American Classic Kimberlite 700 X 40mm Tires: Checkpoint

American Classic Kimberlite 700 X 40mm Tires: Checkpoint – by Guitar Ted

Close up detail shot of the branding on the side wall of an American Classic Kimberlite tire.
The American Classic Kimberlite tire.

The American Classic Kimberlite tires represent a choice in the class of “Minimalist Tread” gravel tires. Tires which are best purposed for mixed terrain, pavement-gravel-pavement type rides. Rides where speed on pavement and volume for the unpaved sections is prized above traction and cornering prowess in deeper grounds. American Classic recently upgraded their line and this tire we have on test is one of those upgraded tires. As we said in the introduction to the Kimberlite, this new version is quite different from the older one.

Now with several gravel rides on this tire I am ready to update the review with my take on this smooth treaded, medium sized gravel tire. Let’s first take a quick look at where we are with tire width and anything having to do with tubeless air retention.

A bicycle leaned up against a wooden fence
Guitar Ted mounted the Kimberlite tires to Irwin Ion Carbon 35 wheels which are fitted to his Raleigh Tamland Two.

You might recall that I was a bit disappointed in the width of this tire initially. The Kimberlite wasn’t quite 40mm wide measuring out at 38.6mm. Well, after several rides I am now juuuusssst barely under 40mm at 39.6mm in width. That’ll do.

Tubeless performance has been above average. The Kimberlites retain air well. There is no sealant seepage, (using WTB’s new sealant), and I haven’t had any issues in this area with the Kimberlites.

Ride Performance: The Kimberlite tires were interesting right out of the gates as I found out in my roll down testing. The results were a bit backward from what I expected. The paved section result was merely average. I was a bit surprised that I wasn’t seeing results like I had with the Goodyear County tires, or the WTB Byways. However; that wasn’t the biggest surprise as I found that in my gravel roll down test the Kimberlite out-performed those other two tires handily. After some further observations, I think I know why this was the case.

A bicycle with the Kimberlite tires leaning on an Armco barrier in a rural setting.
The Kimberlites tamed the chunky gravel roads in a much calmer way than GT was expecting.

The Kimberlite has a more flattened crown to its casing, whereas the recently reviewed Goodyear County tires have a more peaked casing. I have found that a flatter profile tire tends to roll up and over gravel better, and more freely, than other tires which have more pronounced “C” shaped tire profiles. This translated over to my gravel rides where, despite the slight penalty in width over, say the County, which turned out to be 42+mm in width, the Kimberlite rolled smoother and with more control.

Detail shot of the tread of a Kimberlite tire
The flatter crown profile of the Kimberlite gives this tire an edge in loose gravel over other minimalist tread gravel tires.

I was also pleased with the ride quality of the revised Kimberlite. It felt less wooden and stiff than the previous versions of American Classic tires and more akin to a tire costing much more. As an example, the Goodyear County tires cost about 70 dollars each and the Kimberlites felt smoother than those did. The Kimberlites are now $45.00, so that’s a better value now than it was before American Classic effected these changes to their gravel tire range.

So Far… Two questions I was left with after the introductory post now have been answered. The width came out to be more to what my expectations were. Also, the ride performance was pleasantly surprising. I appreciated the more stable ride feel and damping qualities that this revised casing has over the previous generation of American Classic tires. This difference has improved the tire’s ride feel and performance and has elevated this tire into the realm of being comparable to more expensive tires.

Tubeless performance has been very good as well, so everything seems to be pointing to a good outcome for the Kimberlite tires in this review. I want to spend a bit more time with them, paying close attention to wear characteristics and to see how this tire does in urban settings where glass and other nasties await me. I’ll be swapping these over to another wheel set and a different bike to conclude this review as well. So, stay tuned for all of that. I should be back in a month or so with a final evaluation of the Kimberlite tires.

For more information on the Kimberlite and the American Classic tire range see their website here;

Note: American Classic sent over the pair of Kimberlite tires at no cost to Riding Gravel for testing and review. We were not paid, nor bribed for this review and we will always strive to give our honest thoughts and opinions throughout.


Author: Guitar Ted

Guitar Ted hails from Iowa. Home of over 70,000 miles of gravel and back roads. An inaugural member of the Gravel Cycling Hall of Fame and Co-creator of Trans Iowa in late 2004- Guitar Ted has been at the forefront of the growth of gravel events and riding since then. Creator of Gravel Grinder News in 2008, he produced the premier calendar of gravel and back road events. GT joined forces with Riding Gravel in late 2014.

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