Does anyone know of a solution for running a 30.9 post in the ibis frame? I would hate to have to part with my Specialized command post.

Gravity dropper has a shim to go from 30.9 to 31.6. It's for their 5" post.
I've seen it, it's like a beer can thickness.
I'd give them a call and see if you could buy one.
I imagine they would have some in stock. I could see damaging one pretty easily if say, it fell on the ground and you stepped on it accidentally.
Based on their website it might be about $6.

edit, it would be sweet if Ibis had the 30.9 to 31.6 shim in their online store.

 

I have been running a shim in my reign x for 4 years with no issues, but a word of warning, check with Ibis first to make sure it won't cause any issues. I know that Knolly cautions against shims because it localizes the forces on the seat tube and can cause frame failure.

Good luck!

 

I will drop Ibis an email to see what they have to say and if it's ok. Will also have a look at the gravity dropper web site.
Thanks

 

Looks like the gravity dropper shim wont work as they are 27.2 ID not 30.9. There may not be anything available that small? .7mm difference in size would mean a wall thickness of .35mm.

 

Looks like the gravity dropper shim wont work as they are 27.2 ID not 30.9. There may not be anything available that small? .7mm difference in size would mean a wall thickness of .35mm.

Yes it will, you need to call them and ask about the 30.9 to 31.6 shim. It's not listed on their website. I know it exists, I've held it in my hands. It's super thin.

 

I have the 30.9 to 31.6, bought it with my AMP post. They definitely exist.

 

Beershim

Gravity dropper has a shim to go from 30.9 to 31.6. It's for their 5" post.
I've seen it, it's like a beer can thickness.

Speaking of beer can thickness, when my buddy first got his Mojo, he and I were poised for his Mojo's maiden voyage on an away (Tahoe) trip before he realized his dropper post was 30.9 vs. 31.6. In desperation we literally cut a rectangular shim out of a beer can. Worked perfectly for three all-day rides. (Though you better check w/ Ibis before trying that.)

 

(Though you better check w/ Ibis before trying that.)

They'd probably say it's fine, as long as it's not Coors or Bud Light.
Guiness can is recommended if the frame is the right color. :thumbsup:

 

Thanks All, I will give gravity dropper a call.

 

I have the 30.9 to 31.6, bought it with my AMP post. They definitely exist.

The AMP post is 27.2. Mine came with a Cane Creek shim. CC might have a shim size to fit the Command Post.

Otherwise sounds like a beer can shim could work. Ideally the shim should be 4 inches long into the seat tube to maintain long term durability of the seat tube. A beer can shim could be difficult to get to fit well.