Howdy, just put Metzler 4:00x18 K-Block tires on my 68 R50/2 with Steib TR-500. Really fills out the front fender. The owners manual calls out for 24 to 27 lbs. of air, depending on the position. I have been told to run them up in the high 30 lb. range and I am really unsure about where to set the tire pressure. I have plenty of time as there is over 2 feet of snow and temps. way below zero up here in far north Minnesota. Will higher pressure contribute to steering wobble? I need all the help I can get. First side car rig for me and first BMW. Thanks, Bob
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Tires for R50/2 with Stieb sidecar
- Thread starter fargobob
- Start date
Bob -
I think the manual pressures from yore are for a different tire and construction that we have today. I'm running Metzeler Block C tires on my R69S. I run 32 front and 36 rear. I suspect you should be in the same range...can't offer what the sidecar tire should be. There was something years ago called the 10% rule. That suggested that if your tire pressure increases by more than 10% over a typical run, then the starting pressure was too low...the sidewall is working back/forth too much increase the temperature. On the other side, if the increase was less than 10%, the sidewalls were too stiff and the starting pressure is too high. I don't know if that still holds today for the newer stiffer sidewall tires. In the old days, we had tube-type tires and you could install them with just your hands...can't do that today with the tubeless rubber being used.
I think the manual pressures from yore are for a different tire and construction that we have today. I'm running Metzeler Block C tires on my R69S. I run 32 front and 36 rear. I suspect you should be in the same range...can't offer what the sidecar tire should be. There was something years ago called the 10% rule. That suggested that if your tire pressure increases by more than 10% over a typical run, then the starting pressure was too low...the sidewall is working back/forth too much increase the temperature. On the other side, if the increase was less than 10%, the sidewalls were too stiff and the starting pressure is too high. I don't know if that still holds today for the newer stiffer sidewall tires. In the old days, we had tube-type tires and you could install them with just your hands...can't do that today with the tubeless rubber being used.
Tire pressures with
Thanks for the info on your R69. The C-block and K-block seem pretty much the same. I just got the bike and haven't ridden it 10 miles. Now waiting for spring. It had Avon Road Riders on it, and a low speed steering wobble that scared the daylights out of me. Never did get over 30 mph. Will do tapered steer head bearings as there's a real significant notch at straight ahead. I've had a lot of bikes over the past 66 years. This one is truly unique. I love it! Thanks again, Bob
Thanks for the info on your R69. The C-block and K-block seem pretty much the same. I just got the bike and haven't ridden it 10 miles. Now waiting for spring. It had Avon Road Riders on it, and a low speed steering wobble that scared the daylights out of me. Never did get over 30 mph. Will do tapered steer head bearings as there's a real significant notch at straight ahead. I've had a lot of bikes over the past 66 years. This one is truly unique. I love it! Thanks again, Bob
The difference should just be the shape of the tread...the K-Block is more squarish since you're not leaning over with the sidecar. Yeah, the first thing I did on mine was to remove those ball bearings in the steering stem and replace with tapered roller bearings. It's somewhat of a special size...got mine from Vech at Bench Mark Works...they've been bought out by MaxBMW now.
fmdualexhaust
Member
Been using the 10% rule for 45 years. Still works.
