My 42mm tires measure 45mm with a 25id rim, not sure what a 45mm tire would run on a 25id rim
Yeah, a bit like talking about tire pressures without rider/bike weight data as well… tire width spec is lacking without context of the inner rim width used. Considering people may talking about wheels ranging from 19mm (old stuff) to 25mm (new stuff), that can have a large impact on functional, measured tire width.
For reference, my WTB 40mm tires measure 44mm actual width on my 25mm internal rim width wheels.
For context, when I put 45mm Ramblers on my Aspero last year, it was on a 23mm internal rim and they measured 45mm.
Tyres as well… Getaways 45c on a 25IW are 48 measured
What do you all think about the LAUF? It seems well spec’s for the price and would have a similar ride as the Chekpoint.
- Based on what? The geo between these seems rather different to my eyes.
Don’t need any context, just use measured width.
Sure, but that’s not the number most people toss out in these discussions. They are listing the rated tire spec far too often. In most cases, noone bothers to mention which they are actually taking about anyway (specified vs measured), so the ambiguity is more present than it should be.
I think most people don’t have calipers or care to know what it measures.
They just want the east answer. Only when you get into the anal retentive people who bracket tire pressure and so on do you get the data your looking for
- Very true in some cases, but it matters as well when people look to push beyond a frame/fork’s max rated tire size (as is being done right above), which is not just the AR people mentioned (again… context matters)
Kind of a harsh reply. I didn’t look at the numbers but have ridden the Checkpoint and it felt low and slack. I would think the LAUF would feel similar low and slack—in other words. Stable at speeds and technical terrain but sluggish in turns. Would love to hear from others that have actually ridden the LAUF.
No harshness intended, just cutting straight to geo values that I spend way too much time reviewing
I’ve been seriously considering a Seigla - mainly for the suspension and value for what I’m looking for - but do have some reservations about the higher bottom bracket and some reported cases of speed wobble. I’m looking more for an all-around adventure bike than a pure racer, though.
The Lauf has a high bottom bracket….one of the highest I have seen for a gravel bike (65mm BB drop). As you can see from the chart Chad posted, the Checkpoint has a lower BB, which will inherently lower the center of gravity, creating a more stable bike, especially when descending or at speed. I don’t think the Lauf will handle similarly to a Checkpoint, at all.
I did a quick run with my Sag Sketch in SolidWorks on the Lauf Seigla, Medium size frame, with 30mm of total fork travel:
- 10% sag of 3.0mm at the fork, drops the BB by 1.1mm
- 15% sag of 4.5mm at the fork, drops the BB by 1.7mm
- 20% sag of 6.0mm at the fork, drops the BB by 2.3mm
So, the effective BB drop with a rider on board will increases by about 1-2mm, which means the unladen BB Drop of 65mm will become around 67mm BB Drop from my estimates. This puts it in the normal CX bike BB height realm and still higher than the 70-80mm range that seems more common with other gravel bikes.
Checking this from a different perspective:
- The Giant Revolt X that comes stock with suspension, it has 68-69mm BB Drop across the line.
- The new Santa Cruz also offers a suspension option, and the geo is built upon a longer rigid fork (suspension length) so the geo will be the same with or without suspension IIRC. That has 78-74mm BB Drop range between sizes.
- So, the presence of suspension doesn’t seem to be a locked connection to taller BB’s in all cases. Lauf is choosing to be different for one reason or another.
I think there is not a ton of need to make large changes in BB Drop for these bikes considering the limited amount of travel in play. Even at fork compression of 30mm, the BB Drop at that point is still only 11.5mm lower. Notable, but not likely enough to cause pedal clearance problems, since I really hope nobody is pedaling at a point of full fork smash
Touching back on the specifics now that I am on PC again:
With respect to “low and slack” on the Checkpoint you rode, that makes sense from the geo numbers. The latest gen has a good 76mm BB Drop along with a long-ish Wheelbase and Front Center. The one thing I have always considered a bit odd with the CP is the relatively steep 72.2* Head Tube Angle. They couple that with a 45mm Fork Offset to give a 65.4mm Trail value. It seems to work fine from all the reports I’ve read, but it is sort of an outlier in the broader world of gravel geos.
Comparing that to the Seigla via the chart I linked, this runs a slightly shorter Chainstay (-8mm at horizontal to the CP), but grows the Wheelbase by 13mm and the Front Center (Hor) by 21.3mm. That is all connected to and a result of the slacker 70.5* Head Tube Angle. They use a 47mm Fork Offset to give a final Trail of 76.2mm. All of that will lead to a level of straight line stability that is quite different from the Checkpoint IMO. Of course, this all ignores the taller BB of the Seigla which is sort of a can of worms. Higher BB’s are less “stable” and potentially more able to change directions in lean/cornering. Lower BB’s can give more stability via being closer to the ground, and potentially hold a corner better from the coupled lower center of mass when loaded properly via a dropped outside pedal.
This all lines up with your thoughts that the Seigla will be stable & straight focused, but not a ripper in the turns. The CP is more in the other direction with some stability but more eager to turn by comparison.
In the end, I see these two bikes are notably different when it comes to how the weight distribution plays out, coupled with the noted geo differences above. If I had to pick between the CP and Seigla, I’d pick the CP since it has decent stability, but the shorter front and longer rear would help weight the front wheel better, which is what I value when cornering one of these bikes at real speed.
But my preferences are not the same as a great many gravel riders. I have seen great comments on the Seigla along with other LLS (Long, Low, Slack) gravel bikes. So much depends on the rider, their skills and preferences, and where they ride. Great to have all these options, but it can make picking a bike that really fits a rider’s expectations a challenge
I’ve been riding/racing the Marin Headlands 2 since January of this year. I couldn’t be happier. I didn’t purchase it as built by Marin though. It was built up with a Rival 1 (which isn’t an option from Marin). I also put on some Roval Terra wheels, discover bar/seatpost and a cane creek eesilk stem. Handling is great, ride is great, and it’s fun not seeing anyone else with my bike.
Was at the LBS yesterday. They sell BMC. Man, those URSs sure are pretty.
@moukari I’m catching up on old posts and trying to get people’s perspective on the Seigla. I’m super interested in it but have concerns about 1) speed wobble reported online by some and 2) any noticeable riding difference due to the high bottom bracket. Related to 1), I think I’m interested in a more all-around / adventure gravel bike (rigid fork, fork mounts, etc) versus something designed for pure racing, but have seen enough bike packing setups to know that the Seigla can work. Anyway, I’m interested in your thoughts on 1) and 2). Thanks!!
@mcneese.chad so true. Regarding the Seigla geometry, it seems to me like the seat tube angle may be misleading in that if you trace the tube down it intersects forward of the bottom bracket. One of my other concerns with the Seigla’s geometry has been getting my seat far enough forward since I like to be over the bottom bracket, but this might be less of a concern.