redsnapper Posted May 16, 2020 Share Posted May 16, 2020 I recently bought a used V8 from a guy on the west coast. Although the guy said the wheel was running AOK, once I got it and took it out for a spin I realised something was amiss with the rim as there was a distinct wobble as speed increased. Checking trueness of rim, I find an abrupt 2mm warp as you spin wheel (likely caused by an impact at some point). I got the wheel at a good price and although the guy did not disclose I am not considering the hassle of sending it back or contesting at paypal (with all the attending ugliness). Seems like a good guy based on my dealings with him - he is riding another wheel so he may not even have known about this. My question is, save replacing the rim, is there anything DIY I might consider doing to compensate for this? The wheel is pretty rideable but I noticed that especially on dirt or tailings trails, I have to be much more careful as the wheel seems less stable above 20kph and closer to the edge of control loss. Car tires are balanced with little lead weights (of course this does not fix a bent rim) but I am hoping there may be some kind of similar diy I could try? I was really looking forward to an upgrade from my crappy 9bots but this wobble is a pita :-( I tested my 2 9bots for rim trueness and there was <0.5mm max variation so to me there is no doubt this 2mm variation was not born in the factory. Anyone have any ideas on a diy fix? Also in debugging this, I realise it would be good to have a stand for running the wheel during testing - something that allows you to adjust angle/speed in a controlled way. Surely the "mod-maniacs" (meant in the most complimentary way) have developed something for this purpose? Cheers and thx for any help! Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 I've balanced both of mine with car weights from new as above 15/17mph you could feel the unbalance, after a crude balance it will go all the way to cut out with no noticeable wobble. Does it vibrate if you hold it or use the stand and gradually build the speed up. Balancing may help but if it's not true it may make it worse. Can maybe straighten the rim, if it's a gradual buckle around the circumference then you probably can't, if it's a ding from say a rock or something maybe you can if it an outward bend. A photo would help. I guess do the balance as you can always take the weights back off. Quote Link to comment Share on other sites More sharing options...
redsnapper Posted May 16, 2020 Author Share Posted May 16, 2020 11 minutes ago, Delmeekc said: I've balanced both of mine with car weights from new as above 15/17mph you could feel the unbalance, after a crude balance it will go all the way to cut out with no noticeable wobble. Does it vibrate if you hold it or use the stand and gradually build the speed up. Balancing may help but if it's not true it may make it worse. Can maybe straighten the rim, if it's a gradual buckle around the circumference then you probably can't, if it's a ding from say a rock or something maybe you can if it an outward bend. A photo would help. I guess do the balance as you can always take the weights back off. ya it vibrates. here is a vid showing the gap - https://drive.google.com/open?id=1pkor8WA33OyySB-cTjvT3hdbE53uTX27 not a great vid sry... Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 Video just shows the tyre, is the rim also like that. You can get the tyre straight on the rim, deflate it and pull and push it so it sits equal around the circumference, there should be lines where it's near the rim. The valve also sometimes pushes the tyre out at that point. Quote Link to comment Share on other sites More sharing options...
redsnapper Posted May 16, 2020 Author Share Posted May 16, 2020 (edited) 26 minutes ago, Delmeekc said: Video just shows the tyre, is the rim also like that. You can get the tyre straight on the rim, deflate it and pull and push it so it sits equal around the circumference, there should be lines where it's near the rim. The valve also sometimes pushes the tyre out at that point. Same gap on rim... I'll try tire balancing weights and see if that helps. I fear will be of limited help though... Hard to test since once you place the weight you have ruined the adhesive backing. Logically where should weights go to counter balance a warp - 180deg from the warp point? Edited May 16, 2020 by amelanso Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 I followed this but didn't bother marking it as I just looked for the heavy point. Takes a while to get the wheel in the right place not to overload the kitchen scales and get a decent reading. Balanced mine within a gram and makes a massive difference when running on the stand. Before I would get a noticeable wobble on the MCM5 and the MSuperX above 15 mph (used the app for speed) but now I can take it cutout with nothing, steady as. On the weights I out them both sides but I used anything (bits of metal double sided taped to start with to see what weight I needed) then when I fitted the weights I used some double sided tape on the side that normally shows until it was all done. Then I marked the rim either side of each with insulation tape, removed the weights, cleaned up the rim then did final fitment. I cut then into small sizes that fitted on the rim. Could you also counter the bend by moving the tyre at that point so at least the tyre is true. 1 Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 The reading is multiples less than the weight required due to the wood etc. Mine both read about 14 grams out. Added about 50-60 gram weights. I then show no difference when it was scales. I zero the scales at the valve for reference. Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 You could deflate the tyre and use a g clamp with wood on the true side to try and push the bend out but could be a risk incase It splits the alloy. Quote Link to comment Share on other sites More sharing options...
RockyTop Posted May 16, 2020 Share Posted May 16, 2020 37 minutes ago, Delmeekc said: I followed this but didn't bother marking it as I just looked for the heavy point. Takes a while to get the wheel in the right place not to overload the kitchen scales and get a decent reading. Balanced mine within a gram and makes a massive difference when running on the stand. Before I would get a noticeable wobble on the MCM5 and the MSuperX above 15 mph (used the app for speed) but now I can take it cutout with nothing, steady as. On the weights I out them both sides but I used anything (bits of metal double sided taped to start with to see what weight I needed) then when I fitted the weights I used some double sided tape on the side that normally shows until it was all done. Then I marked the rim either side of each with insulation tape, removed the weights, cleaned up the rim then did final fitment. I cut then into small sizes that fitted on the rim. Could you also counter the bend by moving the tyre at that point so at least the tyre is true. Ahhhh NO!! You made that way too simple.... Redo the video and mix things up a bit. Add a few unnecessary numbers and calculation to scare people off. If too many people see this video everyone will be riding around on nicely balanced wheels. 1 Quote Link to comment Share on other sites More sharing options...
Delmeekc Posted May 16, 2020 Share Posted May 16, 2020 (edited) Not my video. Just found it previously. It made a massive difference on the MCM5, not sure about the MSuperX as did it before I rode it above 15mph. Edited May 16, 2020 by Delmeekc Added info 1 Quote Link to comment Share on other sites More sharing options...
redsnapper Posted May 17, 2020 Author Share Posted May 17, 2020 thx for good vid. i'll give it a shot but in this case the wobble is the result of a rim deformation. theoretically it could appear in balance via this method but worth a shot still... will report bk. 1 Quote Link to comment Share on other sites More sharing options...
h3X Posted May 17, 2020 Share Posted May 17, 2020 If you want to remove the dent in the rotor without splitting the aluminium, you would need to heat it up. This runs the danger of demagnetizing the permanent magnets, so you probably need to remove them first. If I were to do this, I'd remove the magnets and pay an auto rim shop to fix the dent for me. It sounds quite costly though. Quote Link to comment Share on other sites More sharing options...
OneLeg Posted May 21, 2020 Share Posted May 21, 2020 On 5/17/2020 at 2:33 AM, Delmeekc said: Not my video. Just found it previously. It made a massive difference on the MCM5, not sure about the MSuperX as did it before I rode it above 15mph. i am noticing vertical wobble on my MCM5.... I think it is probably the low quality tires.... they are too soft and get distorted? Quote Link to comment Share on other sites More sharing options...
alcatraz Posted May 24, 2020 Share Posted May 24, 2020 On 5/17/2020 at 11:15 AM, amelanso said: thx for good vid. i'll give it a shot but in this case the wobble is the result of a rim deformation. theoretically it could appear in balance via this method but worth a shot still... will report bk. Radial untrue is hard to fix but lateral you can adjust a bit if you find a tool that can grip the rim. I bought a used tesla and the rim looked like crap all wobbly. Now it's fine and no vibrations. Sure it had a low spot but as long as the tire is held on and doesn't have a bulge because of lateral untrue, then it doesn't really matter. Then doing the balancing trick can help to take out the last imbalance. For the rest of you remember that tubes and tires affect wheel balance. Make sure they're mounted nice and center. When they and the rim are near perfect only the valve creates a tiny imbalance. If your tire isn't centered there's no point to attach weights. Also switching the tire (or even rotating it, lets say after fixing a puncture) requires rebalancing unless you remember the position and direction. I noticed that on my tesla with the rim that looks like crap, after just getting the tire centered to within a 1mm precision, there are no vibrations at high speeds. So just don't skimp on doing a proper tire installation. The pro tire installer could even attempt to find the tire's own heavy spot and try to cancel out the one in the rim by installing it 180 degrees from eachother. Then less weights are needed to achieve perfect balance. 1 Quote Link to comment Share on other sites More sharing options...
redsnapper Posted May 24, 2020 Author Share Posted May 24, 2020 1 hour ago, alcatraz said: Radial untrue is hard to fix but lateral you can adjust a bit if you find a tool that can grip the rim. I bought a used tesla and the rim looked like crap all wobbly. Now it's fine and no vibrations. can u clarify? when I spin this wheel there is a 2mm lateral deviation. not sure I follow how to correct? I get the part abt the tire but trueing the rim? Quote Link to comment Share on other sites More sharing options...
alcatraz Posted May 24, 2020 Share Posted May 24, 2020 Lateral you can bend or knock back (carefully, and yes I'm aware aluminum shouldn't be bent). Radial you can't do much about (rim pushed inwards towards the axle). Every rim looks different. I tried an adjustable wrench but I couldn't get a good grip. I ended up using a hammer to knock the lateral untrue into the right position. That is risky because you don't want the shock to go into the bearings or motor. Support the opposite side of the rim on something a bit soft. Ideally you find a solution without impacts. Quote Link to comment Share on other sites More sharing options...
redsnapper Posted August 7, 2020 Author Share Posted August 7, 2020 A happy turn of events puts a positive close on this bent rim saga. The original seller of this used v8 had offered to cover 50% cost of repair which I declined since would have still been quite expensive to ship and replace rim etc. However I recently found an almost new rim for sale on Fbook marketplace from someone parting out a v8 that had recently had the motor replaced. I was able to score the replacement rim at a very good price which the original seller agreed to pay for in full ( in exchange for me doing the labor ). So I will soon have a true rim on this v8 and all will be right with the world! Hats off to the seller - you know who you are - for being such a stand-up guy... Quote Link to comment Share on other sites More sharing options...
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