If you’ve been on the hunt for a quality replacement axle for your bike, The Robert Axle Project Lighting Bolt-On thru-axle has a lot of the features we like in an axle. They fit well, help avoid axle impacts, are made in the USA, are lightweight, and can be ordered to work with Hexlox for additional security.
Words/Photos Jason Nixon
Front and rear bike axles have been getting wider for some time now and when manufactures use quick release style thru-axles it can make your bike have an even wider stance on the trail.
As long time cyclists, we are not fans of having our parts sticking out. Our Lightning Bolt-On replacement thru-axles offer a lower profile design without sacrificing strength and durability. Our axles are carefully machined to the highest standards in the industry, for the best fit. – Robert Axle Project
On more than one occasion we’ve had a quick release lever contact a rock or obstruction on the trail. This can often lead to cosmetic axle damages, crashing, or unexpected jarring on the trail that can throw you off your line.
Enter the Robert Axle Project Lightning Bolt-On. While this article focuses on their replacement thru-axles , The Robert Axle Project also makes axles for bike trailers, cargo trailers, wide thru-axles for bikes to work on stationary bike trainers, and more. The Lightning Bolt-On will set you back $42-$48 (MSRP) at the time of testing.
The Robert Axle comes in a wide range of sizes to suit just about every 12mm or 15mm axle and thread pitch. You can use their automated axle finder to pick the correct axle. They offer just about every combination in 12mm or 15mm including ones that are boost compatible, eBikes, gravel bikes, and more.
If you don’t see your manufacturer in their automated tool, you can also enter in your axle details manually or request help to make sure you get the right axle.
The Robert Project axles tuck into the frame or fork to give riders extra clearance. There are less moving parts in comparison to quick releases that can work their way loose, wear out, or fail with age given their complexity.
You can see a stock thru-axle below for comparison. Many stock quick release axles from manufactures stick out from the bike but have the benefit of being tool-free removal.
The Robert Axle features a slender head and a 6mm hex/allen interface that is deep to allow for easy installation or removal.
Taking a look at a common RockShox Maxle Ultimate front QR axle found on many forks today you can see how they stick out from the fork leg. The QR on any fork needs to be properly installed every time to ensure you don’t get hurt as a result of improper installation.
With the Robert Axle Project, you can see how much more clearance you get as the quick release portion isn’t needed.
The 2020 RockShox Maxle Stealth axle on the Lyrik’s Ulitmate fork pictured below is a hex/allen option from RockShox instead of a quick release.
The Lightning Bolt-On head is a little bit wider than the slimmer RockShox Maxle Stealth ~2mm by our rough measurement but that also gives you more surface to grab onto when installing or removing the axle and the difference here is pretty insignificant in terms of obstacle avoidance.
Similarly, FOX offers the Kabolt thru-axle if you’re after a FOX factory hex axle option. If you already have one of these hex thru-axles from FOX or RockShox we’d suggest focusing on replacing your rear axle first.
You can see some comparison shots between the Maxle Stealth below. Some axles like the Maxle have a relief on the backside of the axle head or a washer to fit in-between the axle and the frame/fork but Robert Axle doesn’t use one. Usually this helps with friction but we’ve had any issues with the Robert Axle to date and we used grease and assembly lube for installation.
We’ve reached out to them to inquire further and will update this if they have anything significant to add.
Like the front axle, the rear axle on the bike can present similar clearance concerns if you have a quick release thru-axle. It is perhaps more important on the trail as it seems we’ve caught the rear quick release on obstacles much easier than the front axle due in part to the wider nature of the rear drop outs.
You can see how the Robert Axle below compares to the stock axle photo above. It tucks in quite a bit more to give you a little bit of extra room to sneak in-between rocks or other obstacles naturally.
The Lightning Bolt is a great option if you want more clearance. The only downside we see with a rear axle that tucks in like this is that your frame is now possibly going to be a bit more exposed in the event you get too close to an object. We haven’t had this problem so far on the bike however as the axle tends to give just enough clearance to intuitively avoid impact.
Weight wise you will most likely drop a few grams with a Robert Axle if you have a quick-release style thru-axle. For comparison sake
15×110 boost Maxle Ultimate QR – 77.5g
15×110 boost Maxle Stealth – 40.4g
15×110 boost Robert Axle ProjectLighting Bolt-On – 50.8g
Rear 12×148 boost Robert Axle Project Lighting Bolt-On – 41.2g
Rear 12×148 boost Formula QR at 91.9g
Torque required is 12NM and it’s displayed on the end of each Lightning Bolt-On clearly.
The Lightning Bolt can also be ordered in a Hexlox compatible version as well which can add some safety and security to your bike if needed.
In conclusion we’re a fan of these replacement thru-axles and the additional clearance they provide. As long as you’re not depending on your quick release axles to help protect your frame these axles are much cleaner, lighter, and greatly reduce the chance that the quick release lever will cause an inadvertent incident on the trail. Currently they’ll cost you $42-48 but check the Robert Axle Project website for the most up to date pricing.