Latex inner tube sizing


So I am riding a month in Calpe in February and would like to ride with 32mm tyres (GP5000) to get a bit more comfort (Riding an SL7) on some of the roads there that can be a bit shitty.

I am a bit unsure though on inner tubes.

I am currently running these inner tubes with my 28mm GP5000:

Would they work with 32mm tyre as well, or would I need to buy this larger size for 30/38?

I’d get the larger size and perhaps use the smaller ones as get me home spares. My GP5000 32mm come up 34 mm on my rims

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Thats my thinking as well, but there must be a limit before they can fail more easily etc.

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So possibly relevant anecdote - I run latex tubes and 28mm tyres on tubeless ready rims (i.e. ones with a channel in the middle). Had a double puncture day recently and borrowed a butyl tube from a friend which turned out to be a 20-25mm tube. Couldn’t get the tyre to fully seat with it despite pumping up about as high as I was comfortable with using CO2 and then topping up with minipump with no gauge. Good enough to ride home on but could both see and feel (small bump with every rotation while riding) that there was a section of bead that wasn’t quite right.

Swapped the tube out when I got home and put a 25-28mm latex one in and sure enough the bead popped right into place at around 60-70psi as normal. My not very scientific (with hindsight should at least have got the track pump on the butyl tube to check what pressure I’d put in there at the roadside and test whether higher pressure would seat it) N=1 conclusion was that the smaller diameter tube might have been at least partially responsible for the difficulty seating the bead. I can’t quite see how this would be since even at 50psi I can’t imagine a butyl tube (and certainly not latex) would be doing anything other than expanding to fill all available space. But since even latex tubes are relatively cheap in the greater scheme of things I decided to make sure both the tubes I’m running and any spares I carry are appropriately sized for the tyres I’m using.

I used to hand make 650c latex tubes for Jr athletes who needed them. (I never stopped doing that but the jr athletes eventually grew into 700c wheels) Because resources can be limited & you can’t make a 650c latex tube at the drop of a hat, we had to run 25/28 width tubes in 30mm tires.

Never had a problem. Latex tubes will expend to fill up anything.

I think it will be OK but be sure to give it a large trial period before it really matters on race day.

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I wish you would have checked the pressure when you got home. I recently had a similar experiencing but was able to get it to seat with a floor pump when I got home.

Maybe. I did use CO2 before the pump and that normally does the job. And my pump claims to go up to 120psi and I know from previously checking with a track pump that it’s got me up to ~90psi before (narrower tyres). Possibly just one of those things, also entirely possible I overlooked something given that I was on my second puncture, already fed up, and just wanted to get home!

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I’d go smaller rather than bigger. They’ll expand just fine and they’ should be easier to fit without getting trapped under the bead on installation.

Agreed, especially with latex.

They should all just expand to fill in the volume of the tyre.