I've now done the Ironman Louisville bike course two and a half times (minus the 2nd loop). The half of a ride was my first attempt at the course. I ended up getting a little lost, ran out of hydration and bonked. But I'm beginning to get a feel for the course and thought I'd write some of my observations – keep in mind these are the writings of an inexperienced cyclist and one person's slight incline is another's mountain:
Click here to see a google map of the course. Please note that this course is slightly incorrect. The course goes up L'esprit Road, rather than Cedar Run Road as the map indicates.
River Road, the start of the course, is flat. This road goes from concrete, to two lane black top with some bumps, to smooth black top and then back to black top with some bumps. It stretches for about ten miles until it hits a stop light on Highway 42. That is when you turn left onto the highway. Many cyclists ride on River Road and, while the road is always busy, motorists are generally aware that there are cyclists in thee area.
If you are going out for a practice ride, Highway 42 is the most dangerous stretch. Its four lanes for a while, but then switches to two lanes within a mile or so. The start of Highway 42 is also where you'll find the first long hill of the course. On race day you'll be able to gather some speed going up to it, but there are traffic lights that make it tough to gain momentum on practice rides.
I believe its about 17 miles from the start that you'll turn right on 1694 for the turnaround stretch. The entire turnaround is around 10 miles (5 miles each way). In both directions it runs flat for a little while and then descends quickly for a long stretch followed immediately by an equally long incline. When I say "immediately" – I mean there is about 20 yards between the finish of the decline and the start of the incline. One issue is that at this exact point there is a bridge that has a few bumps to look out for – nothing too bad but something to be aware of.
Coming back out of the turnaround, you head right toward the loop that starts on 393. It is here that you start to experience the rolling hills. On their own, not many are that difficult, for me the difficulty is in that they just keep coming. A good rule of thumb is that for every hill you go up or down is going to pretty much go the opposite way within a few yards. There aren't many long plateaus.
As I said, the loop that is circled twice starts on 393. This stretch is a lot easier to practice on – the traffic isn't too bad. The road is also pretty well paved. Again, it has rolling hills.
The left turn onto k-146 is a turn onto a busy two lane road that leads through a number of small towns – including La Grange that is advertised as a viewing area. This road is a mixed bag with some smooth and some rugged spots.
Coming down a long hill, you take a quick left onto a very narrow road – Ballard School Rd. This is a black top road with a series of small but sometimes steep inclines and declines. It's very remote and there is little to no traffic on it at all times.
You take a right onto Old Sligo and than another onto L'Esprit. These roads again contain rolling hills and are fairly smooth. While not as remote as Ballard School, you'll probably find as many horses as cars on these roads.
With a quick ride after you turn left onto 153, you are back on Highway 42 where you'll either head back to do the loop again or head back toward the river. The loop is about 30 miles (haven't measured it exactly).
If you're sightseeing during the event J, along the way you'll see a number of horse farms and fences that are synonymous with Kentucky. You'll also go through a number of small towns. The course is shaded through much of those first and last ten miles of the course on River Road and there are some patches of shade through the rest of the ride. However, for the most part, it's out in the wide open.
As I ride the course and notice other things or someone gives me better detail – I'll update this post.