Author Topic: Bike Design  (Read 4817 times)

Re: Bike Design
« Reply #25 on: February 28, 2018, 09:45:02 am »
Looking back on 50 years of riding I would say that the improvements that made a difference  to safety are lights, brakes, rim materials and so  forth.

Bike design and geometry are another factor.  In my view , a safer bike  would be  a tourer , roadster, Raleigh 20 or a 1st generation MTB.
But the industry often only offers  the new cyclist  a Porsche when  what the person  need a Morris Minor
Very true - but if you go to a 'cycling' city like York, you see a lot of cargo bikes, trailers etc (not so many Helios, although I've seen one around). These are all good designs.

I think maybe good hub gears and hub brakes that work in all weathers should be added to the list. Although these existed in days of yore, weight has come down a lot and power of brakes has gone up.
<i>Marmite slave</i>

Karla

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    • Lost Byway - around the world by bike
Re: Bike Design
« Reply #26 on: February 28, 2018, 11:57:19 am »
Bike design and geometry are another factor.  In my view , a safer bike  would be  a tourer , roadster, Raleigh 20 or a 1st generation MTB.
But the industry often only offers  the new cyclist  a Porsche when  what the person  need a Morris Minor

Wouldn't it be nice if everyone rode an old boring person's bike, eh?  That way they might become old boring people faster.

Re: Bike Design
« Reply #27 on: February 28, 2018, 12:06:45 pm »
Try riding a bike with rod brakes (and chromed rims) in the wet. Just don't go anywhere where you actually need to stop in less than 20 yards. Or go downhill!

IMO modern bicycles are fundamentally pretty safe. It's all the traffic around them that is the problem.

Re: Bike Design
« Reply #28 on: March 04, 2018, 08:55:45 pm »
I agree most bikes don't break catastrophically that often, and certainly not ones you pay a decent amount for. Structurally not much goes wrong.

The only thing we've ever known in our lifetime is the DF. Perhaps we should know more about it?
Cruzbike V2k

Re: Bike Design
« Reply #29 on: March 05, 2018, 01:01:56 pm »
The only thing we've ever known in our lifetime is the DF. Perhaps we should know more about it?
Eh?
This from a person with a reference to a Cuzbike in their sigline?

One of the great manufacturing successes in the UK is the Brompton. That isn't a diamond frame. It is much imitated.

DF is hardly 'the only thing we've ever known'.

I'd agree there are very limited variations in riding position, but that is a function of the shape of the human body.
<i>Marmite slave</i>

Re: Bike Design
« Reply #30 on: March 07, 2018, 05:41:04 pm »
The only useful way of improving safety is by increasing everybody's sense of self-preservation. While all the improvements to vehicle and environment work to reduce awareness of danger and the sense of self-preservation that goes with it, the benefits of the improvements will never add up to reasonable expectations of reducing accidents. The only difficulty is how one convinces well-sheltered car drivers that their lives are at risk (perhaps the best advance in road safety will be achieved by compulsary arms and weapons training for cyclists).

Socks

  • FFCT rally, France 2012
Re: Bike Design
« Reply #31 on: March 07, 2018, 07:32:13 pm »
The only useful way of improving safety is by increasing everybody's sense of self-preservation. While all the improvements to vehicle and environment work to reduce awareness of danger and the sense of self-preservation that goes with it, the benefits of the improvements will never add up to reasonable expectations of reducing accidents.

Seems to me that we're better off than we've ever been in relation to bike design and options:

- plastic (sorry - carbon) frames and standard components at very reasonable prices
- good quality folding bikes such as Bromton, Dahon etc
- off-road options
- recumbent bikes and trikes
- electric assist

So why aren't more people cycling .....

zigzag

  • unfuckwithable
Re: Bike Design
« Reply #32 on: March 07, 2018, 08:10:03 pm »
the guys in the video talk about recumbents as if they are better and safer than df bikes in all scenarios. it's not as simple as that - df bikes are more manouvrable, easier to handle (especially on loose surfaces), safer in city traffic as you can stand up and see over the roofs of most cars, safer because the legs and pedals which can be covered in reflective gear is very eye-catching at night (not the case on recumbents). also - one big safety feature of df bikes is the ability to bunny hop obstacles and holes on the road; i'd have wrecked several recumbents that way throughout my cycling career.
regarding riding in a group - imagine there is a pile-up in a recumbent peloton. what's the probability of following rider's chainrings/pedals/cranks hitting the front rider's head or shoulders at full force causing serious injuries?
i can see the advantages of recumbents too, but they are too specific and niche to become widely accepted as a mode of transport and included in cycling sport.

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Bike Design
« Reply #33 on: March 07, 2018, 09:39:46 pm »
It does all read like yet another recumbentist superiority complex.  That's hardly surprising though.

Mr Larrington

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Re: Bike Design
« Reply #34 on: March 08, 2018, 11:52:10 am »
Not much you can do about recumbent cranks but AFAIK all recumbent race organisers have mandated chainring guards on unfaired machines with the cranks out front for a couple of decades now. Probably prompted by Axel Fehlau getting a chainring in his ear during the crits at the 1993 Europeans.  He got back on and deprived me of a place in the final with a spot of last-corner insanity, the git.
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Kim

  • Timelord
Re: Bike Design
« Reply #35 on: March 08, 2018, 01:33:45 pm »
I've got a leg that suggests chainring guard technology has room for improvement...
Careful, Kim. Your sarcasm's showing...

Re: Bike Design
« Reply #36 on: March 10, 2018, 01:12:03 pm »

I'd agree there are very limited variations in riding position, but that is a function of the shape of the human body.

You forgot Moulton, also banned by UCI, but still the same riding position.

And that function is your assumption. Always* like this, therefore like this always.

* Not really.
Cruzbike V2k

Re: Bike Design
« Reply #37 on: March 10, 2018, 01:39:26 pm »

I'd agree there are very limited variations in riding position, but that is a function of the shape of the human body.

You forgot Moulton, also banned by UCI, but still the same riding position.

And that function is your assumption. Always* like this, therefore like this always.

* Not really.
Then you invent some more (practical) riding positions.

It was *you* that said
Quote
The only thing we've ever known in our lifetime is the DF.
Now you are mentioning Moultons? Don't they kind of prove my point, that there are alternatives to the DF?
<i>Marmite slave</i>

Re: Bike Design
« Reply #38 on: March 11, 2018, 12:15:39 pm »
I think you've rather missed the point.  I think we can take DF as shorthand for upright position in all its forms. This is about the normative riding position, and what we know about it. You've provided useful scrutiny all the same, since this was in danger of becoming about recumbent vs upright, and that's not the point at all.

If we go back to what was originally posited, is it worthwhile scientifically investigating the benefits and consequences of being upright? And once we know a bit more, what do we do with that information? Is the general confirmation bias too strong?
Cruzbike V2k

Kim

  • Timelord
Re: Bike Design
« Reply #39 on: March 11, 2018, 01:02:12 pm »
I think you've rather missed the point.  I think we can take DF as shorthand for upright position in all its forms. This is about the normative riding position, and what we know about it.

I thought it was about safety aspects of bike design?  I'd suggest that there may well be safety differences between a DF, a step-through frame and a small-wheeled bike with the same upright riding position, and that that there may well be safety differences between different kinds of recumbents with the same riding position.

Given that riding position tends to be dictated by what the bike's being used for, (being able to see where you're going, ease of starting/stopping, aerodynamic efficiency, ability to shift your bodyweight around, that sort of thing), it's the decisions that come after that (eg. what type of handlebars, braking systems, how exposed the transmission is) that have the most scope for being influenced by safety.

If safety were the only concern, we'd all be riding tadpole trikes.
Careful, Kim. Your sarcasm's showing...

Re: Bike Design
« Reply #40 on: March 11, 2018, 01:32:18 pm »
If safety were the only concern, we'd all be riding recumbent tadpole trikes.
FTFY

Re: Bike Design
« Reply #41 on: March 11, 2018, 01:39:30 pm »
I think you've rather missed the point.  I think we can take DF as shorthand for upright position in all its forms. This is about the normative riding position, and what we know about it.

I thought it was about safety aspects of bike design?  I'd suggest that there may well be safety differences between a DF, a step-through frame and a small-wheeled bike with the same upright riding position, and that that there may well be safety differences between different kinds of recumbents with the same riding position.

Given that riding position tends to be dictated by what the bike's being used for, (being able to see where you're going, ease of starting/stopping, aerodynamic efficiency, ability to shift your bodyweight around, that sort of thing), it's the decisions that come after that (eg. what type of handlebars, braking systems, how exposed the transmission is) that have the most scope for being influenced by safety.

If safety were the only concern, we'd all be riding tadpole trikes.
Quite

It is somewhat ridiculous to say that "all upright riding positions are the same".

Riding down on tri bars on a very low time-trial bike is very very different from riding a sit-up city bike, to take two extremes. I would not like to ride the city bike down a mountain col, give me a race bike for that, please (and I'm talking from a position of safety here, not about riding faster).

If we assume poor road surfaces, then that has to be considered in bike design. Small wheels do not cope as well as large wheels when riding through deep potholes. Are we discussing riding in heavy traffic?

Choose the bike for the circumstances.
<i>Marmite slave</i>

Kim

  • Timelord
Re: Bike Design
« Reply #42 on: March 11, 2018, 02:07:04 pm »
Riding down on tri bars on a very low time-trial bike is very very different from riding a sit-up city bike, to take two extremes. I would not like to ride the city bike down a mountain col, give me a race bike for that, please (and I'm talking from a position of safety here, not about riding faster).

If we're playing that game I think I'd prefer the upright city bike, assuming it was a decently made German-style one with proper brakes.  The about-to-land-on-your-face factor of DF racing bikes is terrifying downhill, as are rigid bikes with skinny tyres.  The more speed you can shed through aerodynamic drag the less braking you have to do.

Obviously a recumbent is even better.  Something like a HPVelotechnik Speedmachine would probably be about right.  No fear of road surfaces, all the braking you could wish for, and the ability to go round corners[1] at speed, which the city bike may be lacking in.

OTOH, I know which I'd rather ride *up* the col...


Quote
If we assume poor road surfaces, then that has to be considered in bike design. Small wheels do not cope as well as large wheels when riding through deep potholes.

Quite.  Small wheels are strong and light, but shit at potholes.  Skinny tyres are a liability on bad surfaces.  If the riding position involves either sitting bolt-upright on a saddle or lying in a recumbent seat, you benefit from rear suspension.  If it involves bearing weight on your wrists, you benefit from front suspension.  But then you're adding weight, and unless handled with tranquillity, suspension can waste energy at the drivetrain.  How important is efficiency?  This stuff is the bread and butter of bike specification, particularly recumbents, where people are less committed to a few standard designs.



[1] I can generally descend faster on my Streetmachine (an overengineered heavy tourer with wide tyres and suspension) than on my Baron (a skinny-tyred low-racer), simply because in the real world resilience to crappy road surfaces is usually more important than coefficient of drag.  The exception is when it's not a straight line; the Streetmachine is designed for stability, and is rubbish at high-speed cornering.
Careful, Kim. Your sarcasm's showing...

Re: Bike Design
« Reply #43 on: March 11, 2018, 05:47:58 pm »
Riding down on tri bars on a very low time-trial bike is very very different from riding a sit-up city bike, to take two extremes. I would not like to ride the city bike down a mountain col, give me a race bike for that, please (and I'm talking from a position of safety here, not about riding faster).

If we're playing that game I think I'd prefer the upright city bike, assuming it was a decently made German-style one with proper brakes.
I've had Shimano roller brakes fade and fail from overheating - a good pair of DPs are more reliable in that situation. The city bike won't be great once speed gets up and high speed shimmy when there are sheer drops next to the road would be bloody terrifying. Had that happen first time I took a Gazelle town bike off to the North York Moors. Never again.

It just highlights that it is best to pick the bike designed for the riding style, skill of the rider and conditions. Danny Macaskill can take a road bike offroad and off jumps, but normal mortals would be better off will a full-on sus downhill mtb
<i>Marmite slave</i>

Kim

  • Timelord
Re: Bike Design
« Reply #44 on: March 11, 2018, 06:05:16 pm »
Riding down on tri bars on a very low time-trial bike is very very different from riding a sit-up city bike, to take two extremes. I would not like to ride the city bike down a mountain col, give me a race bike for that, please (and I'm talking from a position of safety here, not about riding faster).

If we're playing that game I think I'd prefer the upright city bike, assuming it was a decently made German-style one with proper brakes.

I've had Shimano roller brakes fade and fail from overheating - a good pair of DPs are more reliable in that situation.

I was thinking Magura HS11s or something, rather than roller brakes.  Germans fit them because they're cheap and low-maintenance, but they're also surprisingly good at braking.


Quote
The city bike won't be great once speed gets up and high speed shimmy when there are sheer drops next to the road would be bloody terrifying. Had that happen first time I took a Gazelle town bike off to the North York Moors. Never again.

That's a fair point, while I've done short-and-steep I don't think I've ridden one at speeds in excess of 25mph.  On the gripping hand, if you only care about safety then you want to descend at low speed, and the really important thing is brakes that can dissipate all that heat.  At which point the tadpole recumbent trike starts to look like a good idea again (they're mostly contraindicated by high-speed cornering).


Quote
It just highlights that it is best to pick the bike designed for the riding style, skill of the rider and conditions. Danny Macaskill can take a road bike offroad and off jumps, but normal mortals would be better off will a full-on sus downhill mtb

Quite.  The best answer is always n+1.
Careful, Kim. Your sarcasm's showing...

Mr Larrington

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Re: Bike Design
« Reply #45 on: March 12, 2018, 06:46:22 pm »
Chap I know once told me he melted the brake lines on a set of Magura rim brakes, albeit under slightly unusual circumstances, viz. trying to hold a fully-faired recumbent bike down to the speed limit descending from San Bernardino towards the Salton Sea.
External Transparent Wall Inspection Operative & Mayor of Mortagne-au-Perche
Satisfying the Bloodlust of the Masses in Peacetime

Re: Bike Design
« Reply #46 on: March 12, 2018, 08:35:18 pm »
I think you've rather missed the point.  I think we can take DF as shorthand for upright position in all its forms. This is about the normative riding position, and what we know about it. You've provided useful scrutiny all the same, since this was in danger of becoming about recumbent vs upright, and that's not the point at all.

If we go back to what was originally posited, is it worthwhile scientifically investigating the benefits and consequences of being upright? And once we know a bit more, what do we do with that information? Is the general confirmation bias too strong?

I think the first thing to investigate is what part bike design actually plays in contributing to accident risk or accident avoidance. I would suspect that it actually plays a very small, even insignificant, part in the cause of accidents. Other factors, such as roaduser education and infrastructure architecture will play a far greater part and rider "clothing" will play a great part in the level of injury resulting from accidents.
This is not to say that mechanical condition doesn't play its part and ease of maintenance aspects of bike design might make a positive contribution to rider safety (so might regular bike MoTs but that's another story)

Kim

  • Timelord
Re: Bike Design
« Reply #47 on: March 12, 2018, 08:38:16 pm »
If that paper on single-vehicle bicycle accidents I read a while back was anything to go by, a substantial safety improvement could be made by fitting them with proper racks and panniers.
Careful, Kim. Your sarcasm's showing...

Re: Bike Design
« Reply #48 on: March 13, 2018, 01:13:13 pm »
If that paper on single-vehicle bicycle accidents I read a while back was anything to go by, a substantial safety improvement could be made by fitting them with proper racks and panniers.
Handbags and shopping bags tangling in front wheels?
<i>Marmite slave</i>

Re: Bike Design
« Reply #49 on: March 13, 2018, 09:40:59 pm »
https://www.fastcompany.com/3044557/designed-with-a-roll-cage-this-bicycle-can-survive-a-crash-with-a-semi
Potentially a bit of a Dramatic Event fallacy, but an interesting experiment. Does one belt into that bike instead of hoping to separate? But at least it's the first one I've seen to even model the failure, or 'off', modes for the safety of the rider.


And now for something completely different.
http://birdofpreybicycles.ning.com/
Still can't make up my mind if it's genius or somthing else. If you're tipped out the side of it, much harder to keep head and chin off the deck, but that's only what I think.
Cruzbike V2k