Foam (silicone) grips can decrease hand pain and fatigue, and increase on-bike performance.
Foam (silicone) MTB grips have been around for a while. From what I can tell, ESI Grips were the OG silicone grips for MTB. Other companies like Wolf Tooth and ODI have followed suit.
I used to think they were ridiculous… until I ran a set myself. I ran a set of the Wolf Tooth Mega Fat Paw grips on my 2020 Santa Cruz Hightower for over a year. They have a massive 40mm installed diameter. To put that in perspective, most stock grips will come in right at 28-30mm. As it turns out, there are several key benefits to running foam grips. Allow me to go into more detail than you ever thought possible on foam grips. (scroll all the way down for road bike and gravel bike application)
Foam grips kill the vibes.
It’s a well-known and well researched fact that vibration can have some seriously detrimental effects on human performance. Individuals who run power tools and jackhammers can suffer serious consequences including nerve damage and impaired blood flow from constant vibration coming into their hands and forearms. Vibration decreases the endurance of grip strength, and increases oxygen demand and blood flow to forearm muscles causing the dreaded "forearm pump". It should go without saying then that us cyclists should do everything we can to "kill the vibes". If you’re lucky enough to land yourself a set of the Wolf Tooth foam grips, they’ll tell you on the back of the package, “This a 100% silicone compound. It provides excellent vibration damping.” Anecdotally, I agree. Riding downhills in Brevard, NC that used to really give me trouble with forearm pump were noticeably not as bad this past year while running the Wolf Tooth Mega Fat Paw grips.
Foam grips come in a variety of sizes.
As it turns out, size does matter. This is especially if you’re talking about the diameter of a cylinder, and how it relates to grip strength. There has been a plethora of research in the field of ergonomics to help workers using hand tools perform better and prevent injury. I reviewed several studies and found their recommendations to be very similar across multiple studies. They recommend a handle grip diameter of 18-19.5% the individual’s hand length. As an example, my hand length is 195mm. 195mm x 18% = 35mm. That puts me in prime position to be using the Wolf Tooth Fat Paw grips which come in a 36mm installed diameter. I have in fact been running these on my Kona Hei Hei and I love them. After running these, I realized the Mega Fat Paws were probably a bit too large for me. But rest assured, the Fat Paws are still exponentially more padded and thicker than typical stock lock- on grips.
Foam grips are moldable.
Shoe inserts aren’t straight, rigid apparatuses. That’s because your foot has curves, and it’s intuitive that having some cushion that can mold to those curves and is more comfortable. The same logic can then apply to foam grips. The foam can contour to your not-completely-flat hands and take pressure off from key areas like your carpal tunnel which, when compressed, can lead to hand numbness and pain. This point really shouldn’t be a hard sell.
Foam grips grip.
The silicone compound used in the Wolf Tooth and ESI grips has a super-tacky feel. That carries over well to on-trail grip. I always ride with gloves, but if I were going to chose a gloveless grip, I’d chose the silicone grips every time.
What about for the road bike?
Wanting to get the same benefits described above for your drop bar road or gravel bike? Wolf Tooth has you covered with two different sizes and multiple colors with their Supple and Supple Lite Bar Tape. I've been running the Supple tape on my Kona Rove for on-road and off-road, and I love it. It may take some getting used to if you're used to paper-thin grips from the good ol days, but they're worth a try, especially if you're dealing with numbness or pain.
If you haven’t already, check out the I have a YouTube review video on Foam Grips that goes into detail on what I’ve already explained here, and I have an install and uninstall video that can help you remove the grips in the event you want to change bars and preserve the grips. Go check em out! https://www.youtube.com/watch?v=ZGJrZI2FbHY&t=1s