Sliding dropout question


Well-Known Member
I have a Surly Instigator setup with the 142mm sliding dropout MDS chips. Have been running it with the axle all the way fwd in the slots, but if I want to slide it back, is there supposed to be something to "lock" it in place, like a tensioner would, or is tightening down the axle like I did on my old BMX bikes enough? The through axle does have bolts on both ends. I would like to think I can lay down more power than I did in my middle school days when I was on the BMX, and wasn't sure if relying on the tension of the axle bolts is enough to keep the wheel from slipping and perhaps getting jammed up back there.

I have been running as 26+ with 2.8" tires and really like the short chainstay feel of having it all the way fwd, but I may try a 27.5 wheel with a 2.6" tire which will probably need a little extra room back there.

Perhaps this should be obvious, but it's my only bike with sliding dropouts.


Well-Known Member
Thanks, not sure how I missed that instruction sheet! It definitely doesn't show anything additional besides the axle. I guess I just need to tighten it to 16 NM before "getting rad".

The dropout system is pretty slick.


Formerly 1sh0t1b33r
Team MTBNJ Halter's
Do you have the axle with the Allen bolts? If not, you can upgrade to the Ultra New or whatever they call it. Haven’t slipped since switching.


Well-Known Member
I ended up reaching out to Surly and they confirmed that I shouldnt need anything with the sliding MDS chip. I guess I’ll give it a go and see what happens.