跟读练习: Everything You Didn’t Know About Titanium Bikes - 通过视频学习英语口语

Titanium is a material that many people regard as the best.

But what actually is titanium?

How does it differ from other materials?

And why the hell would you make a bike from it?

To find out more, I'm going to go speak to an expert.

Titanium bikes do feel smoother.

The cost is always high.

What you're really paying for is energy.

Higher density than aluminum, a lower density than steel, higher stiffness than aluminum, lower stiffness than steel.

They last significantly longer, but it's not very strong.

Tom Sturdy is the man behind Sturdy Cycles

and has been making custom titanium bikes since 2014 using a

combination of titanium tubes as well as 3D printed sections and components.

Tom has got qualifications in aerospace engineering and sports biomechanics, which in my mind makes him the perfect person to help answer my questions.

Let's start right the beginning and find out what titanium actually is.

Titanium is an element, it's number 22 on the periodic table.

When you're talking about it being used in bikes, it's very rare that it would be used in its pure form.

You can use pure titanium metal for various things, but more often than not,

when it's used to make something like a bike or anything structural, it will be alloyed with some other elements.

Normally, aluminum and vanadium in different quantities.

To try to change the properties of it.

Why would you not use titanium just by itself?

Pure titanium, and it can be a bit confusing

because a lot of these alloys will have lots of different names and they're all very similar.

It can be confusing.

Pure titanium, titanium, it's got lots of useful characteristics of titanium,

so it doesn't corrode very, very, very slowly.

Essentially, it's corrosion resistant, but it's not very strong.

It'll bend quite easily and fatigue quite easily as well.

In terms of trying to make a bike from titanium, how are we going about doing it?

Is it in tube form?

Is it shaped and then welded together? like give us an explainer on that.

Yeah, so probably the main downside of titanium is

that it's difficult to work with and that kind of means sort of in all different ways of working with metal.

So it's very difficult to change its shape and

that typically is one of the challenges with it

but it will normally be used in tube form

so this is a drawn tube

and then yeah tubes will be cut to length butted up once again against one another

and welded together you can also change its shape in other ways

so yeah for making bikes sometimes it might be cast

or 3d printed and you can get different shapes from it that way.

You can also machine it.

Typically, the alloy that you would use for tubing would be different to the alloy

that you might use for a machined part.

This is like a machined part.

This is a chainring.

You've made this in -house.

This, explain to us how the hell we go from something that looks like this to something that looks like this.

Yes.

This is, that's a raw stock.

Well, it's come out of a big bar and they cut a little slice off it.

So this is a grade of titanium that is better suited to machining.

It's quite high strength, but it'd be very difficult to make tubes from this grade of titanium.

It can be done and some companies do it, but it comes with challenges with the material becoming brittle and that sort of thing.

This is well suited to machining.

In this case, we'll hold this in a CNC machine and gradually remove material until we're left with that.

I guess that's the same principle as what you have with other materials, that there's slightly different versions of it which are tweaked to suit the application.

In terms of looking at that titanium tube, how does something like that compare in its properties compared to like a steel tube or an aluminum tube?

What are the differences, especially if we looked at like for like profiles and shapes?

Yes.

Titanium is, it sits sort of, if we're thinking about the materials that you build bikes from,

titanium sits nicely in the middle in terms of its mechanical properties.

If you were to have the exact same tube and it were made out of aluminium.

The aluminium one would be lighter than this one.

But it'd be very rare that you'd have an aluminium tube with

that thickness because aluminium wouldn't be strong enough in that thickness.

So an aluminium tube would have to be thicker to be stronger?

Thicker, so the actual weight difference

when you are using it in a practical sense would be

less than the theoretical difference in terms of just the density but yeah

so titanium is is has a higher density than than aluminium

a lower density than steel higher stiffness than aluminium lower stiffness than steel strength will vary depending on the alloy

so it sits kind of nicely in the middle of the range of mechanical properties certainly for metals

that would be used to make bikes and

so you can use it to then design and make quite a broad range of types of bike.

You can make stiff bikes, flexible bikes, that sort of thing.

Quite fit in the balance of what you want to achieve.

In terms of looking at overall bikes built up ready to go, what are some of the reasons why somebody might want to

consider maybe a titanium bike over an aluminum one or a steel one or maybe even a carbon one?

There are lots of different considerations.

I think, generally speaking, certainly in the bike industry, different materials tend to have these different assumptions made about it.

So people will often assume that a carbon bike

rides in a particular way or performs in a particular way and the same is true of aluminium, titanium, steel.

So titanium is famously quite comfortable.

It's not really as simple as saying that because you've made a bike out of titanium it will be comfortable.

It'd be very easy to make an uncomfortable titanium bike.

Generally speaking, it will have these kind of sweet spots.

Because of the inherent properties of titanium, and then when you start to make it into a bike, it can tend to produce bikes that are quite comfortable.

There are other reasons.

It's essentially corrosion resistant, so it's not going to rust like a steel bike.

It's not going to easy to look after in the sense that because it doesn't corrode,

you don't need to paint it, so you don't have to worry about scratching paint, that type of thing.

You can ride it all year round, you don't have to worry about riding it.

What about in terms of robustness, actually?

Because when people talk about carbon fiber frames, one thing they say is, oh, you've got to be careful with it.

You don't want to bang it in the wrong ways or it's only strong in certain directions.

How would titanium compare in that sense?

So titanium is, I mean, it's inherently probably more robust in some ways than a composite just

100

because it's a metal and metals are homogeneous so they've kind of got equal strength in all directions.

101

So yeah, it's not like a carbon tube that if you crushed it in the wrong way you might damage it.

102

You could dent titanium if you hit it hard enough, but it's relatively difficult to do that.

103

It's quite tough, but every material has its limit.

104

Generally speaking, titanium has got a really good fatigue life and it is very strong for its weight.

105

Actually in absolute terms, it's very strong as well.

106

It is generally pretty robust, but there's no such thing as something that's - It's not indestructible, is it?

107

I'm sorry that people often say when you're talking about entertaining bikes, it's like, oh, there's that like entertaining buzz that you get.

108

Is that a thing and what on earth, how would you explain that to someone that wouldn't know what to expect?

109

It is to a certain extent, yes.

110

The material property is quite a, for want of a better word, it's quite a springy material.

111

It does tend to respond slightly differently to,

112

for example, the vibrations that you get from riding over a road, that road buzz.

113

That high -frequency stuff.

114

Yes, it will respond differently to other materials just because it has underlying properties.

115

I think as a general rule, titanium bikes do feel smoother to ride than other materials, but it's a little bit,

116

it'd be oversimplifying it to say that any titanium bike will because you can't.

117

It all comes down to the quality of the build, I guess.

118

Yes.

119

In terms of pricing, when you look at, I think, titanium bikes, I think it's fair to say typically you could say you

120

see far more custom titanium bikes than what you do in other materials,

121

but how would you rank a titanium bike and as a material in terms of price compared to other materials?

122

Yes.

123

It's pretty much the main downside of the material from a consumer point of view is

124

that the cost is always high

125

so titanium as a as an element is actually quite abundant there's a lot of it on earth

126

but it is very difficult to get it from its kind of raw or form into a useful

127

material and basically what you're really paying for is energy

128

and energy costs perpetually get higher right

129

and they're never really going to go down

130

so titanium will always be a relatively expensive metal from

131

that point of view and and it because it's difficult to work with

132

so for example machining the chainring that yeah yeah

133

if you were machining the exact same shape out of aluminium it would take a fraction of the time

134

because it's quite difficult to work with titanium and keep it in the right condition.

135

The problem really is that titanium bikes will always end up being more expensive

136

and that's why it tends to be used not at the lower end of the market.

137

Yes, it does tend to be at the high end custom type bike.

138

Yes, that's interesting.

139

Also, there is an additional way of starting to look at working with titanium, which is something that you are a big fan of.

140

Tell us more about something like this 3D printed lever.

141

3D printing is increasingly a common way of working with metals.

142

Aluminium, titanium, steel can all be printed.

143

One of the good things about it is that because titanium is very difficult to get into a particular shape.

144

3D printing is a great way that you can achieve that.

145

Of course, there are strengths and weaknesses of using additive manufacturing full stop,

146

but it's a great way that you can get the raw material into a shape that you want for some design application.

147

Or an intricate part like that.

148

Exactly.

149

We use it a lot to get a particular design intent from a performance point of view,

150

an aesthetic point of view.

151

We use it a lot in conjunction with, for example, machining.

152

Rather than starting out with a big block and removing a lot of material.

153

A lot of material.

154

When you compare this, it's crazy, isn't it?

155

Yeah, so additive manufacturing can be a really useful way of,

156

you know, you could print something that is nearly the shape you need and then machine the rest of it away.

157

And you could do that with casting as well.

158

There's different strength benefits one way or the other.

159

And of course, in a sense, for me, for my application where every bike we make is different and custom,

160

3D printing has an obvious advantage because you don't have to pay for tooling costs of a cast part.

161

That's a really interesting point there.

162

That's covered off loads of really important and useful information about titanium.

163

One key question I do want to ask you is,

164

do you think we're ever going to see titanium bikes and parts start to become more mainstream and more commonplace,

165

or do you think it's going to stay as that not quite elusive material, material, but a bit more of a niche material rather than something that's mainstream?

166

I think it will come down.

167

Cost is probably the main factor to consider there because it's so expensive as a raw material, it's difficult to work with or certainly slow to work with.

168

All of those things, the costs

169

that are added to the already high cost of the raw material are ones that are difficult to reduce.

170

I don't see an easy way that they would come down.

171

There is more automation that gets built into processes like additive manufacturing and machining as well.

172

But I think the main problem with it being used on a widespread level is,

173

yeah, it's just going to come down to the fact that cost and as we're seeing at the moment,

174

one of the big problems with bikes is that there aren't many at the low end of the market.

175

Yes, it certainly doesn't feel like a material that's going to lend itself to the budget end of the scale

176

or as an entry point into cycling.

177

I guess, like you said, if the cost of the raw material is already high, even in the future with whatever technology and process are developed,

178

if you're able to reduce the processing costs afterwards, you're already at a higher starting point, so it's always going to be difficult.

179

Yes, exactly.

180

That piece of titanium that makes that chain ring, just buying

181

that bit of material is already multiple times what it would cost me to buy an already finished aluminum chain ring.

182

I guess there is potentially the argument on the flip side of that, is that whilst the chain is more expensive in the initial outlay,

183

it could last an aluminum part over multiple times again.

184

Yes.

185

That's one of the reasons that, for example, that's one of the reasons that we make those chainrings is that they last significantly longer.

186

So over the kind of service life of the part, probably.

187

works out about the same if not a bit cheaper depending on how you want to do that.

188

That's actually a really good point.

189

Titanium is going to be a high price, it's unlikely to ever change, but one of the big advantages are its strength,

190

robustness, and the chance that it could outlive and outperform other different materials many times.

191

Yes, certainly.

192

Again, the bikes that we make here, they're all intended as lifetime bikes.

193

I'm expecting that those bikes will be in existence for as long as their owner wants to ride a bike.

194

That's certainly something that you wouldn't perhaps say of other materials that inherently just won't have such a long service life.

195

For me, that's one of the key draws and advantages for titanium.

196

I think that's what also draw other people to it as a choice material.

197

I think we've covered off pretty much everything that I could think about talking about.

198

Tom, thanks very much for your time.

199

It's all right.

200

No problem.

201

Hopefully, you found this video interesting and informative.

202

I certainly know I enjoyed speaking to Tom.

203

For me, a titanium bike is one which I wish to own, but unfortunately, it still seems to be a little bit out of my price brackets.

204

Remember, for all things bike and bike tech related, subscribe to GCN Tech because it also helps support what we do.

205

See you later.

什么是跟读法？

跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。

跟读练习: Everything You Didn’t Know About Titanium Bikes - 通过视频学习英语口语

本片段的口语学习目标

实用短语库

攻克你的薄弱点

什么是跟读法？