RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: punkdSICO on July 09, 2011, 06:41 PM
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Hi - just assembled some forks to a GT headset. First thing I noticed was that the very first thing you drop down onto the forks has about 0.5mm+ of play in it. Got the old one out that came with the bike (DP Firebird Freestyler) and that also has play. There does not appear to be anyway to push it down into a force fit despite seeing somone mention this in a YouTube vid.
So, carry on I thought...
All is fine but, that small play in the housing thingy is now felt in the forks. The headset is defo assembled nice and tight, the play is only coming from this first housing thing..
Any thoughts? Maybe I do need to take it apart and give it a gentle tap with wood+hammer? Like I said, nothing appears to be taperred so I cant see how it will force fit into a tight position, but maybe I missed something??
ta,
Paul
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pics would help. :daumenhoch:
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so the bearing race that goes on the forks isn't fitting tight? that will cause the play for sure :daumenhoch:
bang up some close up piccies of the race on the fork crown
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you need to whack these on mate. i use a piece of steel tubing to fit mine ( grease the inside to held it on and for if you ever need to remove )
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If its seated right down the chromers have polished away the tolerance ::) easy fix tho ;) use a beer or coke can and add and remove a thin shim of it till u get it tight :daumenhoch: done this loads of times . A pain but fixable 8) Oh and b careful not 2 bash ur hands on the cut can ::)
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Hey, thanks all.. This one sounds like my problem:
If its seated right down the chromers have polished away the tolerance ::) easy fix tho ;) use a beer or coke can and add and remove a thin shim of it till u get it tight :daumenhoch: done this loads of times . A pain but fixable 8) Oh and b careful not 2 bash ur hands on the cut can ::)
Yeah, this sounds plausible.. Im going out shortly but ill de-assemble tomorrow and look to see if the new chrome has taken away the small "force fit" area. If so, I have a Dremal so I can carefully remove the new chrome to this area without a coke can.
Will let you know how I get on..
ta,
Paul
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Bugger!! This did not seem to be my problem as there is nothing to remove, indeed, I need to add metal to stop the racer from moving:
Shows small amount of play at bottom:
(http://farm7.static.flickr.com/6129/5923377998_fd5d03d601_z.jpg)
Shows small amount of play at top:
(http://farm7.static.flickr.com/6010/5923377894_f8b47e366f_z.jpg)
Racer sits all the way down to the main ridge.
(http://farm7.static.flickr.com/6016/5923377960_2b2e727aae_z.jpg)
So, I have tried Racers from two headset and, two different sets of forks with all combinations having the same problem with a small amount of play. Also, when I stripped my Firebird for chroming, I dont recal having to use any force to get the racer off so I expect this play was always there..
I have three other BMXs that I got assembled. I guess during the week ill remove their forks to see if the racer has the same play..
Any thoughts??
ta,
Paul
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Don't bother just shim it and it will b perfect ;)
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Don't bother just shim it and it will b perfect ;)
Hi - shim what? I cant see what surface to shim, indeed, I can see what parts of the tube should be thicker to give the racer a better fit but not where to shim. Also, I have tried my two racers on a never assembled Aero Reflex and again, there is some play..
:(
ta,
Paul
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Shim this bit all the way round:
(http://i1236.photobucket.com/albums/ff443/dannywhack/shim.jpg)
use a cut up Coke can (or soft/booze drink can of your choice), and cut a strip off from AROUND the can, not vertically on it. Cut to length so it fits all around the fork (or length needed to secure it), slide the race over, tap on and you're away :)
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+1
this was a more extreme example but sure you'll get the idea you can get race seats in different sizes but a shim is easyer use beer/coke tins or soup tins or similar to get thicker shims, pack it out so that you to have to force the bearing seat on the crown to eliminate the play if you dont the head set will crack or you will damage the crown on the forks, these ones were ready to be tapped down to secure the race seat
(http://www.radbmx.co.uk/archive/albums/ff98/jimjdld/bmx/Tiger/collar1.jpg)
(http://www.radbmx.co.uk/archive/albums/ff98/jimjdld/bmx/Tiger/1g.jpg)
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Ahhh!!! I get it :)
I was reading "shim" as removing girth from the forks and clearly, I need to add girth to my forks. So, I use a coke can to add girth! Nice.. I have done this before with a seat post so, cool...
And those pics above were great!!
Many many thanks for the effort, guys...
I might not be back onto this for a few days as quite oftem dont get time during the week, but, I will report progress back to the forum..
thanks again,
Paul
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are you using the right size bearings ?
just a thought, if you are shim it like steve said
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The crown race should be a tight fit so shim the fork to fit and all will be perfect :daumenhoch:
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Putting some loving back into the forum..
I did the coke can think and works fab!! I put some folds in the can to ensure the can says in place, as shown:
(http://farm7.static.flickr.com/6006/5951849482_d24ce290db_z.jpg)
(http://farm7.static.flickr.com/6145/5951850852_6287fa9a06_z.jpg)
(http://farm7.static.flickr.com/6023/5951297481_6f8bbc5c85_z.jpg)
Finally, with it all assembled and clamped down, pretty much invisible:
(http://farm7.static.flickr.com/6009/5951299171_9cae7c6448_z.jpg)
Huge thanks to all that helped out!!
Paul