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Re-posted in correct forum.
I have a second hand set of 1 1/8 steerer 29er forks measuring 188mm and am looking to fit them to a frame with a steel 44mm - 120mm long head tube.
Not yet ordered - so want to check first!!
I am thinking it will fit but there are not many dimensions on the HOPE website, so assuming all Hope components.
Top Bearing - should be 2mm ish (integral/ integrated?)
Bottom Bearing - 1.5" external 12mm ish
Reducer crown 1.5" to 1 1/8" - 3mm ish.
Stem - 45mm ish.
120 + 2 + 12 + 3 + 45 = 182
So it seems that I will have room for a couple of spacers.
Anyone with better knowledge of the measurements able to assist?
Your measurements seem reasonably sound, from memory of mine.
I'd add another 3mm onto the top bearing maesuremnt as you have the lip of the cup then the plate type bit probably taking it closer to 5mm.
I am presuming these calcualtions are to figure out wether or not to go for the external lower cup as you could go for a standard zerostack lower cup?
If you are wanting exact size give Hope a call they are generally a very helpfull bunch.
If you're worried about steerer length, why are you using the 1.5" External bottom cup?
Hope do a 44mm internal (They call it the "semi-integrated" or "integral") - it's the Lower type "B".
Cotic frames with a 44mm headtube are designed to run with an external bottom cup only. Running an internal bottom cup won't leave enough room for fork knob downtube clearance.
Running an internal bottom cup won't leave enough room for fork knob downtube clearance.
depends on the forks
Well... an external cup, such as the Hope one Orangejohn is looking at, will take ANY fork safely in future (whatever the knobs are, including those with tapered steerers), and won't change the handling.
[url= http://www.cotic.co.uk/geek/44mm ]www.cotic.co.uk/geek/44mm[/url]
Every day is a school day, I wouldn't have even thought a frame would be designed with a external lower cup in mind.
I still think Orangejohn will be ok with the steerer length he has but it will be pretty tight.
If Cotic are selling the frames with the Hope headsets as recommended parts then I would hope they would also be able to shed some light on the minimum steerer length a fork would be required to have to fit a particular sized frame.
With a 44mm headtube, you have to use an external bottom cup to fit a tapered steerer in (I think), so makes sense to design around that. Internal on the top makes sense to keep the bars low however.
Thanks all.
Was following the Cotic website re the 1.5 outer lower cup.
John
You definitely have to use external bottom cups on the Solaris and Rocket.
Regarding your calcs, you've got it all correct apart from the top cup. As mentioned by someone else, stack height is nearer 6mm on that. Your stem will go on.