Mountain Bike Whee/Tire Sizes!

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Mar 31, 2017
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IL
Well, I had been away from the mountain bike game since 2012. Over the past couple of years, I've been riding my single speed road commuter bike around town and even on longer distant rides. However, I've been dying to get back on the trails. Saturday, I scored a new 2017 27.5 Giant Anthem 3 for an incredible deal.

One thing I've noticed is the tire sizes have completely changed. 26 inch bikes don't exist anymore. Now it's all 27.5 and 29's. Then to add more craziness you get the plus/fat tire sizes. [censored] happened? I am more confused than ever about what tires will/won't work on my new bike. What prompted these changes? It just seems like everyone became in love with giant tires/wheels at the expense of light XC bikes. Can anyone explain this?

I am glad that I didn't pull the trigger on a used 2008 carbon 26 inch frame, as it look like the market is leaving the 26 inch wheels behind for support.
 
I bought a 29" bike a number of years ago. I had no idea about 27.5" MTBs... My father had a 27" road bike years ago - like late 70s.
 
What happened is that bicycle manufacturers have a large, hidden presence in the popular cycling forums and want to push their latest.

Don't get me wrong, there are advantages to a larger wheel for navigating large obstacles or straight line stability, but all else equal it also increases your rotational mass as do fatter tires, which impacts both acceleration and twitch handling.

It does not look like the market is leaving 26 inch wheels behind. There are tons of existing models and tons of support in available tires. They just aren't releasing so many new models because it would literally be reinventing the wheel (pun intended).

Try a few different wheels and frames too (not just size) then make up your own mind. If you just decide based on numbers and text someone wrote, you are unlikely to end up with what suits your use best.

This is within the context that you don't seem to value riding as fast as possible, or else your road bike wouldn't be single speed. Many people don't, it's just one of many choices but the issue remains that manufacturers didn't pick 26" out of thin air. A smaller wheel is more optimal for most built-trails where you don't have fallen trees to get over, and along with a (rounding down) smaller frame, far, far more optimal for tight quarters urban riding.

Call fat tires a fad, when not used on a low density surface. Many who pick that will eventually go back to narrower tires or own at least two bikes, or three if there is also road use.

27.5" is a fair compromise choice if you want only one do-everything MTB, but similarly with fat tires, something in-between fat and skinny is the norm for MTB and the best compromise.
 
I think the OP bought a bike already from the sounds of it. Some bikes can run 29 regular or 27.5 fat, if your new bike is 27.5 x 2.3ish then 3.0 tires probably won't fit.

I bought a 27.5 x 3.0 bike in 2016 and it's a hoot for around here. No longer a need to avoid sand. More traction on steep slickrock that muscle. 11 psi front and 14 psi rear damps the sharp chatter on the rock strewn trails nicely.

Not fast on hard smooth trails and feels like crap on pavement but not the intended use. Fast all the time is behind me, fun every ride is hard to beat.

I guess 3.0 is considered mid-fat?
 
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I'm in the market for a new bike and am studying all of this. 27.5" is 650B and 29" is 700C.

26" is dead and the only new bikes with it are cheap bikes. It is going away like the 27" road bike tire did, which was replaced by 700C.
 
I prefer the 29'rs, they are better over rough ground and usually have a little more clearance. You can also use them if you want to go fast on gravel or pavement, especially if you can lock the shocks.
 
Originally Posted by jcartwright99
It just seems like everyone became in love with giant tires/wheels at the expense of light XC bikes. Can anyone explain this?




The origin of this depends a bit on who's option you find valid... According to a lot of internet keyboard warriors, a vast cabal in the bicycle industrial complex came up with idea in order to sell more bikes. Since I'm part of that cabal, I will say it's a bit more, um, nuanced.

Most manufacturers did NOT want to go to a new wheel size. It just meant more complexity (and more work!) for everyone. However, Kirk Pacenti started selling rims and tires in the 650B size, and lots of folks seemed to like how they rode. It's funny, because GT tried this in the 90's with the "700D size", but it just never caught on. Folks started doing conversions, putting 650B wheels and tires on their 26" bikes, and then some small manufacturers started to make dedicated 650B bikes. Then Giant co-opted 650B, but called it "27.5", and went chips in on it, converting most of their bikes to 27.5/650B. The rest is history. IMO, it was really driven by customer demand, and manufacturers just didn't want to miss out--so most jumped on the 27.5 bandwagon.

The basic idea is that the larger wheels roll over obstacles more easily, but 27.5 is a bit more maneuverable than 700C/29'er. Also, smaller riders can have fit issues with 29" bikes, and 27.5 seemed to be the sweet spot. I really liked the old 700D, but you couldn't get tires for it--so I'll all for the move. If I were racing XC, I would absolutely use a 29'er, as it's almost always the fastest option for XC, but mtb is just a fun activity for me.

Next thing, tires and rims started to get wider, and plus size was born. The steam went a bit out of this engine, because for more advanced riders, they're generally slower and offer a lot less feedback on the trail. 2.2 to 2.6 seems to be about the max tire size for maximum performance. Thing is, they are more forgiving for recreational riders, so I think they have their place. I also think they make sense for E-bikes, where the weight penalty is less of an issue once you add a motor to the mix, and razor sharp handling is less of a priority.

As far as your Anthem, you should be able to fit a 2.6" in the rear and 2.8" in the front. I have an Anthem Advances and I'm running 2.4 rear, 2.6 front, and very happy with it.
 
Originally Posted by JOD
Originally Posted by jcartwright99
It just seems like everyone became in love with giant tires/wheels at the expense of light XC bikes. Can anyone explain this?




The origin of this depends a bit on who's option you find valid... According to a lot of internet keyboard warriors, a vast cabal in the bicycle industrial complex came up with idea in order to sell more bikes. Since I'm part of that cabal, I will say it's a bit more, um, nuanced.

Most manufacturers did NOT want to go to a new wheel size. It just meant more complexity (and more work!) for everyone. However, Kirk Pacenti started selling rims and tires in the 650B size, and lots of folks seemed to like how they rode. It's funny, because GT tried this in the 90's with the "700D size", but it just never caught on. Folks started doing conversions, putting 650B wheels and tires on their 26" bikes, and then some small manufacturers started to make dedicated 650B bikes. Then Giant co-opted 650B, but called it "27.5", and went chips in on it, converting most of their bikes to 27.5/650B. The rest is history. IMO, it was really driven by customer demand, and manufacturers just didn't want to miss out--so most jumped on the 27.5 bandwagon.

The basic idea is that the larger wheels roll over obstacles more easily, but 27.5 is a bit more maneuverable than 700C/29'er. Also, smaller riders can have fit issues with 29" bikes, and 27.5 seemed to be the sweet spot. I really liked the old 700D, but you couldn't get tires for it--so I'll all for the move. If I were racing XC, I would absolutely use a 29'er, as it's almost always the fastest option for XC, but mtb is just a fun activity for me.

Next thing, tires and rims started to get wider, and plus size was born. The steam went a bit out of this engine, because for more advanced riders, they're generally slower and offer a lot less feedback on the trail. 2.2 to 2.6 seems to be about the max tire size for maximum performance. Thing is, they are more forgiving for recreational riders, so I think they have their place. I also think they make sense for E-bikes, where the weight penalty is less of an issue once you add a motor to the mix, and razor sharp handling is less of a priority.

As far as your Anthem, you should be able to fit a 2.6" in the rear and 2.8" in the front. I have an Anthem Advances and I'm running 2.4 rear, 2.6 front, and very happy with it.


Thanks for the information. I've literally have been reading articles and watching youtube to understand all of these differences. My last bike was a 2003 Jamis Dakar. It lasted me 10 years. Now I am back and I feel like I have no idea what's going on. Boost, through axle, and wheel/tire sizes have made me re-educate myself.
 
Originally Posted by JOD
Originally Posted by jcartwright99
It just seems like everyone became in love with giant tires/wheels at the expense of light XC bikes. Can anyone explain this?




The origin of this depends a bit on who's option you find valid... According to a lot of internet keyboard warriors, a vast cabal in the bicycle industrial complex came up with idea in order to sell more bikes. Since I'm part of that cabal, I will say it's a bit more, um, nuanced.

Most manufacturers did NOT want to go to a new wheel size. It just meant more complexity (and more work!) for everyone. However, Kirk Pacenti started selling rims and tires in the 650B size, and lots of folks seemed to like how they rode. It's funny, because GT tried this in the 90's with the "700D size", but it just never caught on. Folks started doing conversions, putting 650B wheels and tires on their 26" bikes, and then some small manufacturers started to make dedicated 650B bikes. Then Giant co-opted 650B, but called it "27.5", and went chips in on it, converting most of their bikes to 27.5/650B. The rest is history. IMO, it was really driven by customer demand, and manufacturers just didn't want to miss out--so most jumped on the 27.5 bandwagon.

The basic idea is that the larger wheels roll over obstacles more easily, but 27.5 is a bit more maneuverable than 700C/29'er. Also, smaller riders can have fit issues with 29" bikes, and 27.5 seemed to be the sweet spot. I really liked the old 700D, but you couldn't get tires for it--so I'll all for the move. If I were racing XC, I would absolutely use a 29'er, as it's almost always the fastest option for XC, but mtb is just a fun activity for me.

Next thing, tires and rims started to get wider, and plus size was born. The steam went a bit out of this engine, because for more advanced riders, they're generally slower and offer a lot less feedback on the trail. 2.2 to 2.6 seems to be about the max tire size for maximum performance. Thing is, they are more forgiving for recreational riders, so I think they have their place. I also think they make sense for E-bikes, where the weight penalty is less of an issue once you add a motor to the mix, and razor sharp handling is less of a priority.

As far as your Anthem, you should be able to fit a 2.6" in the rear and 2.8" in the front. I have an Anthem Advances and I'm running 2.4 rear, 2.6 front, and very happy with it.


Thanks for the information. I've literally have been reading articles and watching YouTube to understand all of these differences. My last bike was a 2003 Jamis Dakar. It lasted me 10 years. Now I am back and I feel like I have no idea what's going on. Boost, through axle, and wheel/tire sizes have made me re-educate myself.
 
Originally Posted by jcartwright99

Thanks for the information. I've literally have been reading articles and watching YouTube to understand all of these differences. My last bike was a 2003 Jamis Dakar. It lasted me 10 years. Now I am back and I feel like I have no idea what's going on. Boost, through axle, and wheel/tire sizes have made me re-educate myself.


No problem--there's a lot to digest! After frankly a lot of years of stagnation, there have been a lot of advances over the last 10 years, and almost all of it has been really positive. As a hardcore road racer, I had taken a long time away from the dirt scene, and I have to say that bikes now are truly remarkable. When I got back into it, I realized that they have completely changed how I ride a mountain bike As someone who started riding in the mid-90's, where line-picking was a thing, and a lot of rides ended up being more "observed trials" than pedaling, it's taken me a while to get used to just pointing and shooting. Eventually, you'll learn to trust the bike, and it will be a wonderful feeling.

Thru axles and oversizes steerers really do add to stiffness, hydraulic brakes that you can really use one finger, dropper posts...all of it adds to the enjoyment of riding off road. For my money though, the best changes have been to suspension forks and tires. If I went out with my Mag21 and 1.75 Onza Porcupines, and rode at the speeds I do now, I would literally be dead within 5 minutes. Modern tires and suspension are just so good that you can ride stuff faster and more safely than you ever could "back in the day".
 
Ive been building bikes and wheels through all of these changes. Being a 6 foot 5 Clydesdale, I welcome just about all of them. Through axles are a godsend. Boost makes for a slightly stronger wheel because of increased triangulation. My two favorite bikes in my garage are currently a Surly Krampus which has 40mm wide rims and a 3 inch tire on the rear and a three and a quarter inch tire on the front. 29 inch. Love this bike. My other is a fat bike with 26 inch rims and 5 inch wide tires. Our trails on Long Island are pretty sandy so I welcome the float and traction provided by these larger tires.
Most people who come to me for a custom built bike are looking for fat or plus. Usually, its a fat bike with a set of fat wheels and a set of 29 plus wheels. Ill usually build a 27.5 plus bike for a person that 29 plus would be too big for. Otherwise, pretty much anyone who fits a Medium on up gets 29 plus.

I used to wash out a lot in turns on 2.25 inch tires. I havent fallen in a long time since I made the change.
 
^^^ Pretty neat perspective.

I can't ride much anymore after 2 knee surgeries, but I rode a couple 29s and then the 27.5 we bought my son. I was an XC guy with a bit of love for trials, way back then. He settled on a 27.5 because the 29 felt too numb for him. The 27.5 to me felt clumsy, and I missed the lightness and precision afforded by the 26. The 27.5 did feel faster on mild terrain. But, I'm an average size at 5'10", and even then rode a longer frame to stretch out. 6' 5", I can see the larger sizing being a good fit to you!
 
Originally Posted by meep
^^^ Pretty neat perspective.

I can't ride much anymore after 2 knee surgeries, but I rode a couple 29s and then the 27.5 we bought my son. I was an XC guy with a bit of love for trials, way back then. He settled on a 27.5 because the 29 felt too numb for him. The 27.5 to me felt clumsy, and I missed the lightness and precision afforded by the 26. The 27.5 did feel faster on mild terrain. But, I'm an average size at 5'10", and even then rode a longer frame to stretch out. 6' 5", I can see the larger sizing being a good fit to you!


I'm 5'10" as well.
I ride the following: 26" wheel trail bike with 160 mm travel both ends, a 29" wheel hardtail with 100mm travel in the front, and a "rigid" fat-bike (26" wheels with 4.8" tires)
I think the biggest handling difference comes from geometry, not wheel size, at least with similar width tires.

The improved roll-over of the 29er is nice (and quite noticeable even though I was skeptical about it at first) and I'd pick it for an XC race bike but otherwise, not that big a deal.
Fat bikes are fun but are a bit of a one-trick pony (snow/sand) and are noticeably slower than a normal bike everywhere else and have interesting handling on off-camber surfaces. I haven't tried a bike with plus-sized tires but I can see them being a fun trail or bike-park bike.

The acceptance of 29ers in XC racing (even in the women's field where a lot of smaller sized frames are used) and increasing use in DH and enduro tells me that, from a performance perspective, there's got to be an advantage. Of course, the pros have a lot of tricks and one-off parts available to tweak bike geometry to get the handling they want that us mere mortals don't have access to (not to mention pressure from sponsors to use specific bikes or components).
 
IMO the importance of tire size depends what type of trails your riding and the pace you want to go. I still ride my old 26" with v-brakes and keep up with everyone I ride with just fine, usually fastest down the intermediate trails even, but we are old and I'm the only one who did some XC races and a few DH races 20 years ago. Now I see groups of fast guys going down rough expert trails fast enough that wheel size, tire width, and suspension start to matter, but I'm not trying to keep up with them so my old bike is fine.
A dropper post is a big deal though if you like to hit some jumps or go down some tricky steep stuff, that's the best mod I've ever done to a bike. 26" tires are still made, and I think there is enough selection, certainly for trail riding, if not for serious racing.

For riding with my kids I like the cheap fat tire bike I bought in Australia for van camping, as it gives me a workout while going at their pace as well. I was going to sell it when we left but I decided to bring it home as its just fun to ride. It is slower overall, but the fun with is staying off the brakes and trusting those big tires in corners, or running monster truck lines using the sides of the trail, over rocks, roots, logs, loose stuff. I don't know if its just these cheap tires on it but they give a bit of howl when they slide on hard pack dirt or pavement which is pretty cool.
 
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