RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: uk-fresh on September 07, 2014, 05:28 PM
-
Hi Guys
"help"
Bought a bottom bracket set off ebay to go on 81 Takagi MX crank. Unfortunately it does not screw on all the way so the chain wheel is not tight on & wobbles about. I take it I have bought the wrong bottom bracket! Any suggestions please and what I need?
cheers
-
Is there a large washer/spacer in the packet?
Are you using a cheap thin chain wheel?
-
44t suntour.
The bracket doesn't go all the way down the thread. Goes on nice and smooth and after a couple of turns will go no further.
-
44t suntour.
The bracket doesn't go all the way down the thread. Goes on nice and smooth and after a couple of turns will go no further.
Are threads still showing?
Check them for a cross thread :daumenhoch:
-
All threads look good. I just tried to see if the other nut will screw on the other thread and that doesn't screw on either.
-
pictures will help
-
24tpi / 28tpi ?
Just a thought if it's only going on a couple of threads.
-
I bet you have a 24tpi cranks and your trying to fit a 28tpi bb, I say that because I had a NOS Takagi MX 175 x 28tpi OPC cranks and i've never seen another set, they are quite rare and were mostly 24tpi
If you can't screw it on by hand it's the wrong pitch.
Try a 24 tpi bb
24 = 24 Threads Per Inch
28 = 28 Threads per Inch , so 4 more threads in that inch makes them slighty different but enough to jam the thread.
Even though they are the same diameter
-
Any one no of good place to get 24tpi?
-
Any one no of good place to get 24tpi?
ebay there's hundreds of them
-
Has the crank arm got 24 engraved on it ? and a pic of the bb or the ebay number would help
-
Just noticed the 24 on crank. Off to fleabay to purchase another BB.
-
Right this is doing my head in now. Maybe I have made a silly school boy error somewhere I don't know. I now have a 24tpi BB and still no joy. See pics. The bracket is screwed on as far as it will go and still a big gap.
Any more suggestions?
[attachment=1][attachment=1]
-
Pic of thread[attachment=1]
-
Cant make out the locating pin on the arm through the oval hole. Daft question i know but you have got it on the right arm havn't you?
-
[attachment=1]
-
lets get it right youve tried both 28 and 24 tpi and both dont work, are you sure the thread is ok?
have you tried the other 24 tpi nut on the other side of crank like you did the 28 tpi?
are you sure the new one you bought is 24tpi?
-
not sure if this is possible as not done 1pc for a long time but you havent used the wrong nut on that side, ie screwed it over the first thread then tried to screw it on the other one? one should be slightly larger diameter to slip over the one thread and screw on the other one
i think anyway
I have a reason to my madness as the nut in pic has notches in it like you would use a screwdriver to undo the bb when you want to get it off
-
not sure if this is possible as not done 1pc for a long time but you havent used the wrong nut on that side, ie screwed it over the first thread then tried to screw it on the other one? one should be slightly larger diameter to slip over the one thread and screw on the other one
i think anyway
I have a reason to my madness as the nut in pic has notches in it like you would use a screwdriver to undo the bb when you want to get it off
Agree with Paul here - that looks like the non drive side nut...
-
the bracket shown is the correct one, its the only one that will go over the first thread. It has more thread on it than the first set of BB I bought. But I just tried screwing the second bracket on the left side and I get one turn on it and no more. Looks like I may have bought a dodgy crank!! Thing is the threads look ok on the crank to me.
Also I thought I saw 24 on my crank but it is actually T7 81.
-
i would try put up more pics of everything you have including crank markings etc
surely something must fit if its not stripped
-
Get pics up like has been said, but i would agree with Jaan and Antique, thats the non drive side nut.
-
can you tell us whats stamped on the arms?
if its not got X24 then most likely 28TPI cranks in which case you have tried two 24TPI BB on it