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Newby crank help

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bai13y:
Hi guys,

Been reading the forum for a while and I've decided to build my first bmx (new skool for now,untill i get some money and some skills,lol) and found all the threads really helpful.

But now I'm stuck.

I have a diamond back joker f+f that a mate gave me for free, only need a new wheels and tyre, but ive gone and changed all the parts. Plan is to just use it as a cruser to get me onto campus, then buy another to learn on.

So i have a prism 3pce crank and an exposure 44 tooth chainwheel. (only buying cheap bits to start off with)

Problem is i dont have a clue how to fit the crank.
Ive alredy mounted the bearing cups in the frame.

these are the parts i have....


theres also a small adapter with the chainwheel. (but it wont fit onto the crank with it)

Any help would be great..... the simpilar the explanation the better..lol

cheers
bailey

stidds:
Ok here goes:

1st ignore the small adapter (top had washer), you won't need it with this chainring.

As the cups are in next would be the bearings in the cups, then you have the thin dust covers (big black discs under above the bearing on the right in the picture and below the bearing on the left).

Now put the axle through the bottom bracket.  Now you have to put the threaded nuts (top right and bottom left in the picture)on the crank axle, easy to know which is which as they have different size threads so they can only go on one side.  If you look at the nuts they both have 1 side that looks the same, this side is fitted against the bearings and bearing dust covers.  Lastly you have the toothed washer and lock nut, these go on the same side and once again will only screw onto one side of the axle. 

So basically you have to do one side at a time otherwise you will not be able to put the axle through the bottom bracket and also you will find that the bearings keep falling out.

Remember to grease the bearings 1st.

perry:
todays how to is brought to you with the magic of paint  ;D



to start with i havnt numbered the seals , im not a believer in trying to seal caged bearings , id rather whip it apart to give it a proper clean

does 2 fit onto 1 without too much of a gap ??? about a mill should be fine ( 9 shouldnt be needed here , its an adapter for smaller number 1s )

get the right hand crank arm and slide it on to the right hand side of number 1 as viewed in the pic , that way you can get the orientation right for the bolt that holds the arm to number 2

put the bolt in ( its not shown but it will be needed otherwise pedalling wont move number 2 )

screw number 3 on , from memory its right hand thread , dont do it too tight , just finger tight for now , well do it dry ( without grease ) first

take a number 4 and place in the instaled cups in the frame ( ball side first ) itl be obvious if its the wrong way around

pop the lot on

put the other number 4 in the other side and screw number 5 on ( might be left hand thread )

next is number 6

then 7

lastly 8

does number 2 touch the chainstay at all ? does it look correct ?

if your happy with it take it apart as far as number 3 and tighten with a hammer and drift ( flat screwdriver ) slather the bearings in grease , maybe some on the middle of number 1 to ward off corrosion , some on the threads is ok , youl notice it screws together easier as the the threads were chassed while doing it dry  ;)

5 is the preload and 8 is the lock nut , slightly on the tight side is good as itl settle in and should be just about right , but getting it right is down to feel so expect to tighten/loosen these a few times

stidds:
 :LolLolLolLol: :LolLolLolLol:


Good work Perry, you have got too much time on your hands mate.

perry:
tell me about it  ::)

i was mid sandwich and thought , shall i number them  ;D makes explaining much easier in the long run

you often dont know if your explaining to an engineer who just hasnt done it before or a granny whos never seen a spanner

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