dabac said:Hi guys,
I've got an old (apparently roadster-style) bicycle that needs new tires and tubes. Tire size according to the old ones is 27 1 1/2 (40x609). The most easily accessible LBS sells a combination tube for the sizes 27-28 (32x622-44x635).
Now I've occasionally come across bikes that have given a bumpy ride because the tube have actually been folded double somewhere in the tyre, so I'm a bit wary about using a tube that potentially could be too long. Would I be able to/better off using a standard 26" or MTB 26" tube instead? (584/559 mm)
Well, 27" is ISO 630 mm, and SHeldon Brown doesn't list other sizes for 27", nor anything that goes with 609 mm. I would suggest that you double check the tire, or that you compare the rim with a 700c rim (ISO 622 mm), which should have a larger diametre by 8 mm.
Normally tubes are the same for 700c and 27", so go for 700x30-40 if you want a lightweight tube, or 700x35-45 if you want a beefier one. The tire will be different. I don't remember seeing 27 x 1 1/2" in our LBSs, but that size wouldn't fit on my bike anyway. OTOH, I haven't seen your rim, but 27 x 1 3/8" would fit the same rim without problems (if that wheel is 630 mm). OTOH, you can't fit a 700c tire on a 27" wheel.
