Stem faceplate uniformity
 

This may be a dumb question, but I don't have a bunch of stems laying around to test this:

Are most (not all but at least most) 4 bolt stems uniform in the distance between bolt holes on the face? For example, if I'm holding Thomson X4 and Ritchey Classic stem faceplates in my hand, would the bolt holes line up? Or does each brand have a different standard and measurement?

I can't speak to your specific example, but I know from experience that horizontal spacing is not uniform. I have a MOST out-front mount that will work with a Zipp stem but not with many others I have tried.

That's what I'm getting at really. Iffin I were to buy a computer mount that bolts up to the stem, then would it be expected to work with pretty much any 4 bolt stem? Cane Creek make this sort of thing, but I think it's awfully inelegant. Maybe if I made my own faceplate and mount unit, that would look a little nicer.

Thanks for the input!

There is likely some overlap between brands (for example, I think the older Enve faceplates had the same bolt c-c as Paragon faceplates, commonly used on custom ti stems...), but as a general rule, there's lots of variation.

I wouldn't count on it. Not only do different brands often use different bolt spacing, there is sometimes different bolt spacing on different models of the same brand.

Check out the F3 Cycling computer mount. It works fine and is very secure once aligned and tightened down. It looks good, too.

I have one of those, recently replaced my Zipp stem with an S-Works so had to use the F3 for the first time. While it looks ok, I much prefer the MOST one I had before, for two reasons:

- it’s very difficult to get the moveable arms to end up symmetric; after torquing one bolt tightening the second will cause the mount to shift a bit. Not a big deal but if you’re OCD about things lining up it may bother you (it does me, though I can live with it).
- the curvature of the underside of the mount will not allow the use of a GoPro mount with the existing bolts. I’m planning to visit a hardware store to try and get longer ones but am not optimistic about finding stock. Presumably I can find some at McMaster.

F3 also sells a $9 bridge tool that holds the arms in place while you tighten the bolts. I spent the extra dollars because, yes, I can be OCD and couldn’t live with it.

https://www.sefiles.net/images/libra...40869_10_m.jpg
https://cdn.sanity.io/images/pbcwwn3...4-1180x640.png
https://cdn.shoplightspeed.com/shops...m-mtb-road.jpg

It is absolutely not a safe assumption that bolt spacing is the same on all 4-bolt stems when spacing is not uniform within a single brand.

Nearly every bolt spacing pattern you could ask for... They're good about listing some brands within their mounts, but also provide the c-c bolt spacing for those one off stems they don't mention...

https://framesandgear.com/en-us/coll...omputer-mounts

I think this guy is sleek enough and should fit your needs.

https://www.amazon.com/Dymoece-Exten...1H/ref=sr_1_10