You may have noticed that lately more and more bicycles come equipped with a 15 or 20 mm thru axle, or in QR15 and QR20 in abbreviated form. QR comes from “quick release”, as this is system facilitates a quick wheel removal, without the use of any tools.
Most of mid-level bikes are and will be equipped with the QR15 axle. In this article, we present the advantages of this system compared to the one used so far, QR 9.
QR 9 is the classic wheel clamping system, composed by a thin shaft that enters the hub axle and has an acorn nut that threads to the opposite side of the skewer. It represented a revolution when it entered the market, because no key was required for unlocking the screws attaching the wheel to the fork. However, the system is slightly outdated today, as the new QR15 system is responsible for this evolution.
What are the advantages of the new QR15 thru axle?
The most obvious advantage of QR 15 is the stiffening of the fork and also of the front wheel. This latter won’t flex so much, especially on turn, and if you use it with the right fork you’ll immediately notice the differences. Then, clamping becomes extra safe because if for QR 9 axles a minimum risk of breaking open still existed, with QR 15 you can simply forget about it. It is because the axle is mechanically clamped to the fork lowers, so the chances of breaking open are basically zero!
Also the QR15 axle construction is more solid. QR 9 can bend in heavy operating conditions, practically tearing itself apart in the middle. Due to the fact that QR 15 is hollow, it is stiffer and more resistant, regardless of riding conditions.
Sometimes, when we remove and re-assemble a QR9 thru axle front wheel, the caliper must be aligned, because you don’t get to the perfect spot every time. So, after installing the wheel, you will have to finely tune the wheel until the brake pads no longer touch the disc, or adjust the caliper. All these operations cost you time. With the QR 15 thru axle, this problem disappears as the wheel and the thru-axle will always have the same position.
Mounting the wheel is much easier. Besides the skewer, the QR 9 axle also contains the two acorn nuts. QR 15 is a single axle, without any adjacent components. You remove it, and you can safely store it without risking losing other parts composing it. Once unscrewed from the wheel, you just remove the axle and the wheel pops out by itself. Closing the QR 15 is the same as for QR 9, by pushing the skewer toward the fork.
If using a QR 15 axle, weight may increase by approximately 80 grams. We included here the modified fork, the hub and the axle which gets slightly heavier. However, the 80 extra grams are fully justified when you’re out there pedaling or when you quickly have to remove the front wheel.
In conclusion, we recommend using a QR15 axle. The arguments above are enough for this new system to be put in a very good light, advantages being are obvious. However, a small problem still remains, namely the budget. If you want to switch to a QR 15 axle, you’ll you to change the fork and the front hub. However, QR 15 and QR 20 are about to become the new standard for most of new bikes.