Since I parted out my fixie, I've been riding my road bike. The ride home tonight was soooo smooth, I couldn't believe it. It got me thinking about all the different factors that come into play.

Aluminum is stiff but because it doesn't absorb vibration it is inherently harsh. Steel is flexy and absorbs vibration, Carbon fiber is very stiff but also absorbs vibration, so both give smooth rides. These can be the frames, forks, bars, stems, or seatposts. There is also the matter of tire size, bar wrap or grips, gloves, and your saddle.

So what I'm wondering about is the common range of difference between these factors which can make a bike ride harsh or smooth.

e.g., at what point will similarly aggressive framesets in all aluminum, steel, and carbon match each other's ride quality simply by changing tire size, or bar wrap, gloves and saddle?

tire width. spoke type, wheel type. fork type, bar type, stem type, seat post type, saddle type. gel inserts under the handlbar tape tire height. the list of things that could be changed out that will make minute differences are endless.

Sheldon Brown, rest his soul, has a post about how you can achieve whatever ride quality you want with aluminum/steel/carbon. You just have to compromise for the weight/size of tubing. Aluminum is, for a given tube size/diameter not as strong as steel. But you can make a light aluminum bike with lots of power transfer with stiff oversized tubes etc. So to sort of answer your question you can smooth out a
stiff aluminum frame with a carbon fork, or make a springy steel bike stiffer by putting a Thomson stem/seatpost on it. . . I'm not really sure what you mean because you can't compare steel to aluminum or carbon--they are all pretty different. You can work around the limitations of each. . .or something. Go with steel.

For sure. This is why I wonder why people have such predisposition against aluminum frames.

Me too. I don't believe there's that much difference between the cheap aluminum and cheap steel most of us are riding. I ride an NYCbikes City Fixed and any harshness was resolved by dropping my tire pressure 10-15psi.

Aluminum makes a good bike. I rode a Kona Jake that I really liked. I just have a thing
for bikes made out of mid-range decent steel. Maybe it is in my head but 6-3-1
is a great ride and is pretty dang light. But to answer your question you can almost certainly get whatever
ride you seek with the bike you have by tweaking the set up.

cheap metal is trash no mater what it is.
same goes for cheap carbon.

back in my motorcycle days i have seen cheap carbon fiber bodywork that was worth less than fiber glass.


I think most peoples predispositions are based on what they read. and it is a weight-vs-strength vs what is does at a certain shape. the really cool thing about carbon is it can be mold into a lot of interesting shapes more cost effectively than alot of other materials and my doing different layups in different directions it allows more precise control of your results. my main gripe with carbon. is i crash a fair amount. on the other hand I am against oversize tubing and find smaller tubes more pleasing to the eye. Hence I prefer steel bikes. Both of my bikes are steel and ride nicely. but my road bike has more padding than a couch. (a heavily padded seat and gel bars) and lots of carbon bits. my fixed gear had stupid tight geos a aluminum fork( you can hear it hum sometimes) aluminum bars and a very very harsh ride. both steel. different worlds.

so in the end lots of variables.

Pretty much agree with everything said in here. Out of the box, steel will ride nicer than aluminum given both frames have all the same components / PSI is the same. But an aluminum frame, carbon fork, tubular tires not over inflated, carbon stem/seatpost, comfy saddle like an Arione, thick cork tape with the gel, and good fit probably wouldn't ride harsh at all.

I never put much thought into it before, but does stiffer seatpost (i.e. Thomson) = harsher ride on the gooch? Does it in turn somehow also equal better power transfer? I always thought the only good thing about a stiffer seatpost was less likelyhood of failure under a lot of weight and force.

true--stiffer stem seems to give more power transfer/responsiveness,
especially when climbing.

Stiffer seatpost does make the ride a little bit more harsh. I think
a nominal increase in power transfer occurs because the seatpost
is one less thing that flexes quite as much--so slightly more kinetic
energy goes to the wheels. The general idea is that
all kinetic energy that gets spent flexing metal is not transferred to the road.
Not that any of this matters in my case
except for the purpose of having fun.

Whenever I feel like my ride is really smooth I know I need to pump up my tires.

That wasn't the issue, I pumped mine up that morning to 110 psi. Whenever I feel like my ride is really sluggish I know I need to pump up my tires.

i can always feel a split-second delay on a quick turn or a skip stop when my tire pressure is low.

the biggest factors in determining harshness or smoothness of a ride:

tire size and inflation

ass size and inflation

If it's a harsher ride on the gooch (which I would imagine it is-slightly), I don't care. Seatpost failure was not a fun experience.

curious, what brand seatpost failed on you? was it carbon?

I think it's mostly because they look like butt. And not in that good way I like.

Were you riding your usual route home? Nothing makes for a buttery smooth ride like fresh asphalt.

Agreed, most aluminum frames you will find have fugly HUGE welds. That said, I feel that there are some mad glorious aluminum frames out there, ie. pista concepts etc. The reason aluminum tends to feel stiffer is because it needs to be thicker and/or the tubes larger to achieve similar strength to steel. The weight difference makes these thicker tubes about the same weight or lighter, but you lose some of the flexibility you find in thinner, smaller tubes. Replace the fork with something carbon or steel and your ride should be fine.

I have a lot of bikes and the reason I have any of them is because they are first and foremost, comfortable because if I am comfortable I can ride farther and faster and be a much happier camper.

Running your tires at their maximum pressure isn't always the best idea as too much tire pressure prevents the tire from absorbing shock, can make handling sketchy, and cause increased fatigue. The rated tire pressure is only a suggestion and you need to account for your own weight and riding style when setting pressure. I'm a small guy so running my tires at their max does not make sense... YMMV.

The material a bike is made of doesn't affect the ride as much as the geometry, build quality, and other components, especially the wheels and tires.

A tale of 2 well made bikes, one is new and Al while the other is vintage steel.

My Trek 7500 is an incredibly comfortable and fast ride...it runs on Schwalbe CX Compe cross tires (700:35) that I keep inflated to 65 psi / road and 40 psi / trail. The frame is a ZX series aluminum while the fork is steel, I have Ritchey CX drop bars, and a Bontrager saddle that is a good match for the bike (and my butt) and I would have no reservations about riding a century on this bike.

This bike really depends on it's tires for it's ride qualities as the frame is very stiff and almost identical to the frame on my 6700 HT... I have a set of road tires I can run and at high pressure the ride quality really falls off... but the bike does get much faster.



I also have a 1982 Trek 750 that is a fully lugged and built on Reynolds 531 tubing. It runs 700:26 Kenda slicks which are far narrower than the CX tires on my 7500 and run at a higher but not maxed out pressure (90-95 psi) which would make one think it was a harsher ride than the 7500 CX bike but the frame on this bike is really second to none, absorbs a lot of shock, and it too is incredibly comfortable... and fast.

i would second the geometry comment, only with my limited experience of my super vitus steel tubed gitane criterium with mavic ma3s provides a much harsher and jolty ride than my 7001 aluminum bmc streetfire with fulcrum wheels, and i think the gitane has steeper angles,higher bottom brackter and an all around tighter geometry but i'm yet to bust out the protractor.....

I think that with so many folks choosing track bikes as their platform for urban fixed gear builds you are getting a lot of bikes with short stays, tight geometries, high psi tyres, and rigid frames that are really suited for a smooth track and not the real world.

The nose down / bum up posture is also great for racing but not so good for urban assaults as it puts a lot more weight on the arms and wrists.

Road bikes and touring bikes have longer stays and more relaxed geometry that lends itself to making the ride far more comfortable.

MY fixed mtb is a vintage Kuwahara Cascade which is really a cross country / expedition bike with very relaxed geometry and long rear stays. With 26 by 2 slicks at 60-65 psi it still rolls out pretty quickly and is very comfortable.

My favourite fixed gear (a 1962 Peugeot) is probably the least comfortable of all my road bikes as it has tight geometry, a rigid steel frame, the riding position is fairly aggressive, and I do run slightly higher tyre pressures in the 700:28 rear and the 700:25 front.

I can still ride this bike all day.

my fixed gear is nuts actually. the wheel base is almost six inches shorter than my road bike. and the ride is incredibly harsh. granted it is built for head down tail up sprinting. really short wheel base so i would expect little else from it.

it is steel and everyone usually says should it be a plush ride?
nah they used steel for smaller diameter tubing. i love the way the bike looks.

ahhhhhhhh

AMEN!!

This is why, while purists and hipsters may scoff, i think steel frame conversions make the most sense for urban riding. Slacker road geometry will let the frame absorb more impact heading over bumps, and sit you more upright where it wont hurt the taint and hands so much. All else being equal, steel gives a smoother ride where you wont cringe every time you hit a pothole.

However i would like to set the record straight on aluminum. The "harshnes" of aluminum is not because the material itself doesn't absorb vibration. The ride of an aluminum bike is mostly a consequence of aluminum having a fatigue limit and the tubing gages required to accommodate this and make the frame durable.

Unlike the alloys of steel used in bike frames, no matter how lightly you bend aluminum, if you do it enough times it will eventually fail. This is why you never see springs made of aluminum, and the pop top on a beer can will fall off even if you just slightly bend it a few times. If kept bellow certain limits, steel can bend or "cycle" an infinite number of times.

So, aluminum bikes must have much less flex for the same loads as steel bikes if they are going to last more than one ride. This means very large tubing diameters. Big tubes mean little flex, and thus a harsh ride, but great power transfer and handling characteristics.

Steel could be made to have just as "harsh" a ride as aluminum if the tube sections were increased, but this isnt done because (among other reasons) its harder to draw steel into the tiny wall thinnesses that would allow for a reasonable weight bike with big tubes. Aluminum is just plain easier to work and weld into crazy buttings, and steel cant be replaced in terms of flexibility and comfort, so its the material of choice when durability and comfort take precedence over weight and performance.

very nice explanation. i finally understand the whole steel vs. aluminum thing concisely.

but one thing - what about the aluminum road bikes from the 80's with tubing diameters the same as standard steel? i still see some of those being ridden.

I've been told aluminum frames has a limited lifespan of about 7 years of use. Maybe after those first frames were introduced, and they started cracking, that engineers came up with bigger tube frame designs.