Suspended Reality: Three Gravel Bikes With Unique Suspension Systems in Review
I think at this point that we are past the question as to whether or not you need a gravel bike. (Answer: you know if you do, and most likely you've already looked into getting one for yourself). But the next question is whether you need a gravel bike with suspension. Cue the people saying "I don't need suspension! I have a wider tire!"
We have three of the industry's premier gravel bikes with suspension, including the BMC URS, Cannondale Topstone Carbon, and Lauf True Grit for a comparison to help you determine which bike best suits you and your needs.
The ideology is twofold. The first thought is that gravel bike suspension makes the bike more capable, allowing riders to ride singletrack that they might consider boring on their full-suspension bike. Suspension provides added control over these surfaces, and these three bikes offer little to no sacrifice elsewhere. The other thought relates to comfort, as even a bit of suspension amplifies the effects of a wide tire without adding rotational weight.
URS Means UnReStricted, but Only to 10 mm
Like the two other bikes here, we've gone into the techy bits of this bike a bit further in our BMC URS First Look. And like the two other gravel bikes here, the URS takes some tech from the mountain bike world, though BMC went a few steps further. Much of it here has to do with frame geometry; it features a 74-degree seat angle steeper than many XC hardtails, reach measurements size-per-size that match those same frames, and trail numbers that lends to tons of stability.
BMC's magic comes courtesy of their MTT suspension. While there are frame points that are designed to flex, the MTT suspension is designed much like a traditional "soft tail" mountain bike. MTT is built around two aluminum shafts that slide on self-lubricating bushings. This is covered a rubber elastomer that acts to cover the bushings but also to provide damping in the system as well.
The MTT suspension, in conjunction with the bike's D-shaped post, is at it's best when the rider is seated and trying to power through high-speed washboard terrain. Normally, most riders would have to slow down and deal with the bike buzzing through, or they stand up out of the saddle and lose a bit of control. There's little feeling of being bucked around as the rear wheel simply does a better job of tracking through terrain. The feeling isn't far off from riding a bike with wider tires.
BMC took some chances on the URS, a gravel bike that approaches rider needs with an XC perspective. The MTT suspension makes a difference and has no discernible downside. Kudos to BMC!
Kingpin is the Cannondale Topstone's Linchpin
We were big fans of the first Cannondale Topstone for its go-anywhere feel and awesome value. The Topstone Carbon deviates from its alloy sibling, exhibiting sporty handling, sprightly acceleration, and a bit of engineering they call the Kingpin Suspension System.
We've gone further into it in the past, with our first look at the Cannondale Carbon Topstone. But Kingpin in essence is a simple thru-axle pivot that locks the left and right seat stays together. This pivot floats between two bumpers in the seattube that allow for a total 30 mm travel, with 75% off that happening around the saddle, and the rest at the rear axle. Cannondale claims this is the same as increasing tire width by 9 mm for both comfort and grip.
The suspension itself is fairly subtle in use. You won't feel any type of suspension bob when climbing out of the saddle, though Cannondale says that the extra give in the suspension offers more tire traction than the 40c tire width might indicate. Where one feels it the most is riding through a number of sharp edges; the suspension doesn't feel particularly supple off the top and it needs repeated hits (like riding down a pothole-stricken road) to activate. The suspension really starts to work when paired to the Cannondale SAVE carbon seatpost found on the higher-spec models, as the suspension itself provides some flex like the URS's D-shaped post
It seems that while the Kingpin Suspension was designed to make the Topstone Carbon more capable, it's greatest asset is added compliance. The pivot merely adds some flex in a place where the frame naturally does it. The frameset weighs in at 1305 grams in a size medium. This is about a half-pound heavier compared to both the BMC and the Lauf, though complete bike weight is very similar to the BMC. I think of it as the icing on the cake of an already-capable gravel bike, making for a comfortable, composed ride that never feels mushy when pedaling.
Lauf Leaf Spring Says: "Just Ride!"
We have talked about the Lauf True Grit at length in the past, with a first-look review HERE, as well as a comparison with the veritable OPEN U.P. HERE. We are fond of the Lauf Cycling approach to design, and their brand slogan - "Just Ride!" - fits what they make as a company. And while their foray into the cycling world first came with their leaf spring suspension forks, it was the True Grit gravel bike that really caught our eye.
The True Grit features the brand's unique Lauf Grit SL Fork that draws attention in a way that the BMC and Cannondale don't often do. The magic here is the Lauf Spring System, a series of twelve undamped composite leaf springs bonded between a carbon fiber fork and a 15mm thru-axle dropout. The Grit SL fork adds something like 3/4 lb over a standard carbon fork, but this is a weight that really makes a difference off the beaten path.
Having a leaf spring suspension means that the spring rates are generally progressive, and it shows here. Riding quickly down dirt roads shows that a very composed front end, particularly as speed as the bike tracks straight with minimal rider inputs. It also makes the bike feel particularly capable descending through singletrack; though it is no match for a suspension fork, the front wheel still tracks with grip and assurance lacking in many a gravel bike.
Like the other suspension options here, there is nary a drawback. Brake dive is minimal to nonexistent, and while one might be able to see the leaf springs compress when pedaling out of the saddle, it in no way feels sloppy or imprecise. The rear end certainly doesn't have the compliance of the others.
If there's any drawback here, its that the bike - unlike the Topstone and URS - is designed solely for a 700c wheelset. A 700 x 45c tire (which it fits) is plenty grippy in most terrain, though a 650 x 47b tire offers much of the comfort with greater zippiness and slightly snappier handling. If you're a 700c die-hard on gravel (as many people are), then this should not be an issue.
Which One is for You?
Good question. We think of it like this: the Cannondale Topstone Carbon and BMC URS have rear suspension systems that aid in pedaling comfort. It replicates what a wider tire can do without the added rotational weight and sponginess that can come with wider tires. The Lauf Grit SL fork, on the other hand, adds control and capability that makes you a better rider. Neither point has major flaws, and all three suspension systems prove that suspension on a gravel bike isn't merely a gimmick.
Have any questions about the BMC URS, Cannondale Topstone Carbon, or Lauf True Grit gravel bike? Give us a call during business hours, or send us an email any time at firstname.lastname@example.org.