CMC arthritis (thumb)


CMC (carpometacarpal) is the most common type of thumb arthritis. The joint at the base of the thumb deteriorates, causing pain when grasping. I think years of shoveling, running fire hose, air-powered tools, etc. probably did it to me.

Modifications made to a Haibike HardNine 1.0 medium frame. I'm 6' tall. My guess is if you fall between two frame sizes, the larger frame will help you get your hands higher. I'm happy with the medium frame but wonder if the large woulda been better.

AFAIC the first thing to do is get the weight off your hands. I bought an Outerdo stem extender. This moved the bars up to a more neutral position. If I felt like I needed more I'd replace the OEM stem with an adjustable stem like this bomb-proof Ritchey. Notice the Ritchey has three different extensions. I don't know which length would be best. The shortest one would keep the bars closer to the steerer tube so you're not reaching as far forward, but would also give you less height if you've got the stem cranked nearly vertical. I bought the 90mm but have not installed it.

A friend has a Radbike with a Zoom adjustable stem. He's a big guy so he puts some stress on the parts but he hasn't ridden the bike all that much. The stem started to clank around. We disassembled it and found some of the splines had worn. We were able to get a bite on some fresh splines (hard to explain but it's possible) but I expect the problem to come back. The Zoom is much cheaper than the Ritchey, but you get what you pay for.

If you're going to move body weight off the bars to the seat you need a comfortable seat. Bought a Cloud 9. Big improvement.

I cut an inch or so off each end of the handlebars. Think about it: as the bars go wider, what part of your hands reach the bar first and take more pressure? That's right, the thumb area. Exactly what I didn't want.

Ergon GP5 grips. The GP5's big bar ends provide several options for moving your hands around. You can lay your hands flat across the bar ends and grips. Grasp the bar ends. Etc.

One note about the Ergons. The Small grip is identical to the Large grip except for the round part of the grip opposite the paddle. The Large has a little bit more rubber than the Small, so the diameter is bigger. That spreads the thumb joint a little bit more than the Small. I bought Large for myself and Small for my wife. Now I wish I'd bought Small for myself too.

Take a look at the push brand MetaGrip. It's the best brace I've found for protecting the joint. If you have wrist pain on top of thumb pain, the MetaGrip can be worn underneath the Wrist Brace Splint. I wear a MetaGrip on my left thumb and a Wrist Brace Splint on my right wrist.

Don't get the Wrist Brace! Get the Wrist Brace Splint. The Wrist Brace is designed to immobilize the wrist and it's just too bulky.

Speaking of bulky, you'll probably/definitely have to go shopping for some bigger gloves. Especially if you use both the MetaGrip and the Splint!


Well-Known Member
I've been having some pain/discomfort in my right thumb when I ride MTB trails for 2+ hours (though it seems much less debilitating than your condition). The MetaGrip looks perfect for the support I need, but $80 is a chunk of change!

Although it's not particulalry good for riding off-road, I use a $10 "Thumb Stabilizer" to expedite healing post-ride. That and Arnica, which seems to help me despite AMA's denial of its effectiveness.


Staff member
@Telkwa , thank you for sharing your experiences and taking the initiative to start a new thread. And, thanks @LimboJim for sharing your tips also. :) This thread will be a good place for folks to share their own modifications and what has helped them with thumb-related difficulties.


I'll try to get back with some pictures and more specific comments.

The push products aren't cheap. But they work. I tried three or four over-the-counter drug store thumb braces. The push works better than all of them. The other ones not only didn't work as well, they were big and fuzzy and there's no way you could fit biking gloves over them.