frostyllama Posted May 17, 2022 Share Posted May 17, 2022 Just picked up a used kingsong s18. After driving it a while noticed a thudding noise particularly on hard deceleration. Occasionally it will start thudding on acceleration from a stop, if I hop off and start again it tends to go away. I've inflated the tires and suspension system. Concerned it may be the hub motor. Looking for any recommendations for diagnosis/repair. 1 1 Quote Link to comment Share on other sites More sharing options...
Whalesmash Posted May 17, 2022 Share Posted May 17, 2022 Mine did this. Took the wheel apart, cleaned out the bearing area around the axel and then made sure the axel nuts were really tight. Issues went away after I did that so I'm not sure which resolved it. Quote Link to comment Share on other sites More sharing options...
frostyllama Posted May 17, 2022 Author Share Posted May 17, 2022 I'll try that before replacing the hub motor. It sounds an awful lot like fender rub and will pick up randomly sometimes 1 Quote Link to comment Share on other sites More sharing options...
meepmeepmayer Posted May 17, 2022 Share Posted May 17, 2022 Maybe just some screws are loose. Just disassemble a bit, check that everything is tight (especially around the motor-rest connection), and maybe you see something. Quote Link to comment Share on other sites More sharing options...
frostyllama Posted May 18, 2022 Author Share Posted May 18, 2022 (edited) It seems to be a lot more prevalent with the suspension set to open. It's possibly the shock dropping too far causing fender rub. It is inflated to 200 hi 100 low but might need more pressure or the shock might be failing. Here's a video: https://photos.app.goo.gl/sBCbWXf4rhnu7r4M7 The blue ring appears to be 2/3 the way down, so not bottomed out Edited May 18, 2022 by frostyllama Quote Link to comment Share on other sites More sharing options...
Tawpie Posted May 18, 2022 Share Posted May 18, 2022 That sounds like something is rubbing on your tire? 1 1 Quote Link to comment Share on other sites More sharing options...
mrelwood Posted May 18, 2022 Share Posted May 18, 2022 Yeah, definitely a tire rub. The fender sits in quite loose on the S18, and is sometimes bent from the suspension compressing. Whether it affects the rubbing or not, you might be riding too low on the suspension. If you fill the shock with the block method, 200/100 is very deflated. There won’t be much pressure holding you up once the block is removed. We once put something like 280/50 with the block method to get a good response for a 75kg rider. Quote Link to comment Share on other sites More sharing options...
frostyllama Posted May 18, 2022 Author Share Posted May 18, 2022 I've been using the block method, that must be it. I'm close to 100kg. Tried it with increased pressure close to 300/100 seemed to dramatically help the problem, may just be a little too heavy for open suspension on the wheel 1 Quote Link to comment Share on other sites More sharing options...
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