (a friend bought it off me) and perhaps it proves that the initial treatment and care in manufacture of a steel frame makes the difference. But I can't be bothered with further experimentation given that I've already had, umm, 2 steel track bikes and 6 steel road bikes. And seriously - be they a custom frame, a Colnago or a Gitane, or even an Apollo or a Shogun - they weren't any more comfy or faster for being made of a rusty metal.

Which brings me to carbon. My Look KG76 (skinny carbon/kevlar tubes bonded to aluminium lugs) distinguished itself almost immediately by being the first bike in my experience to make 200km feel like a doddle. Seriously, it was a revelation and even put my comfy steel-framed Colnago into perspective. Whilst I can't say it was the carbon alone that made the difference, I can say that over 20 years later it's still rideable. In fact I'd race it without hesitation. What I would say is that the laid-back French frame angles matched with light but less-than-stiff wheels was the real differentiator in the comfort stakes.

One thing I have learnt from my 35 odd years of bike riding is that things break. My brother broke the steel forks on our old steel road bike. But the frame was getting close to 50 years old by that stage and the forks may have been original! Anyway, they broke catastrophically and without warning, much like my lightweight aluminium seatpost did years later...

Which brings me to aluminium frames. I have just 2 of those, both by Felt. They are ridden almost every day in all kinds of weather and raced on fine summer days. The F50, an aluminium frame with carbon fork is 6 years old (and counting) and has just broken its first spoke. The F75 is just 4 months old and has a carbon rear-end to go with a carbon fork. It's a size smaller than the F50 which fits me better but is noticeably more lively. Given the extra carbon some readers may think it would be more comfy but it's not, it's stiffer and harsher - as well as faster. I put that down to the smaller sized frame and the newer, slightly stiffer wheels rather than frame materials.

Now it gets complicated. I use 3 road bikes regularly but each is a different size with different angles, and a different mix of frame materials and wheelsets. I have Mavic vs Velocity clinchers and a variety of tyres, too. So how could I definitively "prove" what I feel? I can swap wheelsets around a bit and standardise on tyres, I guess. And I can run some tests using my power meter. But frankly, whilst I will almost certainly run some comparisons just for the heck of it, I don't think it matters too much. I can simply summarise my feelings and you can pick and choose what you want to believe. I'll even link to some further opinion afterwards ;-)   

In summary I believe that :
  • Frame materials do NOT inherently "feel" different. If the angles are the same and the material stiffness is the same then they will "feel" the same - to me at least. Which debunks the 'steel or carbon fibre is more comfy' theory
  • However my Look KG76 Carbon Kevlar is the most comfortable road bike I've ever owned - but I put that extra comfort down to the wheelset and frame angles rather than the carbon
  • Wheels really matter - stiffer wheels degrade comfort but add speed; lighter wheels add speed (or acceleration) but may be softer, especially when cornering (depends on stiffness, again)
  • Carbon frames (at least those made by Look) can be stiff or soft by design and can last 20 years or more, even when raced and trained on, without any noticeable change in "feel", either
  • Aluminium fails suddenly and catastrophically and like all frames should be keenly examined for damage, but after 6 years of training and racing my aluminium Felt F50 remains failure-free (touch wood!) and just as nice to ride as on day one
  • Steel rusts. It can be stiff or soft by design. It also doesn't "age" and become somehow less "springy". At least not in my experience! 
Some other people think differently, at least in part....

Is Carbon Fiber really worth the cost of a new bike? | Ask MetaFilter
I have been convinced that carbon fiber ages significantly every time it flexes, as does aluminum to a much lesser degree. Steel on the other hand, can flex a million times with very little measurable change in springiness. Just imagine how well a coil spring made of carbon fiber or aluminum would last.

Bicycle Frame Materials - Steel, Aluminum, Titanium and Carbon Fiber, by Sheldon Brown
Did you know that:
* Aluminum frames have a harsh ride?
* Titanium frames are soft and whippy?
* Steel frames go soft with age, but they have a nicer ride quality?
* England's Queen Elizabeth is a kingpin of the international drug trade?
All of the above statements are equally false. There is an amazing amount of folkloric "conventional wisdom" about bicycle frames and materials that is widely disseminated, but has no basis in fact.

The reality is that you can make a good bike frame out of any of these metals, with any desired riding qualities, by selecting appropriate tubing diamters, wall thicknesses and frame geometry.

Lifespan of Carbon Fiber Frame - Topic Powered by Social Strata
I have over 15000 miles on a 2004 Trek 5200 and I personally cannot tell any difference in the ride from the firt day to today. The frame has its share of scratches dings and such but its as supple as the day I bought it. My feeling on CF bikes is when there is a major malfunction it will just break and thats the time to replce it. I rode Steel in the 80'2 and could definitely tell age on the ride and performance after many miles. Same for an aluminum bike in the 90's. Probably not the most scientific answer you could get but its just my $.02 worth. 300 miles on a frame isnt much if you feel the bike has been cared for.
But let us not deceive ourselves. The slight weight disadvantage that comes with a steel frame makes it unusable for racing at the highest levels. A steel frame can be made that weighs in the mid to low 3-pound range. Over a non-compact aluminum frame, this is a penalty of about one pound. This is just too heavy to chase Tyler Hamilton up a category-one climb. That is why the professional peloton uses aluminum or carbon. But for the rider who does not compete at the elite level, that one-pound penalty as part of a whole rider/bike package that approaches 200 pounds (or may generously exceed it) is insignificant. And for that pound, the rider gets a bike that can take advantage of the high-tensile strength and springy elasticity of modern steel and ride a bike that is an absolute dream. No bike rides as well as a steel bike built by a skilled builder. People who disagree with this conclusion usually have either a commercial interest in other materials, or have not ridden modern steel bikes.
I believe that the feel of the road is a large part of the feedback I am looking for as I ride my bike. I am not looking to isolate myself from my cycling environment. I want to be part of it. For me, then, carbon works against my cycling goals. I have never ridden a carbon frame or fork that gives the fine, pleasant, comfortable ride under the widest set of condition that steel gives.