When we launched the True Grit back in 2017, its geometry changed the gravel game. It uniquely combines the fast fit and feel of a road bike, with the stability and control associated with XC mountain bikes. It’s a bike that enables you to ride faster, and at the same time makes you long for that speed.

Lauf Seigla has that same legendary geometry, only now combined with equally legendary tire clearance and more rear compliance…

It’s no problem to make a bike with massive tire clearance. The tricky thing is doing so without sacrificing other desirable traits. Our goal for the Seigla was to keep the go-fast-attitude of our older True Grit bike, with its short 425mm chainstays and fast rider position, while leaving no stone unturned in our hunt for tire clearance. The headline grabbing result ended up becoming: Up to 57mm 700c tire clearance, or equivalently 2.25” 29ers.

To achieve this, we were NOT ready to:

• Sacrifice clearance between chainring and chainstay. It’s unacceptable for a chainring to be so close to a chainstay that a dropped chain damages the chainstay.
• Resort to a dropped or elevated drivetrain-side chainstay. For reasons we cover below.

Fitting a Maxxis Reckon Race 2.25” 29er still leaves good clearance around the tire.

Read more about the tire clearance here

The absence of a front derailleur mount is not just that, the absence of something. Its absence brings the presence of approximately 5mm extra tire clearance. Using space that would otherwise be reserved for an inner chainring, even though you’re riding a 1x configuration. As we strongly prefer 1x on our bikes for its simplicity, light weight and robustness, this “tradeoff” was an obvious choice to make.

While most gravel bikes use a road-sized bottom bracket shell, e.g. BSA 68, we opted for the 5mm wider BSA 73. We do however not do this to then go ahead and use MTB cranksets with their wide q-factors (L/R distance between pedals). This would have detracted from the go-fast attitude of the Lauf Seigla.

We can use BSA 73 because we’ve worked with SRAM to get fitting road cranksets that maintain a slim q-factor while also providing additional 5mm tire clearance.

These, in our opinion, gravel-optimal cranksets could also be used with a BSA 68 bottom bracket shell, with the help of 2x2.5mm spindle spacers. However, this would be painfully sub-optimal. The narrower BSA 68 frame would have inferior strength/stiffness/lightness due to:
a) The narrower connection to the crankset requiring thicker carbon in the bottom bracket shell for given strength/stiffness, and
b) The wider BSA 73 shell makes for a smoother fiber flow back to the chainstays = less structural imperfections and less stress concentration.

Going for BSA 73 on gravel bikes can only catch on. Look at it this way, if BSA 73 was already the norm on gravel bikes, nobody in their right mind would ever suggest making it 5mm narrower!

The drivetrain-side chainstay on Seigla is solid carbon in its most squeezed location, between the chainring and the tire. We combined this with an oversized vertical dimension to get to the astounding 6mm width (or the lack thereof), maximizing tire space. An added benefit of this solid (and slim) chainstay is better than ever impact resistance. No dropped chain is going to mess with solid 6mm of carbon fiber!

This might sound like a strange selling point. “Normal” straight chainstays. But we didn’t choose straight chainstays because we overlooked dropped or elevated ones.
Dropping or elevating the drivetrain-side chainstay is a common method to squeeze in more tire clearance on gravel bikes.

We didn’t opt for dropped chainstays because: 

• Dropped chainstays are structurally inferior. As a straight “beam” is better than a kinked one. Especially when the kink can also lead to quality defects in fiber flow.
• Dropping both chainstays has a negative impact on the compliance of a bike frame. The “suspension” path of the rear axle turns further forward, which is clearly not good when dealing with incoming hits from below.
• Dropping just the drivetrain-side chainstay makes the rear end stiffer, and makes the (very limited) chainstay flex imbalanced left/right.

We didn’t opt for elevated chainstays because:

• When elevating both sides, the bracing angle of the rear triangle gets much smaller. Resulting in drastically higher stress on frame members. Hence, greatly increased wall thickness becomes required, with associated additional weight.
• If only elevating one side, it makes the rear end stiffer, and makes the (very limited) chainstay flex imbalanced left/right.

In the Lauf dictionary ICE stands for, Integrated Compliance Engineering.

What does it mean when we’ve ICE’d something? It means we focused our engineering efforts on achieving controlled suspension (flex/compliance), without resorting to more complicated solutions adding weight and maintenance.

There is an old saying in Icelandic “don’t cross a river for water” (“ekki sækja vatnið yfir lækinn”). When there is a chance to do something simply, don’t complicate it! This holds true to this day.

ICE’d in the front – Our Smoothie handlebar has long been Lauf’s flagship of the ICE’d concept.
Many choose carbon handlebars over aluminum ones to get that extra compliance (flex). With the Smoothie we took things further. Our novel use of impact resistant high-end glass fibers in the central portion of the Smoothie translates into 2x the compliance (flex) of competing carbon bars! Resulting in a noticeable ride quality improvement. Without links, pivots, extra structures or proprietary standards.

ICE’d in the back
One of our top-priorities when developing the Lauf Seigla was for the rear to better match the front’s comfort, traction and speed. Offered by the Grit fork and the Smoothie handlebar.

We’re doing it through a partnership of 5 things:

1. The slim rear-portion of the top tube transforms the top tube / seat tube junction to a virtual pivot. For maximum effect, the use of a standard seat-clamp means that the virtual pivot is as close to the optimal (rearmost) location as possible.
2. The vertically slim seatstays allow twist up/down while the generous lateral dimensions resist lateral flex.
3. The dropped seatstays channel the ground force so that it bends the seat tube (since 1. and 2. above permit), resulting in a back/down movement of the saddle and a little dose of rear axle travel to go with it.
4. The offset and tilted seat tube doesn’t just provide tire clearance, it translates into a (more desirable) more downwardly suspension path for the saddle. Note that the rearwards portion of seatpost flex doesn’t add comfort, it is only the downwards component that counts.
5. More exposed seatpost than on the True Grit and Anywhere (+14-20mm, depending on frame size).

As a result, Lauf Seigla has approximately 3x the saddle-towards-rear-axle compliance of the True Grit.

Some gravel bikes resort to the smaller 650b (27.5”) wheel size standard to squeeze in more tire width. Seigla doesn’t. This was never an option for our development of Lauf Seigla. The larger diameter 700c (29”) standard simply rolls faster on rough roads.

Think of a small-wheeled shopping cart on a rough parking lot. Imagine how much easier it would be to push that shopping cart if it had bigger wheels. The same physics apply to 650b vs 700c for gravel riding.

We’d argue that rolling fast is pretty important for a go-fast gravel bike.

Stands for Lauf’s Impact Resistant Modulus fiber layup. We like to achieve our low frame and fork weights through careful shape and layup designs combined with good manufacturing methods. Rather than using more brittle high-modulus or intermediate-modulus carbon fibers.

Yes, we are boasting about exclusively using “normal” carbon fiber in our products!

By doing so, we are rejecting shortcuts to lower frame weights. Higher modulus carbon makes it easier to pass compulsory fatigue tests, as microcracks don’t develop as much in/around the stiffer fibers. The stiffer fibers effectively “lock” frame members from flex. This would however demand sacrifices we’re not ready to make. Impact resistance of higher modulus fibers is far worse than for standard modulus carbon, and the stiffer fibers can make a bike feel overly harsh.

We believe a carbon gravel bike should not just be light, it should also be reliable. Lauf frames, forks and handlebars represent our preferred combination of the two.

Designing a bike is a balance art. You need to decide what things are worth adding. Because adding comes at a cost. We are focused on keeping things clean and focused.

We added everything you might need and want for that gravel race: 3x bottle cage mounts and a bento box top tube mount. Obviously, there is also the option of using a frame bag, saddle bag or a handlebar roll.

We chose not to add rack or fender mounts, nor fork luggage mounts. Because, why would we? There are perfectly good clip-on options out there, and you don’t want these mounts standing in your way when racing or when going for that local KOM/QOM.

We were a bit torn on this one. We want to keep things as focused as we can, and we honestly think dropper posts are rarely appropriate on a gravel bike. They inevitably make a bike heavier and require maintenance. Plus, they would reduce our ICE’d rear compliance. However, at the same time we recognise that some (few) actually ride gravel bikes where a dropper is beneficial. So, during our development of Seigla we reached out to SRAM and got to know that they had a wireless one coming up. Perfect! This meant we could avoid adding “unclean” routing holes to our frames. Case closed.

Our gravel bikes pass MTB strength and durability testing. We also do not take the shortcut of using lighter but more brittle high-modulus fibers in our layup designs.

A broken frame is not a good frame, no matter how light it might have been.

Our gravel bikes are designed to deal with tough conditions and heavy use. Within that envelope, we chase the lowest weight possible. This is achieved through clever shaping, sophisticated manufacturing methods and attention to detail.

Our Seigla frame and fork weights are:

Seigla Medium frame, ready to paint, without parts = 1030g*.
Seigla Medium frame, Obsidian Black, with seat-clamp, thick rubber chainstay protector and all bottle cage screws = 1163g*.

JAF 2nd gen, ready to paint, without axle, full length uncut steerer = 412g*.
JAF 2nd gen, Obsidian Black, without axle, full length uncut steerer = 428g*.

*Average weights. Each unit can differ slightly.