Geometry of a 29er :: Is It For You?

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Carla Hukee out on her Niner E.M.D.9

In the cycling world, innovations that change the way we think about and ride bikes don’t come along often.  While 29″ wheeled mountain bikes are obviously here to stay, not everyone has come around to the idea.  As a matter of fact, there are still staunch opposers of big wheels.

Taking a 29er on a test ride is the best way to see the difference for yourself.  But for some, especially small riders, getting a demo opportunity can be tough.  There are still only a few extra small sized frames on the market and the likelihood of your local shop having one in stock might be slim.  Riding a bike that is way too big is certainly not a good indication of performance either.

Standing at 5’2″ on a good day, I had been challenged to spend much time in the cockpit of a 29er, until recently.  My first full-on ride was at Interbike’s Dirt Demo a couple years back.  I was slated to ride with Katerina Nash of the Luna Pro Team on an Orbea mountain bike.  But since I was late signing up, my only option was a 16″ Alma 29er.  I was not about to pass up the opportunity so I hopped on.  Although the bike was way too big, I felt some noticeable differences from the wheel size.  We ended up on a pretty technical, rocky trail and I was very surprised at the ease in which I rolled over the obstacles.  I spent a significant amount of time out of the saddle to aid in controlling the way-too-big bike.  That ride left me desperate to find an appropriately sized 29er to ride and with a huge girl crush.  Katerina is not only an amazing athlete but a wonderful ambassador of the bike.

Until that day, my head had been filled with suggestions that a 29er wasn’t right for me, with a lack of personal experience, I believed them.  Since that time, I’ve ridden a few different models that fit and have been very pleased.  I’ve also sought out experts to help me understand all the negative feedback surrounding 29ers for small people.  I’ve discussed the subject with Sky Yeager, noted bike designer, currently working with Spot Brand and James Bleakley of Black Sheep Bikes.  James has been building custom 29ers for small ladies for several years.

This week I had a chat with Carla Hukee of Niner Bikes continuing a conversation we had at Interbike – a bicycle industry trade show – in September.  I thought I would share with you some of her insights in to the world of 29er bike design.

What, besides the obvious wheel size, are the differences in 29 vs 26?

Generally speaking, there are a few absolute differences in 29er design.  First, because the wheels are larger in diameter, the front end of the bike has to be a bit higher – approximately 1.5”. As bike designers, we can accommodate this by making headtubes smaller, but we are limited by the minimum length of a tapered steerer and by the minimum amount of material we need in the front end of a bike to make it a safe leverage point for the fork.

Also, this additional height and diameter affects other parts of the frame design – stand over, top tube length, head tube angle, wheelbase, etc. The key is to get all of these numbers into the best proportions so that they add up to a great bike.

I bake quite a bit, and it is very similar to making a cake – there are lots of great variations but you still have to stick to certain ratios or they don’t add up to a yummy dessert. There are also a few ingredients that should
never be a part of your recipe – toe overlap, for example.

In a well designed bike, geometry is considered holistically. This is one of our bigger communication challenges at Niner – to help folks to understand that a single angle or length does not tell you everything you need to know about how a bike rides. In the same way, neither does the wheel size. Just as you can have great 26” bikes and not so great 26” bikes, you can also have good and bad 29er designs.

What are the benefits to 29 inch wheels? Are there any downsides?

The two biggest advantages are that larger diameter wheels roll over and onto obstacles more easily than do
smaller wheels.  Consider the difference between hitting a pebble with a rollerskate vs. running over the same pebble
with your car tire.

And 29ers are faster in most conditions. There was a lot of debate about this when we first started making bikes, but there is significant independent verification now. Several independent magazines have conducted careful 26 vs 29 tests around this claim.

(Check out the Singletrack article Revisiting the Rancor: 26 vs. 29)

I worry sometimes that the women’s riding community doesn’t think that these advantages apply across the skills spectrum. A beginner will see as much benefit from 29er wheels as will an advanced rider. For the newbie, a 29er is going to help them tackle skills challenges and be a bit faster when riding with groups. For the advanced rider, a 29er is going to help them to move faster through more technical terrain. No matter what your skill level is – the easier it is to ride a bike, the faster you will go.

The downsides to 29ers are pretty predictable – for small women who want big wheels, it can be hard to find a little 29er to test ride. Especially in towns with few bike shops, going to 29 can be a leap of faith. Unlike when I started mountain biking, there are now online communities that can be solid resources. We also have a demo program that travels the country to help with this issue.

How has 29er geometry evolved over the years?

Fork manufacturers have changed their 29er fork offsets to improve handling – early 29ers often felt sluggish because the fork offset was not adjusted to account for the increased trail. The newest 29er forks offer handling on par with any
wheelsize – both in suspension and rigid varieties. Additionally, because “trail” is a function of offset combined with head angle, with increased offset forks, we can use a slacker head angle.

Bottom line – these changes mean we have more room to make a shorter cockpit without toe overlap – an advantage for small riders.

As a small woman, I have been told that 29ers are not for me, would you agree?

The first woman I ever met on a 29er was 5’2”. She couldn’t stop raving about the confidence-inspiring ride of big wheels (Hi Ms. C!). Since working with Niner, I have met dozens of smaller women who have embraced these advantages. This isn’t just a woman’s question – there are a lot of guys shorter than 5’6” who have been told that 29ers aren’t for them, too.

It is my belief that a properly set up bike can be great in any wheel size, but there are some differences between setting up a 26”and a 29er mountain bike.

Current XC fit philosophy dictates that your saddle should be approximately even with or slightly above your handlebars. I am an advocate of having people ride in the way they are comfortable, but this is a good starting point. For small women, this often means using a negative rise stem that helps to lower the handlebar.

For riders switching from smaller wheels to a 29er for the first time, you will typically go with a shorter stem and wider bar than on your 26” set up.  I currently use bars between 710cm and 750cm and my stem lengths now range between 70 and 50cm – almost half the length of the stems I used 10 years ago. The wider bar and shorter stem help riders to take advantage of the cornering capabilities of a 29er – you will definitely notice the ability to really rail. This is an advantage to small riders who might think they need 20-21 inch top tubes in a 29er – the shorter stems increase the potential range of frames that fit them (and they get better handling in the bargain). Our extra small frame has a 22.5” top tube – riders in the 5’ to 5’5 range should look at stems between 50 and 70cm in length for optimal handling in this size.

The danger here is that these ideas support Niner’s geometry and can come off as hype. I can’t really dispel that without getting every single woman out on a 29er, but hey, maybe we can make that happen this year .

Typically, 29ers are better set up with flat bars than with risers. Because of the higher front end, usually only the very tallest riders need the extra height provided by a riser bar. For a small rider, risers can be detrimental to keeping the front end on the ground when climbing.

We don’t call any of our bikes “women’s specific” for the above reasons. There are a lot of women out there that don’t fit the big-bike company definition of what a woman’s proportions should be, myself included. There are plenty of women who have longer torsos/shorter legs, just as there are a lot of guys with short torsos and long legs. I personally have owned both WSD and non-WSD bikes and it has always been bike setup that determines if they are the right bike for me, not the marketing behind it. Underestimating a woman’s ability to know what she needs is a mistake – we are smarter than ad campaigns.

What are the challenges associated with making a smaller 29er?

Convincing the guys that women want big wheels!

Just kidding! At Niner this isn’t a problem – the guys are strong advocates of women’s cycling. However, as a small, independent company, we do have to be careful any time we add a new size – our resources are limited and we have to be
sure that if we invest in a new size that there will be support from customers that will in turn feed the 20 families that depend on Niner. We are passionate, but there are practical aspects to consider.

As far as engineering challenges go, I have covered most of them in the questions above. Chris, the president of the company, is actually my height – between him and I, there is a high standard set for our small bikes. They have to ride as well as our large bikes, they undergo the same engineering standards and are subjected to the same abuse by our ride-testing crew as any other Niner product. We never allow toe overlap, for both safety and ride quality reasons.

As we push into longer travel suspension projects, we will have to be creative to get a tiny bike into the lineup – it is easy to make a Large 29er with 7 inches of travel, Extra Small is more challenging, but our engineers love tough projects!

Carla Hukee

A little background on Carla and her experience in the cycling industry…

“I started riding mountain bikes in 1992 as a great way to get around the university campus. After spending too much of my funding on beer, I was compelled to find employment. The university bike repair shop was willing to teach me how to be a bike mechanic and while working there, I discovered how many amazing, intelligent people ride bikes and work in the cycling industry (including one particular bike mechanic, to whom I have been married for 14 years).

My second bike job was working in a woman-owned shop as a sales person, at a time when a woman in a bike shop was extremely unusual. The owner of the shop was an inconoclast, and spent a lot of time thinking about women’s fit vs. men’s before it was a marketing thing. It was in that shop that I learned most of the fundamentals that I apply in my work today – the ideas have evolved, but the need for critical thinking is the same.

Over the years my role has evolved – I spent time building my professional design career in the corporate world and racing road bikes (I am a cat 1 with a few nice successes and a lot of water bottle hauling experience), but my heart has always been on the trail. Eighteen years into my career, I am the brand manager for Niner Bikes. Helping to build a company like Niner is a privilege and a challenge – I know how lucky I am to make my living in bikes.”

Niner E.M.D. 9

This past week, Niner introduced an x-small E.M.D. 9, something we have been asking the owners and designers about for a long time.  We are very excited about the announcement and will keep you posted on the ride as soon as we get our hands on one!

By Sarai Snyder – Founder, Girl Bike Love and itty-bitty rider of big wheels.

 

 

  • http://www.toughchik.com Shannon

    I love my Niner. My confidence has grown tremendously on this bike. I am a taller gal (5’7″) so I didn’t have any issues finding a good fit. I think this is a great bike for newer riders! I ride a Niner Jet 9 and boy can that baby climb.

  • Ann

    …yea…what Shannon said!
    I’m about 5’1-1/2″ and I ride a small Jet 9. That bike is magic. Many, many times I stop after a descent and kiss & hug her – and after a ride, I thank her~
    My first big ride on my new bike was at Allegrippis in central PA. Those trails are 34 miles of roller coaster perma-grin fun. I couldn’t believe how fast I went. I actually left my husband so far behind I thought he stopped to pee.
    Later, he bought the same bike so, as he says, ‘he could keep up with me.’
    Yea…29ers…this is how we roll, isn’t it ladies?

  • Cristin

    i feel the exact same way about my jet 9. i love it. and same goes for leaving my guy in the dust…now he wants the same bike too. i used to hate climbing and was a downhill junkie…although i still love bombing descents, i don’t loathe the climbs the way i used to. in fact, i actually enjoy them. riding a niner has rounded out my skills tremendously. it’s actually changed the way i ride…for the better.

  • http://www.greaserag.org Kat

    I’d be interested in hearing the author’s thoughts on 69’ers (29inch front wheel & 26 inch rear wheel), such as the Carver bikes.
    Are they a good match for a smaller rider that wants the rolling power of a 29er wheel, but the compact fit of a 26in bike? Or does the weird geometry influence the handling of the bike?

    • http://thebruisereport.com/ Female Cyclist

      Oh, good question. I haven’t had a lot of experience with 69’ers. I will keep you posted as I find one to ride and a few experts to ask questions.

  • http://www.gracieswrench.com Tori

    This is a really great article and really demystifies the 29er. I have to say I’m really excited for the 650b’s to catch on, though. I think it will be the best of both worlds for me!

  • Jen

    I am 5’3. I recently bought a womens small 29er. I was told by some of my girl cyclist friends that the frame was too big for my size. And they added because it is so big I am using more energy when I ride. Also, I will be changing my tires to slicks for my tri. What kind should I buy? Thoughts? Suggestions?
    Thanks so much!

    • http://thebruisereport.com/ Sarai Snyder

      Jen – it is possible that the bike is too big for you, but that isn’t necessarily because it is a 29er.  Bike fit is a very specific thing to each individual.  Anytime a bike fit is off there is going to be issues with energy transfer.  It might be a good idea to get a professional bike fit if you feel uncomfortable.  

      There are other things you might want to look at as well for better energy transfer like upgrading to lighter wheels and tires.  This is where you will get the most significant benefit from an upgrade.

      As far as slicks… there are a lot of great options out there, check with your local shop to see what they suggest for your local road and weather conditions.  Look for something light weight!