Where should ti bolts be used in place of aluminium bolts?

Discuss light weight issues concerning mountain bikes & parts.

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Adam W
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Joined: Thu May 15, 2003 9:34 pm

by Adam W

I have read Ninos post about ti bolts.

Surely he's made a mistake but first claiming that ti is lighter in the table of figures, but then goes on to contradict himself by saying that aluminium is 1/2 the weight of ti? This is not a rant just an observation.

I also read on one of the articles that ti bolts should not really be use other than stem and seatpost, 'anywhere else would be a mistake'.

Are there any places ti bolts should not be used, i.e. disc brake bolts / axle bolts / shock mounting bolts etc?

All help will be much appreciated,

I have left the original message in but the new question is, 'Where should titanium bolts be used in place of aluminium bolts for extra strength?'.

ADAM
Last edited by Adam W on Sun May 18, 2003 9:29 am, edited 1 time in total.

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Florian
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by Florian

Adam W wrote:I have read Ninos post about ti bolts.

Surely he's made a mistake but first claiming that ti is lighter in the table of figures, but then goes on to contradict himself by saying that aluminium is 1/2 the weight of ti? This is not a rant just an observation.


I think Nino is correct:

Titanium is about 1/3 lighter than steel.

-> Ti = 2/3 of Steel
Aluminium is 1/3 the weight of steel and ½ the weight of Titanium.

-> when Ti is 2/3 the weight of Steel, then 1/2 of 2/3 = 1/3
So Al is 1/2 the weight of Ti, which is 2/3 of Steel.

Or where does he contradict himself?

About your question:
the only place where I wouldn't use Ti bolts are rear shock mounting bolts.

P.S.: Why didn't you post in the original thread? :wink:

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Adam W
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by Adam W

In the tables of weights in his article he shows comparable weights of aluminium and titanium, and the titanium items are almost always 1/2 the weight of the same aluminium item.

I thought titanium was lighter than aluminium, and still do, so i was wondering if he made a mistake by saying that aluminium is lighter than titanium, because it clearly isnt.

So to clear things up, are titanium bolts, nuts, washer etc lighter or heavier than the same aluminium items?

The reason i didnt post in the original post was because i clicked the wrong button.

Cheers

ADAM

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Florian
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by Florian

Adam W wrote:In the tables of weights in his article he shows comparable weights of aluminium and titanium, and the titanium items are almost always 1/2 the weight of the same aluminium item.

I thought titanium was lighter than aluminium, and still do, so i was wondering if he made a mistake by saying that aluminium is lighter than titanium, because it clearly isnt.


Now you contradict yourself. :wink:

Pure Aluminium has a specific weight of 2,7 g/cm^3,
while pure Titanium has a specific weight of 4,5 g/cm^3.
In fact Aluminium alloys are slight heavier and Titanium alloys are slightly lighter than the pure elements.

If you don't believe me, look at these sites:
http://www.goodfellow.com/csp/active/static/E/AL00.HTML
http://www.goodfellow.com/csp/active/static/E/TI00.HTML
http://www.goodfellow.com/csp/active/static/E/TI04.HTML

Adam W
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by Adam W

So, to get to the point, are titanium bolts etc lighter than aluminium bolts?

And how did i contradict myself?

Dont think im trying to start an argument, i just thought that titanium was lighter than aluminium, which is lighter than steel. Im in the process of doing my bike up, so need the best advice possible,

Cheers

ADAM

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Florian
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by Florian

Adam W wrote:And how did i contradict myself?


"In the tables of weights in his article he shows comparable weights of aluminium and titanium, and the titanium items are almost always 1/2 the weight of the same aluminium item."

followed by

"I thought titanium was lighter than aluminium..."

Maybe you missed the minus signs in the first listings?

About the whole bolt tuning thingie:
when you compare the saving with the money you have to spent,
many replacements don't make much sense.
For example replacing steel chainring bolts with a mix of Al and Ti bolts makes sense, but replacing V-Brake cable fixing bolts or aheadcap bolts is a waste of money.

Adam W
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by Adam W

Ok, i understnadn now.

So titanium is lighter than aluminium.

Nino in his article said showed in tables that titanium almost nearly half the weight of aluminium, but he then went on to say that ali was lighter than ti.

It doenst matter anyway, titanium is lighter than aluminium but is uneccesary in some places.

ADAM

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Florian
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by Florian

Adam W wrote:Ok, i understnadn now.

So titanium is lighter than aluminium.


No.
Look above: the specific weight of Al is 2,7 g/cm^3, while Ti is 4,5 g/cm^3.
Example:
let's say you'd have two 1000 cm^3 monoblocks of Al and Ti.
The Al block would weigh ~ 2700 g, while the Ti block would weigh ~ 4500 g.
Got it?

Adam W wrote:Nino in his article said showed in tables that titanium almost nearly half the weight of aluminium, but he then went on to say that ali was lighter than ti.


You really missed the minus signs. :)
The first listing shows the weight savings compared to the overall steel weight.

nikh

by nikh

Lack of communication I think :wink:

This is what Nino wrote:

Remember:
Titanium is about 1/3 lighter than steel.
Aluminium is 1/3 the weight of steel and ½ the weight of Titanium.
Carbon is about ½ the weight of aluminium

Read that middle sentence its sound as though Nino is saying that Al is half the weight of Ti, I think its just bad wording.

But yes Adam Ti is lighter than Al but more costly and in some circumstances it just isn't worth bothering with the extra cost unless your mad....like me :lol:

popawheelie
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by popawheelie

wherever posible use alauminum because it is lighter than Ti. Alau. is not strong enough in many places so you would have to use Ti. Ti is much more expensive also. Years ago the motocross bikes were using Ti axles to lighten up things and there were a few accidents when they failed so the racing governing body ruled you couldn't use Ti for axles. The shock mounting bolt is the same kind of high stress area.

Adam W
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by Adam W

Ok, it seems that people on this board have different opinions.

Heres a website i found comparing ali, ti and steel:

http://www.nylonalloys.co.uk/homepage.htm

Ali is 60% lighter than steel - ti is 40% than steel.

Therefore ali is 20% lighter than ti.

Ok, so aluiminium is not as strong as ti, therefore should be replaced with ti.

Where should ti bolts be used in place of aluminium bolts? (ive decided to change the title)

Cheers

ADAM

Mantra

by Mantra

Titanium is as strong as steel, but 45% lighter. It is 60% heavier than aluminum, but twice as strong

Adam W
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by Adam W

Ok,

Heres a list of all bolts on my bike, with exception to rear mech, chainring and cranks.

The items listed in red im not sure if they would need to be titanium, so what do you think. Also feel free to comment on the choices of material for the other bolts.

[size=7][size=9]Part Metric Thread Bolt Length - mm Head Style Quantity Material
Brake Lever M5 * 0.8 10 Socket Head 2 Aluminium
Disc M5 * 0.8 8 Tapered 12 Titanium
Disc Caliper M6 * 1.0 20 Socket Head 4 Titanium
Gear Shifter M6 * 1.0 15 Socket Head 1 Aluminium
Stem Front Clamp M6 * 1.0 20 Tapered 2 Titanium
Stem Steerer Clamp M6 * 1.0 35 Socket Head 2 Titanium
Headset M6 * 1.0 30 Socket Head 1 Aluminium
Fork Top Clamp M6 * 1.0 25 Socket Head 3 ?
Fork Lower Clamp M5 * 0.8 20 Socket Head 4 ?
Wheel Clamp Bolts M5 * 0.8 15 Socket Head 4 Titanium
Seatpost Clamp M6 * 1.0 30 Socket Head 1 Titanium
Seatpost Clamp M6 * 1.0 50 Socket Head 1 Titanium
Pivot M6 * 1.0 30 Socket Head 2 ?
Pivot M5 * 0.8 10 Button Head 2 ?
Shock Mounting M5 * 0.8 50 Socket Head 2 Titanium
Washer M5 / / 4 Aluminium
Nyloc Nuts M5 * 0.8 / / 2 Aluminium
[/size][/size]

For your information the bike in question is an Orange 222. - see picture below.

Cheers

ADAM
Attachments
Orange 222.jpg

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Florian
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by Florian

Excuse me, but bolt tuning on this bike is money-squandering. :shock:

Just my 2 cents...

by Weenie


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Adam W
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by Adam W

Whats you reasoning for that.

My bike is not exactly hte same as in the pic, it has lighter components, tubeless wheel etc.

Im only asking for help, it seems to me your just here to argue.

Does anyone have anything helpfull ot say?

ADAM

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