My bike has a 1” threadless steerer tube with a shim to accept 9/8” stems. If I want to add some height, is a standard 9/8” extender the only way to go?

Threadless one inch stems are not easy to acquire. What is available is pretty limited in choices. So probably, 1 1/8 inch stem is the easiest way to go with the most choices. How long is the steerer tube and is there enough length for the stem and some spacers?

I am not sure what you're asking.

​​​​​​Here are a few things to know though.

A 1 1/8 stem with a shim is by far your best bet. For most models, it's your only option.

1" spacers are available on Amazon and eBay if you look. It's easy to forget the fine print and have 1 1/8 sent instead. Be detailed in reading product descriptions.

You can raise your handlebars three ways with a threadless stem.
1. Get a new stem with a higher angle. Adjustable is even available. Typically not a great aesthetic choice but probably the easiest and most accurate way.

2. Add spacers under the stem, not possible if the fork is already cut. I bet you can't do this with your bike or you probably wouldn't be asking. Of course this becomes possible again if you buy a new fork but I'm assuming you don't want to do that.

3. Get a commercially available extension. You install it around the steerer and put the stem above that. You'll probably still need your shim. This limits you to a minimum of 2" raised up. It's a great option for a big change, not micro tweaking.

How much higher do you need? I very strongly prefer high angle stems to steerer extenders. Stem Comparison Tool | yojimg.net is a great tool to figure out what stem you need to acheive a given change of handlebar position.

1 1/8 steerer extender a 1" steerer sounds sketch to me

if you use one of those, you will have to in some way account for the difference in diameter with your spacers. it can get a little fussy to make it all look and function right. what i've done is used a chromoly 1" quill steer column extension. it fits down in your existing steerer column and tightens up like any quill stem and you just cut off the height as you need it. shove a star nut down in it for your preload, add more 1" spacers and continue to use your existing shim/stem and top cap. fyi, uno makes some decent looking 1" threadless stems. otoh, there are sometimes good deals with ebay on vintage ones.


it fits snugly with no play and remains nice and tight. very secure feeling
https://www.ebay.com/itm/CROMO-Quill...g/153214219733

If your adapter is already as high as it can safely go, you've got two choices:

1) A longer 1" threaded to 1-1/8" threadless adapter. The really long ones tend to be steel, heavy, and crappy. (Maybe someone makes a long-quill version that doesn't suck, and if so, buy that one and Bob's yer Uncle.) This is the easiest, cheapest way to do this.

2) Replace the adapter-and-stem combo with a high-rise 1" threaded stem. These are not hard to find, but the good ones aren't cheap. (Nitto, mostly... really well made, in Japan, and priced accordingly.) Depending on your handlebars, you may need new ones. You will have to strip and re-wrap the bars... quill stems, for reasons unknown to anyone, don't have removable faceplates. This is the more expensive, better looking, and more correct way to do this.

--Shannon

PS: I have a threadless adapter and stem on my '85 Fuji. It works and looks fine, given where my bars are.

4) use a BMX seat post clamp to lock down the headset:

And then run a good ole fashioned quill stem:

Sky's the limit

Dude.

I can't decide if that's genius or madness.

Bike Hack Hall of Fame, this. I am unworthy.

--Shannon

[QUOTE=ShannonM;22070710]Bike Hack Hall of Fame, this.[​​​​​/QUOTE]
It's okay, a clever kludge.

You want bike hack hall of fame, I reckon my internal Di2 retromod rates, except nobody seems to give a crap, wtf