Front and rear? If not what front tire?
Also how long did they take to get from that website you ordered from, if you’re in the US.
Agreed. I like this video because it’s a real world test that attempts to do a more scientific-style evaluation.
BRR is probably the best data available for MTB tires, but I don’t think it accurately captures the benefit of wider tires being able to run lower pressures on chunky terrain.
My very anecdotal experience with wider, lower pressure tires seems to align with the video.
I was referring to actual tests that @JoeK1ng did and posted his results over on MTBR in the XC Tire Thread there. Sort of along the lines that @DaveWh is saying, BRR tends to be right in some scenarios, potentially not in others.
I’ve been thinking I’ll do something similar as I have a bunch of mildly sloped gravel pretty close to the house. But, we’ll see if I get around to it.
For anyone else looking for Aspen st.
Bike tires direct has them listed now, every spec says shipping 5/16
Anyone know the difference between the team spec and normal? They’re both maxxspeed/exo and offered In 2.25 and 24, and 120 or 170 tpi
I wonder if it’s a problem with their system, according to maxxis the team spec is the 170, there is no other 170tpi
- Rubber: MaxxSpeed
- Casing:
120 TPI + EXO (XC Race)
170 TPI + EXO Team Spec (Ultra Lightweight XC) - Sizes:
29×2.40 (Designed around modern 30mm XC Rims)
29×2.25 (Narrower rims) - Tubeless Ready (TR)
1 Like
Agreed. The part numbers on BTD for the 170 tpi non-Team Spec looks like a Maxxis part number but is not listed on Maxxis site.
1 Like
A lot to go through here, but wild the 2017 Mezcal TNT is ‘faster’ than the 2023 mezcal XC Race tire still per BRR. Note - not the newest Mezcal, but '23 XC Race.
I think I might just stick with a Barzo/Mezcal or Barzo/Barzo. I was really intrigued by the Kenda Rush though and might give that a crack this year or Scorpion XC RC setup. For the one marathon race I do, there is about 12 miles total of pavement and gravel. So, I am kinda into a faster rolling tire, but some of the newest ones look like gravel tires haha.
Someone mentioned a second wheelset with a ‘fun’ combo. I ran Assegai front and rear last year for my ‘fun’ setup and had a blast. Good for the big days in Crested Butte at Dr Park, Teocali and high alpine in Summit. I’ll probably do something similar but with Ground Controls this year.
I would go Schwalbe wicked will (F) rocket Ron (R), or Pirelli scorpions XC M front and rear.
I do like Maxxis tires, but their in-between tire offer is … meh …
Thanks for the suggestion but I‘m not looking at buying new tires but rather use those that I already have.
2 Likes
Seems like a lot on here go with low rolling resistance and minimal traction. I’ve done that experiment and quite frankly miss the grip. Am I the only one or anyone else beefing up the tread?
2 Likes
BRR numbers are great and all, but boy do I love the grip of the fat Barzo front out at Fort Ord.
1 Like
This is why I was interested in the testing of the Rush actually. I have felt that it doesn’t lose much on grip to something like an Ikon (which I ran for a while before the Rush) but has seemingly lower rolling resistance. And while it didn’t test as well as the Race King and some of the Schwalbe’s, it seemed pretty comparable to some other XC tires like the Mezcal, so I felt it somewhat confirmed what I was feeling. I’m not confident enough in my descending skills to run some of the more minimalist traction tires, so the Rush checks a lot of boxes for me. I’m also interested in other XC tires that have good rolling resistance but don’t sacrifice as much on the traction. So no, you’re not alone in not wanting to give up too much on the traction front.
1 Like
I already have done my standard rolling test and the Aspen ST 170 2.4 are faster (like 7 percent faster) than both the Rush PRO SCT 2.4 and the RaceKing Protection Black Chili 2.2. AND they offer more cornering grip.
9 Likes
In my testing I wasn’t able to determine if the meaty tires gripped way better or that I was simply going so much slower that every corner was easy. We’re talking 30 seconds slower per 14 minute lap swapping only the front tire!
Joe
2 Likes
I highly doubt that he properly applied statistical analysis to those findings. He was talking about time differences of 0.07% being statistically significant. I call BS. It might be statically significant if the only margin of error you consider is the stopwatch, but it certainly isn’t when you consider the reaction time of the human operating it, the tire pressure accuracy, and most importantly he can’t ensure that he took exactly the same path, resulting in hitting exactly the same bumps and total distance travelled every time.
In fact, he talks about the courses used having slick roots, jumps, etc and only did 2-3 runs per tire (“24 runs across the 3 trails” and 3 tires). Yet draws conclusions about the widths being X.X% faster than each other. That’s preposterous! He can’t possibly claim that level of precision in the results. At best his margin of error is 1%, probably higher.
Using the scientific method is only one small part of correctly investigating something. First of all your experimental design has to be very good, which in this case it wasn’t. Then the scientific method has to be properly applied, which is way harder than it sounds. Next, you have to do all the analysis correctly, also very difficult. Finally and hardest of all is drawing the proper conclusions. That’s why peer review is so important in science, it’s to try to address those potential pitfalls.
But there’s way better controlled testing out there that shows that if tire construction is kept constant and tire pressure is adjusted for equal tire drop then tire width doesn’t affect rolling resistance. And additional testing that shows that hysteresis losses are sensitive to tire width and terrain bumpiness.
7 Likes
The controlled testing you link to is for road tires, tested on a steel drum. That testing is far from real world mountainbike conditions. Believe it is best suited to test the suppleness of the carcass, not impedance losses that are very important in the real world. I am more inclined to believe the conclusions and findings from Silca
Wider, higher volume tires allows for lower air pressures. Leading to less rolling resistance, should you believe their findings.
1 Like
Agrred and I actually meant to also link the Silca article. My other link was to real world roll down testing with a person.
In context of the BRR conversation, the roller and real world results agree that tire width does not matter (if controlling for same tire deflection) to pure rolling resistance effect of tire construction. That’s my point (besides the YouTube video being a bad).
And we know real world has to account for impedance losses, especially off road. So wider tires at appropriate pressures are going to better, right?
Maybe. One thing the BRR tests are very good at showing is that despite being the same model of tire with supposedly the same specs, there are sometimes still differences in construction that the manufacturer doesn’t tell us.
For example, as the tire gets wider they might increase the tread thickness. Or the various plies might be the same width on a 2.1 vs 2.4 tire resulting in less overlap of the plies on the 2.4, but then the 2.6 uses wider plies and is actually slower than either on the drum. Stuff like that can throw off the actual results compared to expectations. There’s also manufacturing tolerance variation and design changes (undisclosed ones) over time. This is why people keep voting for a sixth variant of GP 5000 instead of something with more variety.
2 Likes
So all that is to say that we must draw all of our understanding of real world fastest tires and pressures from real world data. Just like with training, the best measure of performance is performance itself.
But also, there are useful things that we can learn from roller tests. We can learn half the story, energy loses in the tire, from the roller. This tells us if a given road tire has higher or lower tread and carcass loses. It’s questionable though how much the geometry of different knobs affects the results. But given that knob design doesn’t seem to have a large impact to roller results, it doesn’t seem to matter much.
So look at it this way. Roller testing is like testing new medicines for humans in lab rats. It tells us something useful, but it’s not enough on its own. We have to understand how well those results do and don’t translate to humans to guide our interpretation. We ultimately have to do a human trial to further understand if it’s effective.
But lab rats trials allow more precision (at the cost of accuracy) than human trials do. We can genetically engineer rats in all sorts of manners, completely control their environments, dissect them, etc. You can never get that precision with human trials.
1 Like
All of that is probably true. I would not be surprised if a carcass hysteresis properties will vary with the width and volume of the tire, due to everything you mentioned. The big question is, is that more or less important than reducing the impedance/bump absorption?
I am sure I am not the only one who has discovered that higher volume tires allow for less air pressure before running into problems with rim strikes or tire roll in corners. From the Silca findings, being able to run low pressures seems to be more important. In fact it suggest I should be running 13.5 PSI, which would be impossible for me to achieve without destroying my rims.
Here is another source of testing, looking into tire pressure. I will not vouch for the testing method, as that is beyond my qualifications. More Speed Less Power