Chainstay Length - Building With Sliding Dropouts

[Tom Gagliardi]

I'm working on a single speed mountain bike frame that will be using sliding dropouts, and was hoping for some input as to position of the sliders during the design/build. i.e. If I'm looking to build a 439mm chainstay should I spec the 439mm measurement with the sliders in the middle, all the way back or all the way forward? I'm thinking if I want 439mm to be the max length I should start with the slider all the way back measuring 439mm, but wanted to get some input. Thanks in advance.

[jon_norstog]

I'm working on a single speed mountain bike frame that will be using sliding dropouts, and was hoping for some input as to position of the sliders during the design/build. i.e. If I'm looking to build a 439mm chainstay should I spec the 439mm measurement with the sliders in the middle, all the way back or all the way forward? I'm thinking if I want 439mm to be the max length I should start with the slider all the way back measuring 439mm, but wanted to get some input. Thanks in advance.

Thomas,

You don't really need sliders on a SS. Just use HZ rear entry drops and adjust the disk tab position so the caliper is more or less parallel with the dropout slot. It's lighter, cheaper, and has less stuff to break. If you already have the sliders, you might be able to sell them.

Good luck!

jn

"Thursday"

[Eric Estlund]

With any adjustable part, think about what happens with the system and why you are adjusting it. Moving the wheel for/ aft (with either sliders or track ends) will change the tires position relative to everything, as well as how/ where the chain tension occurs. Figure out where you want your wheel, where it has to go in real space to get to your location, and build to that.

[fortyfour]

Generally what I do when building a mountain frame with Paragon Sliding Dropouts is position the sliders in the middle of their stroke and optimize the chainstay length at that position so when the user slides them back to tension the chain, it ends up in that position. In practice it may end up just before this or just ahead of this due to the ring/cog combo. I also take note of what cog and chainring they typically use and measure things out so that this is where my settings end up. So if you add/subtract a tooth from cog or ring, you have adjustment range fore/aft and have some room for things to be repositioned with wear/chain stretch. I prefer to use the PMW sliders that are hooded for some extra stiffness / material to weld. I prefer that joining method than brazing them (that's just my preference). It's also nice to have the choice of ISO, Post Mount and include a hanger or not as I've recently had a bunch of requests for a "singlespeedable" mountain bike. I've ridden my own pretty hard this season without any issues thus far. The addition of the dual washer and upgrade for the ti combo bolts is a nice touch as well as the micro adjustment knobs that they come with.

If this is a "singlespeedable" mountain frame, I optimize tire clearance so I know I am giving the customer enough clearance in both the extremes so they have plenty of room to fiddle to find their preferred settings for different terrain. I optimize tire clearance in the middle of the stroke where I would prefer them to have their settings placed for tire clearance and SS mode. I generally have been building 29" 1x10 dedicated sliders with 16" (406.4mm) to 16.8" (426.72mm). I've found 16.5" to be ideal for long days and technical fast/slow speed riding and a "best of both worlds" feel.