Dissapointed...

[bonj2]

Errrr... the frame of a bike is indeed a moving part, sorry but it is

only in the sense that it moves relative to the road along with the rest of the bike when you pedal forwards.

 

[bonj2]

Theres a very good reason that no-one gas ever made a spring out of aluminum. If subject to flex aluminum will suffer from fatigue and fail. The tubes of Alu frames are of a greater diameter than those of steel in order to minimise the possibility of fatigue through flexing (doubling the diameter of a tube quadruples its stiffness). Its widely known that steel and Ti frames are more flexible than Alu or resin composite frames, anyone who has ridden a Reynolds 531st frame loaded with panniers into a fast corner will tell you how sketchy a whippy steel frame can be.

But they don't have to increase the diameter by enough to make it heavier than it would be if it was steel.
Steel was what they used to make bikes out of in the sixties. Then improvements in welding techniques and methods of extruding came along, and manufacturers learnt how to build frames out of aluminium. They were lighter, but with no discernible disadvantage*, which is why most bikes today are made of aluminium.

*other than not being able to be made at rock-bottom price, which is why the very cheapest of the halfords apollo/shockwave bikes tend to be steel.

Traditionalists like steel framed bikes because they like traditional things, and they like to wander around saying 'eeeeh, thi' dawnt mek 'em laaahk thi' yoooused ter!'. A certain minority of these traditionalists like to confuse people by pretending there is actually a tangible advantage to steel framed bikes, but a lot of people (not enough, mind) can see through the reasons why they make these claims. I am, unfortunately for your argument, one of those people.

Oh, and I'm sorry, but anybody that claims they "can feel their bike flex" when going round a corner really is talking out of their rectum, I'm afraid.

 

[mickle]

The concept of materials elasticity is lost on you methinks.

1960s Generic ladies steel frame.
1980s Alan, skinny tubed, lugged aluminum.
2000s Cannondale, fat tubed, welded aluminum.

You would appear to be suggesting that there would be no measureable differences in the flexibility under load of the aforementioned frame designs.

 

[Jacomus-rides-Gen]

I must disagree with you here bonj, I have a steel frame roadbike and an alu/carbon framed roadbike, I also have a steel fram mtb and had an alu mtb for a while too.

The steel framed roadbike does give a softer, almost spongy ride, and leaning into fast corners on it really makes you aware of the frame flexing underneath the rider.

My alu/carbon roadbike has carbon forks, alu main triangle, alu chainstays and carbon seatstays. The difference is amazing, immidiately the whole bike feels tighter and more responsive. Cornering fast, leant right over is a totally different feeling, with the bike responding to bumps in the road in a more twitchy, but less destabilizing way.

I did notice the distance between my regular steel mtb and the alu one I had before some to$$er reversed into the bike stands it was parked in The alu framed bike was more twitchy and tight feeling than the steel. On road it was pretty hard to tell the difference between the two, other than I preferred my steel frame.

If you don't have a roadbike, it is very hard to see what people mean by feeling the frame flex, as mtb's just can't be used in the same way.

 

[peejay78]

sorry just revisited this thread, i didn't realise the bonj had been here.

really, some interesting comments - especially the 'flame' response to my 'rhythm and pacing' observation.


pj:"absolutely - i'm much more aware of pacing and rhythm when riding fixed up hills. i try and maintain a cadence and smooth pedal motion. it's a lot of effort, but it's good effort.
bonj:
Gobbledegook. "Pacing" and "rhythm" are complete mumbo jumbo terms whose place is in fashionable london tea-room/cafe chat, not in technical discussion."

normally i wouldn't respond to you, bonj, but in this case you're so far wide of the mark it's almost funny.

why are you trolling? these are silly comments, ignorant and aggressive. typical male internet forum lurker flaming. i don't mind your opinion, but you're just being rude and obnoxious, and being obnoxious is not, the last time i checked, a nice attribute. feel free to continue in this vein, as per usual, but be aware that you are being unpleasant.

and for the love of god, please please work out the difference between subjectivity and objectivity before you deploy any more of your 'advice'.

 

[mickle]

I dont have a problem with people not knowing something, theres certainly a lot that I dont know about all kinds of stuff, but I do find it extraordinary that someone who is so utterly ignorant of the facts can write with such utter conviction and closed-minded arrogance. More to the point, you casually accuse people of invention when their experience of the world exceeds your rather limited world view.

I hereby abandon this thread in the hope that someone else with more patience picks up the challenge of educating muppet features here about materials technology.

 

[Zoiders]

only in the sense that it moves relative to the road along with the rest of the bike when you pedal forwards.

Not true

Point map a frame, film it as it is being ridden and you would see those points move into relationship to one another, the frame will flex, it will move

There is no such thing as a 100 percent rigid structure, even steel framed sky scrapers flex, if they did not they would break

 

[bonj2]

I must disagree with you here bonj, I have a steel frame roadbike and an alu/carbon framed roadbike, I also have a steel fram mtb and had an alu mtb for a while too.

The steel framed roadbike does give a softer, almost spongy ride, and leaning into fast corners on it really makes you aware of the frame flexing underneath the rider.

so what actual sensation do you get that "makes you aware of the frame flexing underneath you"?
Is it like, when you steer round a corner it 'bends' left to right, and when you exit the corner it bends back
By how many millimetres does it 'bend'? Can you make it flex by this amount with your hands when you're off the bike and it's stationary?

If you don't have a roadbike, it is very hard to see what people mean by feeling the frame flex, as mtb's just can't be used in the same way.

I have got a road bike, which is aluminium. It doesn't flex. But I also have ridden a steel road bike, but at no point when riding it did I notice any phenomenon that I would have described as it "flexing".

 

[bonj2]

I hereby abandon this thread in the hope that someone else with more patience picks up the challenge of educating muppet features here about materials technology. knowledge that I am wrong.

hmmmm... doesn't surprise me.

 

[Zoiders]

Ever heard your chain set rub your front mech when you are giving it some welly out of the saddle?

Thats the frame flexing under power

 

[bonj2]

sorry just revisited this thread, i didn't realise the bonj had been here.

really, some interesting comments - especially the 'flame' response to my 'rhythm and pacing' observation.


pj:"absolutely - i'm much more aware of pacing and rhythm when riding fixed up hills. i try and maintain a cadence and smooth pedal motion. it's a lot of effort, but it's good effort.
bonj:
Gobbledegook. "Pacing" and "rhythm" are complete mumbo jumbo terms whose place is in fashionable london tea-room/cafe chat, not in technical discussion."

normally i wouldn't respond to you, bonj, but in this case you're so far wide of the mark it's almost funny.

why are you trolling? these are silly comments, ignorant and aggressive. typical male internet forum lurker flaming. i don't mind your opinion, but you're just being rude and obnoxious, and being obnoxious is not, the last time i checked, a nice attribute. feel free to continue in this vein, as per usual, but be aware that you are being unpleasant.

and for the love of god, please please work out the difference between subjectivity and objectivity before you deploy any more of your 'advice'.

in other words, you know I'm right. If you like fixed bikes that much, why do you feel the need to make up imaginary benefits of them? (That you can't explain?) If you think they're tangible benefits, then explain what you actually mean by 'rhythm' and 'pacing'.
I'm not trolling, i'm not trying to be unpleasant and i'm sorry if i've offended you - I didn't mean to. If I have, then please just politely say, 'sorry bonj, i'm offended by this thread, and i'm therefore stepping out of it.' and then actually do. But don't go saying 'you're offensive, for starters, but while i'm at it i'm also going to try and say you're wrong because of x, y and z.' because it's only natural that I should then respond to x, y and z.
Like i say i'm not trolling and i never intend to deliberately cause offence. I just have quite a passionate desire to learn what people actually see in the whole weird/old bike thing but mixed with a certain cynical desire to shatter the myths they put forward as their reasoning for liking them. For instance, i don't understand why people are embarrassed to admit they only like some things purely because they're fashionable? I don't see anything wrong with fashion. A perfect example was recumbents, it took quite a bit of ranting and cynicism from me before people could actually be bothered to explain in layman's terms what the advantage of them was and just why they weren't mainstream, and I had to wade through an awful lot of "but you just haven't seen the light bonj" type responses before I actually got any sense.

 

[bonj2]

Not true

Point map a frame, film it as it is being ridden and you would see those points move into relationship to one another, the frame will flex, it will move

There is no such thing as a 100 percent rigid structure, even steel framed sky scrapers flex, if they did not they would break

yeah but insignificant flex, that you can't feel, isn't what we're talking about. Course everything flexes. But enough to notice?

 

[Zoiders]

Bonj

You are being a bit of tool, we are only trying to point out that frames do flex and that you can tell the difference between them, we are not gushing about steel being this and that though

We are just pointing out that they do differ

 

[Jacomus-rides-Gen]

so what actual sensation do you get that "makes you aware of the frame flexing underneath you"?
Is it like, when you steer round a corner it 'bends' left to right, and when you exit the corner it bends back

Quite a challenge you have set there bonj *scratches head* I'll do my best to describe it.

Ok, here is the situation: Leaning into a LH corner at the bottom of a hill that I use a fair few times a week, entry speed is about 32mph. The road is fairly smooth, and it doesn't require braking, but you do need to lean in with full commitment. Just past the apex there are a couple of small "whoops" or smooth ridges in the tarmac.

On the steel roadbike - When I hit the ridges it feels as if the front wheel is being forced forward, and backwards lengthening and shortening the wheelbase but without shaking the bars side to side. I am aware of my outside foot, which is weighting the pedal in the 6'o'cock position, wobbling/flexing out and in again at 90 degrees to the direction of travel.

I guess the best word to describe the feeling is that the bike "wallows" in the corner.

On the alu/carbon roadbike - Hitting the same bumps, but a little faster than on the steeley, I don't experience the same wallowing feeling. This bike shakes its bars more and the frame almost jumps hitting the bumps. Its not actually jumping, but it is more of a shock *bump* that shoots through the frame rather than a more protracted *whump* that shivers through the steel frame.

So hard to put into words!! Thats my best effort

By how many millimetres does it 'bend'? Can you make it flex by this amount with your hands when you're off the bike and it's stationary?

"Quite a lot" would be my answer to this. The only way that I can think of testing this is the old classic to test the ridgidity around the BB. Sit on the bike and apply both brakes. Put power through a pedal at around the 3'o'clock position for maximum power. Look down at the BB as you do this and you will notice it flex, and flex back when you release the pressure on the pedal.

This isn't a very accurate measure by a long shot, but it will give you an idea of relative flex, my steeley flexes significantly more than my alu.

I have got a road bike, which is aluminium. It doesn't flex. But I also have ridden a steel road bike, but at no point when riding it did I notice any phenomenon that I would have described as it "flexing".

Apologies, I thought you were mtb only

Your alu framed roadbike will flex, just not as much as a steel frame would.

I think that I find the difference between the two bikes very noticable because I spend a lot of time in the saddle of both of them, and do cover the same roads close to home on both of them.

For riding predictably my steele bike wins, the flex of the frame soaks up bumps and imperfections better than my alu bike. But when it comes to which bike is better to make progress on the Alu frame wins, it is so taut and responsive, and I know what the tyres are doing with much more clarity.

 

[domtyler]

I dont have a problem with people not knowing something, theres certainly a lot that I dont know about all kinds of stuff, but I do find it extraordinary that someone who is so utterly ignorant of the facts can write with such utter conviction and closed-minded arrogance. More to the point, you casually accuse people of invention when their experience of the world exceeds your rather limited world view.

I hereby abandon this thread in the hope that someone else with more patience picks up the challenge of educating muppet features here about materials technology.

I think you'll find this is roast beef and yorkshire pudding, with homemade apple crumble and custard afters to our friend bonj, I can see him rubbing his hands with glee!