Dean Ti seatpost lightening hardware

[RockiMtn]

hey therapy, i've read your post. hence why i want to move forward with replacing the barrel/bolt set. however i don't have the resources/tools to make my own barrels.

i'm thinking 1mm isn't too far off for the OD, and 15.5mm should provide enough contact area, although i'd be happier if it was closer to 20mm.

 

[shovelon]

wow, my thread got hijacked by helicoil! and i don't even really know what it is!

That happens to me all the time!

 

[dookie]

is all this hand-wringing really worth 30g? i mean, you could hit the loo before your next ride and drop 10x that...

 

[Andy R]

Agree with that, but there nothing about the direction of the load on a thread . OK, lets end the OT. If we could met, sitting with a cold beer, we certainly could come to terms .

I'm sure we could mate - most things can be sorted out over a beer or two

Sorry for the hijacking BTW

 

[therapy]

is all this hand-wringing really worth 30g?

If you are asking such a question, I'm sorry, but there's no reasonable answer . I'm doing it for fun, just to customize bike by myself, and losing some weight by the way, without sacrifying functionality.

The correct question is are you a weight weenie ?

 

[shovelon]

Those screws look overkill. I have both a Thomson and Syncros, and niether require that large a screw. If you can live with a smaller screw, and use a Ti washer, then a helicoil in a 10mm alum barrel should work really good.

Then dremmel the life out of the clamps and polish up! Done it meself on my Syncro ti Post. Have not swapped out the brass barrels yet but might.

 

[one-eyed_jim]

Cleaning up the flat here, I discover that ITM Big One seat posts (and probably their similar Millenium posts too) have two 10mm diameter by 15mm width aluminium barrel nuts, M6 threaded.

 

[one-eyed_jim]

Your works well, thats good, but hey, we have probabilty .

The point is that Shimano went to the expense of fitting Helicoils as standard to the XTR M900 group's threads, because a Helicoiled thread is normally stronger than a simple thread in aluminium. Single-bolt posts can suffer from bolt breakage and stripped threads because it's hard to get the bolt tight enough. It's quite a high-stress application.

Andy's point about the amount of supporting metal is a good one - a 6mm Helicoil in a 10mm cylindrical nut doesn't have much supporting material.

Sorry Rocki

 

[Cheers!]

Andy R, not that you aren't right, but it depends. For example a helicoil repaired pedal thread in a crank worked well but for few rides. If the load is parallel to the direction of threading, than its mostly ok, but it often causes problems when its not. Every could have its opinion and experience, so also I appreciate yours .

I'm an aerospace engineer. In all blind holes in aluminum and also titanium in which we can not use a through bolt with corresponding nut... the industry requirements is to use a stainless locking helicoil (full thread depth). Installed with Zinc Chromate Primer so that when the primer dries there is zero chance the stainless helicoil will not galvanic corrode with the base metal, and also to anchor the helicoil into the base metal.

 

[Cheers!]

is all this hand-wringing really worth 30g? i mean, you could hit the loo before your next ride and drop 10x that...

As a weight weenie fanatic every gram counts. If you can save 30g in 10 places you have just saved 300g. 454g is 1 pound, so if you are after a weight target you need to pay attension to every last detail. Right down to the length of cable housings, aluminum bolts on the brake levers, shift levers, derailluer clamps, jockey wheel bolts, derailleur pivot bolts, bottle cage bolt and aluminum v brake posts. Then Ti bolts on the stem, seatpost, seatpost binder, pivot bolts for FS bikes, brake caliper mounting bolts, brake disc bolts.