Misc bolt list

Discuss light weight issues concerning road bikes & parts.
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madcow
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by madcow

brian wrote:What about carbon bolts?


Carbon bolts are nice, but unless you are budget less or have done everything else, its hard to recommend using them.

Look at it this way, An al. bolt is 2grams, the carbon is 1 gram. So if you can replace 10 bolts you save 10 grams. Drawback, in the states the carbon bolts are about $20-$30 each. So to replace 10 is $200-$300. Probably there are better places to save weight.

brian
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by brian

madcow wrote:
brian wrote:What about carbon bolts?


Carbon bolts are nice, but unless you are budget less or have done everything else, its hard to recommend using them.

Look at it this way, An al. bolt is 2grams, the carbon is 1 gram. So if you can replace 10 bolts you save 10 grams. Drawback, in the states the carbon bolts are about $20-$30 each. So to replace 10 is $200-$300. Probably there are better places to save weight.


a gram`s a gram!!!!

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gandini
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by gandini

Can anyone help me out with the specifications of the bolts on a Cinelli RAM bar-stem? They use a 5mm Allen wrench, and have a relatively coarse thread, but I don't know exactly.

thanks,
philip

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Superlite
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by Superlite

Unless it is some special bolt a 5mm allen head denotes a M6 bolt, you need to measure the length of the bolt from bottom of head to end on bolt for length.

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gandini
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by gandini

Unfortunately it is a special bolt. Cinelli don't make too many threadless stems, so I can't go by my older quill stems from them. And the bolt is very different from any I've seen on TTT or other threadless stems.
Also a correction: it takes a 6mm Allen wrench, but is a different thread to other 6mm Allen bolts on a bicycle (like the derailler clamp bolts.) It's about 20mm long.

thanks,

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madcow
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by madcow

2004 Ram, used 2 M6x16 bolts for mounting the stem and 2 M4x12bolts for mounting the computer arm. They did however use a 5mm allen key not a 6mm. I seem to remember the 05 version is the same, but I don't have any to check against right now.

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Superlite
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by Superlite

gandini wrote
Unfortunately it is a special bolt. Cinelli don't make too many threadless stems, so I can't go by my older quill stems from them. And the bolt is very different from any I've seen on TTT or other threadless stems.
Also a correction: it takes a 6mm Allen wrench, but is a different thread to other 6mm Allen bolts on a bicycle (like the derailler clamp bolts.) It's about 20mm long.


Metric bolt of a certian size are always the same, there are differences in threading. It is most likely an oversized head that is causing the confusion, meaning the bolt is smaller then you think, sounds like an M6 bolt with an 6mm key, instead of the usual 5mm key.

Also, you sure the bolt isn't just worn or the threading on the bar isn't stripped? Only thing I can think of is a english bolt is used, but that wouldn't make sense. :?

Madcow wrote
2004 Ram, used 2 M6x16 bolts for mounting the stem and 2 M4x12bolts for mounting the computer arm. They did however use a 5mm allen key not a 6mm. I seem to remember the 05 version is the same, but I don't have any to check against right now.


Standard for M6 socket bolts is 5mm key. The number folloing the M, in the case M6 represents two things, the thread diameter and the head height, not the key size. Oversized keys can be found usually on taper head screws, like on Shimano deraileur bolts in which an M5 bolt has a 5mm key, instead of the standard 4mm key on a M5 socket bolt.

Hope that clearifies things. Just dont want to confuse people. :wink:

So, here is how it works,

M-stands for Metric

Number after M-stands for thread diameter and head height

To calculate head diameter you take the number following M, divide it by 2, and add the original number plus one half M plus 1 for head diameter.

Head diameter = M + (M/2) + 1, where M represents the number following M.

So here is an example, well use M6 since that is what we are talking about.

M6
Thread diameter = 6mm
Head height = 6mm
Socket = 5mm
Head width 6+(6/2)+1=13mm

And lenght of bolt is always from the bottom of the head to the bottom of the screw, head height is not included, unless otherwise noted.

Hope this helps for future purchasing of bolts! Or did I just confuse everyone? :hmm: :D

ONE LAST THING!!!

If you are buying Ti bolts for weight savings purposes taper heads are about 5-20% lighter, depending on length, due to the head structure. Socket heads have considerably more material in them then the heads of a taper bolt.

On my Ritchey stem the weight savings of the Ti socket head bolts averaged 10.5g, with the taper head bolts it was 12.5g saved.

I just bought some socket head type bolts because I thougth the taper heads didnt have the strength needed, but I recently learned Zipp uses them on their stems, so I think they are safe to use and save a few more grams. :twisted:

fdegrove
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by fdegrove

Hi,

Since this is a sticky thread I thought I'd add my 2 cents:

http://euler9.tripod.com/bolt-database/22.html

http://www.boltscience.com/pages/glossary.htm

http://www.sizes.com/tools/thread_screw.htm

Anyone wanting to add good sources for Ti and Alloy or whatever bolts and tidbits on a per continent basis?

Ciao, :wink:
Being a snob is an expensive hobby.

zakeen
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by zakeen

whats the size bolt of a spoke thread?

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fayrwerks
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by fayrwerks

just curious how much do those round bolts that goes onto the tubes valvestem weigh?
“Maximize strength to weight through optimized geometry” -ZG

mathi
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by mathi

Nice one MadCow , a link that is usefull to all of us . :thumbup:

DYG
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by DYG

What are some good vendors of high quality Al and Ti bolts in the USA? Thanks.

King Weel
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by King Weel

I have good experiences with SRP (www.srp-usa.com). They sell some al and ti kits to upgrade ders, brakes etc.
Specialized S-Works Allez (the shiny one :) )
Turner Czar

DYG
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by DYG

Thanks for the tip. I did not know SRP was still around.

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madcow
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by madcow

DYG wrote:What are some good vendors of high quality Al and Ti bolts in the USA? Thanks.


Personally the only ti bolts I will use anymore are those from Pro Bolt. There are alot of places to get bolts in the U.S, most of them claim 6/4 ti, but with almost all of the companies getting ti bolts from the far east the quality is very questionable. I've bought from lots of U.S companies and some have been ok, but the only ones we've never had a problem with are from Probolt. They are expensive, and you usually have to get them from the UK, but in my opinion they are worth it.

BSR Aerotek, usually makes nice bolts, but again they are in the UK.

If you have to buy ti bolts in the U.S., My first choice would be redmist motorsports, with maybe yoyodyne behind them. Racebolts used to be nice, but the quality of their bolts has gone down, we've since had to stop buying from them.

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