Jim’s Tech Talk
By Jim Langley
This has probably happened to you: friends visit your house for the first time and when they see multiple bikes in your garage (or office, etc. if yours are there), they say, “Geez Louise, why do you need so many bikes?!”
When this happens, I say, “You don’t expect a musician to only have one instrument do you?” They usually understand that. So I continue, “Well just like how different instruments make different music, each of these bikes has a unique ride and I enjoy every one.”
Wanting a New Ride
With the idea of a new and unique ride in mind I’ve been watching the “gravel bike” fad evolve considering if one made sense for me. I put gravel bike in quotes because I think “all road” bike, which I believe Jan Heine at Bicycle Quarterly magazine came up with (or at least made popular), is a better descriptor.
They used to be known as “cross bikes,” which could have come from “cyclocross” bikes though some would probably say it comes from “cross terrain” as in good on tarmac and dirt. You’ve probably heard of “hybrid bikes,” too, but that term is usually for 2-wheelers that resemble flat-bar mountain bikes adapted to road use versus gravel, all-road and cross bikes which are typically equipped with dropped handlebars.
My Wish List
I like the name “all road” but “gravel bike” has a nice ring to it and I’m fine with whatever people want to call these bikes. My rides will almost always include pavement. And, because of that, one of the most important things to me was for the bike to have the efficient, light, fast and lively feel of a road racer on the blacktop.
I was looking for stability and control on loose gravel, sand, rocks and mud, too. This has to do with the frame geometry, wheelbase, fork offset and trail, all of which can either help or hurt when the terrain gets dicey. I know how great bikes handle because for several years in the 1980s I raced cyclocross every winter and was competitive in the California state and USA national championships.
On the best bikes, instead of crashing or losing control and having to put a foot down, the bike saves you finding the right line almost on its own. And lets you balance in place for a second or two when trying to keep going up a rocky climb in order to get your rear wheel on something that provides enough traction so you can power over the top.
For those wall-like trails I wanted lower than road bike gearing, too, something like a 30 tooth chainring and 34 tooth cassette cog to have a low of around 22-24 gear inches.
Also on my list was the ability to run a range of tire widths to be able to dial in the ride to best suit the terrain I’m spending most of the ride on. Having two sets of wheels is the easiest setup for quickly switching between hoops for riding with road-only friends and then gravel grinding with another group. So at some point I’ll get more wheels and tires for the new sled.
Tubeless tires are a nice feature on most gravel bikes, too. You get pinch-flat resistance, ability to run lower pressures and the sealant inside usually fixes any small punctures so you don’t suffer flats.
Lastly, I was looking for a gravel bike for a maximum of $3,500. Under 3K would be even better.
It turned out that my price point was the thing that knocked most of the G bikes I looked at out of the running. In the process of looking at and testing bikes, I decided that I wanted to go with Shimano GRX components and that ruled out some other candidates that only came with other components.
Luckily, two friends tipped me off to Trek’s Checkpoint line of gravel bikes, which a local shop stocked (thanks John K. and Tom P.). They’re just down the street so I visited and rode a few models. I ended up choosing their first carbon frame bike the Checkpoint SL-5 – complete details are here: https://www.trekbikes.com/us/en_US/bikes/road-bikes/gravel-bikes/checkpoint/checkpoint-sl-5/p/35169/?colorCode=grey_greydark.
Thinking I might not be able to tell the difference, I tested the aluminum frame version of the bike first and it rode nicely. But the carbon one was noticeably quicker, lighter and smoother so it was an easy choice to spend up a little.
Here’s a well done overview of all the SL-5’s features from Trek:
Grinding the Gravel
I’ve had a week of test rides now on pretty rugged gravelly and rocky dirt roads around Bouse, Arizona (where General Patton trained the tank troops for World War II). We’re camping here in our RV on Bureau of Land Management land (BLM – free to stay for up to 14 days).
Here’s What I Like So Far:
- The overall ride is excellent. It has the road bike ride I wanted with easy and predictable handling on the gravel roads and trails.
- The 40mm wide Bontrager tires roll nicely on the pavement and grip well on the loose stuff. I’m trying 36.5 psi in front and 38 in the rear to start, which feels good on both surfaces. Max pressure is 50. The bike can take up to 45mm tires should I want to go fatter. The tires came set up tubeless from Trek and so far even with all the desert sharps everywhere, no flats yet.
- The Shimano GRX components shift and brake just as well as I expected (shifting is cable-operated not electronic). Due to a parts shortage my bike came with a Praxis Alba 48/32 crankset instead of the GRX’s 46/30. I still get a nice low gear that’s working fine. I especially like the wide GRX shift/brake levers and rubber hoods, which feel great to operate and grip respectively.
- There’s a nifty storage compartment inside the down tube. A little lever lets you release and lift off the trap door (the bottle and cage comes with it). Inside is a nice little bag for tools with a pull tab so you can easily yank it out. No tools are included with the bike but there is a little cardboard template showing you which accessories to buy and where they go (CO2 pump, spare tube). The internal cables run through the down tube so you have easy access to them, too.
- The flared-drop Bontrager aluminum handlebars are extra wide for more control, which feels great off road and on.
- There are mounts (threaded holes sealed with press-fit rubber plugs) for adding every conceivable accessory from fenders to racks to bags to multiple bottles. And Trek even makes proprietary bags for the bike. I doubt I’ll ever use most of these features, but it’s nice to know it’s an option and should I sell the bike it’ll appeal to more cyclists.
- The Bontrager seatpost has an excellent 2-bolt clamp that makes swapping out seats simple and leveling them as easy as tightening one bolt and loosening the other. But, the Bontrager seat was too squishy – about ¾ of an inch of padding, which for me just compresses and essentially gets in the way. I went to a firmer model.
- A really nice feature is the removable rubber protective panel underneath the down tube that protects the carbon frame from the rocks thrown at it from the front tire. There’s a smaller protector on the chainstay to protect it.
- There’s also a chain keeper to prevent the chain falling off the small chainring, which can happen on super rough terrain and if you crash, which I’ve done a couple of times already.
Other Observations and Thoughts So Far
- Isospeed suspension. I wasn’t looking for a gravel bike with suspension and didn’t even realize I’d bought one with it until I got my new bike home and swapped out the seat. That’s when I noticed the Isospeed sticker. Trek’s Isospeed decoupler rear suspension on the SL-5 is a spring device inside the frame along with a seatpost (27.2mm diameter) that can move fore/aft slightly both of which are said to offer some shock damping. They’ve been dialing in IsoSpeed for many years so I believe it’s doing something but I can’t say that I can feel the seat moving or seatpost flexing over the bumps. Learn more about Isospeed: https://www.trekbikes.com/us/en_US/inside_trek/isospeed/.
- Frame sizing. I got the 56cm frame size because the next size up was 58cm, which was too big. From the length of the top tube, I expected the stock 9.5cm stem to be on the short side and thought I’d need a 10.5 or 11. However, the handlebars on the bike and the GRX levers provide more reach that I expected so the 9.5cm stem has been working fine. And even though I had to extend the seatpost out of the frame, the seat is not a lot higher than the bars so it’s a comfortable riding position. Still if you’re between sizes be sure to try the bikes out to figure out which one is best.
- Built-in tool holder but no tool. Back to the storage compartment in the down tube, there is also included a little plastic holder for a mini tool beneath the trap door. I know that’s what it’s for because I asked at the shop when I picked up the bike. It turns out that there’s a specific Trek mini tool that fits. In my experience, most companies provide the tools with bikes when they make dedicated spots for them and I think Trek should have with the SL-5.
That last bullet point about the dedicated mini tool not coming with the bike is my only complaint. Otherwise, the SL-5 is exactly what I was looking for and I’m enjoying having a bike that rides significantly different than all my others. While I don’t feel the Isospeed suspension, the 40mm tires, sweet handling carbon frame and fork, comfortable riding position and low low gearing let you hop off the pavement and hit a dirt road or trail anytime you want. I’ve always done that on my road bikes but now I have a bike actually made for it.
That’s my gravel bike story. If you’re shopping for one or already picked a winner it would be great to hear your story. It seems like more and more of my roadie friends are venturing off the blacktop on these rigs and your tips and knowledge will surely be well received. I’m also happy to answer any questions about my Checkpoint if you’re interested in learning more.
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.