Every thorn has it's rose

Drum roll please...as you look at this plot, keep the following in mind:

  • This compares a Trek Fuel 26" wheeled bike and a Salsa Dos Niner 29" wheeled bike
  • Bikes were similarly equiped - near identical weight
  • Identical tread pattern, Specialized Fast Traks all the way around
  • I changed the crankset on the Dos to accomodate a 30T middle ring to more closely match the Fuel's gearing

The data is the result of daylight laps at the 24 Hours in the Old Pueblo race.  When I say race, I mean it was full on...see the OP race post if interested.  The upshot of this was that I did everything possible to go as fast as possible, within the limits of the event.  No prior subjectivity could have skewed the results.  The displayed lap times are the time on the course.  Pit times are not included.  I threw out the night laps for publication because of the eyesight issue - the 9th and 10th laps are extreme outliers due to extenuating circumstances.

OK...giving this a minute to sink in...each point represents the x, y pair of average power and lap time.  In other words, the dots in blue show the relationship between power and lap time when riding the Fuel.  More power = faster laps.  Make sense?  The black lines show a linear regression (done by MS Excel) to illustrate a trend, or predicted values.  The two pink squares show what happened on the Dos Niner.

I added the red rectangles to show the "what if" scenarios.  Consider the case where average power over a lap is 188 watts.  Based on this data, a lap time of 67 minutes would be predicted for the Fuel, while the predicted time for the Dos is just under 69 minutes.  Looking at it from another angle, for a lap time of just under 69 minutes, I'd have to average 175 watts on the Fuel but 186 watts on the Dos. 

So there you have it.  It's cut and dried in my mind.  The 29ers in my testing have lost in rolly, twisty singletrack, and also on climbs.  They might fare better on downhills, and almost certainly in sand and maybe even rocky stuff...but right now I'm losing interest fast.

Anyone interested in a tricked out Dos Niner with a Power Tap hub?

Published Tuesday, February 21, 2006 6:25 PM by Dave
Filed Under: ,


# @ Wednesday, February 22, 2006 5:14 AM

You are a man with some thick skin. I am sure you'll get a lot of flack from the 29 masses, but I am glad somebody is out there working some numbers THAT ISN'T TRYING TO SELL BIKES. I wish I had the time/resources to test equipment my thouroughly. Are you going to continue testing? Did one bike "seem" faster or cause less perceived fatigue than the other?


# @ Wednesday, February 22, 2006 5:50 AM

Hey Dicky,

It was very interesting to ride both bikes in the same event on the same day. I haven't done that before. The 26er was way livelier, or snappier than the Dos. It was night and day. The Fuel was downright easier to pedal. In fact, in the morning when I had enough sight to get back on the course, I wouldn't even consider getting on the Dos - it was the Fuel all the way.

You're a light climber type, right? My money says your experience would be similar, except it could be different in a SS application. Maybe that's the test I need to do...but I just don't know if I care enough to do it now.


# @ Wednesday, February 22, 2006 11:09 AM

Yeah, I am a light climber. I would love to see the differences (in numbers) for a full rigid SS 26 and 29'er. It would get rid of any effect the suspension had on the test (selfishly they are the two types of bike I would choose to ride anyhow). I don't get enough time on a MTB to do what I would consider a fair test on both rigs.
In my limited experiences on a 29'er I had fun, but I was riding a bike in the woods. How can that not be fun?


# @ Wednesday, February 22, 2006 12:27 PM

I'm not gonna post this on mtbr! I learned my lesson last time. And I don't want to flog your inbox.

Good job on the race...sorry to hear about the eyes thing, but hey in a few years you might be able to get new ones!



# @ Wednesday, February 22, 2006 12:44 PM

29ers rule


# @ Wednesday, February 22, 2006 2:03 PM

Could you identify which lap represents each dot? Did you ride the 29er early on or later in the day Saturday? Certainly you must have fatigued a little bit on your laps later in the day. You mention backing down after 3 laps.


# @ Wednesday, February 22, 2006 2:08 PM

Could you identify which lap represents each dot? Did you ride the 29er early on or later in the day Saturday? Certainly you must have fatigued a little bit on your laps later in the day. You mention backing down after 3 laps.


# @ Wednesday, February 22, 2006 2:31 PM

Steve - good question. I've updated the image with lap counts, but it hasn't updated yet...I'll check back later to make sure it's updated.


# @ Wednesday, February 22, 2006 2:53 PM

Hmm.....Lots of effort expended in your testin, and I appreciate that. I'm glad you were able to come to a satisfactory conclusion.......for yourself.

Different chassis, mounted with the same engine will always yeild different results. The wheel size is part of that, but this test doesn't allow for these discrepencies to a point that I can say, "Yes, it's the wheel size."

That is to be expected with the tools you had at your disposal. A huge budget allowing for everything but the wheels to be equal is simply not possible here, I know. So, I'm not dissing you, I'm just not convinced. My experience tells me otherwise, yours does not. I'm okay with that.

Thanks again for all your trouble. I learned alot.

Guitar Ted

# @ Wednesday, February 22, 2006 10:11 PM

Dave -

I've really enjoyed reading your test reports and looking at the data you've collected.

To me it has to be either the wheels or the suspension configurations. If it is the wheels, it begs the question, what about 24" wheels :)

- Rich

Rich Abbott

# @ Thursday, February 23, 2006 1:38 PM

This is really interesting stuff!

One question - have you made any attempt to match the suspension travel on both bikes?


# @ Thursday, February 23, 2006 2:04 PM

Glad some folks are finding this interesting!

As for suspension, the two bikes are just plain different - there really is no way to match them.

My basic question is "which races faster, the Dos or the Fuel?". Wheel size is the biggest factor in their differences, but not the only factor.


# @ Thursday, March 02, 2006 11:41 PM

Hi Dave, Got to this via cyclingnews.com...

Have you seen the Carver 96'r? It is shown in the latest issue of "Mountain Bike Enquirer" - er.. "Action". No suspension, but has a 26" rear wheel with the 29" in front. They said that the 29" rolled over things well, while the smaller rear wheel accelerated and dug in a bit better for climbing. Since they never really give a critical review of any product, I can't say that the review is too defining, but I have always thought that might be an interesting combo. I ride 26", but have a friend that rides a 29" and in rougher conditions he says he feels a lot more comfortable on it, and a bit faster - if it's not tight with switchbacks, that is. Good luck racing this season.

Scott Edwards
Castro Valley, CA


# @ Friday, March 03, 2006 4:45 AM

Hi Scott,

Thanks for stopping by....I've seen the Carver in ads and it looks like a nice bike to me. Travis Brown has ridden that same wheel setup to numerous victories on his SS (but is it the bike or the rider??) and there are several other manufacturers making them. From what I've seen - proponents say it is a good way to get smaller riders half the benefit of 29ers as it makes it a little easier to construct the geometry (for small riders), while opponents say it is just a compromise.

I haven't ridden a 96er, do can only speculate...but based on my back and forth testing where I get on 26 then immediately a 29er, the one thing about 29ers I like is how well the front wheel hugs the ground in sketchy turns/corners. What I really dislike is how the gearing is changed. So the 96er sounds like great idea to me - like it will offer the most benefits of the 29er while preserving the tight gear ratios of the 26er.


# @ Friday, March 03, 2006 12:39 PM


This is an interesting study. I appreciate the time and effort that you took to do this. Is there any chance I could get you to send me the excel file with your data? I would like to play around with it a little. I walso want to put it into SPSS, a more advanced statistical program than Excel. I would not publish anything I found, rather send it to you.

I also have some other questions I would like to ask you over e-mail.

[email protected]

Sean Noonan

# @ Tuesday, March 07, 2006 10:40 AM


I find your study very interesting, thanks for taking the time to bring a bit of more credible science into the mix. It seems like there is a lot of hype and armchair theory over this debate.

I work at a shop in Portland, OR and many customers and co-workers are moving in the 29er Single-Speed direction (a few of these guys are endurance racing at a pro level), anyhow, all of the supporting talk of the 29er aims at the "contact-patch" and all of the additional traction you can get with a 29er rear wheel. What did you feel about traction while really givin' it on each of the bikes? I think this might be a bigger isssue with a single-speed configuration, but still might make a case for comparing the contact-patch of each with constant like watts or something. Thanks,



# @ Tuesday, March 07, 2006 11:09 AM

Thanks Joe. Here's a link to an image of a contact patch comparison on MTBR:


Not very convincing there's a perceptible difference. By the science of it, the contact patch is not bigger, but different in shape. A bit longer and narrower than a 26er tire.

Have I felt this to be an advantage? Absolutely, at times. On difficult climbs that are ledgey or loose, the 29er is awesome. Overall, though, I find them to be slower than the 26ers, at least on the endurance courses in the southwest.

Purely subjective here...but I suspect there's a good reason that 29ers are taking off in certain parts of the country (world) while not in others. This is probably dictated to a large degree by the local terrain and how well it matches up with 29er benefits.


# @ Tuesday, March 07, 2006 3:16 PM

Can you show the data for the missing laps? (1,7,8,9,10) In the OP report you said 4 DOS laps - just curious how bad they were.


# @ Tuesday, March 07, 2006 3:36 PM

Here ya go Chuck. You can't read anything into this about the bikes, though. The 9th and 10th (the Dos night laps) are when I was losing my sight. It's amazing how much energy is wasted by running into cacti, sandpits, and other riders...

What is interesting here, though, is that the Fuel night laps were as "efficient" as the Dos day laps. So it would appear that the difference for me between the Fuel and the Dos is literally day and night...



# @ Tuesday, March 07, 2006 3:38 PM

Oh, forgot to mention: the first lap isn't valid for the analysis since in included the run and the first few miles were not on the normal course. They routed us on a dirt road to avoid the early race singletrack bottleneck.


# @ Friday, March 10, 2006 8:04 PM

Great work on this topic. Thanks. Until its 26"Apples vs. 29"Apples it don't mean much to me. I've ridden a Fuel for 4 years and that is one nice XC fully - I doubt the DOS9er is as forgiving/smooth.....Hopefully Trek will make a 29er Fuel soon and the test can then be done on simular platforms.

I'm on my first 29er [hard tail] and it has been most impressive to me. Though since the gear inches are larger [~ 9% bigger cog necessary on the 29er vs. the 26er] it has taken a bit getting used to - the standard middle ring climbs on my 26er now require working the granny ring a bit.

Cheers for your work and web site, Cliff NEW ZEALAND


# @ Sunday, March 12, 2006 6:16 PM

I'd be interested in comparing like-for-like bikes... It seems to me like full suspension (the Fuel) would be an advantage over the softtail, particularly later in the race, when you'd be able to remain seated longer...

BTW: I'd love to volunteer for some trials- we have two SS On-One Inbreds in the garage: This Missus' 26" and my 29er (which we raced at 24HitOP): with very close geometry (and a very reasonable frame price), they'd be good platforms from which to compare. I'd also like to see similar parts used- a 29er *will be heavier* with the same parts- that should be taken into account...

Marc B

# @ Saturday, April 01, 2006 7:56 PM

What is the calculation to "correct" the measured power reading? Is there an estimate of accuracy between the two PowerTaps? Can you calculate the standard deviation of the average power for each lap? I am assuming the course didn't change during the event.

More data over the course of a season would be nice. Eliminating lapse 2,3 and night 29er, leaves a nice grouping of data. Calculating error estimates of this data would be interesting.

Cool work. Why not make this a full year project? That would be really awesome data.


# @ Wednesday, April 12, 2006 8:01 AM

Nice. Thanks for the work! It is SO refreshing to see responsibly gathered data to test a theory!

I think a little more data collection is in order to establish that there is a significant difference between the two platforms (as stated above). If one were to remove laps two and three from the plot, the 26 and 29 would be essentially indistinguishable. Also, laps 12 and 13 are outliers from the group. They "look" to be as far off of the line as the Dos data... Another way to look at the data may be to compare the slope and Y-intercept of each plot (fuel vs dos). This would let you know how much avg power would be req'd to have a 0 time lap on each bike (less power/lower intercept=more effiecient). The slope would let you compare the bike's response to power input.