Trek BB90 + creaking Ultegra 6800 hollowtech 2. Anyone like a mystery?

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

Hi fellow WWs...

A friends bike is creaking under load. Even when pedaling with only one leg (both sides).

After tightening the left crank arm bolts the creak is less but it never really goes away.

Tried cleaning/greasing/changing bolts.

He is a heavier guy and in his best shape at the moment, practicing sprints and is putting the bike under new pressures it's never endured before.

It's a domane that came with Enduro MR2437LLB bearings as the bottom bracket. They were replaced by me after about 7000km. Replaced bearings were NSK6805 japanese steel bearings (given to us by the same shop that sold the bike, we asked for the same enduro ones). These NSK have 25mm inner diameter and to reduce it to 24 they come with plastic inserts. When I pressed in the bearings they both needed a fair amount of pressure to seat so the tolerances seemed fine. Also I used a tiny amount of loctite 641 gap filler to be on the safe side.

The bike had a creak before the bearings were swapped. It started when the crank was first removed. This was done to check if the bearings needed replacement. After this the bike very rarely stayed quiet.

I'vr tried setting the preload adjustment loose/tight/loosen after bolting. Seems I tried weverything.

I'd like to know what are the official instructions to installing a hollowtech crank?

I've before suspected the creak comes from somewhere else but seeing as it started after first removing the crank and only changes intensity by tightening the crank bolts, it's probabpy here the problem is.

Could the splines simply be damaged? Like no matter how much it's torqued it won't stay quiet. What if one bolt is always more loose than the other so it kind of bolts on crooked?

Crank came off multiple times to clean and regrease. At first install it's quiet for a few minutes and gets quite loud. After retightening the bolts it gets silent again but displays some creaking after a while (mostly under load), one more tightening (now very difficult) the creak is again quieter but never completely gone. Weird.

Anyone have any ideas? Teflon tape? Change the whole crank? /a


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by MoreRideTime

Here's the link to the installation details from Shimano for you:

The only thing I can think of is to check the chainring bolts if you haven't already done that.

by Weenie

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by Mr.Gib

Before touching the BB or cranks, test the bike with a different set of wheels with good quality, tight, well cleaned and lubed quick releases to eliminate that from the equation.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

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by SLN57

I had exactly the same problem on my Trek, it drove me mad for months. I tried swapping wheels, skewers, pedals, chain, tightening chain ring bolts, re-greasing and tightening everything in the drive chain. Even though they were nearly brand new and felt in perfect condition it turned out to be the FSA BB bearings I had fitted to replace the rusted originals. I changed them to Shimano bearings and the click disappeared. There were subtle differences on the plastic inserts of the bearings so perhaps it was that.

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by FIJIGabe

You say it's a Domane, so I've got a question: is the bike making noise on the stand? When you put it on the stand, does the crank make noise, or does it only make noise when it's back on the ground, and your friend is riding it?

For the time being, I would loosen and tighten the chainring bolts, making sure that everything is properly torqued down. It doesn't seem like the BB bearings are the issue, but you didn't say how long ago you replaced them, so you may want to throw in another set of bearings, just in case. Also, I would check the cassette and skewers.

One thing that you haven't looked at is the bearing holding the IsoSpeed together. For some background, the IsoSpeed is centered around a bearing between the top tube and seat tube. If all else fails, I would take the bike in and have the shop inspect that bearing, especially if the creaking only occurs when the bike is on the ground.

Also, check the headset bearings. The reason I say this is that if the bearings are "dry", they may creak. This happened to me with my Madone, and a little grease cured the problems.
Madone 9
Madone 5

Madone 4, Cobia. I own a lot of Treks.

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by mmancini

I have a 2017 Domane SLR7 with BB90 and Ultegra 6800 crankset. After a few months it developed a creak as well. It was most noticeable during high intensity activities (climbing out of the saddle and sprinting). I removed the cranks, re-lubed everything and put everything back together. The creaking was gone for a few miles and then returned. It turns out that when I was performing maintenance a few weeks before the creaking appeared, I accidentally chipped a piece off of the internal part of the drive side BB90 dust cover. After replacing it and using much less grease, the noise has gone away and I have been noise free for the last few hundred miles. The part I replaced is:

BB90 Dust Cover
SKU: W326785
MSRP: $2.99

Be careful on installation. They are so frickin tight. I broke the first one and had to wait another week for my LBS to get more in.

I hope this is your problem and solution. I went insane for a few weeks trying to solve this!

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by alcatraz

Thank you so much everyone for your suggestions.

Since the new bearings are of a different standard 6805s instead of the shimano standard enduro 2437 ones it doesnt use a conventional dust cover anymore. They were changed 2 months ago maybe.

It's a round L-profiled plastic insert that goes in the bearing to make the inner diameter 24mm and to act as a dust cover. It's quite hard, not any kind of rubber on it. Might be squeaking.

My problem is the noise (always under load, never on flats unless accelerating) always becomes louder after removing the crank. So now I'm a bit reluctant to take it apart again.

It's not a tick, it' definitely a creak/squeak when pushing the pedals.

I'll definitely check the chainring bolts.

What I just can't wrap my head around is that the noise does change immediately after fiddling with the left crank arm bolts, BUT the noise is still reproduceable with only one leg (either side).

What of the preload adjuster cap. Should this be left at the finger tight tension used or unscrewed a little to not flex with the arm?

The noise is quite low at the moment so there is no panic to get it fixed, but when the time comes that we do have a good look I think it's important to have all the possible suggestions and check everything off one by one.

I was sceptical to the NSK bearings but they are really heavy duty amd without the slightest feeling of grittyness when holding them. What I don't like is the hard plastic insert. I was afraid it could rub agaist the tube that goes between the bearings in the frame.


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by Patto

My trek domane has had every creak twice but never bb. It has cheap eBay bearings in bb after the originals rusted. Now I repack the outer seals every 1500km and they have 15000km on them.

Skewers and seatpost are the most common culprits. The duo trap even creaked once .

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by glam2deaf

Are the cleats tight or worn? What condition are the pedals in? Only other thing in that area that come to mind.

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by alcatraz

Havent checked the chainring bolts. The pedal threads were recently regreased.

If cleat issue (spd, not spd-sl, rider likes ability to walk) then wouldn't it be more on one side compared to the other?


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by JScycle

In my knowledge the preload cap just needs to be tightened until there is no play.
If it still creaks try tightening it a tiny bit more

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by kwakekeham

Firstly, a bit of a reminder on what BB90 is. BB90 is plain bearings on a carbon seat that is molded into the frame. It's unique to Trek.

I've been struggling with my 2012 Madone with BB noise recently and NDS bearing failures. If a bb90 develops noise or bearing play there are two options. Two former trek employees who used to do this repair explained to me. The noise is normally the slight amount of bearing movement and they suggest moving to V2 bearings (37.1mm diameter instead of 37.0). These are only available from Trek so you need a trek dealer to order them If that fails, or in time fails, then the frame goes back and they do an operation to bring the BB back into tolerance.

I have some play, and mine aren't tight like you described so I'm likely to get V2 bearings soon. Recently, I used two angular contact bearings from wheels mfg which help (2437) but due to the NDS water leakage problem of older frames the NDS one got destroyed quickly. I replaced the NDS with enduro 2437 and now I have a click. However the bearing isn't tight in the frame.

If your bearing seat is tight, I'd suggest that maybe the shim in the ring of the 6805 (This bearing is more commonly found on Campagnolo) could be the problem. I would consider getting proper 2437 bearings and the bearing cover (which is necessary to prevent water ingress). Personally I liked the angular contact ones but they dealt poorly with water ingress -- and I don't ride in the rain ever. So sweat + waterbottle water only.

Also, be careful of over-tightening the Shimano cap. The spec on these are very low, below most torque wrenches actually. Wrenching on these puts a lot of lateral load on the bearings that they were never designed for and can cause accelerated wear.

For swapping stuff, as suggested before, my go to is pedals. These can be a common source of "clicking" feel since seldom do I hear of people rebuilding or replacing pedal bearings in my circles.

by Weenie

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