"Canadian" wheel size

I'm not aware of a comprehensive, on-line, tire/wheel sizing chart. I'm aware of at least eight, incompatible, 26" sizes. Start by examining the rim itself for an alpha-numeric designation. The most common 26" rim for this era was EA3. The Canadian 26"rim was F12. EA3 uses a 590mm BSD (bead seat diameter), while F12 uses a 571mm BSD.

In addition to the traditional sizing, current tires carry an ISO/ETRTO sizing designation with format xx-yyy, where xx is the width in millimeters and yyy is the BSD in millimetres. Knowing the BSD of the tire and rim is the best way to determine fit. If your rim has a designation other than EA3 or F12, post it here and I"ll  look up the BSD for you. 

Hi T-Mar,

Thanks for the reply.  Sorry for getting back to you so late.  I got distracted by other projects.

The rims on this suppercycle have no marking unlike most I have seen. They are on a c. 1970s Canadian Tire SuperCycle 3 speed (Shimano 333) hub. The rims don't look well built.  The join is evident and creates a slight radial warp that can't be taken out.

Is there any way I can measure to determine the exact size.  Any chance there would be markings inside the rim (I'll check).

Thanks,

Daryl

p.s.

I did have a 590 on the wheel.  It was seated very tight and difficulr to get on/off.  What would be the next size up?

Thanks and take care,

Daryl

Given the era and make, EA3 / 590 BSD is the most likely candidate. Most of the Supercyle from this era came from either Raleigh or CCM, who favoured the EA3. However, there is always the possibility that it is a replacement rim. The next size up is 597 BSD, which is also a 26 x 1-3/8" tire. It was common in the USA where it was used on Schwinn S-5 & S-6 rims. Consequently, they are not too hard to find.

To determine what you actually have, you can try to measure the rim's outside diameter. 590 BSD has a diameter of 602 mm, while 597 BSD has a diameter of 609 mm. Unfortunately this can sometimes be difficult to measure accurately. Used rims are rarely perfectly round and measuring over the dish of the spokes increases the actual measurement slightly. 

Alternately, you can try rolling the rim one revolution along the floor. Mark a starting point on the rim sidewall with tape and do the same on the floor. Put some sort of reference on the floor to ensure you are rolling the wheel straight. Mark the end point of one revolution with tape on the floor and measure between the two pieces ot tape. A 590 BSD rim should roll out 1890mm over one revolution while a 597 BSD rim would be 1912 mm.

Slight flats or humps in the rim at the joint are fairly common. Sometimes the rim is actually round and the deviation is from inadequate or excessive grinding of the weld. Other times, it actually is out of round. Personally, I tend to ignore it, unless it is noticeable when ridng (or braking if it is equipped with caliper brakes).

I've also noticed that tires are getting harder to mount and remove. While this could be due to better bead material or manufacturers erring on the tight side due to liability concerns,  I've personally attributed it to decreasing strength as I age.

Thanks so much for getting back to me T-Mar.

It was an EA3/590.  It did some measurements and came to that conclusion.  I also concluded it was the weld.  Since it did produce a significant "bump" when riding, I swapped it out with another 590 I had.  The 590 tire fit fine (snug but fine) and the bicycle rides beautifully now.  It has been a day of tires for me.  I am learning to use the ISO(?) measurement more so than the inch designation.

Thanks for the insight into CCM/Raleigh making some SuperCycles. This one was "Made in Poland"  I remember reading somewhere where this was common too.

Thanks for the notes.

Take care,

Daryl 

I'm glad to hear that things eventually worked out for you. The Polish origin suggests an early 1970s, boom era model. When, the boom hit, major suppliers had trouble meeting the sudden increase in demand. This forced many private label brands to seek non-traditional sources, including manufacturers from iron curtain countries.

Thanks.  From what I can put toghether it is a 1973. Thanks for the history.  It really adds to the story of these bicycles.

Take care,

Daryl