With both of our 30 hp Stanley cars, they were prone to start hopping down the road at higher speeds due to engines being out of balance. Our 1916 Mt Wagon didn't have too much of a balance problem but the bouncing was still there starting at about 55 mph. Our 1911 model 85 7 passenger touring would start bouncing at about 45 mph and it got worse the faster we went. I installed the 30 HP additional counterweights made by REMPCO of Cadillac, Michigan and they are fantastic. The installation was easy as dropping your Stanley's engine cover. So far, I haven't had either of the 30 hp Stanleys much over 60 mph, but they both are now gliding along without any engine balance vibrations. They are now cruising along something like: "as smooth as silk".

Is the gearing on both cars similar,,,Ben

Ben, The '16 Mt. Wagon is geared 50 to 80 and it has the axle driven slow pumps with the heavier rear axle. The '11 model 85 is geared 50 to 60 and it has the lighter rear axle with the faster wrist pin driven pumps. The heavier Mt. Wagon axle surely must have dampened some of the high speed engine vibrations. Interesting in that the perfect gear set up for these models of Stanleys, the gear teeth should total up to 120 teeth for each vehicles. The Mt Wagon is stretching its engine cover to get all 130 teeth in, and the 85's engine is close coupled with no room to spare with 110 teeth. The left over lengths of engine frame rods are another study. The short and the long of it.......

Pat
Where did you add the weight ?
We have added counter weight using Tungsten rod (slugs) pressed in holes drilled along the outer edge of the existing weight.
Rolly

The added two counterweights are clamped between the main bearing clamps and the valve eccentrics. One on each side and in time with the adjacent counterweights. Thinking back about my model 735 at 60 mph, it could have been a smoother ride with the 20 hp engine having additional counter weights installed. Brent Campbell related that his 30 hp model K was geared so tall that the K's engine never did reach the out of balance vibration speed. I wonder how the Stanley Rocket behaved with its out of balance vibration at 150 MPH?

I had to think about that, where is the room.
I remembered doing a drawing on the type 8 bottom end to see how a SKF bearing could be used.
See attached. Looks like you have almost a half inch. Nice modification.
Rolly

Rolly, Using my stock bearings, the 3/4" thick counterweights fit well and with just enough clearance to spare. When I purchase the counterweights from REMCO, they had counter bored the counterweights to accept the SKF bearings you mentioned. I welded the stepped bores back up and then I re-machined their bores to fit my 2.250" diameter crankshafts. REMPCO made their error right with me. REMPCO are very good people to work with.