Wheel Size Facts Part 1-Dimensions, Weight and Strength

The boys over at Banshee Bikes sent this along today it is a good read on wheel size.

"You may have read certain online and printed marketing startegies which talk about wheelsize with a significant bias towards one size. The size they promote will always be either the only size that the source company produces, or the size that they want to push. Intentional marketing spiels are often very misleading and can skew the purchaser's judgement.

I feel it is my duty to set the record straight by writing a series of blog posts that kick off with this one, which addresses two key components of wheel size: weight and dimensions (and little bit of strength thrown in for good measure!). I plan to give unbiased information that you may find useful when deciding what size hoops you want your next purchase to be.

I can offer nonpartisan information (actual facts, rather than marketing blurb) as here at Banshee we offer all 3 mountain bike wheel sizes. We let the customer decide what they want rather than force it upon them, so have no reason to promote one over any other.

Every wheel size has its pros and cons, so picking the best wheelsize for you really comes down to personal preferance. The main things to consider when picking wheel size are your riding style, riding purpose (style or speed), the terrain you ride, and rider height, but there are also many other factors. I'll try my best to cover the main ones.

The following camparisons for this whole series are based on using Maxxis High Roller II 2.3" tires on each wheel size with same rim width for all sizes.

Any comparison I do will be relative to 650b wheels since they are the middle wheel size and so it makes the % change figures clear and consistant.

Dimensions: (Outer tire dimensions taken from official Maxxis 3D files)

Straight away this table is likely to cause some confusion... because as you can see, none of the rims or tires match up to their name sake. You can find out why this is the case by reading from a master of bike knowledge Sheldon Brown.

However, one point to notice is that while 650b is marketed as 27.5", it is only 1" larger diameter than 26", and 1.5" smaller than 29", so it is significantly closer to 26" than 29.  The 650b tire (often marketed as the 27.5") does not actually fall equally between the 26" and the 29" tires, so the characteristics of the 650b are far more similar to 26" than 29" wheels.


Weight:

Static weight

Obviously, tire and wheel build weights can vary significantly for all wheel sizes. So I'm sticking with 2.3" wide High roller II 3C/EXO/TR. For the wheels, I will use Stan's ZTR Flow EX wheels for each size.

Static weight (the weight of an unrotating wheel) is often emphasised by marketing teams. But it only really matters when you lift the bike on and off a rack or carry it on your back. However, static weight does have an effect on the...

Moment of Inertia

Moment of inertia is resistance to angular velocity change about an axis of rotation. Basically, the higher the moment of inertia of a wheel the harder it is to accelerate (and decelerate). This is far more significant than static weight when riding a bike.

Moment of inertia is related to both radius and mass, as Moment of Inertia (I) = Mass x Radius². A low moment of inertia results in a fast accelerating wheel (easy to start spinning). The flip side of this is that a high moment of inertia is harder to decelerate (harder to stop spinning), and so the wheel will carry the speed better once rolling if all other factors are equal.

The below table shows approximate moments of inertia by using the BSD as the effective rotational radius for all wheel sizes. 

What these numbers illustrate is that if you ride flowy trails that do not require lots of braking and accelerating back up to speed, then a larger wheel might be a better choice. However, if the trail demands regular braking and pedaling up to speed again then a smaller wheel might be better suited.

If using the same effective components, then as the wheel size increases the weight and inertia increase accordingly (as you would expect)... but because inertia increases at a rate that is proportional to the radius squared, it goes up more steeply than weight as the wheel size increases.

Strength:

A factor that is strangely often overlooked by marketing teams is that of the strength and stiffness of the wheel. I find this particularily strange as wheels cost a lot of money, and are subject to a lot of abuse, and personally the lifespan of a wheel is a significant factor to me when chosing what set to invest in.

If comparing like to like wheel builds (same rims, hubs etc), smaller wheels will always inherintly be stronger than larger wheels. This is due to wider gaps between spoke eyelets and poorer spoke triangulation etc. So strength to weight ratio is something that will always be won by smaller wheels.

It is however easy enough to compensate for this by getting stronger and stiffer wheels, but they do generally either weigh, or cost more. So something has to give.

It doesn't stop there....

Weight, dimensions and strength are obviously very important factors to take into account when considering what wheel size to choose. But... there are other factors too! And if this mini-blast of physics chat hasn't put you off too much, stay tuned for future blog posts about topics where bigger wheels have the advantage."

Niner Bikes Launches 3 New Models At 2014 Eurobike

Niner WFO 9

From early trips to Whistler and passionate lift-line discussions about wheel size to numerous Burro-Down laps at truly negligent speeds, the WFO 9 has always been a curiosity. A bike without an easy niche except for those riders who are quite certain it’s the best bike on the planet – those converts who choose the WFO 9 to confidently dissect bike parks and black diamonds every weekend. This bike has changed how a lot of riders view long-travel 29ers, evolving from an outlier in the Niner lineup to a bike whose time has come. With trail bikes becoming more and more capable, we’ve shoved the new WFO 9 off the “all mountain” fence firmly into gravity territory. Lower. Slacker. More Travel. So, grab your music, Leatt and full-face before you roll out the door.

While the WFO 9 is an efficient pedaler and will do AM magic under those who have the legs for the climbs, it’s when you adjust your goggles and drop in that it truly shines. You might imagine that the bike’s 150MM of travel puts it into a familiar category of bikes, but it doesn’t ride that way. Coming from a trail bike, the WFO 9 will feel big and capable. If you spend time on DH bikes you will instantly feel at home, except the WFO 9 is likely several pounds lighter than your DH setup. That’s a few extra laps and a few spots higher on any leader board. The long wheelbase puts you in charge of where the bike goes and if you’ve ever had trouble carrying enough speed into that set of 30’ tables, prepare yourself for some hair-raising-shit-eating-grin-overshooting-to-HYFR.

The big wheels bring the kind of speed through the chop and stability in the air that any rider will benefit from. Whips? Snap hard and get sideways. Scrubs? Push a bit earlier to break the increased traction and get the bike down. The wheels stay out of the holes on techy lines, allowing you to get away with 6” of travel in serious clenching moments that just wouldn’t be fun on a trail bike. Float down your favorite trail and wonder when they made it easier. They didn’t.

Bottom line is, all those guys who said 29 will never be fun on big terrain were just plain wrong. That’s ok thoughk we weren’t sure ourselves when when we made the first WFO 9 in 2009. But it’s 2013, we’ve done the homework. This is the new WFO 9 and it redefines what a Niner can do.

• AIRFORMED ALLOY FULL SUSPENSION FROM THE 29ER-ONLY MOUNTAIN BIKE COMPANY
• 150MM OF PATENTED CVA SUSPENSION IS CONTROLLED AND SENSITIVE
• COMPATIBLE WITH 150–170MM FORKS
• TUNED FOR CVA – ROCK SHOX MONARCH PLUS RC3
• ISCG 05 TABS AND OFFSET LINKAGE DESIGN FOR CHAINGUIDE COMPATIBILITY
• FORGED SUSPENSION LINKAGE AND UNIQUE NINER ALLOY HARDWARE
• 142MM X 12MM REAR SPACING

CVA™ SUSPENSION

The WFO 9 features Niner’s patented CVA™ suspension (U.S. Patent No. 7,934,739) and delivers 150mm of fully active travel with superb compliance and damping via a tuned for CVA™ RockShox Monarch Plus RC3 shock. The three modes of the RC3 offer a bit more pedaling efficiency when you need to stomp up to the next stage and the increased shock length and stroke maintain a low leverage ratio for best performance. For those seeking the technical advantages of 29” wheels combined with pedaling efficiency and remarkable sensitivity, CVA™ is the front-runner. The result? A faster, smoother ride up and down the trail.

VERSATILE GEOMETRY

The WFO 9 geometry has been totally revised. Shorter chain stays, slacker head tube angle, shorter head tube, shorter top tube, lower BB height and a lower stand over announce that this bike is ready to get it on.

AIRFORMED TUBING

The next installment of Niner’s airformed trilogy is complete. Shaping the WFO 9 frame tubes with compressed air in a heated mold gives us greater control over wall thickness and material uniformity, allowing the use of less metal. The new WFO 9 is over 300g lighter than its predecessor – total Medium frame weight is 7.3lbs (no Maxle or seat collar) compared to 8lbs (no Maxle or seat collar) for the old model.

TAPERED HEADTUBE

The increased surface area of a tapered headtube allows for a larger downtube, increasing strength and rigidity at this critical intersection. Tapered fork steerer tubes measurably reduce fork deflection, which means your WFO 9 tracks straight and true. The full spectrum of riders from XC racers to those who “only ride park” benefit from these features which is why we incorporate the technology in all our frames.

ATTENTION TO DETAIL

• Dedicated 142 x 12mm drops are custom-forged for a sleek look that flows seamlessly to the stays

• Derailleur hanger mounted inside of drop out for better protection and to preserve the clean lines (optional hanger available for Shimano’s new DM standard)

• New post-mount rear brake mount is hollow to reduce weight

• Custom forged seat stay and chain stay yokes reduce weight and maintain the lines of the airformed tubes

• Bigger Enduro MAX bearings increase durability by distributing suspension load over a larger bearing race and allow

the use of new larger-diameter alloy hardware

• Chainstay/Seatstay tree replaced by massive asymmetrical brace, increasing rigidity and incorporating the look and feel of its shorter travel brethren

• Seat Tube Main Pivot is integrated directly into the tube rather than welded to the front of the seat tube

• Custom Forged BB incorporates the lower forward pivot, ISCG 05 mounts, lower shock mount and BSA BB shell in one beautifully shaped (hollow) work of art. The keyed lower forward alloy pivot bolt does double duty as the third ISCG 05 tab.

• Full housing from shifter to derailleur with dropper routing along the top tube

• Zero Stack/Inset head tube is Angleset compatible

Niner Air 9 Carbon

 

For Niner afficiaonados, the Air 9 Carbon has long been the benchmark for carbon frames. We are confident that this newest incarnation will inspire the same respect for beautiful shaping, quality carbon engineering and perfect technical details. We’ve updated the original Air 9 Carbon by adding features and shaping from our award winning RDO line up. At the same time, we’ve made sure that the complete bike options are a great way for riders to get into a high-quality carbon race bike with some cash left in the piggy bank for travel or entry fees.

• NEW TUBING PROFILES AND CARBON LAYUP
• COMPATIBLE WITH 80–100MM TAPERED FORKS
• NINER’S PROVEN HARDTAIL 29ER GEOMETRY
• LOW PROFILE DISC BRAKE POST MOUNT
• EXCEPTIONAL HEEL AND TIRE CLEARANCE
• 135MM X QR REAR SPACING
• BACKED BY NINER’S 5 YEAR C5 CARBON WARRANTY

REFINED DESIGN

The Air 9 Carbon is now a dedicated geared racing bike with trickle-down RDO features throughout, including reduced diameters and trimmed tube profiles, smaller junctions, molded carbon headset races and a carbon BB shell. Additionally, the rear brake mount is now tucked inside the curving stays to distribute twisting forces evenly, permitting smaller caliper mounts

TAPERED HEADTUBE

The benefits of a tapered headtube aren’t just for riders of long travel bikes. XC racers and riders also see significant advantages, which is why we incorporate the technology in all our new frames. By using tapered steerer suspension forks, we create the stiffest front end possible – leading to increased steering precision as you carve a corner and descend toward the finish line. The integrated headset used in the Air 9 Carbon is light and simple. Installation, cleaning and maintenance take seconds rather than minutes, a boon to anyone who queues up at the starting line without a team mechanic.

PF30 BOTTOM BRACKET

There are several BB standards to choose from – for our dedicated geared only race bikes we like PF30. It’s compatible with any BB30 crankset (as well as standard threaded BB systems, with an adapter) and the bearing cups are delightfully easy to install. The oversized 30mm spindle is light and resists the torque of even the mightiest Ninerds. Oversized bearings spin longer and smoother between overhauls. The plastic cups of the PF30 BB system don’t require a machined aluminum bottom bracket shell insert, allowing a minimalist carbon construction.

INTERNAL SHIFTER ROUTING

Headbadge routing is designed for full-length housing, simplifies cable changes and protects cables from the elements.

NINER HARDTAIL GEOMETRY

As verified over and over again in independent reviews, Niner has hardtail 29er geometry dialed. Climbing or descending, the geometry of the Air 9 is tuned to for great handling and rider positioning. The Air 9 Carbon is intended for 80-100mm forks, allowing you to fine tune your ride.

Niner One 9 RDO

You’ve probably noticed we have a habit of revisiting our classic models and occasionally injecting them with a huge dose of YEAH. In the case of the One 9 RDO, we’ve created a completely new bike – melding the single-mindedness of the legendary One 9 with our award-winning Air 9 RDO carbon chassis. The result is lightning quick, strong as a gorilla but sexy as they come. In other words, the One 9 RDO is going to make you forget all about your other bikes. If loving the One 9 RDO is wrong, you won’t want to be right...

 

REFINED DESIGN

The newest member of our hardtail RDO program, the One 9 RDO is a singlespeed racer designed to go flat out fast. The One 9 RDO is specifically intended as a singlespeed racing bike, utilizing the reduced diameters and trimmed profiles of our RDO hardtail line up throughout. The rear brake mount is tucked inside the curving stays to distribute twisting forces evenly, permitting smaller caliper mounts and decreased wall thicknesses. Even the headset races in the headtube are molded carbon - we shaved grams wherever we found them. The net result? A singlespeed that can’t be matched for quality and weight.

TAPERED HEADTUBE

The benefits of a tapered headtube aren’t just for riders of long travel bikes. XC racers and riders also see significant advantages, which is why we incorporate the technology in all our new frames. By using the newest tapered steerer suspension forks, we create the stiffest front end possible – leading to increased steering precision as you carve a corner and descend toward the finish line. The integrated headset used in the One 9 RDO is light and simple. Installation, cleaning and maintenance take seconds rather than minutes, a boon to anyone who queues up at the starting line without a team mechanic.

BIOCENTRIC BOTTOM BRACKET

The Niner BioCentric II makes adjustments easy across a wide range of gears and eliminates the need for adjustable dropouts, giving the cleanest possible solution for singlespeed use. No bolt on hubs, no chain tensioners cluttering your ride, no brake adjustments with gear changes.

1X DRIVETRAIN COMPATIBILITY

For those who want a little extra versatility, the One 9 RDO is compatible with Niner’s CYA bottom bracket system, enabling riders to run systems such as SRAM’s XX1 or XO1.

REAL WORLD WEIGHT SAVINGS

Sharing key layup and mold features with the Air 9 RDO, combined with the singlespeed simplicity of this frame, gives the One 9 RDO an average weight of 1235g. Combined with the Niner RDO fork, you are looking at one of the lightest mountain bikes available.

NINER HARDTAIL GEOMETRY

As verified over and over again in independent reviews, Niner has hardtail 29er geometry dialed. Climbing or descending, the geometry of the Air 9 is tuned to for great handling and rider positioning. The One 9 RDO is intended for 80 to 100mm forks, allowing you to fine tune your ride.

Intense Carbine 29

The Carbine 29 raises the bar on performance, technology and beauty, offering aggressive geometry, patented VPP suspension, all the design benefits of INTENSE 2nd generation INTENSE carbon fiber, and a look only possible from INTENSE.
 
Designed to allow riders to descend the roughest enduro tracks with confidence, the bike boasts 5.5 inches (140mm) of rear wheel travel, 160mm of travel up front, and a 67 degree head tube angle.
 
The slacker head angle and 51mm 29-specific fork offset on the Carbine 29 work together to create a bike that delivers added agility and improved handling.
Fast, gnarly rock sections never felt so secure. Cornering was never as quick on a 29er. Let go of the brakes and take the rough line to the bottom. The Carbine 29 will allow you to ride hard, and ride fast.
 
The bike offers cutting-edge technology like internal cable routing, Reverb Stealth seat post routing and ISCG 05 chain guide tabs. It will be offered as both a complete bike or frame-only.
 
Frames are fitted with a FOX Float CTD Kashima Coat rear shock. Complete bikes will include the new SRAM 1×11 drive train and a 160mm Rockshox Pike fork.
The new Carbine 29er has proven to be a great Enduro weapon. Raced & tested under wraps for months, the Carbine 29 is already no stranger to the podium.

Geometry 

NINER BIKES REVEALS NEW AIRFORMED RIP 9

The reputation of the R.I.P. 9 is unassailable – in the six years since its introduction it has helped define the new-school genre of trail ripper - both with riders and the cycling press. So how can it be improved? Keep the attitude, boost performance, shed unwanted weight and build on the legend. The changes to this new beast can’t really be called “evolutionary,” because the word implies a slow process of incremental gains and small strides. That just doesn’t describe the changes to the new R.I.P. 9 – there’s nothing incremental about a kick in the pants.

TRAIL BIKE 29

The Niner that is at home on just about any trail or any terrain – The R.I.P. 9 incorporates global rider feedback as well as Niner’s rigorous progression of alloy design, engineering and testing standards. The R.I.P. 9 has over 30 glowing media reviews for ride quality and handling - the new R.I.P. 9 takes these characteristics and ups the ante with air formed aluminum alloy tubes that redefine performance, a lower weight, ISCG compatibility and additional travel.

CVA™ SUSPENSION

The R.I.P. 9 features Niner’s patented CVA suspension (U.S. Patent No. 7,934,739) and delivers 125mm of fully active travel with superb compliance and damping via a tuned for CVA RockShox Monarch RT3 HV shock. For those seeking the technical advantages of 29” wheels combined with pedaling efficiency across all chainring combinations (not just the middle ring), CVA™ is the front-runner. The result? A faster, smoother ride up and down the trail.

VERSATILE GEOMETRY

To progress as a rider you need predictability, balance and nimble handling and Niner is the company that first made fun trail bike 29ers a reality. Climbing or descending, the geometry of the R.I.P. 9 is tuned to keep you in control and ready to conquer new terrain at every turn. The R.I.P. 9 is intended for 120 to 140mm forks, allowing riders to further fine tune the ride.

AIR FORMED TUBING

At just 6.85lbs for a medium frame with shock & hanger, the new R.I.P. 9 pulls within .65lbs (295g) of our carbon flagship R.I.P. 9 RDO frame. To achieve this reduction and actually increase strength over the last R.I.P. 9 frame we looked beyond traditional hydroforming. Shaping the frame tubes with compressed air in a heated mold gives us greater control over wall thickness and material uniformity, allowing the use of less metal. Tubes that are manipulated using this process can be up to 25% lighter than a similar hydroformed shape at the same strength.

TAPERED HEADTUBE

The increased surface area of a tapered headtube allows for a larger downtube, increasing strength and rigidity at this critical intersection. Tapered fork steerer tubes measurably reduce fork deflection, which means your Niner tracks straight and true. The full spectrum of riders from XC racers to All Mountain shredders benefit from these features which is why we incorporate the technology in all our frames.

ATTENTION TO DETAIL

From the head tube to the rear axle, we looked at every single detail and asked “can it be done better?” We’ve revised the shapes of the forged yokes and attachments, subjecting them to mechanical and real world testing to ensure they’re as light and strong as possible. New linkage shapes increase strength and stiffness and shed a few more grams, the lower link has a pronounced asymmetrical form to make room for ISCG tabs and increased chainstay clearance. Larger pivot hardware and a switch to 8mm alloy shock mounting bolts shave weight and increase the bling we love so much. Saving weight doesn’t mean skimping - pivots are still outfitted with Enduro Max full complement sealed cartridge bearings for smooth, friction-free suspension.

• Airformed alloy full suspension trailbike – setting the standard in any wheelsize

• 125mm of patented CVA™ suspension, efficient in every chainring configuration

• Compatible with 120-140mm forks

• Tuned for CVA™ - Rockshox Monarch RT3 HV

• ISCG Tabs and offset linkage design for chainguide compatibility

• Forged suspension linkage and unique Niner Alloy Hardware

• 142x12mm rear spacing

• Medium frame with shock, maxle hanger and seat collar - 7 LBS/3175 g, a half pound lighter over previous iterations.

• $1849 Frame MSRP (includes shock, maxle and seat collar)

• Complete 3-Star XT Bike $4199, Complete 1-Star X7 Bike $2999

• Ships in early May.

Niner Bikes was founded 2004 in Southern California and is headquartered in Fort Collins, Colorado.

The company is dedicated to the ideals of passion, commitment and 29ers only.

Ibis Ripley 29er Announced

Design goals of the Ripley 29

Our goal was to bring the advantages of a 29” wheel to a lightweight, nimble and fun trailbike. We think 120 mm of travel is the sweet spot for a snappy bike that isn’t cumbersome or heavy. We also wanted the Ripley to be configurable for a wide range of terrain and riding styles, so we made it compatible with 120–140 mm travel forks. We asked Dave Weagle (Mr. dw-link) to give the Ripley pedaling efficiency, XC-like acceleration and optimization for 29er specific gearing in addition to the usual dw-attributes such as excellent small bump compliance, predictable travel through the range with no wallowing or harsh bottom out. This version of the dw-link, like the ones he’s done for us in the past, delivers on the promise.

Features of the Ripley 29 - Special Preview

• 120mm rear wheel dw-link travel
• 5.0 Pound frame with X Fusion Microlite Shock, 5.2 lbs with Fox RP23 CTD
• Approved for 120-140mm forks, 32 or 34 stanchion
• Tapered head tube (suitable for various Cane Creeks & Chris King InSet 3)
• Internal TT cable routing with molded carbon cable stops
• Shock Specs: 184mm x 44mm with .4 volume spacer
• Provision for cable-actuated adjustable seat posts
• BB92/Press GXP style integrated BB
• 142mm Maxle rear axle
• 160mm carbon fiber post mount rear brake mounts
• High direct mount front derailleur mounts directly on swingarm
• Headset: IS ZS44/28.6 | EC49/40
• BB height w/ 2.1" tires: 325mm (12.8")
• Geometry measured with 520.8mm axle to crown fork

Ibis Ripley 29"