Bicycle Mechanics - In between tube sizes

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FlatsDomino
06-04-07, 08:06 PM
Hi,
Great forum. I enjoy all the info and the great stories.

I have 700x28 tires and the tube choices are either 700x20/28 or 700x28/35. I'm sure it doesn't make a heck of a lot of difference, but does anyone have a preference when your right in between sizes?

Ride on,
John in Mineesota

MudPie
06-04-07, 09:18 PM
My vote is to go with the smaller of the two.

Right now, I am running tubes for 26x1.9-2.2 in a 26x2.35 tire.

I don't think innertubes are an "exact science". There is seems to be enough elasticity and manufacturing variation in tubes to allow for poetic licensing with tubes. Also, tire sizes seem to vary between manufacturers, and the volume of the void is not exact.
jbucky1
06-04-07, 11:43 PM
smaller :thumbsup:

old and new
06-04-07, 11:51 PM
Good question. With my 28mm Spec. Armadillos the 28/35 (or 32 I forget) fit better than I remember the up to 28s working for 28mm Avocets years ago on another bike. Both worked in each case. I do remember not being quite as sure with the earlier tires with the respective tubes. Anyway 28s seem more like "true" 28s now-a-days, I'd say the bigger MAY have the slight advantage, just my impression, it may not matter much really.
Mach42
06-05-07, 07:19 PM
Go smaller and the tube is stretched out pretty far. Lighter weight, but there's less rubber to protect against flats. Larger and it'd be heavier with thicker rubber all around.

However, I'd say that any flat protection offered by the marginally thicker rubber is minimal, if not nonexistant.
Retro Grouch
06-05-07, 07:44 PM
Given the choice, I always take the smaller of the two. The smaller inner tube is easier to install and is less likely to get caught under the tire bead.

If you think that a slightly smaller inner tube gets stretched out pretty far, try inflating one outside of the tire and see how big it can get.
dynaryder
06-06-07, 12:55 PM
Go smaller and the tube is stretched out pretty far. Lighter weight, but there's less rubber to protect against flats. Larger and it'd be heavier with thicker rubber all around.

However, I'd say that any flat protection offered by the marginally thicker rubber is minimal, if not nonexistant.

Yeah,I usually go with the larger ones for that extra bit of puncture protection. I'm pretty anal-retentive about my tire pressure,so I've never had a prob with pinch flats.