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Discussion Starter · #1 ·
I might have gotten this wrong!? But to me, it seems the stiffer a frame is, the less comfort it offers (more vibrations). Looking at aero vs comfort, seems comfort gets more and more about comfort, and aero on the other hand is most about stiffer and stiffer. Is it not possible to make a stiff aero frame with high reduction of vibrations?
Personally, there are two things i like to reduce while riding.
Vibrations and the input of wind. Anyone who can teach a bit about the stiffness vs comfort?
 

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I think lighter, stiffer and more aero frames are just marketing BS with negligible benefit for the average recreational rider. Your position on the bike will make a bigger difference in aerodynamics.

But if you're determined to get a harsh and crappy riding aero racing frame, there are a number of things that can be done to potentially improve comfort (some are debatable):

- More supple model of tire
- Latex inner tubes
- Tubeless tires
- Wider size tires
- More comfortable model of wheels
- Lower tire pressure
- Wider rims that allow lower tire pressure
- Double wrapped bar tape or gel tape
- Flat top bars
- Bontrager Buzz Kill bar plugs
- More thickly padded gloves
- Saddle with more padding
- Saddle with carbon rails
- Suspension seat post like the Specialized CobL GobL-R or Ergon CR3
- Shorts with thicker padding
 

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You certainly can get bikes that are very efficient in power transmission while still offering a fair degree of comfort. You can also go for extremes. Bikes that are oh-so-comfortable but not ones you would want to ride a leg of the Tour de France on and bikes that are great for a short crit event but would tire you out on a fifteen-mile ride in the country.

As for aero bikes, while they may offer some benefit for headwind or racing a time trial, remember that some of them will offer more surface area for sidewinds to catch.
 

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Burnum Upus Quadricepus
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I'm not an authority. But here's what I've picked up as a rider, and from hanging out of framebuilder forums. All subject to correction and clarification.

There's a lot of verbal shorthand and incomplete sentences when discussing frame stiffness, which leads to the confusion that all stiffness is good/bad and that any stiffness leads to an uncomfortable ride. Where and in what direction counts a lot. Individual areas of the frame can (and should) be resistant to movement (stiff) in one direction, but allow some movement in another direction.

"Laterally stiff yet vertically compliant" became quite cliché a few years back, but as a phrase, it gets the job done.

First, there's torsional stiffness. A bike frame shouldn't twist. Frames that feel "noodly" generally are twisting.

Bottom bracket stiffness is one form of torsional stiffness. Lock my old steel bike into a trainer and you can watch the whole thing twist as the bottom bracket pendulums side-to-side as I pedal. It's this motion that's controlled when they speak of bottom bracket stiffness.

Head tube stiffness is another form of torsional stiffness. Particularly when cornering, a bike with less head tube stiffness will feel a bit queasy over bumps and undulations, and won't quite hold the intended line. More head tube torsional stiffness gives the bike a feeling that it will roll over anything.

Same applies to forks. In this "thinner is better" period, my beloved WoundUp forks are decidedly unfashionable. But both torsionally and laterally (side-to-side), they're incredibly stiff and it feels oh so good in the twisties. Yet, when it comes to ride comfort, they allow so much fore-and-aft movement, I can see it as I ride.

The "vertical compliance" part is tricky. A bike overall, and the rear triangle in particular, needs to bend some so that it doesn't beat up the rider. Early aluminum frames earned their reputation for harsh ride by being too stiff in this direction. A year or two back, Scott made a carbon racing frame that the pro team they sponsored absolutely hated because it beat them up so badly. I don't think a Scott rider podiumed all season. So it's not a simple case of material or of all stiffness being faster.

A bike with too much give in the frame will feel whippy. Back to my old steel bike, the front triangle flexes so much that I get a little extra kick after the wheels have passed over a bump. It goes bump, bump, kick--which is fun for a while, but quickly becomes tiresome.

Where you want extra stiffness in the rear triangle is lengthwise in the chainstays. A bike that's stiff here is said to have efficient power transfer.

It's hard to get the right amount and direction of stiffness and allow the right amount and direction for flex in each part of the frame. And a lot of it is personal preference--you may like something I don't.

A new commuter frame I bought recently very nearly achieves the ideal for me. It has a massive head tube and feels like it will roll over anything. When cornering, bumps don't disturb it. The bottom bracket feels like it came from a Mack truck. My feet move only up and down, even when standing on that 12% cobbled climb on the way to work. The power transfer feels so efficient it's like the bike is pedaling for me. Yet, it's supple enough over most bumps that I compare the ride to both my titanium and steel bikes. Incredibly, it's aluminum and cost only $136 for the frame-only.

EDIT: I don't have a good single place to refer you regarding frame stiffness/compliance. But a recent thread in the Wheels and Tires section linked to a great piece about wheel stiffness. Debunking Wheel Stiffness - Slowtwitch.com
 

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Burnum Upus Quadricepus
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Personally, there are two things i like to reduce while riding.
Vibrations and the input of wind.
From this and other posts of yours I've read, you seem to be a beginning rider. If I'm off base with this, lemme know.

It's easy get caught up in all the marketing and apparent contradictions in cycling.

With regard to aero, the single biggest piece--where the largest and easiest gains can be made--is with the rider. Don't worry about how aero a bike is until after you've learned how to make yourself as aero as possible.

Shaving a quarter-watt off the frame means schidt when your position accounts for 100 watts or more. If you're not already riding down in the drops with a flat-back, head down, shoulders, arms, and legs tucked-in, then an aero frame is just something to extract a little more money from your wallet.

Aero bikes aren't designed for ordinary folk to deal with headwinds better. They're are aimed at stage racers, who are going all out over 200km (125 miles) a day. A little tiny bit means a few seconds at the end of the day.

For most folks, what's a few seconds on an all day ride? Over the course of a day, I could save precious seconds at pee breaks if I let my urologist ream out my prostate. And frankly, improvements to my motor would get me minutes, a half-hour, or even an hour. So I don't concern myself with the seconds an aero frame would save.

Time-trial and triathlon is another story, of course. But keep in mind that those disciplines are time and distance limited. So you can afford to be uncomfortable for a short time.

If headwinds are your trouble, my advice is to first work on optimizing your position, and optimizing your power output. Maybe even try (gasp) aerobars. Save the aero frame for after you've fixed the big stuff. IMHO.
 

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Vibrations and the input of wind. Anyone who can teach a bit about the stiffness vs comfort?
Try one of these with a fairing and wide tires. Comfy, fast, and no wind issues. Less radical - a more aero riding position and wide, low pressure tires (say, 28-32mm wide at 65-85 psi) will do more than anything else to reduce vibrations and the input of wind.
 

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Try one of these with a fairing and wide tires. Comfy, fast, and no wind issues. Less radical - a more aero riding position and wide, low pressure tires (say, 28-32mm wide at 65-85 psi) will do more than anything else to reduce vibrations and the input of wind.
All that thing needs is a handlebar mount for the TV.
 

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What most people seem to forget is that the rider himself is the most non "aero" part of the bike/rider equation. I would work on my position and posture first, make sure to get as low as your core fitness and lower back will allow and then worry about making the bike "aero", and even then I think the whole aero bike thing is pretty much useless to all but racers and pro riders.
 

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I have limited experience, but here goes.

I have only noticed a difference in "stiffness" when I went from a fairly inexpensive steel frame bike to a Cannondale CAAD7 about 8 years ago. The stiffness I felt was simply that I felt a direct power transfer from my pedals to straight ahead motion on the bike. The first time I rode the Cannondale, I felt like it was leaping forward.

I didn't feel a similar difference when I switched to my CF Felt Z frame a couple of years ago. Probably because both are considered pretty stiff and besides that, I'm old, slow and weak and don't tax the stiffness of any bike too much.

As far as comfort - both bikes (the CAAD and the Z) are far and away - night and day, whatever - more comfortable than the less stiff steel bike of old. Why? In order of importance for me:

Better fit - position of the body over the pedals, reach and drop to handlebars, etc. Makes a huge difference.
Finding a saddle I like - huge difference (and it's not padding, it's shape... padding can make a saddle more uncomfortable! I prefer very little)
Good quality tires and/ or larger tires and/or using the correct (usually lower) tire pressure
Figuring out which shorts/bibs and gloves are best for me
Figuring out which handlebar shape is best for me and my shifters.

None of the comfort factors - in my experience - have anything to do with the "stiffness" of the frame, but are totally dependent on fit, tires and contact points (saddle, bars, shorts, gloves)
 

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Discussion Starter · #13 · (Edited)
From this and other posts of yours I've read, you seem to be a beginning rider. If I'm off base with this, lemme know.

It's easy get caught up in all the marketing and apparent contradictions in cycling.

With regard to aero, the single biggest piece--where the largest and easiest gains can be made--is with the rider. Don't worry about how aero a bike is until after you've learned how to make yourself as aero as possible.

Shaving a quarter-watt off the frame means schidt when your position accounts for 100 watts or more. If you're not already riding down in the drops with a flat-back, head down, shoulders, arms, and legs tucked-in, then an aero frame is just something to extract a little more money from your wallet.

Aero bikes aren't designed for ordinary folk to deal with headwinds better. They're are aimed at stage racers, who are going all out over 200km (125 miles) a day. A little tiny bit means a few seconds at the end of the day.

For most folks, what's a few seconds on an all day ride? Over the course of a day, I could save precious seconds at pee breaks if I let my urologist ream out my prostate. And frankly, improvements to my motor would get me minutes, a half-hour, or even an hour. So I don't concern myself with the seconds an aero frame would save.

Time-trial and triathlon is another story, of course. But keep in mind that those disciplines are time and distance limited. So you can afford to be uncomfortable for a short time.

If headwinds are your trouble, my advice is to first work on optimizing your position, and optimizing your power output. Maybe even try (gasp) aerobars. Save the aero frame for after you've fixed the big stuff. IMHO.
It's a nice answer you've laid out here (both of them!) Yes, for sure you are correct. I biked more when i was younger (Stiff steel-frame MTB). I bought a hybrid last year which i pretty fast dismissed as although being nice, was likely the wrong bike for my intents. What first made me drool was the release of Foil. So i went back and bought a Foil 30. Even though financially this was tough, i bought it (i've had many expensive hobbies of which i have loans on still. High end stereo devices and motorcycles). As mentioned, i noticed i picked up many vibrations through handlebar, even with gel gloves. I started off buying a set of (stem, handlebar wrapped with Lizzard skins DSP) to void this as far as possible. PZ racing CR 3.1, two stems and a handlebar. I also went searching for a wheelset i figured was somewhat faster (Fulcrum Red Wind XLR).
Trying to better FD using Rival, i was looking at new Red. My head turned and twist a few times and i ended up buying DA-9000. Sick as i am i am still drooling over Mad fiber clinchers. Ofcourse i contemplate the dreams of a second bike.
I can't honestly answer why i feel head over heels in love with aero. Was it the look of aggro and fast!? I really don't know. But i know in my heart and mind, being brutalized and beaten up while riding, is not what i really get kicks out of. I have a rather awkward position i have sensed. Most frames i am recommended talking pure size, is feeling to laid out for me (to large). I feel more at home with a pretty sharp dip, as long as it won't force my neck too much. I also have a tendency to pull my body closer to the handlebar. This i noticed while riding motorcycles also. Too much stretch make me sore and tired in the back. This is very helpful, what you wrote me. If ideas come up, you are more than welcome to PM me. Very much thank you.
 
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