Tight bottom bracket.

tim_wand

I ve been using the same bottom bracket and chainset combination in 2 different frames. (A FSA Gossamer with a Mega Exo B/B) I know the first frame had never had an external bearing style bottom bracket in it and probably needed re-tapping and threading as the oversize axles can have more pressure placed on them from the bearings.

The second frame according to the previous owner was previously fitted with Shimano Hollowtech 2 bottom bracket and he had no problems.

The other issue is I dont have a Wave Washer.

Is my problem with this chainset?

1 Not fitting the Wave Washer.
2 Does the Bottom Bracket shell need rethereading and Tapping.

I can pick up a better chainset at a good price, But will fitting this style of B/B again result in the same problem?

I m finding original FSA wave washers hard to source, although I can find loads of Wave Washers , does anyone know the metric (M) size I need?

Im either going to fit a new B/B and Wave Washer if this will sort it ? ( cost about £25)

Buy a new chainset and B/B and not get it rethreaded/tapped? (Cost £120)

or do I need to get the B/B Shell rethreaded with a combination of either of the above. ( Rethreading £25)

Money is tight after Christmas.

sturmey

No-one has answered you because things are a bit vague here.
You do not say what sort of bottom bracket shell you have in the frame.
English thread or Italian? or BB30? If it's NOT BB30 no wavy washers needed.If it IS BB30 then the threads should not need any attention at all as the bearings are a press fit. You don't say what you mean by 'tight bottom bracket', do you mean it feels tight when threading something in or the cranks don't roate smooothly.
If the Hollowtech chainset and cups worked ok then I would look at trying a new set of external bearing cups first before considering major surgery to your frame.

nicklouse

if external bearings get the frame checked that it has been faced.

rjsmith

If you are talking about how freely the cranks spin in the FSA bb, then I've found that the alloy FSA cranks/Mega-Exo bb combo does result in it not spinning super freely. Shimano HT2 external bbs are only slightly better in my view. However, it's not much to worry about in terms of losing wattage, unless you are going for the Hour Record or something.

John.T

As far as I know the Gossamer does not use a 'wave washer'. It is the same as Shimano HT2 and adjusts with a cap in the axle end and clamps with 2 allen bolts in the LH crank. Both my sets are like this. I am using Shimano HT2 BBs with both now as the FSA ones did not last very well. Just replaced the Tiagra one fitted on my winter bike after 2.5 winters and about 6000 miles with another Tiagra one. The frame is just as it came from Ribble and has not been faced (I may just have been lucky here.). Make sure that the pre-load is set correctly and you should have no trouble. Some do spin better than others but it has little affect on the bike.

Monty Dog

If the frame was fine with BB then should be no need for facing and chasing - often a ruse by component makers and LBS to generate income - you simply cannot distort a bb cup to that degree unless the thread was seriously borked / worn. The degree of force required to distort a cup sufficiently would likely result in shearing it off.

ilm_zero7

my BB doesnt use an external cup - the third groupset now where these have been spare, but it follows your line I think Monty Dog

nicklouse

Monty Dog wrote:

If the frame was fine with BB then should be no need for facing and chasing - often a ruse by component makers and LBS to generate income - you simply cannot distort a bb cup to that degree unless the thread was seriously borked / worn. The degree of force required to distort a cup sufficiently would likely result in shearing it off.

and it is strange how the BBs in a faced frame last so much longer and spins so much better than they did before.

if the BB uses self aligning bearings then fine if not then do it.

John.T

ILM Zero7 wrote:

my BB doesnt use an external cup - the third groupset now where these have been spare, but it follows your line I think Monty Dog

Not really relevant to the OP. He does have external BB bearings.

tim_wand

To Clarify, Its a FSA GOSSAMER COMPACT chainset English/BSA style with a Mega Exo B/B .

Having read the replies from this post and having checked back on about 6 other bottom bracket queries, it looks like this particular set up (They probably all are) is particularly sensitive to bearing alignment and torque settings.

I dont have a Torque wrench (Need to invest) and tend to go a bit OTT on areas like cranks and pedals to avoid creaks and groans.

Found a previous post where the O/P had removed the non drive side crank and bearings, checked the B/B shell and found the driveside crank and axle to spin freely (as it should) like this,

I ve done the same and then carefully replaced the non drive side bearings ( less torque ) and crank (Again a lot less torque this time) and it all seems to spin fine.

I would imagine I got the initial bearing alignment wrong and over torqued the set up just making things worse.

It seems okay spinning it in my hand at the moment and once there isnt a force ten blowing I will go and ride it and see.

Long term I think I ve damaged the bearings a bit so I will replace the Mega Exo with a shimano HT2 (Tiagra) as most posters seem to think these have a bit of a better tolerance on this set up, and as the mega exo bearings dont have the best seals it makes sense to run a cheaper one and replace it regularly.

Get the expense of Christmas over and I m going to pick up an FSA K Light but this time I ll also buy a torque wrench.

Thanks for the replies, helped a lot.

John.T

You don't need a torque wrench to adjust the pre-load, just light finger pressure on the allen key in the end cap. Just enough to take out any slack and then load slightly. The Shimano tool is a plastic wheel about 2" in diameter but even with this you can over load the bearings.
If your bearings still feel and sound smooth you may as well run them to destruction rather than re-new now.

tim_wand

Thanks John T. (i'm quite literally a spanner) you have answered a question for me. My BBB external bearing spanner has always had a round plastic thing with a flower/star shape pretrusion stuck on to its handle, having never fitted shimano HT2 Cranks before I take it this goes in the jaws of the spanner and then tightens the pre load cap on the non drive side crank arm.

Whoops should have worked that one out by now. :oops:

keef66

The Shimano plastic flower shaped thing should only be done up finger tight. No spanners.

John.T

tim wand wrote:

Thanks John T. (i'm quite literally a spanner) you have answered a question for me. My BBB external bearing spanner has always had a round plastic thing with a flower/star shape pretrusion stuck on to its handle, having never fitted shimano HT2 Cranks before I take it this goes in the jaws of the spanner and then tightens the pre load cap on the non drive side crank arm.

Whoops should have worked that one out by now. :oops:

I don't know about the BBB tool but the round plastic thing with the star / flower shape sounds just like the Shimano tool. You don't need to use any spanner with it. That should give some idea on how tight the pre-load cap should be. IE- not very.

tim_wand

Thanks all I will continue on my "Learning Curve" and try not to hurt anyone whilst doing it.

Much appreciated Tim (Wish my brain was as big as my arms!)