Lauf Grit SL suspension fork review

did we finally reach the comfort heaven?



There is a lot of different solutions for improving riding comfort on a gravel bike (many of them I already tested) but there is still nothing like a Lauf Grit suspension fork. A truly unique construction that polarize not only by its look but also a heavy price. Thanks to Lauf I got the chance to test a newest version of Lauf Grit SL fork and see if it is a real deal or just an overpriced gimmick.

A few weeks ago I said on gravelbikes.cc that the bike industry should focus on improving comfort at the front wheel because we already have many solutions for doing so at the rear (both suspension seatposts and a frames that provides suspension like BMC URS or Cannondale Topstone). Yet in terms of front of the bike we have a Specilized Divervge bike with its FutueShock suspension and a Canyon Grail with an unique hover handlebar. There is also a suspension stem from Shockstop Stem which does a great job of reducing vibrations but that is it (unless you want to go with a proper suspension fork and have a frame to accommodate that). Not a lot of choice so naturally I was very interested in testing the last available option – a Lauf Grit suspension fork.


What is it?

Lauf Grit fork is not a common suspension fork. It uses a glass fiber springs that are mounted to the carbon legs of the fork. Those springs react to bumps allowing up to 30 mm of vertical movement which should make riding on a bumpy road much more tolerable. The main advantage of this construction (comparing to traditional suspension forks) is the quickness of reaction to the series of small bumps (standard fork needs much more time to rebound) and thus Lauf Grit should, at least in theory, be much more useful on a gravel roads where we do not need a 10 cm of suspension but something that will effectively dampen small but fast occurring bumps. However the advantage is also a disadvantage – springs do not absorb the energy (like the standard fork) so it has to be released somewhere. This was the main complaint about the first MTB suspension fork from Lauf that was creating a lot of unwanted bounciness and thus for many it was simply unusable. But we are talking now about a gravel version of this fork and it seems that on gravel the usage of glass fiber springs suspension system makes much more sense…

Is it really working?

Yes, it works. Just stand on the pedals and you feel the nice vertical movement. It is only 30 mm (usually even less) but it is there and subjectively your ride is noticeably more comfortable. Both in a bumpy forest road and on a fast gravel route. What is more – you don’t feel any negative impact of the suspension onto the steering. Everything is nice and crisp just as it should be. And finally, to my surprise, you don’t really feel the bounciness of the fork. Yet I believe it is there. Why? I did a lot of testing with different scenarios (using a suspension stem or not and riding on a tire with 30 psi and 60 psi) and I found out that it is best to somehow help Lauf Grit fork to show its full gravel potential.

Let’s start with the comparison between a rigid fork and a suspension fork from Lauf (without using a suspension stem). When riding on Soma Cazadero supple tires with 30 psi air pressure the difference in favour of Lauf fork on bumpy forest route was only 1.7% which shows that most of the work in that scenario is done by the supple tire itself. But bump the pressure to 60 psi and Lauf Grit SL reduces up to 12,3% more vibrations that a rigid fork. Moving to the fast gravel route we see that at 30 psi Lauf fork is 9,9% more comfortable. Yet this time bumping the tire pressure to 60 psi lowered the advantage over a rigid for to just 5,9%. So what happened?

Not it is time to go back to the bounciness theme. On slow forest route the rebound due to a limited 30 mm travel is gentle and mostly absorbed by the rider so you don’t really feel it even at 60 psi air pressure. But on a fast gravel route the amplitude of vibration is quite high so lot of energy generated by the Lauf fork springs has to go somewhere. When riding with 30 psi air pressure hard work is done mostly by the tire itself but still adding a suspension stem helps and with this setup I got a huge 16,6% less vibration than compared to the bike equipped with just Lauf fork. At 60 psi tire is no longer that effective in absorbing energy so most of the work has to be done by suspension stem (yet it has only 20 mm of travel so it can’t do everything). In result on a fast gravel route at 60 psi I got the same level of vibration regardless if I was using a suspension stem and Lauf fork or just suspension stem (which for me is a proof that Lauf was in the same time suspending the bike and generating vibrations that suspension stem had to absorb).

So in a few words it looks like a 30 mm of spring suspension works best on a slow bumpy forest route and the faster we go on a gravel route (the more high frequency vibrations) the more we need to help Lauf Fork to show it’s full potential (I mean using a low pressure supple tire and a suspension stem that will absorb all the energy generated by Lauf itself).



Is there anything else worth noticing?

Definitely! First we need to talk about the advantage of suspending the bike and not just the rider. Shockstop stem, which is very effective in isolating rider from the road vibrations, works on the handlebar level while the wheel itself is taking the usual beating. This disadvantage was the most apparent when I was testing a Kinekt 2.1 suspension seatpost which also was doing great job of isolating my butt from road vibrations but in the same time the rear wheel was hitting bumps very hard. But the reason I am talking about suspending rider vs suspending the bike approach is that when you use suspension fork like Lauf Grit you are not only gaining more comfort in terms of front of the bike but also at the back. This is very simple but also usually omitted rule – hits from the front wheel are not only going to your arms but through the bike frame also to your back. The less vibration at the front wheel the more comfortable whole riding experience. And my measurements shows that using a Lauf Grit SL fork with a suspension stem lowered the vibrations at the back of the bike by 5,8% of a fast gravel route (compared to the same benchmark bike with only suspension stem at 30 psi tire pressure).

Bike with Laug Grit SL suspension fork


Then there is a huge tire clearance of Lauf Grit SL fork. I mean HUGE! Just look at the pictures with a 42mm Soma Cazadero tire. I easily managed to put a Schwalbe Thunder Burt 650×2,25 inch tire with tons of clearance. I believe that Soma Cazadero 700x50c will also fit nicely (which I will test very soon!). But this huge amount of clearance can be somehow misleading because of the 30 mm of vertical movement of the wheel that always should be taken into account while choosing the wheel and tire  (so it may look that you can put there even 60 mm tire but I would not go as far exactly because on a bigger bumps the tire could start rubbing the fork).


Lauf fork is also totally maintenance free as opposite to more traditional forks. So you just go for the ride no matter the weather and temperature outside (which can be an issue when you use an elastomer based suspension solutions). The only thing you should consider is our own weight because Lauf is limiting this fork to the riders up to 110 kg 😊

So should you buy it?

There is no simple answer here. First you have to take into consideration the huge price you have to pay (especially for the newest SL version of the Lauf Fork which, by the way, looks much better than the older version). Just because of its price for me it should not be the first line of defence against road vibrations.  Just start with the bigger, more supple tire and ride it with low air pressure like 30 psi and see the difference. Then if you still want a more supple ride, buy a Shockstop suspension stem. Only then, if you are still wanting more (just like me) go for a Lauf Grit suspension fork. Combined with a supple tire and suspension stem it will be the most effective and beneficial to your rides. It certainly is for mine.

Lauf Grit SL suspension fork


But before pulling the trigger you should consider one last thing: the geometry of your bike. Lauf Grit SL measures 409 mm (403 if you take a 6 mm sag into account). And it has a 47 mm rake. So there is a good chance that it will change the geometry of your bike noticeably. Mostly because  of its length. Just go to the rondo.cc site and see that adding 10mm of fork length on theirs adjustable fork makes an effective head tube angle 0,5 less steep (which simply means that your bike will be slower in changing direction). If your bike has a 380 mm fork then swapping it for a Lauf Grit SL fork will take away more than 1 degree of head tube angle changing your bike handling quite much (Lauf made its fork with a 47mm rake so it somehow compensates this change but only if your original fork has a rake around 45 mm but many of the new bikes uses forks with at least 50 mm rake which will add another level of slowness to your bike equipped with Grit fork). To deal with that you can always make a switch to 650b wheel but this is another quite expensive upgrade of the bike.

Fortunately my benchmark bike has a very long fork (405 mm long) so swapping it for Lauf Grit SL did not slacken the head tube angle yet the change in rake was still noticeable (from original 53mm to 47mm). But I like the new feel of my bike. I like it so much that I think that a Lauf Grit SL will stay with me for longer. Much longer than I initially anticipated – but I still don’t think that I finally reached the comfort heaven 🙂

UPDATE:
After a weeks of testing I finally got time to just ride and enjoy the fork and (with the help of a windy weather) I found two more things that should be mentioned:
– the fork makes noises 🙂 If the wind is heavy the construction of the fork will work like some sort of whistle and you definetely can hear it.
– riding on the tops is least beneficial in terms of comfort. It seems that the more weight you put on the handlebar the more Lauf fork behaves like a true suspension.