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Testing Which is Fastest- Specialized T7 and T9 Trail and Gravity Tires 8

We grabbed Specialized's most recent tire offerings and lined up a two-stage rolling test. Which was fastest?

Testing Which is Fastest- Specialized T7 and T9 Trail and Gravity Tires

When it comes to customizing or changing the ride qualities of your mountain bike, there is no shortage of options. One of the easiest and more impactful changes a rider can make to their bike is tires. Changing up the casing, compound, or simply the tread pattern can dramatically alter the way your bike handles. There is no shortage of subjective feedback out there and much of it hinges on where a rider lives and how they ride.

 

Vital wanted to dig into the hard numbers behind various tires. How much does tread pattern impact rolling speed? What about compounds and tire construction? Instinctively, a heavier DH casing tire should roll slower and require more energy, due to its greater mass. How much impact does it really have though?

Last year, Vital did a rolling test and found some interesting conclusions. We knew there was more to this story and we wanted to dig deeper. This time, we devised a two part test. Round one would sill take place on a straight test track, but this would be on dirt. We found a hill with a little bit of grade (but not too much) that would showcase a given tire’s acceleration as well as a runout that would display how well that tire carried its speed. Round two added a more real-world element. We used the same bike and utilized a controlled trail. We also swapped testers and had our rider perform a blind test with three tires of differing construction but identical tread patterns.

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With a slew of new tires on the market, we gathered up Specialized’s latest offerings and got to work. We know this is somewhat of a rabbit hole and there are even greater extremes in tread and compounds out there. Vital’s focus was on trail tires, the sort of rubber that most trail, enduro, and downhill riders will legitimately find themselves using in the real world.

Methods

For our straight line test, we mounted a matching set of rubber to our test bike. For the sake of consistency, we used inner tubes. Our tester positioned the bike at the same point on the hill, released the brakes and simply coasted down the hill to the finish line. We set up a point at the base of the hill where the trail flattened out to create time splits.

The goal was to highlight that particular tire in each run. We knew times would be tight already, so we kept our test simple. Even though the Eliminator is billed more as a rear tire, we mounted it front and rear as to show what impacts that particular tread pattern had on the time.

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Part One

We found that in round one of our test, tread pattern and rubber compound had negligible impact on rolling speed. Our Eliminator and Butcher tires each rolled down the hill at the same speed and times, even when using various compounds (T7 and T9). Not surprisingly, the real standout came when we installed a set of T9 Grid Gravity Butchers.

With a time differential of over four seconds in our quarter-mile drag strip, the gravity tires were significantly slower than all the other tires in the test. Subjectively speaking, getting those tires to the top of the hill was took significantly more effort. The bike felt heavier and rolled much slower than with Grid Trail tires, even the T9 compound.

In our quarter-mile straight light test, the Gravity T9 tires were over 4 seconds slower.

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Other than the feeling our tester had on the pedal up the hill, the straight line test was as objective as possible. No rider input or pedaling, no trail variations or line choices. Just simple rolling down the hill. This is where mountain biking gets a little more complex. We don’t ride in straight lines, do we? Line choice matters and carrying speed through corners is paramount.

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Part Two

Now it was time for round two. We decided to pull in Logan Brown, a Vital MTB contributor and test rider. Logan’s bike skills are real but he isn’t the sort of rider that can tell a tire compound by the way the sun reflects off the rubber. He was an ideal tester for the classic “Pepsi Challenge.”

Butcher Grid Gravity T9
Butcher Grid Trail T9
Butcher Grid Trail T7

We grabbed three tires from our test group, the Butcher Grid Gravity T9, Grid Trail T9 and Grid Trail T7. Logan was to ride each set of Butchers for one lap on Stormin Mormon at Eagle Bike Park. This trail features jumps, drops and plenty of corners where speed matters. Our test trail also has a flatter exit to further gauge rolling speed. Stormin Mormon does not have any rocks or optimal line choices which could cause inconsistencies in rider line choices and runs. The technicality comes from timing and speed. As a test loop that is focusing on rolling speed, it is pretty ideal.

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For each of his three laps, Logan did not know what set of tires he was on (Grid Trail T7, Grid Trail T9, and Grid Gravity T9). Logan was given the instruction of using only a single gear on the descent and to keep his efforts as consistant as possible. We would time each lap down the mountain and see how each tire stacked up. Because the loop is short and Logan is fit, fatigue would be rather minimal.

After each lap, we gathered Logan’s subjective feedback to see what he thought. Not knowing if a tire was actually heavier or more sticky, he would have to rely on ride feel alone. As bike nerds, we were a bit surprised by Logan’s initial feedback. Then we considered what he was describing on trail and we could understand where he was coming from. Once we analyzed the times, we were genuinely surprised.

The clock doesn't lie, but only a one-second differential between tires in just under a mile is pretty minor.

Logan felt fastest on what should have been the slowest tire, the Butcher Grid Gravity T9. Stormin Mormon is not a steep trail and requires some pedaling. A heavy tire should be slower, right? In just under one mile, Logan was only two seconds slower than his fastest lap. To an average rider, this is negligible. Without hard GPS data to back us up, we believe the reason Logan felt fastest with the Gravity T9 was due to improved consistency on the trail. Logan was likely going through corners faster and holding a steady pace, even if that peak speed was slightly lower.

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Logan’s ride perceptions on the Grid Trail T7 and T9 tires mirrored the expected ride qualities. Only one second separated these tires, with only one more second separating the Grid Trail T9 from the Grid Gravity T9. With less of a rolling-over sensation in the corners, Logan felt the T9 was better when leaned over but thought it rolled slower overall. The T7 felt quick, but offered him less stability when laying the bike down. Again, Logan was testing these tires completely blind.

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What's the Bottom Line?

What were the key takeaways here? Like so many things in mountain biking, what a rider chooses to run should be based on where you live and how you ride. Moreover, it should be based on what a rider likes to run. A burley tire is slower in a straight line but probably requires less braking for corners. A lighter tire will roll fast but get a little wild in the rough stuff. It is up to the rider to decide their own tradeoffs.

What’s the best tire? The tire that works best for you.

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