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Technical & Reference Section => Tech and Restoration => Topic started by: oldskoolg60 on January 25, 2015, 12:38 AM

Title: chainring hitting chainstay help
Post by: oldskoolg60 on January 25, 2015, 12:38 AM
I bought a 3 piece crankset to replace the OPC on my mongoose. Now I've fitted it the correct way , but when I tighten the non drive side up to seat the bearings, the chain ring ends up touching the chaiinstay

Ive put a couple of washers in between the chainring and tophat bearing washer thingy and that seems to do the trick of pulling it away from the frame. Has anyone else had this problem? The washers i used are 4mm thick but theyre not big enough in diamter to go over the axle so ive jammed them in there to see what size id need, now I need a washer of 40mm outside diameter, 23 ish mm internal and 4mm thick to space it out .
Title: Re: chainring hitting chainstay help
Post by: meerkat333 on January 25, 2015, 07:01 AM
you could get one made up but a cheaper option would be going to a bolt supplier / hardware store (altho dont think b&Q would be any good)
you may need to buy a couple to get the stack height of 4mm
23mm ish internal ? if the diamater of the crank spindle/axle is 22mm a 7/8" washer would be suitable (7/8" = 22.22mm plus they add clearance for bolt so would probably be the 23mm u are looking for)

bear in mind u may need to move your rear wheel over to keep chain in same line, which also may cause problems with freewheel hitting chainstay etc
only other thing would be fitting a smaller chainwheel if u can get it to work in your current set up
Title: Re: chainring hitting chainstay help
Post by: oldtired on January 25, 2015, 08:23 AM
post up some pics :daumenhoch: assuming it's not an ally crankset with  tapered OS type bottom bracket,  it reads like your missing the spacer/ dust cover cones  , should have one thick one and one thin one ,they should be with the bottom bracket ,   thin one goes on the drive side
Title: Re: chainring hitting chainstay help
Post by: oldskoolg60 on January 25, 2015, 08:49 AM
This is the kit I got. (http://i1071.photobucket.com/albums/u505/mannybashah/KGrHqRHJBQFEzL0DlORBROfY3Hpow60_35.jpg) (http://s1071.photobucket.com/user/mannybashah/media/KGrHqRHJBQFEzL0DlORBROfY3Hpow60_35.jpg.html)

Title: Re: chainring hitting chainstay help
Post by: oldskoolg60 on January 25, 2015, 08:53 AM
This is it fitted with a couple of washers in there temporarily to take up the gap, until I can get a washer made up. 
(http://i1071.photobucket.com/albums/u505/mannybashah/DSC_0076_1.jpg) (http://s1071.photobucket.com/user/mannybashah/media/DSC_0076_1.jpg.html)
Title: Re: chainring hitting chainstay help
Post by: Devilock on January 25, 2015, 09:03 AM
What's the axle length?
Title: Re: chainring hitting chainstay help
Post by: oldtired on January 25, 2015, 09:57 AM
ok,  us type bb   :LolLolLolLol: missed the bit about it being a opc on a goose  :idiot2:  :LolLolLolLol:  (click knobhead button and send to me ;D )

in the kit  you have two large washers , the bigger one needs to go between the chain ring and the bit that screws on the axle   with the notches in it ,  have you used the new cups that came with the new crank? some of the older ones can be deeper ,


(http://www.radbmx.co.uk/archive/albums/ff98/jimjdld/bmx/posbb_zps545581ca.jpg)

chain ring  washer screwy on bit  (proper name escapes me at the mo)  :LolLolLolLol: 
Title: Re: chainring hitting chainstay help
Post by: oldskoolg60 on January 25, 2015, 10:41 AM
Oldtired,  you may have solved it for me, I didnt use the new cups, I used the existing ones, I'll knock the old ones out, then try it. If it solves it, I'll knock myself out too for being a fool.  here's hoping. Cheers guys.
Title: Re: chainring hitting chainstay help
Post by: BMXOAP on January 25, 2015, 11:24 AM
Common problem in the days of 44t rings. Best way is a decent 3pc with sealed bb. Much better for getting the spacing right. Be careful it doesn't throw out chain alignment and start the chain rubbing on the seat stay near the freewheel. Sometimes need an extra washer in the rear wheel to stop that happening.


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