sloar 

I bought my mom a Schwinn Town and Country 3 wheeler. Two wheels are the original 24'' S-6 wheels but one was a 26''. The closest I can find to match is a S-7, I know the 7 takes a special tire and the 6 used normal tires. But how much difference will it be and will it be noticeable? I know I can put the 7 on the front so hopefully it should be fine. I hate Schwinn wheels.

curbtender

Best to check the diameter on the old tires and go with that. A 571 to a 597 won't work.

sloar 

I know the tires won’t work, I have S-7 and S-6 tires. I just don’t want the diameter being noticeable while riding.

clubman 

S-6 and S-7 are both 26" tires and are incompatible. S-6 rims will accept S-6 tires, also known as 597mm or EA1 or 26 x 1 1/4 EXCEPT that Schwinn decided to incorrectly label their S-6 tires as a 26 x 1 3/8 which messed up cyclists for the rest of eternity. Look for 597mm bead to be sure.

clubman 

The 571 tires have a higher profile, more appropriate for balloon bikes so the bike may look level but I don't know how you're going to prevent people from noticing. Tell them not to look?

EDIT. I have to admit I'm now confused by your original post. You either have two S-6 rims or not. How can they accept different tire sizes? Oh, a three wheeler. As long as the oddball is the front, it should look fine.

curbtender

I misunderstood your question. If the dropouts work, it shouldn't be an issue. Does it run a front fender?

sloar 

No fenders.