fork selection help (for a 1 3/8", 25cm head tube)
12-01-13, 09:37 PM
#1
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fork selection help (for a 1 3/8", 25cm head tube)
I have to buy a fork to complete (or rather as the first building block for) a very nice Serotta steel and carbon frame.
But I am confounded by how long (and even how big a diameter)I need.
The head tube is 25cm long, 1 3/8" diameter. Period.
The seller says he was using a fork with a 30cm steering tube but that he found it a bit short and so used an adapter. I would like to avoid adapters.
But still, 5cm (2") clearance seems sufficient ... (hmm, maybe not, standard stem seems to be 4cm tall. )
so, how much clearance should I be looking for once the races are installed?
the longest I am seeing on a carbon fork is 30mm.
and what's the steering tube diameter required for a 1 3/8" headtube? I have to imagine it's 1 1/8" no?
But I am confounded by how long (and even how big a diameter)I need.
The head tube is 25cm long, 1 3/8" diameter. Period.
The seller says he was using a fork with a 30cm steering tube but that he found it a bit short and so used an adapter. I would like to avoid adapters.
But still, 5cm (2") clearance seems sufficient ... (hmm, maybe not, standard stem seems to be 4cm tall. )
so, how much clearance should I be looking for once the races are installed?
the longest I am seeing on a carbon fork is 30mm.
and what's the steering tube diameter required for a 1 3/8" headtube? I have to imagine it's 1 1/8" no?
Last edited by pstock; 12-01-13 at 10:03 PM. Reason: typos
12-01-13, 09:46 PM
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I have to buy a fork to complete (or rather as the first building block) a very nice Serotta steel and carbon frame.
But I am confounded by how long (and even how big a diam) I need.
The head tube is 25cm long, 1 3/8" diameter/
the seller says he was using a 30cm but that he found it a bit short and so used an adapter. I would like to avoid adapters.
But still, 5cm (2") clearance seems sufficient ... hmm, standard stem seems to be 40mm tall.
so, how much clearance should I be looking for once the races are installed?
the longest I am seeing on a carbon fork is 30mm.
and what's the steering tube diameter required for a 1 3/8" head tube? I have to imagine it's 1 1/8" no?
thanks
But I am confounded by how long (and even how big a diam) I need.
The head tube is 25cm long, 1 3/8" diameter/
the seller says he was using a 30cm but that he found it a bit short and so used an adapter. I would like to avoid adapters.
But still, 5cm (2") clearance seems sufficient ... hmm, standard stem seems to be 40mm tall.
so, how much clearance should I be looking for once the races are installed?
the longest I am seeing on a carbon fork is 30mm.
and what's the steering tube diameter required for a 1 3/8" head tube? I have to imagine it's 1 1/8" no?
thanks
12-01-13, 09:48 PM
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is the 1 3/8 measurement for the bare frame measurement? if the id of the head tube is 34mm then you need a standard 1 1/8 external cup headset. you can look up the stack height from the manufacturer.
12-01-13, 10:04 PM
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"Perhaps a proof read is in order?"
sorry, it's late.
But still, there's no excuse for bad writing.
sorry, it's late.
But still, there's no excuse for bad writing.
12-02-13, 09:08 AM
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what's the longest steerer tube typical on a fork? if not, how to adapt.
OK, revised question.
having done some research and math it seems that a HS usually has about a 4cm stack, a stem is about 4cm tall and on a 25cm headtube (= 33cm) I am going to need at least 25+4+4+spacers... ~= 35cm steering tube?
Does that even exist? I've not seen one in all my searching around. (30cm seems to be the max.)
If >30cm does not exist, how does one make a 30cm work on a large frame?
having done some research and math it seems that a HS usually has about a 4cm stack, a stem is about 4cm tall and on a 25cm headtube (= 33cm) I am going to need at least 25+4+4+spacers... ~= 35cm steering tube?
Does that even exist? I've not seen one in all my searching around. (30cm seems to be the max.)
If >30cm does not exist, how does one make a 30cm work on a large frame?
12-02-13, 10:55 AM
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A 30 cm threaded fork will work since the steerer need to be only the length of the headtube plus the headset's stack height. Unfortunately 1-1/8" threaded forks, and quill stems, are quite rare. For a threadless set up, yes, a 30 cm steerer won't work on your bike and you need about 35 cm.
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