Has anyone had issues getting a Widgit to work on a 29er?
There is no mention of application specifics on the Widgit site but after recently running into (customer relation) problems after buying one have heard of the Widgit not working on some 29er specific applications
As others mentioned, the frame clearance required to run a 28T or 30T Widgit which is mounted in the "tweener" slot between where a granny or middle ring traditionally sits on a triple crank is not a wheel size dependent issue. Or is it?
Depending on your BB spacing - it could end up sitting too close to the chainstay/yoke area. If using an older cartridge BB, you would just get a wider spindle and jack that thing out enough to the right to erase any clearance issues.
Here is an example
of a 28T Widgit working on a RIP 9. I've seen a few others in the 1 x 9, 1 x 10 threads on various forums.
I've run a 2 x 9 with a 29T Duo inner ring (pretty much would sit in the same spot as a granny "tween" middle slot Widgit) on the Middleburn Duo crank with 110mm and 113mm BB spindles which gave clearance on some of my 29"er frames, but not on other 29"er frames I own. On those others, the chainstay yoke clearance required moving the drivetrain out to the right a bit on some frames with a longer spindle BB. That was the case with a Niner Air 9, Niner JET 9 and I didn't even try it on the RIP.
Now that SRAM 2 x 10, Shimano 2 x 10, Race Face 2 x 10, etc... are out - here's an example from the SRAM document showing measurements needed for clearance with a 2 x 10 drivetrain....
The L2 and L3 measurements as well as W2 and W3 measurements are similar to what you would need to look at to find out if your particular frame could handle a 28T, 30T, 32T or 34T Widgit.
Looking at the L2 measurement (this measurement is very similar to the spot the ring sits for a Widgit 28T or 30T), you'll see that 55mm is needed for a 26T ring, 60mm for a 28T ring, and 64mm for a 30T ring. Nearly a full centimeter difference between a 26T and a 30T - and that's without the chainguides of a Widgit which extend a bit beyond the teeth.
Going back to what I said above about Niner bikes, they don't recommend going over a 26T inner ring on a 2 x 10 drivetrain (the L2 55mm measurement) for their bikes. So I sure wouldn't try running a 28T or 30T with the additional chainguide rings on the Widgit to fit on my Niners if I was going to try and run with the same BB set up that would work with a triple crank. Now if I wanted to jack things out to the right a bit more and had the type of crankset/BB combo that would allow me that option - I'd give it a go.
Or I would just move up to the 32T or 34T Widgit which mounts in the middle ring slot.
I would measure any frame using the SRAM template to see what the L2 measurement is for a particular frame and try and figure out if my bike had the clearance. What's your L2 measurement on the frame you have? Is it possible the same clearance issues you are experiencing may appear on some 26" wheel frames as well? Or are certain 26" wheel frames having issues with the new 2 x 10 drivetrains with the L2 and L3 measurements just like the Niner bikes are?