Uploaded June 2026 | Updated September 2026, 2 weeks ago
Kudos to Winspace (not sponsored) for clean, proper threads on the BB shell and for using carbon encapsulation to fight galvanic corrosion. It's good engineering, and it's becoming more common on newer carbon frames. But it can create a hiccup at install.
You're doing everything right. Fresh frame, clean components, and the bottom bracket just won't start. One side threads in perfectly. The other side? Nothing.
Here's what's happening. Older frames had a machined aluminum surface where the threaded insert met the outside of the shell. Clean, flush, no surprises. Newer frames wrap carbon over and around that insert — it looks clean from the outside, but that carbon lip is sitting higher than the actual threads. Sometimes by 2, even 2.5 millimeters.
Carbon fiber is not threaded. So that lip is physically blocking your bottom bracket from catching.
It's not a defective bottom bracket. It's not a defective frame either — that encapsulation is there to reduce galvanic corrosion, which is a real problem. But the execution creates this situation.
The fix: you need to thread that carbon. Cut right through it so your bottom bracket can engage the actual insert underneath. Once that lip is cleared, the threads catch and it goes in by hand.
We used our polymer stabilizer ring as the final test — if that threads in clean, you're good. And it did.
If you're not comfortable doing this at home, that's fair. Chase the frame or bring it to a shop. We've also got a separate video on facing carbon frames on the BBInfinite channel — worth a watch before you touch anything.
Ever run into this on a new frame? 👇"
Kudos to Winspace (not sponsored) for clean, proper threads on the BB shell and for using carbon encapsulation to fight galvanic corrosion. It's good engineering, and it's becoming more common on newer carbon frames. But it can create a hiccup at install.
You're doing everything right. Fresh frame, clean components, and the bottom bracket just won't start. One side threads in perfectly. The other side? Nothing.
Here's what's happening. Older frames had a machined aluminum surface where the threaded insert met the outside of the shell. Clean, flush, no surprises. Newer frames wrap carbon over and around that insert — it looks clean from the outside, but that carbon lip is sitting higher than the actual threads. Sometimes by 2, even 2.5 millimeters.
Carbon fiber is not threaded. So that lip is physically blocking your bottom bracket from catching.
It's not a defective bottom bracket. It's not a defective frame either — that encapsulation is there to reduce galvanic corrosion, which is a real problem. But the execution creates this situation.
The fix: you need to thread that carbon. Cut right through it so your bottom bracket can engage the actual insert underneath. Once that lip is cleared, the threads catch and it goes in by hand.
We used our polymer stabilizer ring as the final test — if that threads in clean, you're good. And it did.
If you're not comfortable doing this at home, that's fair. Chase the frame or bring it to a shop. We've also got a separate video on facing carbon frames on the BBInfinite channel — worth a watch before you touch anything.
Ever run into this on a new frame? 👇"
