Whether you are new to the sport of mountain biking or you have been out of the loop for a while, you have probably still heard about 29 inch mountain bikes. While some people tout that bigger has to be better, perhaps you have a few reservations about blindly accepting this philosophy without at least having a few facts to back it up with.
The reason why 29 inch mountain bikes are in fact better is at least mostly due to their size. This gives them a number of different advantages over smaller mountain bikes and it definitely makes them a better fit for taller bikers.
However, before you decide if you agree or disagree with whether 29 inch mountain bikes are really better or not, perhaps it is time to look at a few of the facts about this size of mountain bike first. After we have looked at the basic facts, then there are a few other details about them that you might find interesting and even useful to know.
What Exactly Is A 29 Inch Mountain Bike?
It wasn’t too many years ago that there was only one wheel option for mountain bikes, or any kind of bicycles at all for that matter. This one size was the 26” bikes. Nowadays there are several different size options when you go to choose a wheel size and the 26” mountain bikes are becoming less and less common to see, with the 27.5 inch and the 29 inch mountain bikes being the top two bikes to choose from of late.
All the different kinds of bikes that there are available now for mountain biking is a huge step considering the fact that mountain bikes did not get their own category and their own designs until the 1970s. From there it took another 20 years or so of design changes before the idea of suspension on the front tire was introduced.
It wasn’t until the late 1990s that 29 inch mountain bikes first came onto the scene and not until 2002 that they started to really be produced in such a way that they were east to find and readily available to buy. Since then they have become one of the most popular sizes of mountain bikes out there.
There are a countless different names for this kind of bike, ranging from things like 29”, to 29er, to two-niner, to all kinds of other things. Even though it is called a 29er mountain bike, the bike frame itself is not the 29” it is actually the diameter of the wheel that is this size. But, since the frames of mountain bikes are made to fit a specific size of tires, it is called a 29 inch mountain bike since that is the size tire it is made to fit.
What Are The Advantages Of 29 Inch Mountain Bikes?
There are a number of different advantages that 29 inch mountain bikes can have. But since we have to start somewhere, let’s start with the advantages that come from simply having a larger tire size and see why it is so much better to have.
The first benefit is that having larger wheels can really help when going over bumpy parts of a trail. The reason for this is that the larger the wheel is, the smaller the bumps in the path will be in comparison to it. This makes riding down rough trails ever so slightly smoother, and every slight bit of help in this area can really add up if you can’t handle bumpy trails very well.
This in turn helps keep you from wearing out as quickly, since bouncing up and down can admittedly take some of the energy out of anyone. It also helps give your tires better grip on the terrain by keeping them on the ground more instead of in the air due to bouncing up and down over the bumps. The better grip your tires have on the terrain, the more traction your tires will have on the ground and the more control you will have over your bike.
Since bumpy areas can sometimes be the areas that you need to have the most control during, this feature can be especially nice to have. The better grip and traction also can really help when making turns, especially if the terrain is slippery for any reason. This in turn also helps you to keep your bike more stable which is always a good idea for more than one reason. A more stable bike can really give you more confidence, especially if you are new to mountain biking, and this can help your nerves when going over these rough patches.
As you can see, the usefulness of having bigger tires is not so much something that can be easily put in a bullet point list with the different individual advantages being separated and explained. Instead it is more that one of the advantages leads to another advantage which in turn leads to yet another one that you will find useful to have.
But the benefits of having larger tires do not end with the ones that I have already mentioned. Having a larger tire also helps with your momentum. While it can be somewhat slower and harder to get a 29 inch mountain bike going due to the larger wheels, once you do get the bike moving forward these same large wheels will add more weight behind your forward momentum.
An exaggerated example of this would be like the difference between throwing a baseball and throwing a wadded paper ball. You can make them both be the exact same size and throw them both just as hard as each other, but the baseball will always go further because it has more weight behind it.
The same principle is true for 29 inch mountain bikes. These bikes weigh a little more due to their larger size, but the fact that these wheels take longer to rotate all the way around also gives them a little bit of help with their momentum in addition to their weight. This help with the momentum has two main advantages that make it a good thing to have.
The first of these is that once you get going it takes you less energy to keep up the speed you are at or to go faster if you want to. This ties right into the second advantage which is that the less energy you spend on pedaling, the longer you can be on the trail before you start to wear out.
The size of the wheel can also be an advantage when going up steep inclines or hills. The larger diameter of the tires means that your pedaling gets you further ahead with each down-pedal than you would get when pedaling on a bike that has a smaller wheel.
The last set of advantages that the 29 inch mountain bike has is that it can often run with a lower air pressure than smaller tires can. In case you missed it, having a lower psi comes with a long list of advantages all by itself that tie into each other too.
A lower psi means that you are far less likely to have to worry about blowouts or pinch flats. They also are a little shock absorbent which, like the tires has a chain effect of benefits. This chain starts with the fact that the shock absorption makes for less bumps, which in turn makes for a slightly smoother ride, and which also means your bike tires stay on the ground more and therefore gives them better traction and grip as well as giving you better control over your bike.
So, essentially, most of the benefits of having 29 inch mountain bikes are served out in double portions. You get a number of benefits due to the bigger tires, these let you have a lower air pressure which also gives you some of the same benefits as having the bigger tires. This double portion of benefits makes them easier to notice and makes it more likely that you will be able to tell the difference if you were to test ride a bike in order to try these tires out.
Finally, the last benefit that I will mention for 29 inch mountain bikes is that the dropping of the bottom bracket that these bikes most often come with. The bottom bracket is essentially what determines where the bike pedals fall at, and these always have to be placed up enough so that the rider does not hit the ground at the bottom of each down stroke of the pedals.
With 26 inch mountain bikes this means that they must place the bottom bracket above the centerline of the axle in order to give the needed ground clearance. On the other hand, a 29 inch mountain bike can have its pedals, and therefore its bottom bracket, at the same height as a 26 inch mountain bike does. Since the height that the saddle is set at is also determined by the height that the pedals are at, this means that the seat can be the same height on the bike as well.
The result of this is that with the smaller bike you will tend to feel more like you are above the bike. With the bigger tires, however, a bigger bike will give you a lower center of gravity and will make you feel more like you are fitting into the bike instead of being on top of it. This lower center of gravity will not only make you more stable but will also give make you a tiny bit more aerodynamic which will help with your speed.
All in all, there is no other choice for riders who happen to be above average in height than a 29 inch mountain bike. In the past before this size of bike started to get more common, tall riders used to have to be on bikes that were simply too small to fit them properly. They would have to have certain higher seats and/or handlebars to try to make them fit better, but this was able to do nothing for the overall frame or the size of the tires.
What Are The Disadvantages Of 29 Inch Mountain Bikes?
No bike is absolutely perfect for every mountain biker out there who is looking for a new mountain bike, and any that claim to be are possibly just gimmicks. Though they have countless advantages, 29 inch mountain bikes are no different from the rest, and among all of their many wonderful attributes they do have a few flaws as well.
The first of these flaws is the fact that the very size that make a 29 inch mountain bike so ideal for taller bikers can also make it far too tall for people who are not quite that tall in height. While there are certain bike frames that are made for smaller bikers to help them fit the larger tires, these are often not as comfortable to ride as a smaller sized bike would be them, though many still ride these regardless.
The added momentum that is so great once you get going can be a real pain when you first start out and, while the size of the tires might be great at helping you get the most out of peddling when you are going uphill, the added weight will also be making more for you to have to pull up the hill thereby cancelling out much of its own benefits there.
This added momentum has another potential disadvantage as well, and this is that it is harder to stop! Once you really get going forward it will take you longer to come to a complete stop than it would on a smaller, lighter bike. This can be problematic if you are trying to stop to avoid hitting something in front of you.
Finally, while you may very well have better grip when it comes to making turns, the larger size of the wheel does mean that it will take longer for you to turn. So if you are looking for a bike that can do sharp, fast turns on the trail or for technical details then you should possibly consider going with a smaller mountain bike.
Can You Put 29 Inch Mountain Bike Tires On A 27.5 Inch Mountain Bike?
This is another question that a lot of people are asking nowadays. Sometimes it may be because you simply don’t have enough money to buy a whole new bike, while others may simply really like the frame they already have and want to keep it.
The short and sweet answer to this question is that it depends a lot on the frame of the bike that you want to switch over. Some bike frames that have more room around the tires can possibly have the bigger tires placed in them, but for other frames that fit more snuggly up against the smaller tires there is simply no room for them.
Of course, if you were absolutely desperate to make the change in spite of the frame, it is possible to order custom made pieces to replace the areas that are too snug. But doing this will often cost as much as simply buying a new bike that is made to fit the 29 inch tire size. On top of this is the fact that the rest of your bike frame will still not be optimized to go with the 29 inch tires.
By not being optimized I mean that this can be quite a bit problematic for a variety of reasons and that you will not get the full advantages of the 29 inch tires. One of these problems is that of the bottom bracket. As I already mentioned, one of the advantages of 29 inch mountain bikes is that the bottom bracket is often much lower on a 29 inch mountain bike compared to their placement on smaller bikes.
Well, if you were to put 29 inch tires onto a smaller bike you will end up also raising this bottom bracket, and therefore your pedals, even higher up off of the ground than they already were. With this added to the additional height that those tires will give the bike, it can make you rather top heavy, make it harder for you to keep your balance, and give you much higher chances of falling over for the slightest reason.
What Changes Would Need To Be Made For The 29 Inch Tire To Fit?
At the very least you would need to upgrade your front suspension fork to one that will fit the larger tires, this is assuming that your back triangle setup has enough clearance to allow for the larger tire without any changes needing to be made. You will very likely at least have to do some rearranging on the back part of your bike even then however, just how much depending on your bike frame.
The worst case scenario would be that the back frame of your bike will not fit with the larger tire at all and you happen to have a solid one-piece frame. In this case you would have to order a custom made piece to replace that back triangle and then take it to a shop where it would literally have to have the old part sawed off and the new part welded on. All of this for a hefty price, of course.
However, many mountain bikes do not come in one piece – though most hardtail bikes do! – so, while you would still have to have a custom rear triangle made, you could install this yourself if you are up to the challenge. This, again, depends on the type of suspension system you have for your rear tire and you would likely have to replace this as well in order for the change to work.
The front wheel, on the other hand, would be a little more straightforward to upgrade should a 29 inch tire not fit. To do this you would need to replace the whole front fork. While you may be able to find the right pieces to do this online, you will more likely need to have a custom one made that will fit the frame of the bike and the size of the tire.
Once you have it though, putting it on is something that you can do yourself much easier that trying to deal with the whole rear triangle setup. In order to this you should first do some prep work, and make sure that you have a camera on hand to take plenty of pictures of where different things are as you work so that you can have them to look back on as you go to start putting the front part of the bike back together at the end.
Make sure that you are keeping any nuts and bolts all together, having some strips of duct tape that you can attach and stick things to so that they don’t go anywhere can be something handy to do. It can also be a great idea to work over a sheet of some kind so that anything that you might drop will not only be easier for you to see but will also be less likely to roll away.
The first step is to remove the front wheel. To do this you will likely have to remove, or at least loosen, the brakes. Then you can also remove the handlebars by taking the whole stem up and out of the fork. This way the settings for this will be the same at the end. You will also want to detach anything else that might be in your way now, whether they are the front brakes or anything else.
Then you will want to turn your bike upside down so the next part will be easier. Once you have your bike stable in this position, start loosening the nuts and bolts that are holding your front suspension fork to the frame of your bike. There are several different other things here, like the dust cap that will need to be knocked off, as well as one or two different bearing sets.
The bearings may need to be treated with a particular amount of care to prevent the tiny balls from going everywhere depending on whether these are sealed up or not. Once you have everything disconnected, it is time to take off the old front fork. If you got a front fork that you know will fit right with your new, larger tire, then the next part is to install it.
Do this in exactly the reverse of the way that you took your old fork off, referring to your pictures often so that you don’t do anything too badly wrong and have to undue it. When you are done it is time to take it for a test drive so that you can rearrange you handles, seat, and other details to fit the lager tire you have.
What About Having One Tire That Is 29 Inches And Another Tire That Is Smaller?
Believe it or not, while this is something that is certainly less commonly seen or even known about, it is entirely possible to ride a mountain bike with tires of two different sizes. In fact, there are even a few bike frames that are specifically made for people who are looking for this in a bike and that will allow the wheel sizes to be changed around.
Most of the time when this is done the larger tire is put in the front and the smaller tire is put in the back. The most common use for this is probably in the downhill racing community; however some mountain bikers with a history in motor bikes tend to actually prefer it the other way around where the bigger tire is in the back instead of at the front.
Having a bigger tire upfront can actually really help with your aerodynamics and help with your downhill speed in particular. On the other hand, what advantages this setup gives the bike when going downhill tends to make going uphill all the harder. This is the reason why it is only very rarely used for mountain biking in general and is almost solely used for downhill biking instead.
These mismatched bikes even have different names that there are most commonly called by, with 69ers being the name for mountain bikes that roll with a 26 inch tire in the back and a 29 inch tire in the front. Conversely a 96er is the common name for mountain bikes that have the larger 29 inch tire in the back and the smaller 26 inch tire in the front. Whichever way around you have it, there are both pros and cons to this setup, but then again, there are pros and cons to every aspect of mountain biking.