Early registration starts November 21st, 2025! Early registration helps us plan and saves you money. Sign up to challenge yourself. You can always change your distance as your training develops.

You’ve got options.

1. Separate starts for Pro/Elite Cats- 60 Mile USAC + 120 Mile GES Routes

2. Individual mass start for Open 120 mile and 70 mile course. 3-Person Teams start together their registered distances.

3. A 20 or 40-mile course as an individual or your whole crew! Everyone in these distances signs up individually but ride with as many folks as you wish!

Routes will be announced early August. Until then, we can tell you this:

20 mile: mix of gravel, pavement and b-roads. no singletrack. ~1,000 ft. elevation

40 mile: mix of gravel, pavement and b-roads. no singletrack. ~1,500+ ft. elevation

70 mile: mix of all 4 surfaces. ~3,000 ft. elevation

120 mile: mix of all 4 surfaces. ~6,000 ft. elevation

Yes. Categories include womens, mens, non-binary in the open, fatbike, and single speed in the 70 and 120 mile options. We also have age cats! Please check out our Bikereg for details.

Registration fees will not roll forward should a rider need to defer entry. If you need to defer, we’d be happy to save you a seat for the following year! However, registration will still be due for the course of your choosing. Transfers to other riders are allowed up until the regular registration date has closed.

That’s understandable. We built a difficult course because humans are hungry for a challenge. So, yes, it will be hard. But if you knew you could finish, would it even be that appealing to try? We’ve got 120 mile or 70 mile courses with all the surfaces. For those not ready for singletrack try out the 40 or 20 mile options. Just sign up! Go for it. You can always change your distance as your training develops.

Flat bar, drop bar, gravel, mountain bike, touring bike. The choice is yours. Just make sure it’s set up and ready for rowdy terrain (tire width, tubeless, etc).

Yes, the course will be loaded with fast, flowy singletrack. Our best guess is 10 miles (for the 50 mile course) and 20 miles (for the 100 mile course), and rough B-roads mixed in alongside gravel and pavement.

Tire selection depends on hundreds of factors, but a few of these suggestions below might help you decide what's right for you and your rig.

1. TIRE PRESSURE: here's an online tire pressure calculator we like that has never done us wrong. For core4, we recommend picking category 3 or 4 gravel surface. **This tool asks for your tire width AS MEASURED, not just what it says on the tire sidewall, as tire sizes can vary 10% or more depending on brand and rims.

2. TIRE SIZE/TREAD: Depends on your riding style.

For all rider styles, we recommend at the VERY LEAST a 35mm tire with semi-slick tread and at the most to max out the tire size and tread that will fit your bike. If you can fit 52mm tires and you think the single-track will be challenging, then go for it! If you can deal and thrive on bumpiness, slow down, and/or choose your lines VERY carefully, then you can rock 38mm-42mm and be just fine... it's gonna be rough for a few miles... but you will be faster everywhere else. If you have concerns or less experience with bumpy/gnarly trails, a wider tire is gonna be your friend, but it's gonna cost you everywhere else, so choose wisely.

3. PUNCTURES. This one is easy. Choose tires with some puncture resistance/flat protection. It just ain't worth messin around with light and supple tires. Iowa gravel isn't the sharp rocks of Arkansas, but there's fast descents and knobby roots like you've never seen before and some gnarly B-road terrain.

4. RAIN/MUD. This is a rain or shine event, so, yes, we have a wet route for that. It includes fewer miles of single-track and some grassy B-road alt routes, so we recommend sizing down a tire size to allow for mud clearance (if your bike fits 42's and you were planning on running 42's, think about dropping down to 38 or 40's with a slightly knobbier tire.

We won’t leave ya hangin’. Be sure to download your routes for specifics.

First things first, make up a unique team name! Who knows, maybe the best team name wins a prize? Pick a team captain to register and pay for your team on BikeReg. The captain can enter each rider’s info all at once or send links out to each rider to provide their own details after the team registration has been paid. If a coupon code is entered, the discount will apply to all three members' entry fees.