Spub
Hero member
I purchased a set of three drilled stainless brake discs from Jim Bush and installed them on my JOTA recently. I have a late 180 (#7087), but when I purchased it it had cast iron, non drilled discs. The right front and rear went on no problems, however the left front appeared slighly warped. At first I thought it was a "catch" spot on the disc, but after getting a better gauge there appeared to be a slight warp, manifested by a gentle bobbing of the front fork when coming to a stop, and a very slight pulsing at the lever.
Jim was kind enough to send a replacment disc (without even getting back the "bad" one I had), and when I installed the second disc, it too had the same problem. I tried swapping back in the old cast iron disc and the "warp" went away. I thought there was no way two of the discs could be warped, so I swapped the right front disc which was fine to the left side, and again, slight warp. It finally dawned on me to check the carrier itself, and, bingo! the carrier itself was slightly warped. It appears the non drilled cast iron disc that did not have scalloped cut outs between mounting bolts was strong enough to "true" the warped carrier, but the stainless discs were not. A new carrier from Wolfgang solved the problem. Long story short, no warped discs, a warped carrier, and lots of swapping to figure things out.
The stainless discs produced by Jim are gorgeous, are noticeably lighter, and the feel is very nice. Tolerances are spot on, especially the threaded mounting bolts, which are spot on.
Now the only thing to figure out is how to get Jim to believe the second disc was lost in the mail so I can put it on Ebay......
Jim was kind enough to send a replacment disc (without even getting back the "bad" one I had), and when I installed the second disc, it too had the same problem. I tried swapping back in the old cast iron disc and the "warp" went away. I thought there was no way two of the discs could be warped, so I swapped the right front disc which was fine to the left side, and again, slight warp. It finally dawned on me to check the carrier itself, and, bingo! the carrier itself was slightly warped. It appears the non drilled cast iron disc that did not have scalloped cut outs between mounting bolts was strong enough to "true" the warped carrier, but the stainless discs were not. A new carrier from Wolfgang solved the problem. Long story short, no warped discs, a warped carrier, and lots of swapping to figure things out.
The stainless discs produced by Jim are gorgeous, are noticeably lighter, and the feel is very nice. Tolerances are spot on, especially the threaded mounting bolts, which are spot on.
Now the only thing to figure out is how to get Jim to believe the second disc was lost in the mail so I can put it on Ebay......
