Zipper’s supplies products and services to customers worldwide from our location in Elkridge, Maryland. Started in 1981, Zipper’s has been known almost since its inception – ﬁrst locally, then nationally, now internationally as one of the nation’s premier high performance machine shops and R&D facility dedicated to the Harley® V-Twin. What we learn goes into everything we do, and we are still learning every day! All of our services are performed in-house to ensure quality products and maximum performance for your hard-earned dollar.
2019 Sturgis Hall of Fame
We are pleased to announce that Zipper’s Co-Founder, Dan Fitzmaurice was inducted into the 2019 Sturgis Hall of Fame.
P.R.Red Shift Cams and ThunderMax
I have a 2011 Road Glide with a ThunderMax® module and Red Shift® cams. I rode a stock one the other day and it felt like I was on a bicycle. Those two mods are more than worth the price of admission. You can never go wrong with the talent at Zipper’s!”
ThunderMax® is awesome! It really made a huge difference in the performance of my bike. I get quicker throttle response, and better gas mileage. I also installed true duals and bigger cams.”
The ThunderMax® has made my 2012 Street Glide® the best running bike I have ever owned. I wasn't sure if ThunderMax® would live up to what I read and saw, but it is all that and much more. Great product if you have a Harley® Throttle –By-Wire. Get one now and you will not regret it.”
Bought my ThunderMax® in ‘06 for my standard ‘05 FLHTI® when the dealer said I had to buy the H-D® Race Tuner. I love to solve my own problems, so I purchased a ThunderMax® unit. After setting up (easy process) I was amazed how good my bike ran. With a 95” kit, S&S cams, Rinehart exhaust, and my bored out throttle body. A year later, I added the AutoTune for even more simplicit. I’ve changed maps several times, and the AutoTune always works to fine-tune the map. 60 K on the bike and it runs excellent! A positive investment!
Get a ThunderMax® on your bike… you won’t regret it! You’ll be smiling all the way home from Sturgis!”