stem diameter...

cambo

Hi, I have an old marin hawk hill that i use to commute, i have recently bought a brand x stem and handlebar combo from crc, when i attempted to fit the stem to my bike it wouldn't go over the headset (?). I have measured the headset and a 25.4mm stem should fit. Do i need to manipulate the stem with a flat screwdriver in order to force it on, as basically the stem seems to be the exaxt width of the headset and would probably only need a small amount of flex in order to go on. Or altenatively, do i need a wider stem (31.whatever it is)?

Any help appreciated.

I think the hawkhill is around 98 or 99 edition, it may have been the first to have a front suspension fork, if that is of any help to anyone. As my wife would say, its black, if that helps anyone...

Cheers

Cambo

supersonic

Is it a threaded or threadless headset/fork steerer?

the 25.4 and 31.8 refer to the handlebar diameter.

Most modern bikes use a threadless steerer, with a 1+1/8th inch diameter (28.6)

Older 1inch headsets are rarer with threadless systems, which is a 25.4 diamter.

cambo

Hi, its threadless.

Cheers for the quick response.

Cambo

nicklouse

so what was the steerer diameter that you measured? 1 1/8th? 1 1/4? or 1"

cambo

It appears to be 1 1/4", but I'm a metric child, born into a european dream!!!!

nicklouse

so what is it in mm then.

and if it is 1 1/4 and not 1 1/8 good luck as hens teeth would be easier to find.

what is the for? some old rigid fork?

Splasher

cambo wrote:

It appears to be 1 1/4", but I'm a metric child, born into a european dream!!!!

31.75mm?

tjm

cambo wrote:

It appears to be 1 1/4", but I'm a metric child, born into a european dream!!!!

if it helps then 1 1/4" is 31.75mm (or maybe 31.8 clearance). Not to be confused with the 31.8mm that is common for handlebars though if you are looking for that size stem.

I am assuming (as has everyone else) that when you say "goes over the headset" you mean "goes over the steerer tube". The headset is the bearing bit, the steerer tube is the bit that comes up from the forks (through the middle of the headset) that you clamp the stem to.

So you need to measure the steerer tube accurately.

1" = 25.4mm
1 1/8" = 28.6mm
1 1/4" = 31.75mm

Toby

tjm

oh, and to answer one of your original questions - if the stem is the the wrong size (eg 1 1/8th and the tube is 1 1/4) then don't try to open it up and force it on. Even if you managed then there is a big chance of a failure later.

EDIT: On the other hand, if they really do measure the same size then a screwdriver in the slot to open it up slightly is not a problem. but it should only need to be sprung slightly, not bent open!

cambo

Its to go on an old marin i use to commute, its got a suspension fork, buts its so old the fork has no suspension left!!! Thanks for all your replies, i think a trip to my lbs is the order of the day, or i'll have to get used to the uncomfortable overreach...

nicklouse

if sus then i would say it will be 1 1/8th as i am 99% certain there are no 1 1/4 sus forks out there.