gnrboyd

Because I always overthink things......

I have 700c x 32 Continental Gatorskin tires that I use on a Trek FX Hybrid which I ride mostly on a gravel trail. The tubes I have been using are Specialized 700 x 28-38C. Today, I bought some Continental Race that fit 700 x 25-32C (model 0181921) that were on sale.

When I bought them, I was skeptical because the 32 tire is the max size these tubes will fit. The tubes I had been using fit 28-38 and I liked the fact that they would handle a bigger tire. I thought that when I used them in my 32, they would be less expanded therefore less likely to puncture. Because 32 is the top end of the range for this tube, do you feel it is more likely to puncture or am I just overthinking this?

By the way, I do use Mr. Tuffy liners and I also am not concerned about weight savings using a thinner tube.

Thanks for your input.

dsbrantjr

Yes.

Andrew R Stewart 

Generally it's thought that fitting a wider tube results in less stretching as it expands within the tire/rim resulting is less chance of pressure bleed down. Perhaps better in dealing with abrasion from the tire's inner surface. Andy

Tandem Tom

As for abrasion I powder, with baby powder, my tubes before installing. Plus I like the smell!

zacster

If they are spec'ed to 32 then you'll be just fine. It is when you use an underspec'ed tube that you should worry. It may still work but I'd replace it as soon as I could.

gnrboyd

So, it sounds like my theory is correct based upon Andrew Stewart's comment, although likely not a major concern based upon other comments.

(And Tandem Tom, I'm not much for the smell of baby powder, but thanks for the tip.)

Thanks everyone for the input.

jbucky1

In this case, I don't think it really matters, the forming of innertubes / method of manufacture is pretty in-precise from the get go with regard to wall thickness of material that could affect expansion abrasion.

James
​​​​​​​www.buckyrides.com

ksisler

Ditto on that. I have been powdering all my tubes and the inside of my tires since 1974 if not earlier... for same reason. For last 10 years or so, I have switched to powdered cornstarch instead of baby powder as baby powder is now known to cause ovarian cancer in ladies so I don't want it around the shop or on my clothes when going back to the house or tent. Costs the same, so makes sense there also.

JanMM

I stopped using powder on tubes a number of years ago after reading some persuasive arguments that it really serves no purpose. No problems without it. Tubes do sometimes stick a bit to the inside of the tire but pull apart easily.

jbucky1

Kinda off topic but what is the actual science behind baby powder between tube and inside of tyre?

James
​​​​​​​www.buckyrides.com

msu2001la

Maybe I've been under-thinking it?
I use Continental race 28 tubes in both 28mm road 33mm knobby clincher tires. I've used the 20-25 size many times in both of these tire sizes without issues and found no advantages or reason to use the 25-32 size (which is still technically too small for the 33mm cross tires).

The only difference I find is that the 20-25 size fits into my seat bag easier. I usually just buy a few of whichever is cheaper/available at the time.