Seat Post - Help?

MaxBauer
Posts: 5
Joined: Thu May 02, 2013 7:56 pm

Seat Post - Help?

Postby MaxBauer » Fri Jan 17, 2014 6:37 pm

Just wondering if anyone could shed some light on a slight issue I have

I'm looking to change my seat post to a carbon one so I measured the diameter of them with vernier calipers; 27.2mm diameter which seems relatively common on most bikes.
So I went and scored one on eBay however the diameter was smaller than 27.2mm despite clearly being marked the correct size. Dissapointed, I went and got another and again
they were smaller. Both are FSA items and relatively cheap so it doesn't bother me too much but where am I going wrong?

Any help would great!

User avatar
Duck!
Expert
Posts: 9850
Joined: Tue May 21, 2013 8:21 pm
Location: On The Tools

Re: Seat Post - Help?

Postby Duck! » Fri Jan 17, 2014 7:36 pm

How big is the discrepancy? If it's within a few 1/10s of a mm, then it will be fine.
I had a thought, but it got run over as it crossed my mind.

ball bearing
Posts: 951
Joined: Sun Apr 15, 2012 1:43 pm
Location: Watching the ships on the Southern Ocean

Re: Seat Post - Help?

Postby ball bearing » Fri Jan 17, 2014 8:01 pm

Don't forget to apply some carbon assembly paste after you clean the seat tube with alcohol...

http://www.ebay.com.au/itm/FINISH-LINE- ... 5660711c36" onclick="window.open(this.href);return false;

User avatar
KGB
Posts: 1629
Joined: Tue Jul 12, 2011 3:49 pm

Re: Seat Post - Help?

Postby KGB » Fri Jan 17, 2014 9:27 pm

Yep, definitely NO GREASE on a carbon part like a seat post.

Waiting to hear how much smaller than 27.2 the posts are...
Image

ball bearing
Posts: 951
Joined: Sun Apr 15, 2012 1:43 pm
Location: Watching the ships on the Southern Ocean

Re: Seat Post - Help?

Postby ball bearing » Fri Jan 17, 2014 9:53 pm

Speaking of seat posts....I finished my new carbon bike today and the carbon seat post is creaking like anything. I will try turning the clamp around and using a torque wrench. Geeze it makes a lot of noise.

User avatar
Mulger bill
Super Mod
Super Mod
Posts: 29060
Joined: Sun Sep 24, 2006 2:41 pm
Location: Sunbury Vic

Re: Seat Post - Help?

Postby Mulger bill » Fri Jan 17, 2014 10:35 pm

ball bearing wrote:...I will try turning the clamp around...
Ummm, wut?
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011

User avatar
mitchy_
Posts: 878
Joined: Sun Jan 05, 2014 11:15 am
Contact:

Re: Seat Post - Help?

Postby mitchy_ » Fri Jan 17, 2014 10:36 pm

ball bearing wrote:Speaking of seat posts....I finished my new carbon bike today and the carbon seat post is creaking like anything. I will try turning the clamp around and using a torque wrench. Geeze it makes a lot of noise.
Did you use carbon paste?

ball bearing
Posts: 951
Joined: Sun Apr 15, 2012 1:43 pm
Location: Watching the ships on the Southern Ocean

Re: Seat Post - Help?

Postby ball bearing » Fri Jan 17, 2014 10:38 pm

mitchy_ wrote:
ball bearing wrote:Speaking of seat posts....I finished my new carbon bike today and the carbon seat post is creaking like anything. I will try turning the clamp around and using a torque wrench. Geeze it makes a lot of noise.
Did you use carbon paste?
Yes. I'm just heading to the workshop and get to the bottom of this creaking, I hope.

MaxBauer
Posts: 5
Joined: Thu May 02, 2013 7:56 pm

Re: Seat Post - Help?

Postby MaxBauer » Sat Jan 18, 2014 12:59 am

The FSA seat posts I have are a good few mm smaller and doesn't fit snug as I've already tried. I'm tempted to go with another brand and see how that goes but thanks for the heads up on the Fibre Grip stuff guys

User avatar
KGB
Posts: 1629
Joined: Tue Jul 12, 2011 3:49 pm

Re: Seat Post - Help?

Postby KGB » Sat Jan 18, 2014 12:57 pm

A good few mm?!? Thats completely fked. Sounds like they could be ebay knock-offs, I'd be chasing a refund if I were you. Seatpost sizes vary in 0.2mm increments so "a few mm" too small is never going to cut it.
Image

ball bearing
Posts: 951
Joined: Sun Apr 15, 2012 1:43 pm
Location: Watching the ships on the Southern Ocean

Re: Seat Post - Help?

Postby ball bearing » Sat Jan 18, 2014 1:23 pm

I'll dig out my calipers to check the tolerances. My creaking seems to have settled down. I took the bike for it's first real ride this morning. Torque wench appears to have cured the annoying racket. 5Nm is a good amount of energy. I wouldn't be comfortable pushing it that far without the proper tools.

User avatar
trailgumby
Posts: 15469
Joined: Sat Jan 03, 2009 5:30 pm
Location: Northern Beaches, Sydney
Contact:

Re: Seat Post - Help?

Postby trailgumby » Sat Jan 18, 2014 1:29 pm

From memory, 4.8Nm is the recommendation etched on the clamp on my Scalpel, so that sounds about right.

MaxBauer
Posts: 5
Joined: Thu May 02, 2013 7:56 pm

Re: Seat Post - Help?

Postby MaxBauer » Sat Jan 18, 2014 4:22 pm

KGB wrote:A good few mm?!? Thats completely fked.
Yeh when I went to fit it, it's completely loose and it was for both of them! I can't refund now as it's awhile back and only got back to riding unfortunately.

User avatar
Mulger bill
Super Mod
Super Mod
Posts: 29060
Joined: Sun Sep 24, 2006 2:41 pm
Location: Sunbury Vic

Re: Seat Post - Help?

Postby Mulger bill » Sat Jan 18, 2014 8:13 pm

With that sort of difference, it might be worth cutting a beer can up as a shim.
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011

User avatar
KGB
Posts: 1629
Joined: Tue Jul 12, 2011 3:49 pm

Re: Seat Post - Help?

Postby KGB » Sat Jan 18, 2014 9:09 pm

I've done that before but this case sounds like its too much for the old coke can shim.
For those who look down on it as a solution - it was good enough for Greg LeMond's aerobars when he beat Fignon at the Tour!
Image

ball bearing
Posts: 951
Joined: Sun Apr 15, 2012 1:43 pm
Location: Watching the ships on the Southern Ocean

Re: Seat Post - Help?

Postby ball bearing » Sun Jan 19, 2014 11:36 am

trailgumby wrote:From memory, 4.8Nm is the recommendation etched on the clamp on my Scalpel, so that sounds about right.
Damn! The noise is back!!! Never had this problem before. The max torque is stated as being 6.5Nm. Maybe I'll increase it in stages till the creak croaks it.

Who is online

Users browsing this forum: No registered users