Aaron Chamberlain is the Bicycle Sales and Marketing Manager at Maxxis, one of the largest bicycle tire manufacturers in the world known for producing high quality products.
- Where are we at with bike tire widths? Clearly fat and plus tire adoption have peaked so are things looking pretty stable these days in terms of widths?
- What are the considerations when choosing the right tire width, especially when there are so many choices? Will a tenth of an inch in width make a noticeable difference to anyone?
- Do you think bike brands do a good job speccing tires on bikes? Do price and weight get prioritized over performance in some cases?
- Which MTB tire features are a good fit for gravel?
- Is it more difficult to design a gravel tire that’s both lightweight and fast and also durable?
- Do any of the innovations in gravel tires have the potential to filter to MTB?
- With access to pretty much any and every MTB tire you could want, how often do you change your tires: Seasonally? Every ride? Never?
- One of the key specs when looking at tire casings is a number called TPI, threads per inch. What does that number tell us?
- How does TPI work when there are multiple plies or casing layers involved?
- What’s the best way to dispose of worn out bike tires?
- What are some of the trends you’re seeing with pro gravity riders? Are there changes in the key things they’re looking for?
Choosing a mountain bike tire can be overwhelming given the number of options available. An all-conditions tire is a good place to start, and for many riders it’s the best choice. Chamberlain says, “When you’re very used to your setup, and you’re very comfortable with it, you can adjust your pressures up and down as needed for conditions. I would definitely encourage people to experiment with their tire pressure. If it’s wet, drop a couple psi. If it’s dry and hardpack, add a couple psi. That can make a really big difference.”
He goes on to say that most riders tend to run too much tire pressure, though if you’re getting a lot of flats you could be running pressure that is too low. How you ride can make a difference too. Chamberlain recommends buying a good pressure gauge and using it regularly so you understand how pressure affects ride feel and performance.
“Don’t be afraid to mix and match tires. Front flats are typically a lot less common than rear flats. So I think most riders can get away with running a lighter casing tire on the front, and then running a more durable tire on the rear.”
On tire widths, Chamberlain says, “It’s not just the width. Whenever you’re making a tire wider, you’re also going to increase the sidewall height, so you’re increasing the overall volume. So the difference between 2.4, and 2.6, while on paper, is just point two inches — less than a quarter of an inch in width — doesn’t seem like that much, in actuality, the the volume is a lot bigger.” By the law of cubes, tire volume increases many times the width.
Tire volume is just as important when it comes to gravel tires, perhaps even more so than the tread pattern. “Tire volume will go a long way [on gravel tires]. You could you could get a slick, essentially a tire with no tread on it, a 40 millimeter wide tire. And that may be all you need. The tire volume and then running the correct pressure [is important].”
Chamberlain explains that a tire’s TPI rating tells us how many threads per inch there are in a one square inch section of a tire casing. A higher TPI number usually means a lighter, more supple casing since the threads are smaller than on a low TPI casing. Thicker threads are heavier but also more durable. Things get confusing on tire casings with more than one ply, and bike tire manufacturers do not standardize how they communicate the TPI numbers. Some call two, 60 TPI plies a 120 TPI casing, while others say it’s a 60 TPI casing with two plies. “It’s like trying to take a $20 bill, and you fold it in half, and then you say 40 bucks,” Chamberlain says.
Looking at the weight of a tire and its intention (XC vs. gravity) is the best indication of the type of casing the tire uses.
Chamberlain says sponsored gravity riders are riding prototype tires with a new lightweight, puncture protection layer called ZK that is “lighter, more flexible, and stronger than previous materials.” It’s also expensive.
See more at maxxis.com and on Instagram @maxxisbike.
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One question I don’t recall you discussing in the podcast was whether using a softer compound tire in the front makes some sense. I think most of us are generally more concerned with bite at the front end as a bit of rear wheel drift is more manageable. I typically go through about two rear tires for every front tire I wear out, so this might indicate less of a need for the harder compound up front.
Good question! If you’re climbing a lot, rear wheel stickiness can be helpful but it definitely wears quicker.
Sliding tires do not steer. Frankly, I would be content with 42a single durometer front and 50a single durometer rear. I hate placing a tire in the bin when it reaches ~50% wear and all that is left is a crummy hard tread that doesn’t do traction in the least.
If I can have a stellar performance tire, I’ll gladly go through a couple pair per summer. Doesn’t hurt my feelings at all for top performance to be job one.
Who calls 2x 60 tpi plies as 120 tpi? No one.
Well, since you asked 🙂
The DH casing tires claim 660!, though to be fair they are listing the # of plies as well.
Yeah, so not the same. They don’t claim 660 per layer (per layer is how everyone else displays it, except we don’t always know how many layers there are), they say 660 is the total with 6 layers, which is arguably more useful. We can all do math, easy to figure out the tpi is for each layer. That’s very different than saying a double ply 60 is actually a single 120, which is what the pod claimed.
Apologies if it wasn’t clear. I’d still argue that it would make more sense to state the # of plies separately from the TPI. Seems much clearer to say 6 plies at 110 (6×110) rather than make people do math haha. Also, I’m not sure if the addition of the 6/ to the TPI rating is new or if Conti has been doing it that way all along. I just remember being confused myself.
Conti has listed TPI and ply count for a long time.
So another source of my own confusion about TPI and plies is seeing a 120tpi casing listed for American Classic “enduro rated” tires but a 60tpi casing listed for their presumably more supple “trail rated” tires. This runs counter to the overly simplistic idea that lower TPI casings are to be expected on more aggressive tires.
Honestly that told me next to nothing about tyres.
Sounds like you’re all up to speed then!
I should have said, your questions were fine but I found few useful answers and yes, I do plenty of research on tyres.
Jeff, I think one aspect of the tire segment that is ignored is tire construction based on rider/bike weight or load.
Kinda like in the automotive industry, load range B for a Subaru and load range E for a one ton pickemup. The other aspect I have been observing is ebike rating tires being applied to analog bike applications. Again, we’re using load range E tires on Subarus!!
Does a 120# rider on a 25# bike need DH tires to ride singletrack?
Perhaps a 230# rider would need that DH tire and 10ga spokes for gettin a lil rowdy!
Tread pattern and lug depth are a separate topic.
Durometer is also a separate topic.