As the summer tan lines begin to fade, two bike racing series aim to keep the mettle in the pedals for Wisconsin bike riders.

Cross-Shooshko Cyclocross race

Cyclocross is a growing sport that leads riders over mixed terrain, such as pavement, grass, mud, and snow, plus extra challenges like barriers and steep hills to challenge any bike rider. It also features a unique mix of serious competition with a rolling party. Some competitors aim toward the podium while other less-serious riders are on the lookout for the next beer hand-up. The effort is short, but intense, with most races lasting between 30 and 45 minutes.

Cross season kicks off on Sept. 10 in Kosciusko Park in Milwaukee's near South Side neighborhood for the third annual Milwaukee Bicycle Company Cross-Shooshko cyclocross race.

The race winds through grassy fields, around trees and around the pond, and will challenge riders with barriers to jump over and steep hills to climb. When not racing, participants can enjoy samples from Milwaukee Brewing Company, and Valentine Coffee will be available.

Amateur races start at 9 a.m. and are held throughout the day. Women's Elite category races at 12:15 p.m. with more amateur races following. The Men's Elite category closes out the day at 3:15 p.m.

For ladies who are cross-curious, Ben's Cycle/Milwaukee Bicycle Company and Valentine Coffee are teaming up to help run a clinic and cover the costs of the race. First-time women racers can participate in an introductory clinic to understand the ins and outs of cyclocross racing at a free clinic at Ben's Cycle on Sept. 3 from 8-10 a.m. And upon registration, first-time women can enjoy a reduced entry fee (a $15 value) and a free one-day race license (a $10 value), bringing the total cost of the event down to $10. The Milwaukee Bicycle Collective (that is Collective, not Company) will also be providing race-ready cyclocross-style bikes for those who don't have a proper bike on the day.

Riders can register for Cross-Shooshko through USA Cycling, and first-time females can use registration code: milwmn.

The Wheel & Sprocket Hugh Jass fat bike series

Fat bikes are a relatively new entry in the cycling scene, and fat bike racing is newer yet. This year marks the second season of the Hugh Jass fat bike series, put together by Wheel & Sprocket.

Fat bike racing has that competition-x-party feel that is similar to cyclocross, and it shares much of the same grassy, muddy and snowy conditions. The biggest difference (and boy is it big) is the size of the tires, which can be sized as large as 5-inches, over three-inches larger than your typical mountain bike tire and even bigger still than your average cyclocross tire.

Unlike the cyclocross series, these fat bike races are an independent affair, not managed by USA Cycling, so you don't need a racing license, and it's ripe for experimentation; you can earn extra points by wearing a Hawaiian shirt or pounding off a round of lumber-jackian Hammer Schlagen (setting a nail into a stump) between each lap.

The fat biking series kicks off with a preview on Sept. 10 at the Door County Fairgrounds (812 N 14th Ave, Sturgeon Bay, WI 54235) and continues regularly through March. Those registering before Sept. 1 can enjoy the competition for half price. Otherwise, entry ranges from $30-$40. If you don't have a Fat Bike, Wheel & Sprocket will have some to demo for $15.

More details can be found at hughjass.bike.