i don't remember who makes my chain tensioners, but i've attached a picture of them on my iro. i had considered grinding a flat spot on the back of the stamped drops on my peugeot fixie where the piece that rests on your dropouts would go, but never did. i would think you would need a flat area for them to stay on there properly. i would be afraid of them sliding off of the radius on the back of the dropout. redline also makes some nice ones. they're aluminum and light. you might be able to mill out that stopper piece to match the curve of the dropout... on the redlines, the piece that rests against the frame is integrated with the 10 mm hex bolt you use to tighten it. some chain tesionsers have you tighten two bolts right against your frame, which seems like a bad idea, as it would scratch the paint and frame. hope that helps...