Tire Size Shoot Out: 29×2.35 vs. 29×2.6 vs. 27.5×2.8

There was a time when we didn’t have a choice if we wanted wheels and tires on our bikes, they were 26” in diameter, and 2.1” in width.  We’re fortunate that the market has evolved to allow us the option of wheel and tire sizes to best suit our needs.  With this “Tire Size Shootout:29×2.35, 29×2.6, and 27.5×2.8” we wanted to better understand the strengths of the most popular sizes.

Here at Crankjoy, we have ridden all these tire sizes in the past like with Perspective Shift: 2.6″ and 2.8″ Tire Opinion.  We’ve never had the opportunity to ride them back to back, on the same day, and on the same bike though.  This shootout was performed with different tire sizes on a 27.5+ hardtail, in order to test ride them all on the same day and reflect on their differences.

Comparison tests like this have been done before.  But most have excluded the 29×2.6 size, and climbing speed wasn’t measured and reported.  This test was structured to fill in these gaps.


Shootout Test Details

Leading up to the test, each wheel was ridden on a variety of trails to get pressures dialed, but the testing and report is based on a 3-mile loop in Harlow Lake Recreation Area just outside of Marquette, MI. The trails on the test loop are fairly fast and aside from a lot of embedded roots, not terribly technical.  The surface is fairly firm with some pockets of loose sand mixed in.  The loop was broken into three timed sections:

  • 1.0 mile mellow descent that loses 250 feet of elevation. It has some roots but generally is pretty smooth with some corners thrown in.
  • 0.8 mile flat and smooth two-track, slightly descends, losing 30 feet of elevation over 0.7 mi.
  • 1.2 mile climb with 280’ of ascent.  The surface was mostly hard packed with a few patches of packed sand and some embedded roots.  The climb got progressively steeper and rootier as it neared the top. 

Tire Shootout Route

In order to minimize factors that could impact the results, all tires were run on the same day, on the same model wheels, and on the same bike.  

The test tire chosen was the Schwalbe Nobby Nic.  In my experience, it is a great all-around trail tire, it falls neither in the full XC nor the DH end of the tire spectrum.  Further, they are available with the same compound and construction for each size, with the exception of the 2.35” tire not having the APEX bead reinforcement added to the wider tires needed for cornering support at the lower pressures these tires allow.

ENVE Composites M6 rims were used, past experience has proven it to be a maintenance-free wheelset that tips the scales at XC weights.  Rim width was chosen for each tire size based on Schwalbe and ENVE recommendations.  

Before the test, each wheelset was ridden enough to establish appropriate tire pressures.  Pressures were set as low as possible to avoid squirm under high loads and to provide adequate bottom-out resistance when changing rock gardens at speed.  For reference, I’m 170lb geared up and ride fairly aggressively.

Tire and wheel dimensions and pressures.

Tire Size Wheel Model Rim Inside Width Tire Model Compound Casing Pressure PSI (F/R) Wheel & Tire Weight Tire Width In. Overall Tire Radius
29×2.35 ENVE M630, 29 30.0 mm Nobby Nic ADDIX SpeedGrip Snakeskin 20.0/24.0 PSI (1.38/1.71) BAR 7.55lb (3.43kg) 2.38 in (60.4mm) 14.62 in. (371mm)
29×2.6 ENVE M635, 29 35.0 mm Nobby Nic ADDIX SpeedGrip Snakeskin / APEX 17.0/20.0 PSI (1.17/1.38 BAR) 8.43lb (3.82kg) 2.59 in (65.8mm) 14.82 in. (376mm)
27.5×2.8 ENVE M640, 27.5 40.0 mm Nobby Nic ADDIX SpeedGrip Snakeskin / APEX 14.0/16.0 PSI (0.96/1.10) BAR 8.10lb (3.69kg) 2.81 in (71.3mm) 14.28 in.  (362mm)

 

The test bike was a Why S7, a Ti framed hardtail that handles like a trail bike, but has that wonderfully direct feel that comes with a hardtail.  The S7 was designed for 27.5+ tires, but with sliding dropouts and clearance for 3.0 width tires, it allowed for each size of tire to fit within the frame.  Further, it has a bottom bracket drop of 65mm, which is slightly lower than most designed to run 29” tires.  This meant with the  29×2.6” tires on the bike, the bottom bracket was still at a normal height.  To minimize variation between the test runs with different tire sizes, the dropouts were set to their midpoint (432mm chainstay length) to allow clearance for the 29×2.6” tire, and left there for the entire test.

Special attention was given to how the test laps were ordered.  The tires were run back to back and then run again in reverse order to better understand if the differences were normal variation or actual differences in tire performance.  Each wheelset was ridden at the same target power, for both the flat and climb segments.  However, the downhill segment was ridden by feel since power targets were difficult to maintain.  Heart rate was also measured for reference.  Ride characteristics were noted after each lap.

Test Results:

Ride Feel & Subjective Ratings: 

My favorite setup was 27.5+, it was the most forgiving of trail and surface irregularities, but it also was the most intuitive and flickable.  Impacts were dulled to a manageable level, allowing me to focus on having fun, rather than managing impacts. 

29×2.6 offered similar impact absorption to the 27.5 setup.  It did handle sharp transitions better than the other two sizes.  However, handling was quite a bit more cumbersome, and it felt like it added more heft than the 1/3 lb. indicated on the scale.  There’s promise for 29×2.6 and I’ve had great experiences with it in the past, but when ridden back to back, the 27.5+ was simply more fun, and it wasn’t any slower.  

29×2.35 was what you’d expect.  Sprightly & quick feeling, but the reduced bump absorption vs. the other two sizes on test detracted significantly from the experience.  This was apparent on both the front (130mm travel) and the rear of the bike.  Further, climbing didn’t FEEL any faster.  I found I had to work harder to maintain traction on the rough sections of the climb, as it was wet on the day of testing.  Despite the drawbacks, if my riding was limited to hammering out hot laps on a smooth XC loop, it may be my choice.  But if I needed anything more versatile, I would choose the 27.5+.

These results surprised me. 

In the past, I hadn’t liked the 27.5+ set up as much, I’d wager that the reduced weight and responsiveness of the high-end wheels and tires improved the ride experience compared to the relatively heavy wheelset I had run with 27.5+ prior.  Further, I’d really enjoyed the 29×2.6 tires coming into the test, but when ridden back to back with the others it offered little advantage at the expense of intuitive handling.  Read on for details.

Subjective Ratings:

page4image43110256

Line Holding

The descent had a number sections of successive root impacts, some off-camber and wet.  The 27.5+ and 29 x 2.6” could be ridden straight through at full speed, with the 2.6 hinting at a slide.  However the 2.35 tires needed more attention, slight slowing and careful management of tire load to make it through.

Cornering Traction

Big tires for the win, both the 2.6 and the 2.8 excelled, they were just bulletproof and could be fully weighted through the corner.  When the 2.35 tires were weighted to maintain traction, they had a far lower threshold before pushing wide in the corner.  

Climbing Traction

It was a draw between the three sizes until I hit the roots, here the 2.8 and 2.6 showed a clear advantage, requiring less body language to stay hooked up.

Handling / Intuitiveness

This was the surprise of the test…27.5+ was the clear winner.  It allowed for easy mid-corner correction, ample traction, & minimal disturbance from trail chatter.  The 29x 2.6 tires were reluctant to accept a mid-corner correction, nearly sending me off the same corner on both test laps.  The 29×2.35 felt the most responsive, but relatively speaking, were disturbed by trail chatter, forcing me to focus more on managing bumps than cornering.

Acceleration

The order of ranking here is no surprise, as they are in order of weight.  The only surprise is how close the different sizes felt to each other when it came to outright acceleration.

Segment Times*

With limited resources and it was only possible to get 2 runs on each tire.  Any differences noted here won’t be statistically significant, but every effort was taken to minimize variability.  The power numbers & heart rate values were surprisingly close for each timed segment, and the test order should have minimized variability between runs due to fatigue and weather.

Descent Segment

The wider tires in the test felt faster, and they were, but the difference was small.  The 27.5×2.8 and the 29×2.6 were tied and came out slightly ahead of the 29×2.35” tires.  Power numbers omitted as they are not relevant for this descent.

 


Descent Times

Tire Size

Segment Time (HH:MM:SS)

Heart Rate Average (BPM)

% From Fastest

27.5 x 2.8

0:03:45

148

Fastest

29 x 2.6

0:03:45

150

0.0%

29 x 2.35

0:03:48

148

1.3%


Smooth Flat Trail

Interestingly, all sizes were within 2 seconds of each other.  It’s important to note though that I didn’t do a great job of matching power through this segment run to run.  The 29×2.35 time, although slowest, was posted using 6-8 fewer watts.  That may be significant, but to claim so would be a guess, I’ll let you be the judge, but I think it’s too close to call.


Smooth Trail Times

Tire Size

Segment Time (HH:MM:SS)

Power Average (W)

Heart Rate Average (BPM)

% From Fastest

27.5 x 2.8

0:02:17

251

167

Fastest

29 x 2.6

0:02:18

249

169

0.7%

29 x 2.35

0:02:19

243

167

1.4%


Climbing 

This is where the biggest difference in speed was, the 29×2.35 tires showed the fastest speed and the lowest power and heart rate.  Are 8 seconds significant?  Not statistically.  But even though it seems like a small difference that’s over a 100’ gap at the top of the climb.  It’s a difference I would love to have if racing at the elite level.


Sustained Climbing Times

Tire Size

Segment Time (HH:MM:SS)

Power Average (W)

Heart Rate Average (BPM)

% From Fastest

29 x 2.35

0:07:39

277

172

Fastest

29 x 2.6

0:07:44

277

174

1.1%

27.5 x 2.8

0:07:47

276

173

1.7%


Overall Lap

There wasn’t much difference here, and since the power and heart rate numbers weren’t met I’d consider it a tie.

 


Complete Lap Times

Tire Size

Segment Time (HH:MM:SS)

Power Average (W)

Heart Rate Average (BPM)

% From Fastest

29 x 2.35

0:14:29

267

165

Fastest

29 x 2.6

0:14:33

265

167

0.5%

27.5 x 2.8

0:14:36

261

165

0.8%


Closing Thoughts

Based on these results, I’m going to keep 27.5+ mounted.  They were just more fun than the other sizes, and the speed advantage to the 2.35 set was small enough that I’m willing to compromise in climbing speed for the superior ride feel.  

The 29×2.6 set offered similar composure to the 27.5+ over rough terrain, but it was resistant to mid-corner correction.  The 2.6 didn’t offer the fun, intuitive feel that the 27.5+ setup had.   Additionally, it did not present a noticeable or measurable decrease in rolling resistance. It wasn’t bad per se, but I didn’t feel that advantage was nearly enough to offset the better handling of the 27.5+ setup elsewhere. 

I’d choose the 29 x 2.35 for a dedicated XC race setup.  Despite similar overall lap times, XC and endurance races are won and lost on the flats and the climbs, and here is where the 29×2.35 showed and advantage. 

In this case, I may have come away with more questions than answers.  Would a mixed wheel size setup combine the best attributes of the 27.5+ and the 29×2.6? How would a dedicated 29×2.25” XC race tire compare to the speed champion (barely) of this test, the 29×2.35?  I intend to repeat this test to answer those questions once the snow melts.  Until then, happy trails.

We chose the Schwalbe Nobby Nic for this test not only because it’s offered in the same casing and rubber compound for all three sizes but because we love the tire too!  Here’s a recent review: The Speedy Trail Slayer: Schwalbe Nobby Nic 2.6″ Review

Share:

This Post Has 11 Comments

  1. Nick C

    Cool comparison, just when I thought 27+ was dead because 29×2.6 seems to have taken over the bike shop. I need to put more time on plus tires to draw my own conclusion. I did something similar a while ago between 27.5 and 29, when 27.5 was all the rage. 29 was faster every time on the stopwatch regardless of what I “felt”.

    1. Alex

      Great write up, really enjoyed the reading.

      I recently went through the same exercise myself and couldn’t find many comparisons at the time.

      I settled on 29×2.35 over 2.6 (haven’t tried 27.5×2.8) primarily because it feels more lively and is much less sensitive to pressure setup. It was though a really tough decision though and I am keen to try a 2.6 that doesn’t weigh a ton and has reasonable sidewalls. This should help with both liveliness and pressure sensitivity.

  2. Brent P

    Nick,

    I think there are a couple reasons for the shift away from 27.5+ in the market. 1. In extremely rough and rugged terrain, riders report that to avoid flats they have to run so much pressure that the benefits of + are negated. 2. Riders also report tire “squirm” under high loads, and again…have had to raise tire pressures. I have not experienced either scenario, despite being a pretty aggressive rider, but this probably doesn’t make their points any less valid. Because these aggressive riders seem to have observed these issues, you don’t see 27.5+ in enduro races and the marketing engine just isn’t behind it any more.

    Regardless, it was enlightening to observe the differences, I’m actually a 29er guy and have been for a very long time…but this bike is going to stay 27.5+ based on what I observed.

  3. Eric R

    Brent, do you still feel the same way? I have the same bike (S7) and have run 27.5 x 3 on it for about 4 months, and recently swapped to 27.5 x 2.8 for the past 30 days or so. I don’t hate the 2.8’s, but find myself wanting to try out the 29″er (2.6) setup on this bike. That’s a fairly hefty investment, and your review gives me pause. Arizona desert riding, rocky, sandy, loose over hard kitty litter conditions.

    1. Brent

      Eric R,

      I still prefer the 27.5 x 2.8. I do admit that if the terrain is very technical I put a 29 x 2.6 on the front only for the improved roll-over and slacked heat tube angle . If I was headed out to ride in Arizona desert (I’ve ridden a lot around Phoenix), I would stick with the 27.5 x 2.8. The only time I’d stray from that is if my focus was on absolute speed in that terrain, in which case I’d go 29 x 2.6 with a faster rolling tread/compound.

      I hope this helps!

  4. Brent

    Eric,

  5. Nick

    Thanks for this post! Really really helpful. I have thoroughly enjoyed 27.5×2.8 but with all the articles pushing 29×2.6 it’s made me consider whether or not I should get a 29er or dedicated 27.5+ for my next steel hardtail. This convinced me to get the 27.5×2.8 Stanton Switchback over the Sonder Signal St and have peace of mind about it.

    I have also noticed that a lot of the articles reporting “squirm” come from people running 35mm inner diameter rims or below. I believe having an i40 is really important for milking the benefits of these tires, and I’m looking forward to investing in cush core eventually.

    1. alwin Meyer

      Thanx Brent for the very useful comparison. I bought the Sonder Signal st and run it with 29 / 2.4 Wolfpack tires. It has a 120 mm fork ( 130 recommended, 120 – 140 within spec). So the head angle is slightly steeper. I was wondering whether the Sonder would become more playful, hoppable, etc. if I would put a 27.5 / 2.6 rear wheel? How much would this lower the bike and would the 27.5 / 2.6 feel noticeably different from the 29 / 2.4?

  6. Herbert Harris

    Hi there. Surfing the net came across your site. One thing that should be mentioned is that dropping down from a 29×2.6 to a 27.5×2.8 the mechanical trail will drop about 5mm. This most likely had an impact on the handling, making the 2.8 setup more lively. How much impact? Not sure.

  7. Jim Todd

    I started riding in 1986 when I took a “converted” Schwinn Varsity to Crested Butte. Later on I used a geared down Typhoon. After a long ride I would feel totally beat up. About 20 years ago I got a used Pro Flex FS. You could really whip around with it on a smooth trail but we both suffered from Endoitis. I’m not a racer and not young so in 2017 I wanted another full suspension bike. I just went all out and got a Norco Fluid with 27.5 x 2.8 WTB Rangers. I did later on put a Ritchy Evolution on the front for a little more traction. I don’t regret getting 2.8, but it does seem to be a little trickier to get the pressure right. Using a light weight casing has not been a problem for me but I am 150lbs and not racing. Calling these a beginner tire, then talking up the 29 2.6 sounds a little contrite as I would think the volumes would be pretty close. My 63” daughter seems a little awkward on her 27.5 wheels. It seems like there would still be a place for 26” but apparently that doesn’t work for mass marketing. JT

    1. ed deneve

      Well put – I bought a 1987 Bike Nashbar 26″ mtb (they called them “mountain bikes’ back then) from the catalog that came to my house, and rode it till the knobs were gone. As with any luxury industry, it’s race on Sunday, sell on Monday. 99.99% of the people reading this would never want to, or be able to push to the ‘limits’ of a 27.5+ tire. The reality is they make riding more fun in almost every situation for most riders out there. But the ‘fast kids’ have spoken, and soon we’ll be lucky to find plus size tires anywhere but the clearance section or on EBAY for a 300% markup.

Leave a comment.

Social Media

Most Popular

Get The Latest Updates

Subscribe To Our Weekly Newsletter

No spam, notifications only about new products, updates.
On Key

Related Posts

Review: Endura MT500 Burner Clipless Shoe

Endura may not be a name you think of when shoe shopping — yet. This Scottish based company with a strong sustainability plan is best known for its mountain bike apparel right now.