I have been riding now since July 09 on a Trek 7.3 FX...First bike I have ever purchased since 1966! Yeap I am old but I sure enjoy it with this new knee...I am 54, 6-2, 250, ole ball player...I have been hunting Ergon Large GC3 now for months after reading post on here with no luck. My fingers go numb after 35 minutes or so...shake them out and then it seems every 15 minutes or so I have to shake them again... My question to everyone, if not the GC3's, what would be my next step to try and get some type of comfortable hand grip...I ride no more than 2 hours a day on the country roads when I do...20-30 miles.
I found that having the right handlebar was much more important than picking the right grip. For me, a swept back bar put my wrists at a more natural angle which reduced numbness. I ended up using a Bontrager Race Lite "Big Sweep" handlebar that swept back 12-degrees. Seems like they've been difficult to find, but there are similar bars available from Origin-8, On One, and Psyclestore among others.
As far as grips, I just use standard ODI lock-on grips in either the Ruffian or Rogue pattern. Ruffian is low-profile, Rogue a bit more cushy.
Obviously, this is a little more expensive and may be overkill for your riding habits, but if you ever decide to start riding longer distances, it is very cheap compared to the cost of a road bike.
I think grips themselves are over-rated in terms of comfort, it is all about hand position, if the hands are wrong, the blood vessels get blocked and your hands fall asleep. No grip is going to fix that. Really, you may be able to get away with just changing the angle of you grips and shifters. In your natural riding position, you want your wrists to be as neutral as possible. Check out section 7. of this link.
I have to agree with the others, numbness can be an indicator of issues beyond soft grips. When I ride my road bike, I get numb fingers if I keep my hands down on the drop bar because of the angle and the amount of weight that I place on my hands. If my hands are on the hoods or even on the flats I can ride all day long without too much issue, for me the most important part is moving my hands early and often, don't get to comfy in one position because that is when the trouble starts.
I have a 7.3FX and went with the Ergon GR2 Mag grip. My hands still go knumb, but not nearly as bad. The small bar end gives me another position. I switch between the two and can go much longer without shaking out my hands. I still have the stock bar. I would agree to switch early and often though. Sometimes I forget.
I do adjust the grips which some days better...I am thick chested, broad shoulders with most of my weight high...probably a lot more weight than should have on hands in riding position. I wonder about raising bar height some, but with trekking bars, maybe this would allow more positions.
Trek Portland/Gary Fisher Hoo Koo E Koo/LeMond Versailles
I am going to chime in just because nobody has mentioned gloves yet. There are types, like the IronMan and others, that have the pads designed with little channels (like the cutouts in saddles) so the pressure from gripping doesn't pinch off critical blood flow paths. That can help quite a bit, and it is a cheap fix.