FSA Gossamer Chainset

Ask for advice or share your fettling tips
User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

FSA Gossamer Chainset

Postby Herbsman » Wed Jan 02, 2013 15:28 pm

I'm using an FSA Gossamer chainset with Shimano Tiagra BB.

If I put any torque on the preload bolt, the BB becomes really tight. If I loosen it off just a tiny bit, there is play in the BB.

I tighten it up until there's no play, then clamp the left crank on. But after a ride, the play comes back.

Any suggestions?

DesWeller
Posts: 5233
Joined: Mon May 05, 2008 15:36 pm

Re: FSA Gossamer Chainset

Postby DesWeller » Wed Jan 02, 2013 23:05 pm

You're not doing up the pinch bolts tightly enough. The axial screw is there purely to eliminate play; once the crank is clamped up it is superfluous (in fact mine fell out some time ago!).

User avatar
tim wand
Posts: 2492
Joined: Tue Mar 10, 2009 16:51 pm

Re: FSA Gossamer Chainset

Postby tim wand » Wed Jan 02, 2013 23:44 pm

^^^^^^^^ +1 as Des says.

Have you got the circular plastic tool with a Torx/Circular/Star shaped protusion in it, Use this to just put the axle cap in finger tight no more.

I had the exact same problem with an FSA gossamer and Shimano HT11 B/B doing a build last year, I felt a right plonker when the penny finally dropped (Thanks Nicklouse) that the round circle thing attached to the handle of my B/B tool was exactly for this job.

I wouldnt run it without the cap personally, but it really does not need a lot of torque at all.

Lightly preload it and then nip up the crank arm bolts. (bit like a head set and stem bolts)

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Thu Jan 03, 2013 10:51 am

The preload cap is a 5mm allen bolt. I am doing the pinch bolts up more than tight enough. If I did them any tighter I would strip the thread or bend the allen key.

Tightened the preload up again yesterday just enough to eliminate play. Turbo trained this morning and there are shiny metal bits on the floor underneath the bottom bracket...

bobones
Posts: 601
Joined: Thu Sep 23, 2010 14:11 pm

Re: FSA Gossamer Chainset

Postby bobones » Thu Jan 03, 2013 11:16 am

Herbsman wrote:Any suggestions?


Just buy a new BB. They do wear and develop play. You should be able to pick one up for less than £20. Won't really make much difference whether it's tiagra, 105 or ultegra. Easy to fit if you have the tools.

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Thu Jan 03, 2013 12:14 pm

That was going to be my next move as I bought quite a few spare ones over the last year (I like to keep parts like that in 'stock') but the current one is fairly new and was fine up until the new crankset was fitted a week ago...

Should there be washers between the crank and BB? It looks like the left crank is scraping the bb cup, hence the shiny bits on the floor after my turbo ride...

DesWeller
Posts: 5233
Joined: Mon May 05, 2008 15:36 pm

Re: FSA Gossamer Chainset

Postby DesWeller » Thu Jan 03, 2013 12:55 pm

Have you driven the crankshaft fully home? The seals can be pretty tight.

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Thu Jan 03, 2013 13:49 pm

Well, I thought I had. I tapped it in with a rubber mallet. Maybe I didn't tap it enough times or hard enough...

mamba80
Posts: 2415
Joined: Fri Nov 06, 2009 13:06 pm

Re: FSA Gossamer Chainset

Postby mamba80 » Thu Jan 03, 2013 13:57 pm

yeah, i think you need the fsa mega exo BB.
As i read your post, it appears that the inside of the crank spider is touching Shimano BB cup?
so hitting the crank will just press the spider up against the bb cup - So if you take off the crank, you should see a neat circle "machined" into the crank by the bb cup?

The FSA tech doc does not specify spacers but i know spesh use them to get a better chain line on some of their triple models, so they r available.

User avatar
Monty Dog
Posts: 20389
Joined: Thu Dec 14, 2006 14:31 pm

Re: FSA Gossamer Chainset

Postby Monty Dog » Thu Jan 03, 2013 19:21 pm

FWIW Gossamer chainset is compatible with HT2 BB so there should be no need to replace - run one for years.
1. Have you checked that the BB shell is within tolerance? BB shell width is critical to most external bearing chainsets.
2. Have you ridden the bike with a loose crank? It doesn't take much to distort the splines on the non-drive crank.
Make mine an Italian, with Campagnolo on the side..

User avatar
tim wand
Posts: 2492
Joined: Tue Mar 10, 2009 16:51 pm

Re: FSA Gossamer Chainset

Postby tim wand » Thu Jan 03, 2013 22:05 pm

This is the thread from when I went through the exact same situation. The answers from John T were what sorted it for me in the end. Went on to do about another 3000 miles no problems.

viewtopic.php?f=40004&t=12828809

DesWeller
Posts: 5233
Joined: Mon May 05, 2008 15:36 pm

Re: FSA Gossamer Chainset

Postby DesWeller » Thu Jan 03, 2013 22:42 pm

Can you see where the swarf is coming from? There should be a witness mark somewhere.

mamba80
Posts: 2415
Joined: Fri Nov 06, 2009 13:06 pm

Re: FSA Gossamer Chainset

Postby mamba80 » Fri Jan 04, 2013 15:02 pm

Monty Dog wrote:FWIW Gossamer chainset is compatible with HT2 BB so there should be no need to replace - run one for years.
1. Have you checked that the BB shell is within tolerance? BB shell width is critical to most external bearing chainsets.
2. Have you ridden the bike with a loose crank? It doesn't take much to distort the splines on the non-drive crank.


He says that when he applies any torq to preload, tightens up BB, otherwise gets play, also after ride with no play, he gets swarf and play again - neither a OOS BB shell or a damaged spline would give these symtoms - he states all was fine until he changed the crank :?: :idea:
the crank is binding against the BB bearing cup OR there is something missing from his tale of sorrow
Put back the old one and see if probems persist.

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Sun Jan 06, 2013 21:29 pm

Problem was as suggested by mamba80.

The cranks are meant to press against the black plastic inner race of the bottom bracket bearings...

On the left bearing the inner race had 'sunk' into the outer race, so tightening the preload bolt was just pressing the crankarm against the outer race...

User avatar
John.T
Posts: 3696
Joined: Fri Nov 12, 2004 16:52 pm

Re: FSA Gossamer Chainset

Postby John.T » Sun Jan 06, 2013 23:32 pm

Knackered bearing then. A 10 min strip down would have found that easily.

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Mon Jan 07, 2013 09:17 am

John.T wrote:Knackered bearing then. A 10 min strip down would have found that easily.


Yes, I did a 10 min stripdown and found it easily. So... Yeah, thanks for your 'help'.

User avatar
John.T
Posts: 3696
Joined: Fri Nov 12, 2004 16:52 pm

Re: FSA Gossamer Chainset

Postby John.T » Mon Jan 07, 2013 09:38 am

Herbsman wrote:
John.T wrote:Knackered bearing then. A 10 min strip down would have found that easily.


Yes, I did a 10 min stripdown and found it easily. So... Yeah, thanks for your 'help'.

Yes but it took you 3 days. The time you spent on here would have sorted it on day one. We are all just guessing without being able to actually see the problem.

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Mon Jan 07, 2013 11:31 am

I actually fixed it on Thursday.

I'm not sure why you need to come and give unhelpful 'advice' after the problem has been fixed. I just cannot understand it. Is it because you have low self-esteem and need to make yourself feel good by making other people feel stupid?

User avatar
John.T
Posts: 3696
Joined: Fri Nov 12, 2004 16:52 pm

Re: FSA Gossamer Chainset

Postby John.T » Mon Jan 07, 2013 12:05 pm

Herbsman wrote:I actually fixed it on Thursday.

I'm not sure why you need to come and give unhelpful 'advice' after the problem has been fixed. I just cannot understand it. Is it because you have low self-esteem and need to make yourself feel good by making other people feel stupid?

Not at all. I was perhaps a little short on my post and should have included how difficult it is to second guess problems from afar. My post was not so much aimed at you but at the many others who go straight on forums without first doing a little trouble shooting themselves. How many times do we see 'my gears don't change properly any more. What should I do', when the answer has been posted on here many many times. If after investigation you can post with better information you have a much better chance of getting a sorted. And may have learned a bit more about bike mechanics (which after over 50 years I am still doing).

User avatar
Herbsman
Posts: 1940
Joined: Mon May 03, 2010 18:31 pm

Re: FSA Gossamer Chainset

Postby Herbsman » Mon Jan 07, 2013 13:21 pm

Fair do's. And apologies for being hostile, it's just the way I am 8)

Only reason I posted originally was because of my uncertainty of compatibility between the FSA crankset and Shimano BB. Have read a few threads & came to the conclusion that it's a very tight fit but should be compatible. The BB worked fine with the Tiagra crankset with no signs of wear or damage, yet upon installing a new crankset, problems started. With the BB being so new I thought it was something to do with different tolerances between the two brands rather than a problem with the BB.


Return to “Workshop”

Who is online

Users browsing this forum: No registered users and 1 guest