Help with new forks please - steerer length

miss notax

Hello

I have my eye on some second hand forks for my Santa Cruz build, but they have quite a short steerer length (180). How can I check that they'll fit? The Santa Cruz is literally in bits - is it a case of measuring the head tube and adding a bit??!

Can someone please explain simply how to check this? I don't want to get them, only to find they won't fit!

davewalsh

Add together the headtube, stack height of the headset and stem, the amount of spacers you want and subtract 3mm. this gives you the steerer length.

miss notax

Thanks - i've ordered a new headset (which isn't here yet) and I have no idea how many spacers I want / need....

Any way to get an indication from the headtube length? Obviously I couldn't care less if the steerer is too long - it just can't be too short!!!

cycleclinic

You will have esimate the hieght you will need the stem at and go from there.

miss notax

Thanks - just measured the bits and the headtube length is 90mm and the height of the stem is 40mm, so 130mm in total. Does this leave enough for the headset....?

Have also just measured the Orange - the headset and spacers etc take up about an additional 40mm (quite a lot because I had to add spacers because of the geometry - the forks hit the frame when twisted otherwise). So 130mm plus 40mm (high estimate!) is 170mm, so they should fit??

Sorry for all the daft questions - with my limited bike knowledge, I am struggling to work out if this work or not! The Santa Cruz is having 100mm forks fitted whereas the Orange has 140mm, so the SC shouldn't have the clearance issues of the Orange....

Anyone follow my logic??!

ricardo_smooth

plus the spacers you will be running (call it 30mm) plus the headset (call that 20mm for top and bottom cup with the associated gubbins) = very tight guess work if they turn out to be too short.

benpinnick

Its very simple to estimate if you know the stem and headset make & model. You just need to measure the headtube, add the stem stack height (which you should be able to google) add the Stem height, and then see where you are at.

miss notax

Thanks

Headset stack height 31.4mm + headtube 90mm + stem height 40mm = 161.4mm

Am thinking these might be worth taking a punt on - if i'm wrong then hey ho!

1mancity2

you should be able to run 15mm of spacer if the steerer is 180mm, so you have some room for error, err adjustment.

miss notax

Thanks for all of your help guys - but as sods law would have it, I didn't win the auction for the forks :?

Hey ho, at least I now know all about steerer lengths!