Dimension

Steerer Adaptor 1" Quill to 1-1/8" Threadless

This part is designed primarily from the MTB folks. For them, this adapter should serve admirably in all respects. It is far stronger than roadies will need so there's a weight penalty for them. It is also a bit too long for most applications (especially small frames) but alternative products are often too short. The effective length of this adapter is 194mm when the wedge lock will begin to hold the adapter in place. The stem clamp area is about 49mm so with a stem like a Thomson X4, there's about 10mm of vertical adjustment.

I bought this quill stem adapter for my 90's era Specialized Rockhopper. I wanted to use a modern 1-1/8" threadless stem and longer handlebar with a 31.8mm thick middle section. The stem adapter is about 7" long and has a minimum insertion of 2-3/8" which leaves up to 4-5/8" for height. The stem adapter appears well made and solid even though it is aluminum. I wouldn't worry about it snapping. The steel angled nut at the end of the stem bolt was drilled slightly crooked, but since it is going inside a 1" steel steerer tube, I am not worried about it. I greased it lightly to prevent seizing and the 13nm torque on the stem bolt appears adequate to prevent movement. It wasn't until I read the instruction sheet that came with the part that I realized this adapter is recommended with a handlebar not longer than 660mm. This is not mentioned on any of the online information. I am using it with a 750mm handlebar, but I will not be engaging in any major jumps or anything beyond typical XC riding. This is not the lightest quill stem adapter out there, but I appreciate the extra length and trust quality of its construction. It is lighter than the chromoly quill stem it is replacing.

This is a nicely made quality product. It works for my road bike application. I was looking for about 2.5 inches (6 centimeters) or more of space from the top of my steerer tube to the bottom of the 1 1/8" part of the adapter and I got it without going over the limit. So I am using 3 FSA spacers that are 2 centimeters each. I am also using a 1 centimeter spacer under the FSA stem to make the top flush with the top of the adapter. It looks reasonably good and is very sturdy. When you get old and have a stiff back, it helps to be more upright on the road bike.