Hollowtech 2 crank not spinning in Trek Crockett

othello

I've picked up a brand new Track Crockett disc frame and I'm having an issue with the bottom bracket and crank.

The frame came with bearings installed (it was a brand new complete bike stripped down and then the frame sold), which are BB90 according to Trek's product page.

I have a set of Hollowtech 2 cranks and when I install them they feel very stiff. The crank preload isn't too tight, but when I spin the cranks without a chain I get 1-1.5 turns. Thats it, and the crank stops. When gently rotating it feels like the crank is tight in the bearings.

Is that OK and it will ease off over time? Or am I doing something wrong?

keef66

Sounds wrong to me. There's a bit of drag from the seals on a new HT2 BB but you can't really feel it at the crank. What do the bearings feel like if you take the crankset out and try to turn them with your fingers?

othello

keef66 wrote:

Sounds wrong to me. There's a bit of drag from the seals on a new HT2 BB but you can't really feel it at the crank. What do the bearings feel like if you take the crankset out and try to turn them with your fingers?

I will pop the crank out later and report back.

When spinning the crank slowly by hand it feels/sounds like there is a scraping. As if something is causing the drag. But the cranks (a set of 105s) look to be fitted correctly.

timothyw

It doesn't sound great, but on the assumption that it isn't convenient for you to simply return it to the shop I would suggest waiting until you've actually ridden on it for a few miles, as there is likely to be at least some wearing in period.

If it fails prematurely then you will be covered by warranty anyway.

keef66

Hmm, you're assuming it was bought from a shop. I assumed it was a private sale (can't imagine why a shop would strip a new bike for it's parts)

Anyhoo, Trek's BB90 is apparently designed to take 24mm spindles like HT2 and GXP so it should in theory work...

othello

keef66 wrote:

Hmm, you're assuming it was bought from a shop. I assumed it was a private sale (can't imagine why a shop would strip a new bike for it's parts)

Anyhoo, Trek's BB90 is apparently designed to take 24mm spindles like HT2 and GXP so it should in theory work...

Was bought from a shop (via eBay) -- not sure why the parts were stripped!

Good to know the Trek BB90 should work, as it means I'm not trying to run an incompatible crank.

ElectronShepherd

othello wrote:

can't imagine why a shop would strip a new bike for it's parts

Just a guess, but if the frame for another customer was replaced under warranty, it's possible that Trek simply sent a new frame, and if the shop had another bike of the same model and equipment in stock, but a different frame size, taking all the part off that bike and putting them on the replacement frame might be the quickest way to get the customer their bike up and working again. After that, the bike shop is now left with a stripped, but effectively new, frame.

The Rookie

If its internal cable check for a cable fouling the crank axle, far from unknown!

timothyw

Oh, that's a thought, check the screw for the bottom bracket cable guide (if there is one) - if the wrong one was used (too long) then it can interfere with the bottom bracket.

devhads

AFAIK the standard bearing kit on a Crockett is for use with GXP cranks. You may need to change the bearings for HT2. My son has a Crockett (bought new) and I changed the cranks for shorter ones and had to get GXP cranks.

https://www.bike24.com/p2154291.html

Edit just re-read, mine was canti Crockett 7 that came with CX1 cranks. Not sure the disc versions did, they came with FSA which should be compatible with HT2

othello

Interestingly I've heard back from the bike shop who sold me the frame:

Hi,yes this is a common question with FSA BB's. I would reccomend knocking out FSA BB and fitting a Shimano item. A shimano hollowtech will fit in the FSABB but its tight. It eventually spins freely, but for £10-£15 you can get a Shimano BB. It originally came with FSA Crankset.

Which chimes with what devhads mentioned, though the HT crank should work.

devhads

Be aware though that you can't just fit standard HT cups that screw in to a threaded shell as you have a Trek proprietary press fit shell.

You'll need something like this and the tools to fit it.

http://www.pedalon.co.uk/acatalog/trek- ... Arbd8P8HAQ