Surly Bikes
It's generally a bad idea to give an engineer a microphone, but since everyone is OOO at a trade show, I've deputized myself and we're going to spend a little time talking about our new 12mm Thru Axle Horizontal chip, Shimano direct mount derailleurs, our bikes, and how the combination affects you.
This minutia might be annoying to read through now, but this knowledge could save you from a much more annoying and wrench-throwing-and-scary-swearing-I-thought-I-had-my-&*$@#!-parts-and-now-the-shop-just-closed Saturday afternoon. So take a second if you need and tuck in!
OK! - Our MDS dropout system gives you the choice to run 12mm rear thru axles if you’re into that kind of thing, and certain bikes even come spec’d with them.
In fact, we have two MDS chip options that work with 12mm rear axles:
12mm thru axle chip:
Single axle position, with a Shimano Direct Mount-only derailleur hanger, shown below (If you bought a complete bike, this is the probably the chip that came with it):
12mm thru axle horizontal chip
14mm of fore-aft axle adjustment, standard (Shimano and SRAM compatible) derailleur hanger, shown below (this is new):
This 12mm thru axle horizontal chip is a new addition to the MDS family that will be a boon to our Surly owners wanting to run a thru axle with a SRAM or single-speed drivetrain (oh yeah!).
Check out this comparison showing the physical differences between our two 12mm thru axle chips:
Since most geared MDS bikes shipped with the single position 12mm chip, there are a few things to keep in mind to ensure a smooth and successful swap:
1) First, the 12mm single position chip has a direct-mount dedicated derailleur hanger. If there is a derailleur hanging from it now and you want to keep using it, it’ll need a little adaptor to make it work with the standard hanger of the new horizontal chip. You can see the difference in derailleur hanger position in the above comparison.
If you buy (or bought) a new direct mount derailleur, no worries it’ll already be on there.
If you bought a complete bike, this part didn’t come with. You will have to order this additional part, but the good news is that QBP sells them! The adaptor part number that works with all stock Surly bikes is:
QBP Part# DP0712
Shimano Part# Y5Y098010
And looks like this:
Please have your dealer double check that number to make sure you’re getting the right setup!!!
Please remember to order this part when you order your chips to save yourself a trip to the shop, unless your shop is one of those cool shops with coffee and beer, and hangouts and rides and stuff, in which case maybe another trip isn’t the end of the world. If you have a shop like that, now is a good time to take a second to appreciate that fact. Hell, maybe bring them a beer, or ice cream, or both!
When you get the part, there’s a circlip, and a bolt, and a washer, but we know you’ll figure it out.
2) The 12mm horizontal chip allows the wheel to be adjusted 14mm fore-aft in the frame. This might affect a few things, depending on the setup you are running:
Tire clearance: The new horizontal chip’s fully forward position is 2.5mm forward from the old single position chip. It’s not a lot, but it might be worth noting if you are running very tight tire or fender clearances.
Shifting: The new horizontal chip allows you to adjust axle position, which changes your axle to derailleur dimension. Moving your axle with a geared setup might affect your rear derailleur body adjustment and overall shifting performance. We have tested and have been satisfied with shifting performance all over the dropout, but hey, we’re all different. If you experience shifting problems, please first give your drivetrain a once over. If that doesn’t fix it, look for a little punch mark on the dropout. That punch marks the the axle position that will provide optimum shifting performance:
Wheel alignment: Not unlike our old Karate Monkey dropout, if you’re not running your wheel fully forward, it’s up to you to make sure your wheel is aligned in your frame before torquin’ it down. I like to eyeball the center seam of the tire to the seat tube.
Wheel slipping: When you install your new chips, that’s a good time to give your axle hardware the old clean and grease. Once that’s all done, align your wheel and torque your axles down to spec to make sure you’re wheel won’t slip under braking or drive forces.
That’s it! I know it’s confusing, but hope this clears it up a little and helps you all avoid some frustration. I had fun and hope you did too.
We love you.
Surly