csport

Hi

Is it OK to cut the crown race of Ritchey Comp headset with Dremel? It has "semi-cartridge" bearings such that the bearing balls do not contact the crown race directly. I know that for example Cane Creek 10 has a split crown race.

I tried greasing it and setting it using a PVC pipe, no success. Both the headset and the fork (Bikeman 26" rigid fork) are new.

Should I remove some metal with a sandpaper?

bboy314

Have you checked that the crown race seat on your fork is the same size as your crown race? Is this a 1” or 1 1/8” (or other) steer tube?

csport

Threadless 1 1/8" 26" canti fork: https://www.bikeman.com/CARV-FK410S-S1009-RK.html
The headset is EC34/30, 30 is the only thing Sheldon Brown's cribsheet lists for threadless 1 1/8".

Edit: thanks for the help, I see that there are multiple standards for 1", this is 1 1/8".

FBinNY 

Since the fork is new, have you measured the crown race seat? New forks are often sold with the crown race seat not cut to final size.

csport

Tried measuring with a digital caliper,
OD of the fork measured 29.95, 29.97, 29.96, 30.03
ID of the crown race measured 29.66, 29.70, 29.49, 29.75, 29.67

According to Park Tool Table #5 the difference should be 0.1 mm (30.1 fork seat, 30.0 crown race - maybe my caliper is off by some amount), mine is less than that.

FBinNY 

First of all, I prefer interference closer to 0.05mm.

Secondly, start by calibrating your caliper on a known dimension. You can use the steerer tube itself, which should measure 28.58mm pretty spot on. Or if you have a printer at home, count 10 sheers of paper which will measure 1mm. You probably can't change the caliper itself, so write the correction factor on it with a Sharpie.

Also, practice taking measurements until you develop the "touch" needed for accurate, consistent measurements. If you cannot get spot on consistency on s dial caliper, it might be a dirty rack.

FWIW - headset parts are generally spot on, so it's pretty safe to assume it's the fork. If so. You have 2 choices; pay a shop to mill the crown to spec. Or use the cut of disc on your Dremel to split the centering cone (not crown race).

BTW if you opt for splitting the cone, do a file test first, because if it's too hard, it may crack when it tries to flex.

maddog34

If your calipers aren't defective, That crown Race is DEFECTIVE... Send it back, Take it Back, or throw it away.

update: out of curiosity i just measured a Cane Creek "40" cr and an FSA Pig cr... and a third crown race from my parts bins...All three Crown Races were spot on at 29.95mm... Mac Tool Digital caliper, 10+ years Machine Shop experience... no "out of round" variances noticed.

csport

I tried measuring the steerer tube at different points several times, and I get 28.54 .. 28.60 mm, which is more or less correct. The fork measured 29.95 .. 30.03, which probably means it was more or less 30 mm and the problem was with my "tool" (PVC pipe) and my skills. I paid the shop to do it, looks like I was able to convert the Hardrock to rigid/threadless. Thanks for the help!

I can change the caliper to some extent, it has a reset button which sets the current position to zero: https://wenproducts.com/products/ele...d-storage-case

I think my problem was the wrong measurement of the inside diameter: if we draw the line through the two points of contact between the jaws and the crown race and this line is x mm from the diameter parallel to it the measurement will be 30 - x^2/15. If we are just 1 mm off of the diameter the measurement will be 0.07 mm off.

Another take home for me is to use proper tools. Probably I was not able to install it because I used a PVC pipe instead of a proper metal tool. I remember how I used a threaded rod instead of a proper headset press in the past and how painful it was. Now I have a headset press and it literally takes 5 minutes to install the cups.