February 5, 20233 yr Hi all, Absolutely loving this community! I really wish I found it before I pulled the trigger on my Swytch kit last year. But, I am where I am. I received the kit this week and frankly, I don't know what I'm doing. And after reading through countless threads here I’m a bit worried about my current options so I’d love some feedback from anyone with experience. Basically I have the new Universal Swytch kit, and (I think) two suitable bikes. Option 1: Kelly’s Cliff Touring Bike (Preferred) On this one the axel fits the dropouts nicely. There is a dimple on the outside of the forks and the torque washers fit it snugly. So I’m pretty sure it doesn't hit this issue. The problem is that even though the width between the dropouts is 100mm as required. When tightened, the shape of the fork causes it to rub against the motor on this side. In red below. And against the disk rotor screws on the other. In green below. I’m confident a washer inside each side of the fork will resolve the rubbing and let the wheel spin freely. But I’m concerned because the fork is already very snug without much tightening. Adding those 2 washers will expand the width of the fork, and based on a lot of threads I read on here, suspension forks are nowhere near as strong as steel/alloy forks. (This is a SR SUNTOUR NEX fork, if that helps.) So… Question 1: Am I being overly cautious in thinking the few extra mm from 2 washers, would be too much/be a safety concern? Or should this/any suspension fork be able to handle this without issue? Question 2: If this extra washer solution is fine. Is there any issue with using a hacked C Washer so that I can apply it directly to the axel on the wire side of the motor cable? The cable will not fit through the plastic bolt cover to let me reorder the current washers. So my option in this case is either use a C Washer. Or else cut the plastic bolt cover, so I can remove it completely from the cable to let me reorder/add the washers. I’m guessing this is a no-no since the cover is to stop water entering the motor. Option 2 - Fuji 1.7 Absolute Hybrid Bike The hybrid fork is also quite snug width wise and will likely require a washer inside the fork to stop rubbing with the brake calliper but its Fuji A1 Alloy fork and not a suspension one. So the expansion doesn’t worry me here. The problem is the dropout width is 9mm and the motor axel is 10mm wide. Swytch’s instructions specifically say not to file anything But when you contact support they just direct you to either join the waitlist for a new wheel with a 9mm axel, or to follow this axel filing video. Ensuring you only file the axel. Question 3: Assuming I follow the Swytch filing video, is it fine to also file the little lip on the torque washers so it fits the 9mm dropout? Or should I look to buy ones that fit a 9mm dropout? Question 4: The torque washer doesn’t fit into the shallow dimple in this case, so I’ll need to add a smaller washer to bridge this gap. But is it important to try match the diameter of that "filler" washer to the diameter of the dimple, or is a gap of a mm or so diameter-wise fine, once the the thickness is thick enough? Thanks! Edited February 5, 20233 yr by mattirl
October 24, 20241 yr Hi Matt, I'm experiencing a very similar issue with the hub rubbing on the fork when tightened. Though for me, it's also pushing on my hydraulic disc brake caliper too. I know you posted this quite a while ago, so I'm curious what solution you managed to settle on? Did you use "hacked" washers to create the clearance you needed? Where there any other resources that helped you navigate the issue? Thanks!
October 24, 20241 yr Hi, start your own thread and include pictures, sounds like your forks are being compressed onto a too narrow wheel hub and perhaps a couple of spacer washers each side or on the disc side only may help? but tbh im out of my depth and this issue is deserving of its own thread and replies.
October 24, 20241 yr The problem is that OP's drop-outs are not fully inboard of the fork legs. Swytch should make it clear that those type of forks are not compatible. Your only choice is to put a 12mm washer inboard of each drop-out. That will probably be OK, though it might make it a bit tight to get the motor in, and a very slight possibility that it might make your suspension a bit stiff. The cable connector will go through the plastic cover. You have to manipulate it a bit, and take the white protective cover off first! When you have 9mm drop-outs, you need to file/grind them to 10mm. We've been doing that for years, long before Swytch ever existed. While you have the file/grinder out, you need to make sure that they're deep enough that the first thing outside the drop-out fits fully within any dimple. It's rare that it would be like that without filing.
October 24, 20241 yr Can't believe those doughnuts recommend filing the hub axle. They seem to be concerned about microstructural defects caused by filing alloy drop outs that could lead to crack initiation and crack growth in the long run. But they are silent about the effect of thinning the walls of the hollow axle where the wires come out. Also there are posts out there showing snapped drop outs which folks associate with filing, though it could be just loose fits and lack of torque arms. For us, non-specialists in structural engineering, hard to know what to believe.
October 24, 20241 yr They seem to be concerned about microstructural defects caused by filing alloy drop outs that could lead to crack initiation and crack growth in the long run. But they are silent about the effect of thinning the walls of the hollow axle where the wires come out. Also there are posts out there showing snapped drop outs which folks associate with filing, though it could be just loose fits and lack of torque arms. For us, non-specialists in structural engineering, hard to know what to believe. Drop-outs on alloy forks break when you don't do the nuts up tight enough or when you have a nut/washer overlapping the lawyers lip (dimple). Filing the drop-outs to make the axle fit properly is very important. For alloy forks, you really need a torque arm for safety. It's not fun when your drop-outs pop and you go straight over the bars onto your face.
October 25, 20241 yr For front forks one has to select suitable forks to work with, typically most have little metal or a gusset that strengthens the drop out. Front shock forks aren't practical for a hub motor so one is best to upgrade to a dececnt steel /chromalloy fork, however folks don't think about putting their safety first so won't spend the money for one. Edited October 25, 20241 yr by Nealh
October 25, 20241 yr I've had to file many a dropout 1 mm deeper to allow the wider 12mm part of the axle remain centered. Was aware of stress fracture issues, so I tried to get round smooth cuts. Have never encountered a 9mm dropout. Don't think I would use one. Removing metal from a hollow axle sure seems "safety last" to me. I get concerned about torquing the nuts up on these motors with half the threads missing. ,
November 13, 20241 yr +1 About getting nervous torqueing up the nuts on motor axles with half the threads missing. Even Sturmey hub gear axles made me think, until I tried to shorten one with a junior hacksaw. And it took the teeth off the cheap saw blade! Besides, how does one use a torque wrench when the motor cable is in the way? hehe
November 15, 20241 yr For situations where I really wanted to use a torque wrench and there was no room....sometimes a crows foot wrench will fit. There's a special way to torque it,
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