It’s one of the most unusual new products we've even seen and has been a talking point since it arrived in the office.
The Lauf Grit fork owes its novel appearance to carbon fibre legs and glass fibre leaf springs providing up to 30mm of suspension travel. Unlike regular suspension forks, there are no moving parts so it’s light - 1kg with uncut steerer - and there’s no maintenance to worry about.
The Icelandic company first launched with a mountain bike version of the fork a few years ago but last year, with the growth of adventure and gravel bikes and riding, introduced a short travel model. With Dirty Reiver on my radar, I’ve been testing all manner of adventure bikes, wheels and tyres, and it seems only natural to throw the Lauf Grit fork into the mix.
I rode the Dirty Reiver last year and in places, the terrain is very rough, even with 40mm tyres, and when you add the fatigue from the long distance there were certainly times when a little front-end cushioning would have been appreciated. That sparked a curiosity in the Lauf fork. It looks to offer that little bit of forgiveness over rough ground without a massive weight penalty that might just go down nicely six hours into a gravel race. I'll be interested to see how it performs.
The Lauf has clearance for up to 42mm tyres or 2.1in tyres on 650b wheels, and is available with 12 or 15mm thru-axles and uses the flat mount standard with native support for a 160mm disc rotor. The axle-to-crown measurement is 409mm when 6mm of sag from the rider sitting on the bike is taken into account.
The obvious comparison to the Lauf Grit is the Lefty Oliver fork on Cannondale's Slate, which also delivers 30mm of suspension travel. The whole suspension fork for gravel bikes could be about to kick off with Fox set to release a short travel suspension fork designed specifically for adventure and gravel bikes.
Here’s the fork in action:
So I’ve got my hands on a Lauf Grit fork to test and I’ll be getting it installed on the Open UP I’m currently testing, and I’ll bring you an update and first ride impression in a couple of weeks. In the meantime, I’ve been chatting with Lauf founder Benedikt Skúlason and asked him a few questions about the unusual fork.
road.cc: Where did the idea for the Lauf fork come from?
Benedikt Skúlason: I have a composite and cycling background, and spending all my cash on bikes and bike equipment since early childhood. After doing my engineering M.Sc I worked at a world-leading carbon fibre prosthetic company. Racing my XC bike on the weekends and designing carbon fibre spring prosthetics in the weekdays, it got me thinking, ”how can the amazing properties of flexing fibres be better utilised in bikes?" This was how Lauf was born.
How long have you been producing them?
We started making our "old" TR29 XC fork back in 2012. It was an immediate success with the marathon cross-country crowd since there is nothing else quite like it for that kind of riding. In marathon XC a lot of guys were and are racing rigid forks since they don't want the weight and energy loss of telescopic forks.
Suddenly racers had a better way of avoiding these two negatives, a way without the terrible harshness and lack of grip of a rigid mountain bike fork. Since then we've learnt a lot, though. While the concept remains the same today, we've made huge improvements in steering accuracy and structure stiffness for all our newer forks.
What are the key benefits of the Lauf?
1. The quickest acting suspension you can have. Gives you unrivalled grip, speed and comfort on rough roads. This is due to zero friction and very low unsprung mass.
2. Low weight.
3. Negligible energy loss in the suspension means that while other suspension forks should be locked out when the road gets smoother, a Lauf should never be locked out. So it's always filtering out all these small bumps and sudden unexpected larger ones. In gravel races, you'd never know if you should leave your telescopic fork open or if you should lock it out. With telescopic forks, you are forced to choose between having suspension or having energy efficient pedalling. With Lauf, you can have both.
4. Zero maintenance, for a long long time. Just ride. No fiddling or fixing, ever. In our cyclic tests of the new Grit, the springs of the fork keep more than 95% of their original stiffness for over 50 years of extensive rough-road gravel riding. While a telescopic fork needs to be rebuilt every few tens of hours of use.
5. It looks badass!
Can you adjust or tune the rate of flex?
Our XC and Fatbike forks come in two different spring rates "Normal" and "Light" sprung. Because their longer travel (60mm compared to 30mm on the Grit) requires it to be more accurate. As the travel of a fork goes down, the need for stiffness adjustments decreases. The adjustability of altering your tire pressures eventually becomes enough.
How do the forks work for lighter or heavier riders?
Consider this weirdly surprising fact: A 70kg rider + 10kg bike is only 33% lighter than an 110kg rider + that same 10kg bike. Yes, the 70kg rider gets less travel from his fork, around 33% less.
But then you need to factor in that a lighter rider in general needs/wants less suspension travel. Since the same obstacles simply won‘t hurt as much as for a heavier rider he will want to bias his setup more towards stiff and responsive, and the lighter rider will/should run a lower tire pressure. So, for a low travel fork like the Grit, it's pretty much one size (spring rate) fits all.
Is there a rider weight limit?
Our weight limit is set at 110kg. We limit it there so that we don’t need to use overly stiff springs for it. We know that most of our customers are safely below 100kg so we don't want to optimise the forks for heavier riders. Strength-wise a Lauf fork is essentially like any rigid carbon fork, with the added safety of the suspension removing load spikes from the carbon structure.
Why not use a [telescopic] suspension fork?
It depends on what you are riding if you should ride a telescopic fork or a Lauf. For a full-suspension bike, a telescopic fork is going to make more sense, for big hit absorbing capability you want the adjustable damping that modern telescopic forks have.
But as the hits get smaller and low weight and durability become more important a Lauf becomes the better option. A telescopic is, in comparison, going to be heavy, slow in its response, energy inefficient and require a lot of maintenance.
How much softer or compliant does your bike become with a Grit?
When measured on a 50psi 38mm tire you are getting roughly threefold suspension travel when on a Grit, compared to what the tire already does for you relative to riding on the naked rim (i.e. when tire gives 6mm, the fork gives additional 12mm).
What about pedal bob?
A 75kg rider needs to pedal at above 150rpm to run into pedal bob (natural frequency of the fork+tire).
How fast can it act?
The Grit can respond to more than 30 hits per second (assuming a 1.2kg wheel and tyre, lower weight makes it able to work even faster). This is a key property of the fork and explains its superiority on quick and small hits. This property does 2 things: a) Filters quick hits from you better than other solutions and b) Makes sure the wheel can stay in contact with the ground on gravel roads.
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.