I have posted several times on the subject of steering geometry for 29"ers in the past. I recently got a question that I thought was a good one and I wanted to share that with you and my answer to it.
The question: What is wrong with companies that make 29"ers? Why has it taken so long for them to figure out how to make a 29"er steer well? (A bit of backround: The question was from a guy that loved the way a certain 26"er he has steers and he wanted to recreate that on his next 29"er)
Well, as I said, good question. The thing is that when "The Tire" hit the scene in '99, only a small hand full of builders were even playing with them. Since there was never a tire before the Nanoraptor that had the fat width, high volume, and large diameter it has, designers were left to theoretical designs that had to be trail tested before anyone would know what did or didn't work. One thing was obvious from the get go. The trail figure for a 29"er was bigger than that of a 26"er.
This soon was found to be a bit of a problem. That and the fact that head angles had to be kept in check to keep the toe overlap situation under control. The next item up for scrutiny was the fork offset, which if it could be lengthened would help reduce the trail figure and get some steering quickness back that is lost by going to a 29"er front wheel. Geometries were still in flux in the early days of this century and Gary Fisher 29"ers, the first modern era production 29"er bikes, were sporting a longer offset Marzocchi suspension fork, but still had some other issues holding it back from being a solution that mimicked 26"er handling. It was a step in the right direction though, and Gary wasn't through tweaking just yet either.
A couple of years later, the Surly posse entered into the 29"er production field with the Karate Monkey frame set. It also sported a somewhat longer fork offset. Still not quite "26"er-like", but then a lot of 29"er folk were skeptical that a 29"er should handle like a 26"er. Yet, as we have seen, new folks getting turned on to the big wheels didn't stop with the slightly longer offsets or with a small change in head angle.
It wasn't long before folks like Salsa, Intense, and a few others were found to be messing with head angles and offsets that would yeild a quicker turning bike. The head angle was an attractive solution, because getting a longer offset suspension fork would require a big time OE commitment to a fork manufacturer to make it happen. Trouble is, you can only go so far with the head angle schtick before you get into some serious troubles elsewhere.
In the meantime, two things happened that would change the landscape for 29"ers in a radical way. One was On One's Superlight fork. It had a 47mm offset, which was a huge change from "standard geometry" 38mm offset. The offset had the effect of bringing the trail figure down into 26"er territory and the resultant handling is very nice in a 29"er package. This was a groundbreaking move. The second thing was the move by Gary Fisher to bring this longer offset concept to suspension forks. Fisher did this for 26"ers too, which perhaps is even more radical, but the new G2 geometry package for 29"ers is a huge step towards solving once and for all the handling issues with 29"ers. Having convinced the suspension manufacturers to come up with 29"er forks with longer offset, Gary Fisher has helped to unleash a new era of 29"er geometry, especially front end geometry.
Now it's going to be fun to see where this goes from here. My bet is that once folks get to ride some of these new Fishers, or bikes with the new "super offset" forks, there will be a fundamental change in the perception of how 29"ers handle. No longer will they be said to be "slower handling" than 26"ers because this new steering geometry will take care of that old problem once and for all.
Until then, ride your bikes this weekend! The summer is about shot, so quit wastin' time!
Wild Hair: Island Lake.
2 days ago