29er vs 24 guni

[Tucson Uni]

I have a 4 mile loop that I like to do in the morning before work. The past couple of weeks I have done this ride on both my KH29 and my KH24 guni, and recorded my time to complete the loop. I was curious which uni is faster overall. This trail is moderately technical and includes a variety of terrain. So far, my best time is on the KH29, but not by much. The 24 guni has the best top speeds. The best time on the KH29 was a pretty clean run with a minimum number of UPDs. The best 24 guni run includes some botched shifts and more UPDs. I do think that I have room for improvement on the 24 guni, and that I am pretty close to maxed out on the KH29.

[johnfoss]

It's funny how those things work. I've done other sorts of comparison rides, and more often than not, ended up with times that were so similar it didn't prove anything. I don't know why.

Once upon A time I could do the IUF/USA Obstacle Course at about the same speed on a 20" or a 24". Go figure...

[nordicnoel]

Interesting. For some sections of trail, I've noticed I have a mental speed limit, so I take the same time on a 26x2, 26x2.7, or 29x2. But you are better and probably don't have that problem...

How much of the time or distance do you spend in each gear on the 24? If you cover the same distance in each gear and use a constant cadence, your result is what I'd expect. The harmonic mean of 24 and 24*1.55 is ~29.2, so I'd expect a constant time between the two unis.

[Nurse Ben]

The difference between a 24 and 29 is more related to their size related difference in stability, tracking, and obstacle "bridging".

It seems like gearing up might allow you to carry more momentum, which could be good or bad.

I find that a fat tire like my Surly Larry can roll into technical sections faster than my 29er, with less deflection and holding more intertia, but it's slower to maneuver and the weight and bulk tire me faster.

Each muni, geared or ungeared, has a best use. If I could only pick one uni, it'd be a 26 x 3 geared because it would have the widest range of uses. I like riding a 26 x 2.5 and a 29 x 2.5, but there are places (rocky and rooty) and seasons (mud/snow) when they just aren't effective.

Now I have a 26" Surly x 3.8 combo and 29" KH x 2.4, so one for tech/mud/snow/DH and one for XC. In the future I plan on adding a geared 26" x 3" for the in between, then picking them according to when and where I ride, just like when I go skiing.

What I think would really change the sport would be a three speed hub, one reduction gear and one overdrive gear, then you could use shorter cranks and still have max climbing ability, good spin, and higher speeds. I'd have a three speed on every one of my unis (26, 29, 36) if it was available.

[Tucson Uni]

I am guessing that I was in high gear for about 60% to 70% of the riding. Low gear was required for a section of technical uphill, some was wash crossings, a section of flat with large rock features, and a section of technical DH. The 29er is faster than the 24 in low gear, and handles larger rock features better (if you are rolling, not hopping). The high gear riding is a split of rocky, curvy sections where the speed advantage over the 29 are not as great as possible, and some relatively rock free sections where speeds in the 11-12 mph range are possible.

I would say that the advantage goes to the 29 for XC trails that are more technical. For trails that have a lower technical level, the 24 guni would dominate. The beauty is that the 24/26 guni makes all those trails that used to be too boring a lot of fun to ride!

[Nurse Ben]

I swear to gawd, if you guys don't stop talking about gunis I am gonna buy one. Then, when next model comes out with disc brakes or heaven forbid, three speeds, then what?

Nah, nah, nah, nah, I can't hear you!

[saskatchewanian]

Not the same thing but I recently did a back to back road ride with my 24" Guni and 32" fixed wheel.

Long story short the 32" was lighter, faster and more responsive but less maneuverable in the tight stuff. here is my little writeup.

Once I get my new rim the hub is going in a 26er.