mountaindave 

IIANM, mode 2 frame vibration would explain why Jan has found that a stiff rear triangle and a DT stiffer than the TT reduces shimmy.

Grand Bois

Seriously?

Kevindale

This might be an example of the kinds of assumptions/conclusions that cloud the issues being discussed here. Or maybe it's totally unrelated confusion. In any event, cheetahs aren't fast because of the elastic energy stored in the flexing spine. A cat's flexible spine is not at all like a spring, and can't store any energy. At rest, the cheetah can curl itself into a very tight ball and go to sleep. If the compressed spine were storing energy, this would be impossible. The cheetah is fast (in part) because it's flexible spine allows it to have an incredibly long stride, over which it's muscles can act. I think in bike terms their spine is like a huge chainring. A huge chainring that requires a very light load to be usable.

There is a huge amount of springiness in the legs of all quadrupeds, both cats, horses, dogs, etc. That's why you can't easily bend your cat or dog's legs in certain directions, especially the rear legs, and why cows can sleep standing up. But that leg springiness is happening in both cats and horses.

Meanwhile, ungulates like horses have to have stiff spines not for endurance (think of cows, which also have stiff spines), but because they're herbivores who eat uncooked grasses which require heavy digestive systems to break down cellulose (those extra stomachs). Their spines are like suspension bridges for their huge bellies. A stiff spine means they can support themselves without wasting energy standing upright.

I suspect a part of the reason a horse can run with good speed for long durations is in part (and to a minor extent) because of the springiness of their spine, as you suggest, but these spines didn't evolve for endurance. There are lots of stiff-spined animals with no running/endurance abilities, and animals (like dogs and wolves) that have moderately flexible spines and tremendous endurance.

Anyway, sorry for the tangential comment, but I thought it somehow relevant.

bulldog1935

If you are going to quote me, I'd rather it be in context - the rest of the post was the important part.
But I'm not the only one who uses the spring analogy.
So I'll get this back on topic.

The harmonic reinforcement of planing is not free energy.
But it's delivery of a little extra energy that we can spare, in a manner that is surprisingly efficient for climbing.
Both the frequency that we're putting in and rate that we're loading it is what the frame is reacting to.
If you're normally spinning at e.g. 62.5 rpm, you won't get this effect. The mash is just as important as the pedal speed.

......................................................................125Hz natural frequency, 2 feet at 62.5 rpm

TimmyT 

Well, you have a lot to quote given the amount of words you use.

FrenchFit 

Yep. Not saying I put a hi-ten fork and chromed steel bars on my Roubaix or Bianchi, but the mass and resonance of hi-ten up front makes for a very plush riding experience. I did swap off the Al bars on one of my Miyatas for a steel drop bar, nice upgrade.

DIMcyclist

To get back to the original subject, I can't say I prefer Hi-Ten overall, but I've noticed it does make a difference in some cases; to wit, my 650b Panasonic. It has an odd (fully lugged) mixed tubeset: DB CroMo main triangle/ Hi-Ten chainstays/ Mangaloy fork & seat stays. The chainstays are the old, bent MTB type; fully 48cm to the back of the dropout, however they're reinforced at the bend with a bracket for mounting either a BB dynamo or a kickstand; so, despite the length of the stays, the rear triangle is surprisingly stiff (no bouncing while going uphill with full panniers), while the DB CroMO keeps the overall weight quite light & yields a responsive, lively ride.

Grand Bois

If you say so.

john hawrylak

I'm not sure weight is the entire answer.
12 lbs of weight = 1 mph slower with the same power input (Schwinn tests).


A lot of 'classic frames' are not High Planers. So the compliance issue is only partially true.


I think the Varisities, et al, had slacker frame angles (more like RBW frames) and this MAY result in a different feeling when riding, compared to the higher "Italian" frame angles.


John Hawrylak
Woodstown NJ

markwesti

Haha this is a good thd. When I was in jr. high school my dad bought me a Schwinn Varsity (my first road bike) my school mate had a Schwinn Continental , he let me ride it . I didn't like my Varsity much after that . My friend Freaky Dave rode a Gios Pro. It was his single mode of transportation , he felt he needed a touring type bike that he could put panniers on so he bought a Trek I don't know which model . He sold the Gios to get the Trek , he cried . In high school I had a entry level Gitane Grand sport , I thought it was pretty nice . A guy I knew, he rode cross country twice on a Colnago informed me it was a POS .

jon c. 

as I was reading this thread, I flipped over to another web page and found sidebar ads for steel tubing. the ad tracking programs seem a bit frightening in their reach.

clubman 

This was my early 60's Supercyle (Raleigh) roadster that I always regretted giving away because it rode sooo nice. Doesn't prove much except that bikes made of all levels of steel can be done right. It was heavy and wasn't fast but I could ride around the city all day without fatigue. It was purpose built.

noglider 

Some designs are better suited to a given task than others. And then there is just personal preference. I love 3-speed upright bikes but not for the way they ride. I don't like sitting up so much and pedaling so slowly. The geometry forces the upright sitting, and the bike in many ways discourages fast pedaling without outright preventing it. Having "grown up" on drop-bar bikes, I just like them better.

BigChief 

There is a physiological component involved. Somewhere in our minds, the experience of fun diverges from what logic would predict. Guitarists call it psychoacoustics. For some mysterious reason, some players find great pleasure playing guitars that break all the rules of what should make a good guitar. I have a drop bar Motobecane with toe straps that I would use if I really wanted to travel any great distance, but for short ride fun, I'll hop on my old, heavy, technically challenged DL-1 everytime. There's nothing rational about it, but the fun is real to me.

bulldog1935

from watching The Great Escape, this has always defined bike for me

mountaindave 

This.

noglider 

I agree, @BigChief.

exmechanic89

I've been surprised how nice both of my cromo main triangle bikes ride, both very good climbers and very stable descenders.

I also believe that a well designed hi-ten frame can outperform a mediocre cromo frame.

But all things being equal, I'd always take a full cromo bike over a hi ten steel, or a mix of the two.

3speedslow

Perfect example Bulldog !

ramzilla

Ishiwata reached perfection in the early 80's with the Fuji Valite bikes. Good, solid, heavy high tension steel alloy bikes. Wonderful to ride. IMHO the best. Be good.

ramzilla

Oh yeah, almost forgot............ Kuwahara also used Ishiwata tubing on their bikes back then. If you can find one buy it. Awesome bikes.

Andy_K 

I was really hoping more people would take up this aspect of the topic.

I've got three bikes now with "tretubi" frames and they all three ride great. I can't seem to get my head wrapped around the metallurgy well enough to understand what difference basic steel stays and forks "should" have or how rider weight plays into that. At some point I had convinced myself that high ends stays and forks "should" be more vertically compliant (given the assumption that whatever low be tubing the tretubi bikes use is thicker).

I was particularly curious as my 1972 Motobecane a Grand Record only uses 531 for the main tubes while later years were full 531. That sounds to me like a decision driven by the marketing department rather than the engineering department.

Grand Bois

T-Mar in a www.bikeforums.net discussion states:

VaLite was reportedly a vanadium steel alloy. It was stronger than hi-tensile but not as strong as chromium molybdenum. It is commonly found on upper entry level and lower mid-range Fuji from the early 1980s. In order to control costs, lower models would often employ Valite main tubes with hi-tensile stays and/or forks, while the better models would often have VaLite forks and/or stays paired with a CrMo main triangle. Forum member Beaverstuff has reported VaLite frame with Ishiwata steerer, so these tubesets appear to have been made by Ishiwata for Fuji.

Kevindale

Sorry, didn't mean to insult you. I wasn't contradicting your main point, only the basis of your animal analogy, so I quoted the relevant parts.

A lot of false 'conventional wisdom,' like the cheetah having a spine that works like a spring, are repeated widely. Doesn't make it true. Likewise, there's a fair amount of bicycling conventional wisdom that is also widely repeated, but which doesn't hold up when examined carefully. I wasn't meaning to contradict the main point you were making, only to say that your animal analogy wasn't meaningful or accurate in this discussion.

bulldog1935

no insult taken - I used an analogy, prefer discussing the on-topic portion of my post, and my reply showed how others use the same analogy - what was being discussed was the stride you feel on a bike
There's a fine line between fastidious and...