The attached pictures show some parts of a swing arm I am building for my new sidecar frame. The sidecar body will be an International but because I intend to connect it to a Yamaha V-Max, I wanted to re-build the International sidecar frame including its swing-arm, wheel spindle, and a 15” Centerline wheel. When complete, the sidecar should weigh around 200 pounds which should make the sidecar more compatible with the 620 pounds of the Yamaha V-Max.
The attached pictures show the steel swing arm bracket (with the swing arm axle installed but without the swing-arm which is visible in the back of the bracket itself). Obviously the bracket holding the swing arm will be welded on the sidecar frame through a steel plate that I have already welded on the tubing of the frame.
However, before I weld the swing-arm bracket on the frame, I would like, by means of a road test, to determine the ideal toe-in for my International/V-Max rig. The idea is to use two 5/8” bolts to temporarily fasten the swing-arm bracket to the frame (the bolts should hold the swing-arm bracket on the sidecar frame bottom plate) therefore allowing the swing-arm to be slightly moved in or out from the initial toe-in set-up of, let’s say, 3/8”). Once the preferred toe-in is reached, the swing arm bracket will be welded to become part of the frame itself.
I have attached two pictures with the approximate locations of the two 5/8” bolts to fasten the swing-arm bracket to the frame. The base of the swing arm bracket is about 3.0” in width and 5.0” in length. One of the two bolts holes will be oval in shape to allow the necessary movement of the swing-arm bracket in reaching the desired toe-in.
I would appreciate ANY suggestion on my “toe-in” adjustment idea.
Thank you
Piero Bassi
Minneapolis, MN
I would sugest setting tow in at "0" none. Ride the rig and adjust tow in untill it feels right. No wondering, goes down the road stright.
Yes! I can do that. However, what do you think about the 5/8" bolts? Would they safely hold the "wheel" for the time of a short road test at low speed?
Piero
Don't Know about the bolts. I would give some thought to making tow in / out part of the lower front attachment as with a volorex (sic) That way you can make changes in tow latter if needed.
I would suggest solidly attaching (welding) the swing-arm tower in alignment with the bike side frame tube of the sidecar chassis.
Any toe-in and lean-out adjustments should be accomplished with adjustable mounts and struts since conditions of subsequent loadings, road cambers, and sidecar to bike load ratios are variables that can be addressed and compensated for later as they present themselves.
Lonnie
Hello Pierro,Long time no see 🙂
I am not sure what your lower mounts coming off the sidecar frame itself are to be like but assume they well be 90 degrees to the sidecar frame.No matter really but In any case I would suggest that the sidecar swingarm be 90 degrees to your lower mounts and your spindle, both swingarm pivot and wheel spindle, be 90 degrees to that.
Do the toe in adjustments with your lower mounts as is usually the case.....or....fabricate a means to adjust toe in at the sidecar wheel itself. If you try and make the toe in adjustment at the swingarm pivot area you may incur a camber change at the sidecar wheel through bump and rebound actions of the sidecar suspension which may not be good. However, if this is something that you were planning to experiment with then please forgive my ramblings here.
To play with this mock it up on blocks or something with a radcal amount of toe in so things will be obvious and then move the swingarm up and down to see what happens.
5/8" bolts would be more than fine. I would do 3 or 4 grade 8.
Thank you to all of you for the useful suggestions. Due to the nature of my motorcycle subframe and lower mounts with straight eye bolts and clevis (no spherical rod eyes) I will be forced to either guess the toe-in and weld the swing arm tower to the sidecar frame OR bolt the swing arm tower (just temporarily until a satisfactory toe-in is obtained) to the sidecar frame. Both the bike rear tire and the sidecar use square shape automotive tires. In the past, with this type of tire arrangement, I had difficulty to compensate for a non ideal toe-in by leaning out the bike. I'll try to post a better picture of the swing arm tower BEFORE I decide to bolt it on the sidecar frame.
Take care,
Piero Bassi
Minneapolis, MN 🙂
Since you are going to use a square profile tire on the sidecar, I think that a very minimum toe-in would be needed, i.e. 1/4" or LESS. In my opinion toe-in should NOT be used to correct push or pull steering. Steering and road crown correction should be done with the lean of the bike.-
Having said all that, I believe two 5/8" grade 8 bolts would work fine for your experiment. I would use heavy (thick, grade 8) flat washers on both ends of the bolts to increase clamping area to ensure minimum slippage of your swingarm tower during your trials.
George,
I appreciate your suggestions.
Thank you
Piero Bassi
Minneapolis, MN
