Wooden bikes • Hacker News Board

Re: Wooden bikes

#141

Post by mancis » Wed, Nov 21, 2018, 3:32 PM UTC

mymythisisthis wrote: post #70

cuban-frisbee wrote: post #46

I use a bike as my primary transportation (I live in a very, very bike friendly city) and I don't think I have ever seen a wooden bike. Vibrations from the road is not something I've ever considered since it has not been a problem in any of the bikes that I've had. My primary considerations when considering a bike would be: * Price * Durability * Cargo support (like basket and rear hub)

If you do a road trip more than 80km, you feel the vibration. I find aluminum is worse than steel. With short, daily trips, I don't think people notice vibration.

Great bikes! Ordered a frame form Materia bikes nearly 4 years ago. The bike is still in perfect condition and I am really enjoying it. If we are talking about bike stiffness and vibration damping - the front triangle (Top-tube, Bottom-tube, seat-tube) is made from solid wood, that is why I found the ride much smoother compared to my old carbon or aluminium bikes. - the rear triangle (seat-tube, chain-stay, seat-stay) is made from laminated wood so the rear end for the bike it is really stiff and hard, what is good for performance.

Re: Wooden bikes

#142

Post by cultus » Wed, Nov 21, 2018, 3:32 PM UTC

toxik wrote: post #138

cultus wrote: post #137

Earlier quoted context omitted.

Too high pressure actually decreases efficiency. While you have less deformation of the rubber, it causes the bike to bounce over irregularities more. The energy from this bouncing is lost. On rougher roads, often pressures below 90 PSI are best.

Ok, yes, assuming traction isn't lost, stiffer is better -- really, smaller contact area is better, but that translates into stiffness. Then there is heat loss to tire deformation, of course.

Stiffness in a tire is bad. That's why more expensive tires are suppler. Energy lost due to rolling resistance on a paved road is primarily viscous dissipation due to flex of the tire.

If the tire is a stiffer material, this dissipates more energy. In addition, suppler tires deform over obstacles more readily, reducing bouncing and vibration.

More or less, your contact patch is pressure/weight, since the tire can't support much weight on its own. It's going to be almost the same no matter what (slick) tire you are running. Wider tires have less rolling resistance for the same pressure (to a point), since the tire deflects less to maintain the same contact patch. Two tires of the same width, one stiff and one supple, will have to bend in the same way, and have nearly identical contact patches. However, the supple one will dissipate less heat doing this.

Re: Wooden bikes

#143

Post by hwillis » Wed, Nov 21, 2018, 3:32 PM UTC

mr_overalls wrote: post #114

Engineered wood is truly an amazing material. While touring a newly-constructed home a few weeks ago, I saw what appeared to be floor joists constructed out of thin, cheap particle-board. It turns out that they're made of engineered wood, and are actually stronger than an equivalent sawed wood beam. https://imgur.com/a/3AkZblF

Not stronger (or weaker)- lighter, but more importantly MUCH more stable. Fiberboard (web) and plywood (flange) is stronger and heavier than wood of the same dimensions, but the biggest draw is that humidity doesn't make it swell or shrink. Since it's all glued in place, they also don't come with any bend or twist, and you can actually make flat floors without low or high spots.

The light weight means you can ship a huge number on the back of a truck, and they stack more efficiently than 2x8s or 2x10s.

Re: Wooden bikes

#144

Post by Lio » Wed, Nov 21, 2018, 3:35 PM UTC

_Wintermute wrote: post #54

Yetanfou wrote: post #48

Earlier quoted context omitted.

Why call those 23c tyres "cheap"? Why mention price at all? Ride comfort is a function of tyre size, not tyre price. You can buy very "exclusive" expensive 23c tyres, pump them up to 7 atm. and have just as hard a ride as the person who just overtook you on his "cheap" 23c tyres. That "magic carpet" ride does come at a price but it is not monetary: the softer the tyre, the more resistance and with that the slower the…

> That "magic carpet" ride does come at a price but it is not monetary: the softer the tyre, the more resistance and with that the slower the ride. Unless you're riding on a velodrome, pumping your tyres up to 120+psi doesn't decrease rolling resistance, infact the the opposite is true. If the tyre can deform around small bumps it rolls much more easily. This is why very expensive and fast tyres have casings with a h…

Fast Fitness produced a little spreadsheet to calculate optimal pressure based on tyre width, bike+rider weight and a very granular assessment of surface.[1]

Something else to take into account is the aerodynamic trade off as tyre width grows. I think I read somewhere that 25mm is roughly the sweet spot. What you gain in lower rolling resistance by going up to 28mm you loose in drag. That's a bit anecdotal (sorry) but I have heard it mentioned in a couple of places. The best source I could come up with was from Zipp's web site.[2]

Of course that might well be worth it to be more comfortable if it means you can keep your body in a more aero position as that will dwarf any loss from the tyres (again a guess).

Hopefully there's some numbers somewhere to back that up. Maybe Bicycle Quarterly or Tour Magazine might be a good bet for anyone interested.

Also https://www.bicyclerollingresistance.com/ is always very interesting ...assuming you obsess over bike tyres as I'm sure everyone does. :P

[1] https://www.youtube.com/watch?v=Clk_LLBYFzA [2] https://zipp.com/support/faq/faq.php

Re: Wooden bikes

#145

Post by gameswithgo » Wed, Nov 21, 2018, 3:37 PM UTC

dabeeeenster wrote: post #128

cultus wrote: post #125

Earlier quoted context omitted.

The gullibility of cyclists is the industry's most valuable asset. In tests, cyclists cannot tell the difference between frame materials when the frame is covered. I think it is just really seductive to think you can get magically faster by a significant amount just by buying a new frame with that new bottom bracket that's claimed to be 30% stiffer.

Although I generally agree, there are a couple of things that can have a big difference. Most obvious one being proper cycling shoes and cleat peddles. Big efficiency gains there.

People have done power and efficiency tests with cleats vs flats, usually with no difference or minimal difference

One such example: https://www.youtube.com/watch?v=CNedIJBZpgM

Re: Wooden bikes

#146

Post by gameswithgo » Wed, Nov 21, 2018, 3:38 PM UTC

cultus wrote: post #135

dabeeeenster wrote: post #128

Earlier quoted context omitted.

Although I generally agree, there are a couple of things that can have a big difference. Most obvious one being proper cycling shoes and cleat peddles. Big efficiency gains there.

Oh for sure. Indexed shifting, better alloys, for example. There have been some major innovations, but most of what has come out in the last 10 years in road bikes hasn't been great. Lots of new BB standards that all creak, thinner chains, too few spokes, etc.

There are certain spoke counts which have non trivial aerodynamic advantage. But going less than, I think it around 12? has greatly diminishing returns. Zipp had some good data on this years ago.

Re: Wooden bikes

#147

Post by jefftk » Wed, Nov 21, 2018, 3:39 PM UTC

I would expect them to have problems over time with the wood-metal joints, since they respond to heat/humidity changes differently. This is often a problem with musical instruments.

Re: Wooden bikes

#148

Post by gameswithgo » Wed, Nov 21, 2018, 3:41 PM UTC

eitally wrote: post #109

gameswithgo wrote: post #82

The vibration dampening is a red herring. As a point of comparison, the differences in dampening between various frames/materials is on the order of ~1psi of tire pressure normally. In other words, if you found yourself with the harshest of frames, you could drop air pressure by 1 or 2psi and be at the same level as the "smoothest" frame.

But dampening happens differently in different parts of the frame. For example, thinner & curved seat stays vs a suspension fork, or round 853 steel tubing vs highly aero-optimized low profile carbon, or deep dish carbon wheels vs traditional aluminum. Your statement is technically accurate, but that doesn't mean the feel of the ride will be equivalent.

Professional level riders are absolutely certain they can feel the difference between deep carbon wheels vs aluminum when they test them.

Then if you disguise the wheels such that they cannot tell which is which, they are completely unable to discern them.

The same is true with frame types typically believed to be vastly different. A professional triathlete and ex cat 1 road racer I know was sure he could tell the difference between Cervelo's comfort, round tube frame (The R series) and their aerodynamic frame (the S series).

He devised a helmet with an obscuring screen so he could test the two in blind fashion, and he was unable to discern which was which, by riding them.

Its all just nonsense, really, imho. There are dozens of examples like these I've seen through the years. People with high degrees of expertise, certain of these feeling differences, blind them, and they can't tell.

Re: Wooden bikes

#149

Post by specialist » Wed, Nov 21, 2018, 3:41 PM UTC

halbritt wrote: post #136

dsego wrote: post #95

Earlier quoted context omitted.

My 2 cents, steel is better, I've had wrist issues with an aluminum bike that I just don't get with the steel one. It seems to dampen and absorb the high frequency vibrations.

Generally speaking this stiffness is the result of the tube shapes necessary to achieve similar strength and stiffness of a steel frame while weighing less. A perfect example of this is the Cannondale CAD3. It had a massive downtube and huge (straight) seat stays as well. It was extraordinarily stiff and terribly unpleasant to ride, for most. Cannondale improved that to some degree by using S-shaped seat stays on the…

"hydroformed tubes"

https://www.youtube.com/watch?v=4WpGsJKVhZY

Thank you. I kinda always wondered how bike frames were made. This is really cool.

Re: Wooden bikes

#150

Post by gameswithgo » Wed, Nov 21, 2018, 3:43 PM UTC

toxik wrote: post #131

gameswithgo wrote: post #82

The vibration dampening is a red herring. As a point of comparison, the differences in dampening between various frames/materials is on the order of ~1psi of tire pressure normally. In other words, if you found yourself with the harshest of frames, you could drop air pressure by 1 or 2psi and be at the same level as the "smoothest" frame.

While true that tire stiffness is a major player in vibration transfer, it also trades off friction. As we all know, stiffer tires (higher pressure) is faster. I think you're reducing a complicated mechanical system to a few variables; mountain bikes, for example, have dedicated shock absorbers. Granted, they're for much harder impacts, but something similar could be said of high-frequency shocks.

> As we all know, stiffer tires (higher pressure) is faster.

This is not correct. Optimum speed comes are optimum pressure, which is usually quite a bit lower than most cyclists imagine. Going too high results in worse rolling resistance, AND worse handling AND worse comfort.

As a ballpack figure for a road bike, a 25c tire will usually have optimum rolling resistance at around 90-100psi for typical male rider mass and road surfaces.

And the faster, better handling tires also have less rolling resistance, but less durability.