How to reduce down from 1 1/8" head tube to 1"? What all is needed?

GrantYoungPhoto · Sep 7, 2014

Hey guys, me again. I apologize for what are probably silly threads but I'm new to all of this! I'm building my bmx/lowrider/ratrod inspired bike and it has a 1 1/8" head tube. All the forks I'd like to use are 1" so I need to reduce down. Can anyone help me out on what parts I will need to change my bike over to accept 1" parts?

I know I need the reducers and the fork, but I imagine bearings and possibly the stem will need to be changed as well. Any help is much appreciated as I hope to get this thing in order pretty quickly.

Bicycle808 · Sep 7, 2014

You'll need the reducer cups, the new fork, and the appropriate 1" headset. You'll need a new stem if you're going to threaded, or you'll need a shim if you're staying threadless.. You could also use a quill-to-threadless adaptor if you're going to a threaded set-up, although i can't imagine why you would.

Generally, they way these things work is like this: show us what you've got and what you want, and we'll help you fill in the blanks to make it work, if possible. :grin:

ozzmonaut · Sep 7, 2014

Not sure what your skillset is, but I'd make adapters. Either weld something into the headtube or weld something onto the cups. Or wrap some thin strip of steel around the cup you want to use and place that into the headtube. Whatever cups you downsize to should have the bearings present. If you purchase a complete headset, it includes cups and bearings. If you get them from a donor bike, then hopefully the bearing are in the cups. You will need a stem with an O.D. that closely matches the I.D. of the steer tube on the fork you want to use. Like said above, show us your start and desired finish point. Everything else is just steps.

GrantYoungPhoto · Sep 7, 2014

I got some photos for you guys, the end goal is to have a black springer front end (can paint it) on the bike for sort of a hot rod/jalopy feel. I do t want the insanely curved springer, just the more mild one.

GrantYoungPhoto · Sep 7, 2014

This shows that it is for a threaded setup, which looks to be how the lowrider forks are set up. This would be all I need I believe.

http://www.bicycledesigner.com/bike-parts/bicycle-headsets/headset-conversion-kit-1-1-8-to-1.html

Bicycle808 · Sep 7, 2014

Yes, that's about it, plus a stem.
http://www.bicycledesigner.com/bike-parts/bicycle-stem/stem-for-threaded-headset-1.html (same retailer you'd already linked.) One pitfall to be aware of is that 1" threaded forks will take either a 26.4 or 27.0mm crown race. Most of these new-school lowrider springers will likely run a 27.0, so I suspect that's what comes with that kit. don't worry too much, but be ready to address that if it becomes a problem....

Your mission right now is to get a length of fat all-thread with a coupla big nutz and washers, to install those reducers and headset cups.... that's a hardware store "tool" that you can get while waiting for components in the mail.....