[Herm99]

I'm looking at a fork that has the steerer precut to 185mm, i want to purchase it but need to know what size steerer i need. Is there a quick way to measure this?
Thanks!

 

[cutthroat]

Measure your headtube, add the stack height of your headset, add the height of your stem, add any spacers that you currently run on your stem to get your desired bar height - your steerer tube needs to be at least this long.

 

[ddraewwg]

I'm looking at a fork that has the steerer precut to 185mm, i want to purchase it but need to know what size steerer i need. Is there a quick way to measure this?
Thanks!

185 mm = 18.5 cm ~ 7.28 in.

There isn't a length steerer tube that you "need" but you need to make sure 7.28 in. is long enough. How you calculate this is pretty simple. You just add up all the dimensions of your front end....

So basically you need to know the following:
-Your HT length (manufacturers typically list this and it's size specific).
-Take into account your headset cup height (unless it's an integrated system)
-Stem height
-Allow for spacers (I always allow at least 1" of spacers underneath the stem jic) unless your headset has a tall "cap".

Remember, you can always cut it short but you can not (not really anyways), lengthen the steerer tube.

 

[Herm99]

why do i need to know the HT length? How do i factor that into the measurement? I was hoping i could just get a measuring tape and measure the length of my steerer from the top of the fork to where it connects to the stem.

According to the website my bike has;
wheelbase of 104.2cm
headtube of 10.5cm
and actual frame size is 40.6cm (whatever that means!)

 

[ddraewwg]

why do i need to know the HT length? How do i factor that into the measurement? I was hoping i could just get a measuring tape and measure the length of my steerer from the top of the fork to where it connects to the stem.

According to the website my bike has;
wheelbase of 104.2cm
headtube of 10.5cm
and actual frame size is 40.6cm (whatever that means!)

The steerer tube has to go "through" 4 things

1st: The bottom headset cup
2nd: Through the headtube (HT)
3rd: Top headset cup
4th: Stem
5th: Any/all spacers.

So to determine how long of a steerer tube you need, you need to make sure that it will go through all 4 of these things from bottom to top or else you're not going to be able to secure the stem. It's not a hard concept but you don't want it short or else you're screwed.

 

[cutthroat]

If you already have a fork, just measure the existing fork's steerer. I assumed you didn't have that measurement. You need to know your HT length because the fork steerer goes in the HT and you need enough space to still install your stem and headset.

 

[Herm99]

LOL...i totally misread that, when you said HT length I thought you meant Hardtail length. I was thinking how did he know i have a hardtail? LOL. HT = headtube. Got it, ok gonna make some measurements here then. THANKS!!!!!

 

[billyboy197]

185mm is going to be tight so you need to measure accurately before you make the purchase. I have three bikes with 100,110,120mm Head Tubes and use 190,200,210mm steerer tubes respectively with fairly 'standard' non integrated headsets and stems and a few 5mm spacers. As a very rough guide HT+90mm so 185 may be snug with a 105HT and no spacers.