Bottom Bracket needs greasing?

[cyberknight]

I am getting a grinding noise when i give the beans in "top" gear ,and only it top gear .
(ie large chain ring smallest cog at back )

I have checked the front mech and it doesnt seem to be catching there at all after checking the high stop and space and the alignment .The crank arms seem tight as well.

If i peddle with less power the sound is a lot quieter but i can still hear it.Other gears do not give the same problem i am flummoxed

 

[peanut]

if its mostly in top gear then its more likely to be your right hand freehub bearing i should have thought. When on the smallest sprocket your freehub is the most heavily loaded because the chain is pulling furthest point from the wheel bearing.

 

[Steve Austin]

You sure its not the chain rubbing on the front mech cage?

 

[cyberknight]

yup had the bike upside down and watched the chain its not touching the mech and the noise does seem to be coming from the front rather than the back

 

[Steve Austin]

You won't see the chain rubbing the front mech, unless its under the same pressure..

squirt the BB with wd40. if it needs greasing or replacing, it will stop grinding whilst he wd40 provides a little lubrication, it will still need greasing.

 

[PpPete]

Give it some welly in a lower gear on a steep incline to see if noise persists.
It could be coming from interface between crank & BB spindle - even if all seems tight there can be enough movement to create a noise.

 

[accountantpete]

Best bet is to take the cranks off and turn the B/B spindle by hand feeling for any abrasiveness -even if the B/B is not the cause it will tell you if the spindle is running freely or not.

 

[Browser]

When you say 'grinding noise', is it actually a grating/scraping noise or a sort of thrashing? Grating I'd say was metal-to-metal somewhere, thrashing could just be a chain in need of lube?
S'kooze me fer askin' like, but what make/model of bike is it on? My current bike is a £190 factory heap and I put the noise in top gear (as you said, largest front/smallest rear sprocket) down to slight flex from the wheel, load on the chain and said chain complaining because I'm making it hinge around the smallest rear sprocket whilst under a fairish load.
p.s. has it only just started this or has it always done it?

 

[peanut]

looks like he's gone on his hols or thrown the bike away

 

[cyberknight]

Or maybe i just got hammered with a 12 hour shift then came home to a screaming toddler, a broken washer and a broken light fitting

When i had the bike upside down and replicated pedal conditions only happened in top gear noise seemed to be coming from bottom bracket not the front mech.In lower gears hacking up some hills the cranks get a similar amout of force yet i dont hear any noise.
The bike is a carrera subway 1 just over a year old its done about 3000 miles.

 

[peanut]

Or maybe i just got hammered with a 12 hour shift then came home to a screaming toddler, a broken washer and a broken light fitting

.

character building

how bad is the washer ? there is a very good electrical appliance forum with loads of washing machine repairmen on it. I kid you not
http://www.diynot.com/forums/viewforum.php?f=11

 

[Browser]

When i had the bike upside down and replicated pedal conditions only happened in top gear noise seemed to be coming from bottom bracket not the front mech.

Erk! That sounds rather like a bearing failure. Is it an oldey-fashiondey B.B. with separate cups and ball races or on eof the new fit-and-forget cassette type? I would have expected far more than 3000 miles out of either to be honest, unless either were incorrectly installed from new, or you have a habit of riding up 1:1 hills in top gear
Having said that, I'dve expected a shafted B.B. to be noisy in any gear Is it still under warranty? If so, gerrit tek'n back to 'em.

 

[cyberknight]

Washing machine has been on the way out for a while from what i read transmission leak staining clothes ..........yearly bonus spent.

Bike wise i have no idea how long its doing it as before only used top gear downhill , now i can push it on the flat with a run up not under warranty i think but i will check i would think its a sealed unit as i cant see the old fashioned bits to undo it ( IR NEWB ).

TBH looking at gettting a second hand road bike anyway and flogging it .

Update had fun tonight anyway had to have plumber out as had a water leak upstairs as well grrrrrrrrrrrr

 

[cyberknight]

Update !!

took the rear freewheel off today and it does seem that the free hub has some play in it.
Checked bicycletutor.com and it says a 10 mm allen key but my freehub looks different to that guess it means a trip to the lbs to tighten it up .

I didnt win the roady as i was not paying the prices people go mad with on ebay for a 7 year old bike and my budget is still tight

 

[alecstilleyedye]

is it an alex rim wheel? they don't have a proper cassette freehub, just some strange non-serviceable one.