Modern Enduro Bike Geometry Compared, Analyzed, and Explained

Photo: Matt Delorme/Trek Bikes

Enduro bike geometry is often a source of debate or confusion, depending on how much you know about the topic. For example, some riders prefer the benefits of short chainstays for their flickability while others say longer is better because of the stability factor. Every rider has their own individual preferences. As it turns out, brands have their own take on “ideal” mountain bike geometry, which is one way they can differentiate themselves in the market.

Then you also have wheel size and suspension travel to consider. Do 27.5″ or 29″ wheels make a better enduro bike? How much squish is enough? While I don’t intend to settle those debates with this article, what I wanted to do was answer the question:

“How big are the differences in enduro bike geometry between brands and between wheel sizes?”

Strap in for a deep dive into the nitty-gritty of geometry figures for a vast array of today’s enduro bikes. And if you haven’t already, be sure to check out the companion to this article that compares geometry between the top trail bikes on the market today.

Definitions

Before we get started, it might be helpful to define what an enduro/all-mountain bike is in general. The term “all-mountain” has been around for at least a couple decades, but in recent years it’s been superseded by the word “enduro.” Basically, bikes in this category have relatively long suspension travel (140-180mm depending on wheel size), geometry that favors descending capability over climbing efficiency, and components that place an importance on durability above weight. These bikes are made to get you to the top of the mountain under your own power and then safely down the rowdiest of descents.

Initially, “enduro” was specifically a race format. In an enduro race, a rider is timed only on the descents, called “stages.” In between the stages you have untimed portions called “transfers.” A typical enduro race will have 3-5 stages, but they can also span several days and many more stages. At the end of the race, the rider with the lowest combined time on the stages is the winner.

The mountain bike enduro race format has been around for the better part of 15 years, but it wasn’t until the last five years or so that it became mainstream. And since it became mainstream, the enduro name has been slapped on everything from bikes to shoes to helmets to gloves to you name it. In my opinion, the most irksome application of the enduro label has been to trails themselves, and to rides. Like when someone says, “I’m going on an enduro ride,” or asks, “is this an enduro trail?” It’s just mountain biking y’all, same as it’s ever been.

As annoying as I find the enduro-ification of mountain biking, I’ve come to accept that it’s now just part of our sport’s parlance. While I’ll use the term enduro in this article, just know it’s interchangeable with all-mountain.

Geometry Terms

I included this glossary in the trail bike compare-o, but those not intimately familiar with all the geometry terms might find it helpful.

  • Head tube angle (HTA)  the angle, in degrees, of the head tube relative to the ground. Generally speaking, the steeper the angle is (closer to 90 degrees), the faster the bike will respond to steering inputs. A steep HTA also aids in climbing, as the front wheel will track straighter. A slack HTA puts the front wheel farther out in front of the bike, slows steering input, lengthens the wheelbase, and increases descending confidence.
  • Seat tube angle (STA) – similar to HTA, except this is the angle that the seat tube forms relative to the ground. A steeper seat tube angle brings the rider’s hips forward, over the bottom bracket. A slacker angle will move the rider’s weight back over the rear wheel. This angle also has an effect on the ETT: a steeper angle creates a shorter ETT measurement, while a slacker seat tube will lengthen it.
  • Reach – this is the horizontal distance between the center of the head tube and a perpendicular line drawn through the center of the bottom bracket. More and more, brands focus on the reach figure since it gives the rider an idea of how the bike will fit when standing on the pedals.
  • Effective top tube length (ETT)  the horizontal distance, measured parallel to the ground, between the center of the head tube and where it intersects the seat tube or seat post. As you go up in frame size, this distance will get longer.
  • Stack – this is the vertical distance between the top of the head tube and the bottom bracket. Stack is important because it will impact how high or low your handlebars will be.
  • Chainstay length (CS)  sometimes also called rear center, this is the horizontal measurement from the center of the bottom bracket to the center of the rear axle. Short chainstays are very much en vogue right now, as they can add a playful character to a bike. However, short chainstays can also detract from high-speed stability.
  • Front Center (FC) – this isn’t included in the illustration above, but I had a few requests to provide the front center measurement. The front center is the horizontal distance from the center of the bottom bracket to the center of the front axle. To determine FC, simply subtract the chainstay length from the wheelbase. Front center tells you how much of a bike’s overall length is located in front of the BB.
  • Bottom bracket height (BB) – the vertical distance from the ground to the center of the bottom bracket. A lower BB height will aid in cornering, but also increases the chance of pedal strikes.
  • Wheelbase (WB) – the horizontal distance between the front and rear axles. A longer wheelbase will increase high-speed stability, and a shorter wheelbase will make the bike more maneuverable on tight trails.

Conditions and Assumptions

With 160mm/150mm travel, you’d think the Rocky Mountain Altitude would classify as an enduro bike. Not so, says Rocky. (photo: Aaron Chamberlain)

Now that I’ve defined what an enduro bike is in general, I’ll let you know how I chose the bikes for the purposes of this particular discussion. Here are the requirements:

  • For 27.5″ wheeled bikes: a minimum of 150mm rear travel and a minimum of 160mm front travel.
  • For 29″ wheeled bikes: a minimum of 140mm rear travel and a minimum of 150mm front travel.

Granted, it’s not a perfect definition since many bikes blur the line between a trail bike and an enduro bike, but it’s more than sufficient for this comparison.

The Pivot Firebird pedals better than any 170mm bike has a right to, but their Mach 6 is a better choice for enduro racing (photo: Pivot)

Also, note that I didn’t always pick the longest-travel bike offered by a brand. That’s because a handful of brands offer bikes that are in yet another category above and beyond trail or enduro. Call them freeride or park bikes if you like, but these beasts have abilities skewed even further towards descending. While you could pedal them to the top of the mountain, you probably wouldn’t want to, especially in a race situation.

If in doubt, I tried to find out what bike a brand’s team used for racing. Most enduro races have plenty of pedaling and climbing, so a bike’s overall capability has to be taken into account. It’s not simply a matter of choosing the most travel and slackest geometry.

Additional things to be aware of:

  • Measurements below are taken for size-large frames.
  • For bikes with adjustable geometry, measurements are from the slackest setting available.
  • For bikes with only the bottom bracket drop listed, I estimated the BB height for the sake of comparison. I assumed a 352mm axle height for 27.5″ wheeled bikes and 372mm axle height for 29″ wheeled bikes. This roughly equates to a 2.30-2.40″ wide tire. The following bikes have estimated BB heights using those criteria:
    •  27.5″
      • Canyon Strive
      • Commencal Meta AM V4.2
      • Cube Stereo 160
      • Fuji Auric
      • Giant Reign
      • Jamis Defcon
      • Nukeproof Mega 275
      • Rocky Mountain Slayer
      • YT Capra
    •  29″
      • Niner RIP 9
      • Nukeproof Mega 290
      • Rocky Mountain Instinct BC Edition
      • Scott Genius 900

I would call this list extensive, but it is by no means definitive. There will always be bikes from smaller brands that are not on my radar. What I tried to provide is a broad, diverse cross-section of bikes from numerous brands.

On to the bikes!

27.5″ Enduro Bikes

Richie Rude, one of the world’s top enduro riders, races mostly on a 27.5″ Yeti (photo: Yeti Cycles)

There’s certainly no shortage of 27.5″ enduro bikes on the market today. In fact, they’re much easier to find than 29″ enduro bikes, which is why this list is nearly twice as long. The 30 bikes below come from a variety of manufacturers and take different paths to reach the same destination.

Head Tube Angle: Slackest to Steepest (°)

The Transition Patrol with its 64° head tube angle is the slackest of the bunch (photo: Transition)

Hands down, the geometry number riders focus on the most seems to be the head tube angle. HTA isn’t the be-all, end-all, but it does give you a fairly good indication of how the designers want the bike to descend. Take the two bikes at opposite ends of the list below, the Transitional Patrol and the Fuji Auric. It’s true that the Patrol is spec’d with a 170mm fork while the Auric has a 160mm fork, but the 3° difference in head tube angle is going to have a much greater impact on descending performance.

Is one inherently better than the other? Not necessarily. What it really boils down to is how and where you ride. If you have ready access to steep, fast, and gnarly terrain, you’ll likely want a bike with the slackest HTA available. However, if your trails aren’t as steep, or if you prefer a snappier bike, a steeper HTA might be a better fit.

Average HTA: 65°

  • Transition Patrol – 64
  • Banshee Rune – 64.5
  • Orange Alpine 6 – 64.5
  • Santa Cruz Nomad – 64.6
  • Evil Insurgent – 64.8
  • YT Capra – 64.8
  • Ibis Mojo HD4 – 64.9
  • Cannondale Jekyll – 65
  • Devinci Spartan – 65
  • Giant Reign – 65
  • Mondraker Dune – 65
  • Norco Range – 65
  • Nukeproof Mega 275 – 65
  • Rocky Mountain Slayer – 65
  • Specialized Enduro 27.5 – 65
  • Whyte G-170 – 65
  • Commencal Meta AM V4.2 – 65.5
  • Guerilla Gravity Megatrail – 65.5
  • Intense Tracer – 65.5
  • Knolly Warden – 65.5
  • Yeti SB6 – 65.5
  • Pivot Mach 6 – 65.8
  • Canyon Strive – 66
  • Cube Stereo 160 – 66
  • GT Sanction – 66
  • Kona Process 153 – 66
  • Marin Attack Trail – 66
  • Polygon XquareOne – 66
  • Jamis Defcon – 66.5
  • Fuji Auric – 67

Reach: Longest to Shortest (mm)

The Mondraker Dune features the longest reach in this comparison followed closely by the Guerilla Gravity Megatrail (photo: Mondraker)

Here we see huge variations in the reach measurements of modern enduro bikes. A whopping 58.1mm or 2.28 inches separate the longest bike, the Mondraker Dune, from the shortest, the Fuji Auric. What does that extra real estate give you? For one, you get a longer wheelbase which provides stability at speed, and you also get a lot of room to move forward and backward depending on what the situation calls for.

Again, reach comes down largely to personal preference but I, for one, am a huge fan of longer bikes. Do they need to be as long as the Mondraker? Maybe not, but in my opinion, most of the bikes here still have plenty of room to grow.

Average Reach: 461mm

  • Dune – 493
  • Megatrail – 490
  • G-170 – 478.8
  • Patrol – 475
  • Process 153 – 475
  • Reign – 473
  • Jekyll – 470
  • Mega 275 – 470
  • Strive – 468
  • Enduro 27.5 – 466
  • Spartan – 465
  • XquareOne – 461.8
  • Alpine 6 – 461
  • Sanction – 461
  • Tracer – 460
  • Warden – 460
  • Mach 6 – 460
  • Attack Trail – 460
  • Meta AM V4.2 – 458
  • Nomad – 456
  • Rune – 455
  • Mojo HD4 – 455
  • Range 452
  • Insurgent – 451
  • SB6 – 447
  • Slayer – 446
  • Capra – 443
  • Stereo 160 – 442
  • Defcon – 436
  • Auric – 434.9

Chainstay Length: Shortest to Longest (mm)

The Cannondale Jekyll has stubby 420mm chainstays — impressive for a bike with 165mm of rear travel (photo: Cannondale)

Chainstay length is probably the second geometry figure people look at, right after the head tube angle. Shorter chainstays make for a snappier bike around corners, but the flipside is they give up some stability at speed. Like the head tube angle, chainstay length has a large impact on the character of a bike, so brands settle on a particular length to give their bikes a certain ride quality.

We don’t see quite the variance in chainstay length as we did with the reach, but there’s still a significant 22mm (0.87″) difference between the Cannondale Jekyll and the Yeti SB6.

Average chainstay length: 432mm

  • Jekyll – 420
  • Strive – 423
  • Process 153 – 425
  • XquareOne – 425
  • Megatrail – 427
  • Slayer – 429
  • Warden – 429
  • G-170 – 430
  • Spartan – 430
  • Alpine 6 – 430
  • Patrol – 430
  • Dune – 430
  • Capra – 430
  • Mojo HD4 – 430
  • Mach 6 – 430.5
  • Nomad – 431
  • Insurgent – 432
  • Tracer – 432
  • Enduro 27.5 – 433
  • Range – 435
  • Attack Trail – 435
  • Mega 275 – 435
  • Reign – 435
  • Defcon – 435
  • Stereo 160 – 436
  • Meta AM V4.2 – 437
  • Rune – 437
  • Auric – 438.1
  • Sanction – 439
  • SB6 – 442

Bottom Bracket Height: Lowest to Highest (mm)

The American-made Guerilla Gravity Megatrail has a belly-dragging 330mm BB height when in “Gravity Mode” (photo: Guerilla Gravity)

Low bottom brackets are nice up to the point where pedal strikes become common. Again, where you ride factors in to how high you prefer your BB to be. As an East Coast rider that has to pedal through technical, flat terrain, I like a slightly higher than fashionable BB. The higher BB keeps my pedals from smacking into rocks when gravity isn’t on my side.

Another thing to keep in mind here is that the heights listed are static, meaning this is how high the BB is before the rider sits on the bike. Adding weight to the bike and setting the suspension sag properly will result in a lower BB.

Average BB height: 342mm

  • Megatrail – 330
  • G-170 – 333.5
  • Insurgent – 334.4
  • Attack Trail – 335.5
  • Warden – 337
  • Spartan – 337
  • Stereo 160 – 338
  • Rune – 338
  • Nomad – 339
  • Strive – 340
  • Slayer – 340
  • Patrol – 340
  • Mega AM V4.2 – 340
  • Mega 275 – 341.9
  • Alpine 6 – 342
  • Range – 342
  • Reign – 342
  • Auric – 342
  • Mojo HD4 – 343
  • Tracer – 343
  • Defcon – 345
  • Sanction – 345
  • Mach 6 – 345.9
  • Process 153 – 348
  • Capra – 348
  • Jekyll – 349
  • Dune – 350
  • Enduro 27.5 – 350.5
  • XquareOne – 354

Wheelbase: Longest to Shortest (mm)

The Whyte G-170 doesn’t lead any one category, but overall, it’s one of the longest, lowest, and slackest bikes on the list (photo: Whyte Bicycles)

The longer the wheelbase, the more stable the bike will be at speed. Longer wheelbases are the byproduct of LLS geometry becoming the norm. That’s because adding suspension travel, slackening the head tube angle, and increasing the reach all have an impact on the overall length of the bike.

It’s really only on the tightest of switchbacks that a long wheelbase becomes a detriment. Unless your trails are overly twisty, the benefits of a long wheelbase will outweigh the downsides.

A massive 67mm (2.6″) separate the longest and shortest bikes on this list.

Average wheelbase: 1214mm

  • Dune – 1243
  • G-170 – 1240.6
  • Megatrail – 1240
  • Patrol – 1238
  • Reign – 1232
  • Alpine 6 – 1231
  • Mega 275 – 1226.1
  • Enduro 27.5 – 1225
  • Spartan – 1224
  • Jekyll – 1220
  • Mojo HD4 – 1219
  • Nomad – 1218
  • Process 153 – 1216
  • Meta AM V4.2 – 1215
  • Range – 1215
  • Sanction – 1215
  • SB6 – 1215
  • Slayer – 1211
  • Rune – 1208
  • Strive – 1207
  • Tracer – 1207
  • Attack Trail – 1205.2
  • Mach 6 – 1204.5
  • Capra – 1203
  • Insurgent – 1202
  • XquareOne – 1201.5
  • Stereo 160 – 1198
  • Warden – 1189
  • Auric – 1180.4
  • Defcon – 1176

29″ Enduro Bikes

Casey Brown (Trek Factory Racing) aboard the 29″ Slash (photo: Matt Delorme/Trek Bikes)

There are comparatively fewer bikes on the 29er list simply because there just aren’t as many full-on enduro bikes with wagon wheels on the market today. I suspect the offerings will continue to grow, though, as the larger wheels are inherently better at plowing through the rough terrain which often factors heavily into enduro race courses.

Like the 27.5″ bikes, we see manufacturers taking different routes to come up with their ideal 29″ enduro bike. However, we don’t see quite the level of variation in geometries with 29 as with 27.5.

Head Tube Angle: Slackest to Steepest (°)

As with the 27.5″ bikes, Transition takes the cake for slackest head tube angle (photo: Transition Bikes)

Once again, a bike from Transition claims the coveted “Slackie Award” for having the slackest head tube angle. Interestingly, Transition went with a custom, shorter offset fork to bring the front wheel back in towards the rider. The combination of a slack HTA and a shorter offset fork are key components in Transition’s Speed Balanced Geometry, which the company claims gives incredible stability at speed without deadening the steering.

At the opposite end of the spectrum sits the Niner RIP 9. The RIP saw a complete overhaul for 2017 that changed it from a modest trail bike with 125mm of rear travel to a full-on enduro bike with 150mm of rear travel paired with a 160mm fork. Despite relaxing the HTA by 2.5°, the new RIP is still fairly conservative by today’s standards with a 67° HTA.

Average head tube angle: 66°

  • Transition Sentinel – 64
  • Orbea Rallon – 65
  • Scott Genius 900 – 65
  • Evil Wreckoning – 65.5
  • Intense Carbine – 65.5
  • Norco Range – 65.5
  • Orange Stage 6 – 65.5
  • Specialized Enduro 29 – 65.5
  • Trek Slash – 65.6
  • Whyte S-150 – 65.6
  • Rocky Mountain Instinct BC Edition – 65.9
  • Process 153 – 66
  • Mega 290 – 66
  • Hightower LT – 66.4
  • Marin Wolf Ridge – 66.5
  • Yeti SB5.5 – 66.5
  • Niner RIP 9 – 67

Reach: Longest to Shortest (mm)

The new Kona Process 29er ties the Transition Sentinel for longest reach (photo: Kona Bikes)

The 29″ list doesn’t have an outlier like the Mondraker Dune in the reach department, but we still see a variance of 33mm (1.3″) between the Transition Sentinel and the Yeti SB5.5. Looking at all these lists, what struck me the most is how the Yeti is at or near the bottom in all measurements. Since the Yeti brand is synonymous with enduro, that came as a surprise.

Average reach: 460mm

  • Sentinel – 475
  • Process 153 – 475
  • S-150 – 474.4
  • Mega 290 – 470
  • Genius 900 – 466.1
  • Wolf Ridge – 462.2
  • Stage 6 – 462
  • Enduro 29 – 462
  • Range  – 461
  • Slash – 459
  • Rallon – 455
  • Carbine – 455
  • Instinct BC Edition – 454
  • Wreckoning – 452
  • RIP 9 – 451
  • Hightower LT – 443
  • SB5.5 – 442

Chainstay Length: Shortest to Longest (mm)

The Yeti SB5.5 hits the average 437mm chainstay length, right on the nose (photo: Yeti Cycles)

Holding all else equal, you’ll always be able to make the chainstays on a 27.5″ bike shorter than those on a 29″ bike. You can only trim away so much material before you run into that larger back wheel. That said, designers have found a way to make chainstay lengths pretty damn close between the wheel sizes. Take the Kona Process: it has the same 425mm long chainstays as its 27.5-wheeled brother, which are also just 5mm longer than the incredibly short chainstays found on the Jekyll.

Average chainstay length: 437mm

  • Process 153 – 425
  • Wreckoning – 432
  • Enduro 29 – 433
  • Slash – 433
  • Sentinel – 435
  • S-150 – 435
  • Wolf Ridge – 435
  • Range – 435
  • Rallon – 435
  • Instinct BC Edition – 435
  • SB5.5 – 437
  • Genius 900 – 438
  • Hightower LT – 438
  • RIP 9 – 440
  • Carbine – 445
  • Mega 290 – 450
  • Stage 6 – 450

Bottom Bracket Height: Lowest to Highest (mm)

Like its smaller-wheeled brother, the Whyte S-150 has a super low bottom bracket (photo: Whyte Bikes)

One of the cool things about well-designed 29ers is how they feel like they’re on rails when cornering. Much of this sensation comes from the increased BB drop compared to 27.5″ bikes. Since the taller wheels have higher axles, the relative distance between the axle height and the BB height is greater. This gives the rider a lower center of gravity relative to the axles and makes you feel like you’re in rather than on the bike.

Average BB height: 343mm

  • S-150 – 335
  • Stage 6 – 335
  • Wolf Ridge – 336
  • Rallon – 336
  • Hightower LT – 338
  • Wreckoning – 339
  • Range – 340
  • Mega 290 – 341.7
  • RIP 9 – 343
  • Genius 900 – 344.4
  • Sentinel – 345
  • Process 153 – 346
  • Enduro 29 – 346
  • SB5.5 – 346
  • Carbine – 348
  • Slash – 352
  • Instinct BC Edition – 353

Wheelbase: Longest to Shortest (mm)

The Orange Stage 6 has the second-longest wheelbase, trailing the Transition Sentinel by just 2mm (photo: Orange Bikes)

Once again, there’s a substantial variance in the overall wheelbase — 52mm (2.05″). The Transition Sentinel is the longest bike in the comparison thanks in large part to its super-slack 64° HTA. The Orange Stage 6 comes in just 2mm shorter than the Sentinel, but it owes more of its sprawling wheelbase to its long, 450mm chainstays. At the other end of the spectrum, the Santa Cruz Hightower LT and Yeti SB5.5 tie for the shortest wheelbase at 1195mm.

Average wheelbase: 1220mm

  • Sentinel – 1247
  • Stage 6 – 1245
  • Mega 290 – 1236.3
  • Carbine – 1233
  • Genius 900 – 1232.1
  • S-150 – 1231.6
  • Slash – 1219
  • Process 153 – 1218
  • Enduro 29 – 1218
  • Rallon – 1217
  • Range – 1217
  • Instinct BC Edition – 1213
  • Wreckoning – 1208
  • Wolf Ridge – 1206
  • RIP 9 – 1204
  • Hightower LT – 1195
  • SB5.5 – 1195

27.5 vs 29 Enduro Bike Geometry

When we use the chart below to compare the average 27.5″ enduro bike to the average 29″ enduro bike, there are remarkably subtle differences. A 27.5″ enduro bike has slightly more suspension travel front and rear, but a majority of the geometry figures are within half a degree or a few millimeters. The one exception is the stack measurement, which is understandable considering the taller wheels raise the front end of the bike.

*Note that values for the averages were rounded off to the nearest whole number for the sake of clarity, but the differences between the averages were not

What this tells me is that there is a narrow range of geometry values that can be used to make a solid, high-performance enduro bike regardless of wheel size.

Conclusion

Hang in there, we’re almost done.

Comparing the first generation Santa Cruz Nomad to the newest, fourth generation. You can see some of the family resemblance, but the differences are quite apparent. (photos: Santa Cruz)

The basic ingredients for an all-mountain or enduro bike haven’t changed much over the past decade or two. Take a full suspension frame, add two parts long travel, and mix with one part burly build; bake and spread over gnarly trails. What has changed are the little pinches of this and a half a teaspoon of that, which totally altered the flavor (that would be the geometry in this analogy). Compared to ten or even just five years ago, the modern enduro bike has radically different geometry. Head tube angles and wheelbases that were once solely in the realm of downhill bikes are now commonplace on the latest crop of enduro bikes.

While bikes like the Mondraker Dune show there is still room to grow, it seems that, largely, brands have settled into a formula that works for their particular design goals. We’ll likely continue to see subtle tweaks to enduro geometry going forward, but it seems doubtful we’ll see things change by leaps and bounds.

It’s simply another sign that we’re in the Golden Age of mountain biking.

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