Rear tire size, how big ?

[Pooka]

Getting ready to set up my rear wheel and disc brake.
I have an Akront 4.25" x 16", laced to pre '84 hub. I will be running this in a Santee ridged frame, with a pre '65 trans.
I don't know if it's needed info but here is the rest of the drive train.
BDL belt (1 1/2 ) inside the primary covers. '50 FL , 4 1/2" stroke , 3 1/2" bore.
Now , back to the tire size. The frame width is stock and I don't want the bike to look like an Indy car from the rear ! My question is.
Can I run a 180 x 16 ? Or a 150 on that 4.25 rim with out clearance trouble at the trans. sprocket ? Can you spacer the trans. sprocket ?
I can spacer the rear sprocket out to clear the tire.
Oh yeah , I will be using a 25 tooth sprocket on the trans.
Thanks , Pooka

[Pantony]

If you have a stock frame, I guess I don't know how you can run anything but a stock 5 X 16 tire, there is no room where the fender meets the frame, so stock size it should be

[Panacea]

pooka, I don't know what kind of rear brake you plan to use, but with the stock mechanical drum there is very little room to spare. A previous owner switched the stock width rim to a swap meet find which was a half inch wider than stock, so to pull the rear wheel, first I must let the air out, remove the roll bar bolt, and take the drum out with the wheel. And this must be done on a lift, Way more work than a half inch is worth! Mike

[Pooka]

"Getting ready to set up my rear wheel and disc brake.
I have an Akront 4.25" x 16", laced to pre '84 hub. I will be running this in a Santee ridged frame, with a pre '65 trans."

O.K. , maybe I didn't say it right or some thing.
The thing I'm not concerned about, is the tire width.
I can get a 150 in the frame with out clearance problems.
Non stock fender. My worry is the alignment to the transmission sprocket.
Spacing out the rear sprocket to clear the tire is no trouble,
but can I move the transmission sprocket out maybe a 1/4" ?
And like I said before, this is a pre '65 transmission, behind a pre '55
engine, with a closed primary.
Thanks to all for your responces.
post script .
This is a new build. And it's not about getting a larger tire on the rear, it's about the rim I'm going to use. It's a very old Akront aluminum, with the raised outer ring. I'm going to match it on the front with a rim from Sportster rear 18" x 3" aluminum.

[Panacea]

If there is enough thread on the drive gear, perhaps you could trim the teeth off an old sprocket to use as a spacer. Mike

[Pooka]

That might work.