funkykeyboard wrote:Not sure I said earlier, but for some reason the wobble went away on the front-end. After that, I moved the seatback a further 2 cm, and put the new tyres on, and now the wobble is back again
Can I just double check the fitting of the front wheels? Is it one or 2?
1. It is wheel bearing-washer-spacer
2. It is wheel bearing-washer-spacer-washer
Williamclark77 wrote:Funkey, I don't know if you will ever get those knobby casters not to wobble. There's so many causes for the caster shake that it's hard to narrow down. The first thing I would do, besides swapping them for smooth tires, is what Shirley said and add a wavy washer under the stem nut to add preload to the caster fork.HotColors wrote:Burgerman wrote: I don't get it with slightly lowered tyre pressures even at 15 or 16 mph. And the casters are free to turn. http://www.wheelchairdriver.com/BM3-con ... /15mph.mp4
Wow, 15mph looks fast from that video. And you are chin pressing a camera and holding a phone. Are you sure you are not a stuntman? Looks really smooth though.
Mike
15mph doesn't sound fast until you're doing it in a motorized recliner.
I believe this is after I geared mine down to 12ish mph.
http://www.willsjunk.com/Other/WillChai ... -MNZFRpG/A
Burgerman wrote:No idea. All depends how you built it.
Burgerman wrote:Looks to me like you have the caster barrel tilted at an angle because the rear is too high.
yes this is spot on, my experience too.inglegrump wrote:I had a huge problem with castor shake on my RWD chair at 6mph which, once I realised (prompted by BM) that the cure was not to put more weight onto the castors but less. I moved my seat back as far as it would go and I drive with the seat tilted slightly and the problem was cured. The chair is also actually better to drive slowly indoors as now the drive determines where it goes and not some dubious grip on the castors.
Burgerman wrote:It depends what we are talking about.
Wheel or caster bearing?
Wheel
I use 10mm axles, drilled and tapped and this goes through the fork as well.
So its Countersunk stainless Bolt > Flat countersunk washer > fork leg > Spacer > bearing > spacer > bearing > spacer > fork leg, countersunk flat washer > countersunk stainless bolt...
Burgerman wrote:Yes axle 2mm short. Spacers should be one either side and one between bearingsin the wheel. No movement it should be clamped tight, and spin very freely.
Burgerman wrote:Looks to me like you have the caster barrel tilted at an angle because the rear is too high.
sorry to hear that mate. Hope things get better for you soon.Burgerman wrote:No idea, stuck on bed. Do it the same as a stock F55 chair to keep caster barrel 90 degrees to the ground.
Burgerman wrote:No idea and stuck on bed. If yours is too high you will get caster shake issues... I can get a finger between tyre top and frame rail once tyres are properly inflated at 8 psi. A bit less than that picture suggests.
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