RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: telelogic on July 18, 2010, 04:31 PM
-
Hi All,
I'm trying to fit a new set of forks on my race bike.
the problem I'm having is that the steerer tube on the new forks is quite a bit shorter than the one on the old forks and it doesn't come to the top of the stem!
the top hat bolt goes on alright with the stem on, gets a purchase, and tightens up.
I'm just not sure if the fork steerer should come all the way up?
when I tried tightening my stem bolts they seemed to tighten way more than before.
any help would be very much appreciated.
-
thanks.
is there a chance that a brand new fork would not be long enough for the job?
-
ideally top of fork steerer should be about 5mm below the top of stem
-
It's more like a half a n inch ???
-
How many spacers have you got below the stem?
-
piccies :daumenhoch:
-
the new macneil forks are short, couldnt use any spacers at all
-
You can buy headsets with a really low stack height - that might sort the problem. :-\
-
:) What frame/headtube (integrated,regular 1 1/8 etc) is it? Some forks that are designed to work with Campy integrated type headsets are too tight fitting to work with frames that use regular headsets.
-
It's a 2007 Kuwahara laserlite.
1-1/8 integrated. the headset is a cane creek (standard on the the bike)
-
:) Do your new forks have a built-in crown race & you`ve fitted a regular crown race onto them? (I know someone who did this!)
-
I'm pretty sure that they don't.
they are budda bing forks from UK bike co.
the crown race that I've moved over from the other forks does look a bit unusual compared to the ones I've seen on tutorials about fitting headsets/forks.
I may just pull it all apart again to see if I've made any obvious rookie mistakes.
-
I've taken it apart and it would appear that it has a built in crown race.
the reason I didn't notice this is that it's such a slight incline at the bottom of the steerer tube!
I've put it back together, the tube still does not come that close to the top of the stem. still about a 4mm gap!
I think I'm going to have to annoy my local bike shop! give you guys a rest ;)
-
:) How many/what size spacers are under the stem? About a 4mm gap sounds just fine to me,especially if you have just one 5mm spacer...
-
I have no spacers.
-
I've got a pair of uk forks and mine dont have a crown race built in
Has the frame you're using got an external or internal headset?
The headtube on this frame is 4 and a half inches and the steerer tube on the forks is 6 and 3 quarter inches measured from bottom of headtube on the frame to the topcap, these are uk forks....
(http://www.radbmx.co.uk/archive/albums/m48/markw33/27-05-10004-3.jpg)
If the forks you've got are secondhand they might have had the steerer tube cut down
-
I have 2 sets of the lugged forks, and neither of them have had this problem!
The new (un-lugged) forks are brand new and haven't been cut down.
the bike has an internal headset.
I think my Funn stem might be unusually high?
some of the Uk forks have a built in race and some don't. I'm hoping mine have. there is a slight ramp at the bottom like I said.
-
That Profile stems an inch and a quarter thick where the steerer goes through
If you've got more than one pair of forks take another pair off a bike and have a comparison
-
my UnKnown forks don't have a crown race built in either and went on fine, i had to use a few spacers as normal :daumenhoch:
4mm though from the top of the stem is about right, you need a small gap so the top nut can clamp down onto to top of the stem :daumenhoch:
-
Mine are just too bloody short >:(
-
Got them off and measured the steerer, 165mm.
I don't know if any of you can hold a tape measure up to your head tube to see if yours are longer than mine? (steady!)
It may be that the head tube on my bike is unusually long?
they aren't going to fit anyway, so the forks that came with the complete are going back on. :'(
this hobby can be a cruel mistress ;)