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HC Bike/Cycling Thread


boomana

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Went on a pretty high intensity ride yesterday, so i had planned to take it easy and just enjoy a short trip in the sun today.

Ended up being caught up in the mood, so the trip ended up as a 108km ride...

i had forgotten my wallet, and only brought  a banana with me, so on the way home i was pretty much running on fumes ?

https://www.strava.com/activities/1799130499

1006664748_Skjermbilde2018-08-26kl_19_41_03.png.290f6434b462253025074f21ffd5a902.png

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jajaja no, no... it´s piece of cake. Only 42 kms probably we´ll only gain 1.500 or 1.800 m 

I live near there so I'm used to going up and down to Las Palmas city and Teror village. This is like one more training. 

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Revision traumatology for a throbbing pain in my left knee. I have been treated only with anti-inflammatory and painkillers.

I have a partial tear of the outer ligament of my left knee. In principle the break is welded naturally but I have ordered total rest for two weeks.

I'm a little fucked up.

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Well, the saga of the bottom bracket continues.

It started making a noise again, so i pulled the axle and inspected the bearings.

They made a slight grinding noise when turning, and it almost felt like they had sand particles inside!

Having only ridden around 300km on the new bearings (in dry conditions), i was obviously not happy with the situation, so it went back to the shop today.

The guy behind the counter was oviuosly having a bad day, and was not happy to receive the bike -  he even told me its normal for bearings to feel gritty!

 

Hope they take it seriously and figure out why the bike keeps eating bearings...

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The guy behind the counter was oviuosly having a bad day, and was not happy to receive the bike -  he even told me its normal for bearings to feel gritty!

Uh, no it isn’t normal for bearings to feel gritty. Guy is a dumbass for even suggesting that!
What kind of crankset!/BB is this?


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27 minutes ago, Pars said:


Uh, no it isn’t normal for bearings to feel gritty. Guy is a dumbass for even suggesting that!
What kind of crankset!/BB is this?


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Yeah i know, i was really close to blowing up when he said that, but in the end i just calmly explained that he was wrong and i was right.

Didn't want him to refuse looking at the bike after all.
 

it's cannondale caad12 with a BB30a SI hollowgram cranks. 

i suspect the new bearings they put in must have been knackered from the factory, and they just didn't check them properly before inserting them, or there is something wrong with the machining tolerances on the frame, making the bearing slightly misaligned and thus ruining them quickly.

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It also depends on the threads being cut parallel in the bottom bracket. Not sure how that is done on a carbon frame. Threaded inserts bonded in? In any event, if the threads are not parallel and/or have a linear offset it is a manufacturing fault, and there is no alternative but a replacement frame.

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In a carbon frame they are press-fitted. In theory, if the frame has no defect, the bearings (at the end of their seat) should be parallel.

It´s possible that frame has some burrs in the area or something that misalign the bearings (paint, resine, fiber…) The normal thing would be to remove the caps from the bottom bracket box and check with a vernier caliper (or better a laser) the measurements on both sides.

like this: 

 

bb90-madone-37mm-cart-bbshell-2.jpg

 

I prefer Shimano PF or BB90/95

 

7MWMjMT.jpg?1

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The caad is aluminium and uses press fit BB, so the only way to mess things up too badly (except for making the opening to big so that the bearing can wobble around) is not aligning the two sides properly when machining them, thus making the axle improperly centered.

So in theory, pressing the bearing directly into the frame is superior to pressing them into cups, as there is one less part to misalign and with the potential to creak.
Unfortunately, it seems a lot of manufacturers get quite sloppy with the tolerances, so it doesn't matter how you mount the bearings, because they will start creaking anyway because they dont fit properly. 
At least they are cheap and easy to replace, so at least thats something... 

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3 minutes ago, bjarnetv said:

The caad is aluminium and uses press fit BB, so the only way to mess things up too badly (except for making the opening to big so that the bearing can wobble around) is not aligning the two sides properly when machining them, thus making the axle improperly centered. 

Oh sorry. I have not seen your photos well. So it's simpler, Do you have a "torno" or CNC machine on your area? 

A "torno" could rectify and align the frame quickly and for very little money.

*I'm sorry I do not know how to say "torno" machine in English.

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i think realigning the BB would be impossible without converting it to another standard, since removing material would make the holes to big for the bearings.

The bike's only 3 months old, so if the BB is indeed badly machined and keeps eating bearings, i would think getting a replacement frame from Cannondale wouldn't be to hard for the dealer.

I suspect they will replace the bearings one more time before considering replacing the frame though.

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