Tube size - best option?



dabac

Well-Known Member
Sep 16, 2003
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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)
 

mgagnonlv

New Member
Sep 25, 2003
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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.
 

serenaslu

New Member
Feb 3, 2004
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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)
Continental specifies their touring tubes as 609-642 (28/37 slim or 32/47 all)
see:
http://www.conti-online.com/generator/www/de/en/continental/bicycle/themes/tires/tubes/tour/tour_en.html
but I have only rarely seen them.

I also would recommend going for the 700c sizing, as mgagnonlv stated, over the 26-inch tubes. Shouldn't be a problem.
 

dabac

Well-Known Member
Sep 16, 2003
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serenaslu said:
I also would recommend going for the 700c sizing, as mgagnonlv stated, over the 26-inch tubes. Shouldn't be a problem.

I bought the 27-28 combo tube and fitted them. They were a tight fit on my wheels, so it'll probably be OK.

Thanks for digging up the conti data though.