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Shimming the Tow Pac wheels
So with this Corona virus thing forcing all of us to stay home, being in the high risk category (old guy with pre-existing conditions) I thought I would put the time to good use and finally play a bit with shimming my Tow Pac cart wheels to be truly vertical (camber)...
Both wheels are off a bit, but the right one ( sitting on bike) was the worst... I didn't take a "before" photo but it was off by about 1 to 1-1/2 degrees Negative camber...
First thing I did was to manufacture some aluminum shims from some stock I had... I purposely made the holes in the shims large to facilitate wheel alignment. See photo below.
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I had previous experience with wheel alignment on the Tow Pac cart and in some cases it is necessary to grind the holes in the plates a bit larger, hence the large holes in the shims... On the right side, it took 2 shims of about 1/8" thickness each to obtain vertical alignment of the wheel... See pics below...
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It was also necessary to fabricate new brackets for the alignment stop screws as seen in the last photo... I will at some point in the future beef these up a bit by welding some additional material to them but I did not want to weld with the cart attached to the bike, so the cold roll plate will do for now...
The end results of the shimming are shown in the photo below...
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After the vertical alignment I did a standard parallel wheel alignment and the right wheel is within 1/32" of an inch or less parallel to the rear tire...
I would have done the left wheel too, but I need 2 additional 5/16-18 bolts for the new parallel adjustment brackets and what with the self quarantine going on here, that will have to wait until the all clear is sounded...
Hopefully, this will end the uneven tire wear from having that negative camber on the tires, and might just improve the high speed fender vibration I experience over 70 mph...
Les
4 Attachment(s)
Shimming Tow Pac wheels part 2
So, re-threaded 2 metric bolts to 5/16-18 and started the other (left) side of trike... First picture shows level before I started...
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Next photo shows fender washers used for shimming which are about 1/16" thick as shown on digital caliper...
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And finally, the finished product as seen on level... Also realigned parallel adjustment to rear tire and is less than 1/32" out... Now, if it ever stops raining, we'll go for a test ride... As it turned out, because the washer was only about 1/16", there was no need to add an extension bracket to the adjustment stop bracket, so I did not need to use the 2 bolts I re-threaded...
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Les
readjust wheel height after shimming
After the reshimming, ( I just added a bit more additional shimming) and test riding, the bike seemed to lean left a bit, and it occurred to me, my height adjustment might be off because of pushing the right wheel further down with the shims... I usually keep the right hand cart wheel about 1/8" to 1/4" higher than the left (additional down force) to compensate for road crown in the right hand lane where I usually ride, but the tilt to the left seemed excessive, so I checked it, and sure enough, it was off... Got that done yesterday... In a day or two, I'm gonna check wheel alignment again ( parrallelism ) just to make sure I didn't shift anything during the reshimming process...
Les