My wife rides a speed concept and servicing these bikes is a bigger pain than any other bike I’ve ever worked on. Especially the rear brakes. Adjusting them is the big problem. Her rear wheel keeps rubbing against one of the brake pads. This has been an ongoing problem. When the bike gets serviced it’s fixed for a a few rides but then the brake calibers shift again and the rubbing begins. I’ve tried to adjust them myself but because on these bikes the whole rear brake mechanism is internal it’s difficult. The problem seems to be that the space between the brake pads is just too narrow. Does anyone who rides a speed concept have a solution for how to widen the space. I haven’t had much luck googling this. And would rather fix it at home than take the bike into the shop again.
Yes they are a pain to adjust! Have your shop set them with as much space as possible. Adjust the shoes so they are centered with your wheel. Be sure that your wheel is locked in tight with the quick release & centered when installed. Hope that may help ya out a bit.
There are several spacers (washers, really) on the brake arms, and if you’re running wide carbon rims (say 25mm-28mm @brake track) all the spacers except the concave washer need to be moved to the outside of the brake arm on both sides. Using carbon-specific pads (cork in particular) also makes a big difference, as cork pads tend to be 1-1.5mm thinner per pad than their aluminum rim counterparts.
Once that’s done, there’s more than enough clearance for any rim I’ve come across. Our own Bontrager D3 series are a good benchmark in this respect, at close to 27mm @ the brake track. With all spacers outboard and Bontrager cork pads there’s over 31mm of pad-to-pad capability on the old SC rear brake.
If all those mods have been made and you’re still rubbing, the brake plate itself may need to be centered better. It’s slotted for this very purpose. All that needs to be removed is the rear brake cover and the brake arms themselves (don’t need to remove the brake wedge from the cable). Then you have access to the two bolts which mount the plate to the frame.
If after that the brakes move off center again it may be because those bolts weren’t adequately tightened…or the threadlock compound has been worn off. An application of Loctite blue threadlocker will take care of that.