pushbikerider wrote:

Wobbler wrote:anyone got any tips on what length cranks I should run?

155mm

HTH(I'm a twerp)

Thats what Im thinking.....

Oli wrote:So by Lennard Zinn's conservative formula I should have 196mm cranks.

How does that compare with the result from JohnnyC's formulae?

Oli wrote:I know! I'm trying to help you, you dumbarse!

So I got a new steed a couple of weeks ago (Scott Scale 35 ) and the BB (I pressume) is starting to make some graunching type noises under load. This has happened to me before on another bike from a different LBS. So two different mechanics from two different shops have said that this happens sometimes with new ones and they just pull it out, repack with grease and away you go. No worries but wondering why this happens ? Am just trying to learn a little more about the workings down there, not having a go at the LBS. 1st rides on both these bikes were wet/dirty ones. Would that contribute?

a lot of bikes come with very little grease on the bb threads, and should be repacked upon assembly IMO, but time constraints usually rule out the repacking. heaps of bikes i see could do with h/s, hubs and bb repacks right out of the box.

shmoodiver wrote:a lot of bikes come with very little grease on the bb threads, and should be repacked upon assembly IMO, but time constraints usually rule out the repacking. heaps of bikes i see could do with h/s, hubs and bb repacks right out of the box.

Are you referring to the threads that the BB cups screw into here? Da onez on the frame BB?

You know what I mean

DogsBollocks wrote:So I got a new steed a couple of weeks ago (Scott Scale 35 ) and the BB (I pressume) is starting to make some graunching type noises under load. This has happened to me before on another bike from a different LBS. So two different mechanics from two different shops have said that this happens sometimes with new ones and they just pull it out, repack with grease and away you go. No worries but wondering why this happens ? Am just trying to learn a little more about the workings down there, not having a go at the LBS. 1st rides on both these bikes were wet/dirty ones. Would that contribute?

New bikes generally take a few rides to "settle" and should be checked over thoroughly after being ridden a few times. Basically bits that are screwed into or onto your bike often loosen a little after the first couple of rides and need to be tightened up. When a threaded item is a little loose and pressure is applied it will often creak, especially if there is a bit of grit present.

A creaking BB on a new bike could be a multitude of things including:
A pedal thread a little loose
A chain ring bolt a little loose
A BB cup a little loose.

A lack of grease when a BB was installed will mean that even if the BB was torqued to the right specification, it might not actually have tightened enough, and that there will be room for grit to sit between the threads and start to creak.

Wheels should be checked after the first few rides too, as the spokes/nipples will settle into the hub/rim.

slowMTB wrote:

shmoodiver wrote:a lot of bikes come with very little grease on the bb threads, and should be repacked upon assembly IMO, but time constraints usually rule out the repacking. heaps of bikes i see could do with h/s, hubs and bb repacks right out of the box.

Are you referring to the threads that the BB cups screw into here? Da onez on the frame BB?

You know what I mean

yarp

I thought my BB was creaking. Turned out to be my seat post...

another one that gets missed lots is the derailleur hanger, but not on a scott

Trail wrote:New bikes generally take a few rides to "settle" and should be checked over thoroughly after being ridden a few times.

generally, things 'settling' are a sign some monkey hasn't done them up to the specified torque in the first place

however, given the minimal pay given to people assembling bikes (and the fact there's probably not a torque wrench in sight), given the options of them under-torquing (noisy/hassle) and over-torquing (stripped/stuffed) I'll go for the former

speeding_ant wrote:I thought my BB was creaking. Turned out to be my seat post...

Yeh, bike mechanics love it when you come along and say "there is a creaking coming from the BB".

Seat rails, Seat posts, suspension pivots, pedals, chainrings, Bottom Brackets, handlebars, headsets, wheels in the dropout... all sorts of things that can creak!!

don't forget danose's knees!

yeah but as I said, it only does it under load so I'm pretty sure it's the BB (same noise as last time and re greasing fixed the issue) Should I get it back in to the LBS quick smart or just get it sorted with the 6 week check up (considering of course that I'm heading to Hanmer this weekend )

and good advise danose

DogsBollocks wrote:yeah but as I said, it only does it under load so I'm pretty sure it's the BB (same noise as last time and re greasing fixed the issue) Should I get it back in to the LBS quick smart or just get it sorted with the 6 week check up (considering of course that I'm heading to Hanmer this weekend )

and good advise danose

Same with me. In fact every time I pedaled, seat up or seat down, it creaked. Noise came from bb area too. Take the seat post and clamp out and see if it does it