
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.

Trek Delivers
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.

Verdict
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.
Your Turn
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.
La suspnsión Isospeed la notarás cuando bajes de la bici y notes que duelen menos partes de tu cuerpo y sobre todo cuando montes en otra bici que no lleve la Isospeed. Tengo una Domane SLR desde hace 7 años y durante ese tiempo ha sido mi bici principal, 45.000 km, las roturas del asfalto se notan como pof en vez de toc mientras el cuadro y el Isospeed absorve esos botes que en otra bici te llegan hasta el cráneo. Isospeed es una sensación difícil de describir pero muy agradable de expèrimentar. Enhorabuena por tu nueva bici, la disfrutarás seguro por muchos kilómetros. El mes pasado tuve un infarto de miocardio y junto a mis 65 años he de cambiar a una bici electrica, Trek las ha puesto muy caras y no puedo llegar a otra Domane con motor, he cogido una BH de aluminio y la verdad que no es lo mismo montar ese cuadro que a mi Domane, pero no me queda otra solución que pasar a la electrica.
You will notice the Isospeed suspension when you get off the bike and notice that less parts of your body hurt and especially when you ride another bike that does not have Isospeed. I have had a Domane SLR for 7 years and during that time it has been my main bike, 45,000 km, the breaks in the asphalt feel like a pof instead of a knock while the frame and Isospeed absorb those bumps that on another bike reach your head skull. Isospeed is a sensation that is difficult to describe but very pleasant to experience. Congratulations on your new bike, you will surely enjoy it for many kilometers. Last month I had a myocardial infarction and with my 65 years I have to change to an electric bike, Trek has made them very expensive and I can’t get to another Domane with a motor, I have taken an aluminum BH and the truth is that it is not It’s the same to mount that frame as to my Domane, but I have no other solution than to go electric.
(per Google translate)
Thanks a lot for translating, Philip!
Jim
Thanks for sharing your positive experience with the Trek Isospeed rear suspension Agustin. I believe your Domane has a different model of Isospeed than the Checkpoint. Yours must be considerably “softer.” Mine is marked “Race.” I have spent another 10 hours on my bike now including a 5.5 hour ride yesterday and I still feel no suspension from mine when riding or after I stop riding.
Thanks,
Jim
As a person who builds bikes (not the frames nor wheel sets), I have had a lot of fun converting some vintage steel road bikes and more modern road bikes to gravel bikes. Of course, one needs to find a bike with adequate space for wider wheels/tires. Can also convert some hybrid type flat bar bikes to drop bar gravel bikes. At the same time, I change out wheels and tires and often change out components/crank sets/cassettes to allow performance compatible with gravel/cross conditions. Of course, these bikes do not have a built in compartment for tools so, I need to add a seat bag.
This is a lot of fun and I can usually complete this for under $1,000 (including the cost of the original bike)…and, often times, for a lot less. This also allows me to re-purpose bikes which are no longer highly desired….And, unless one is using the bike competitively, they work well.
In 2015, back before gravel became a fad, I bought a Specialized CruX Elite EVO (11 speed x2 Shimano 105) as a Swiss army knife kind of bike for $2500. It turned out to be a great choice. Depending on need, I mount anything from 25mm road tires to 33mm CX or 38mm gravel tires. I also switch between Speedplay for road and Eggbeater pedals for offroad. I’ve enjoyed road centuries, CX races, gravel roads and even slightly technical single track. I’ve since replaced the wheels to Spinergy GX-32’s, so 28mm is the narrowest road tire I can use, but that’s a wonderfully comfortable width.
Good review of your Checkpoint. I agree that the multi tool under that removable cover should be included with the bike. Purchased a Domane SL6 last year and it has the same storage compartment. Bought one of the BITS multi tools from Trek. It’s overpriced at around $35 but that’s the only tool that will fit in that door slot.
I bought a Spot Denver Zephur in 2016. It has been my primary bike since then I have a set of carbon fiber wheels that I run tubeless road tires on in a 32-34 size and a 650B set that I run 40-45’s on for gravel & off road. Love the bike and equipment. Di2 Ultegra & Shimano hydraulic disc brakes. Over 25,000 miles so far.
https://bikeyface.com/2016/01/12/new-shoes/
Just recently got a Salsa War Bird (I have a Trek Domane too). I got the War Bird with a front deraileur and full GPX (cable shifting). It’s got quite a bit more clearance for bigger tires than the Trek, No suspension, but feels much more comfortable on gravel than the Domane because of the frame angles. Having two sets of wheels is really a good thing with tubeless setups. It feels fast on the tarmac with and without “skinny” tires. I have not put on many miles yet here in Montana (got it in January) – still on skis most of the time, but the War Bird is a winner in spite of the (gulp) $4600 price tag.
Es posible que al ser la Domane un modelo de carretera la suspensión sea ma´s suave, a´si y todo la suspensión se puede regular, más dura o más suave y yo la puse en un principio a más suave.
Agustin said, “It is possible that, since the Domane is a road model, the suspension is softer, so the suspension can be adjusted, harder or softer and I initially set it to softer.”
Thanks for explaining, Agustin, appreciate it. I don’t see any way to adjust this Isospeed on my bike but I’ll look into it. Thanks again,
Jim
Otra cosa Jim, en mi Domane SLR era todo perfecto excepto una cosa y veo que en tu análisis lo has pasado por alto también como me pasó a mi. Las ruedas Paradigm son lo más sencillo que fabrica Bontrager, me parece un error presentar una bicicleta con tecnología de diseño de cuadros, cambios y demás a la última moda y en cambio que las ruedas que monta sean tan sencillas, al menos deberían avisar en la tienda de que esto es así y por lo que veo a ti tampoco te han avisado. Mi Domane SLR traía de fábrica las Paradigm, en un entreno nocturno y preparando una BRM de 300 km se rompió un radio de la rueda delantera, llevé la bicicleta al taller y al día siguiente lo habían reparado, pero el problema surgió cuando en el km. 100, primer punto de control, de la BRM 300 rompí otro radio y sólo hacía una semana que me habían reparado la primera rotura, los otros 200 km que faltaban de la BRN los tuve que hacer sin freno delantero, lo tuve que abrir para que no rozara con la llanta y la rueda delantera bailando como un 8, no podía pedalear de pie por miedo a romper otro radio. A la vuelta a casa me deshice de las ruedas y compre Aeolus 3 de carbono Bontrager, con buje DT Swiss, con estas ningún problema, las Paradigm, mal resultado.
Here’s a translation of Agustin’s comment:
“Another thing Jim, in my Domane SLR everything was perfect except for one thing and I see that in your analysis you have overlooked it as well as it happened to me. The Paradigm wheels are the simplest thing that Bontrager makes, it seems to me a mistake to present a bicycle with frame design technology, derailleurs and others in the latest fashion and instead that the wheels that it mounts are so simple, they should at least notify in the store that this is so and from what I see you have not been notified either. My Domane SLR came with Paradigms from the factory, in a night training and preparing a 300 km BRM a front wheel spoke broke, I took the bike to the workshop and the next day they had it repaired, but the problem arose when at km . 100, first checkpoint, I broke another spoke on the BRM 300 and the first break had only been repaired a week ago. I had to do the remaining 200 km of the BRN without the front brake, I had to open it so that It didn’t rub against the rim and the front wheel danced like an 8, I couldn’t pedal standing up for fear of breaking another spoke. On my way home I got rid of the wheels and bought Bontrager Aeolus 3 carbon, with a DT Swiss hub, no problem with these, the Paradigms, bad results.”
Very sorry to hear about the broken spokes, Agustin. I took a look at my spokes and the heads are stamped with an “S.” Best I can guess this means that they are “SLE Spokes” made by the company:
Shuhn Lih Enterprise Co., Ltd.
No. 65, Dong Suen St.
Sulin City, Taipei Hsien
Taiwan
R.O.C.
I did place a magnet on the spokes to see if it would stick and it did not, which suggests that the spokes on my wheels are stainless steel. That’s a good thing, however, if they break they are not quality spokes. I’ll be keeping an eye on mine and will rebuild the wheels with DT Swiss spokes if they start breaking spokes like yours did.
Thanks very much for letting me know about this,
Jim
In Spanish:
Siento mucho lo de los radios rotos, Agustín. Eché un vistazo a mis radios y las cabezas están estampadas con una “S”. Lo mejor que puedo adivinar es que son “SLE Spokes” fabricados por la empresa:
Shuhn Lih Empresa Co., Ltd.
No. 65, calle Dong Suen.
Ciudad de Sulin, Taipéi Hsien
Taiwán
ROC
Coloqué un imán en los radios para ver si se pegaba y no lo hizo, lo que sugiere que los radios de mis ruedas son de acero inoxidable. Eso es bueno, sin embargo, si se rompen, no son radios de calidad. Estaré vigilando el mío y reconstruiré las ruedas con radios DT Swiss si comienzan a romper los radios como lo hizo el tuyo.
Muchas gracias por avisarme,
Jim
i just got this very bike (i come from Trek Fuel EX8) and im still getting use to the gravel scene. do you recommend any lightweight, efficient, but minimalistic/elegant/low profile fenders to go with it?