Newbie tube question!

[MetalPig]

Hi all, bear with me

I recently replaced the old Bontrager tyres on my road bike (because one had a big slash on the side wall) with some new schwalbe luganos, the same size 700x23c. Now, to the tubes... the old ones were 700x20/28 but seeing as one of these was damaged beyond repair, i got two new ones which are 700x18-23. I saw straight away that they are a bit thinner when inflated than the 20-28's and when i put everything back together, even though they are inflated to 120psi, there is a bit of "give" in the tyres, especially the back one when i sit on it. I went on a quick 6k ride last night and it definitely feels "softer" than before (the old bontrager ones were rock hard at 120psi).

So... will this cause a problem? Is it due to the luganos being a more supple tyre, or is it the inner tube which is not filling the gap inside the tyre properly (even though its the right size!) and i should buy some more that are a bit bigger? Sorry if this sounds a stupid question lol

 

[the_mikey]

There should be some 'give' in your tyres, I wouldn't see it as a problem. Trust me, at 120psi that tube is filling any gaps that were there. Personally I would use a lower pressure: 100-110 psi. What is the maximum pressure printed on the sidewall?

 

[MetalPig]

Thanks for the reply

Well the tyre actually says max 130psi, which i've never seen anywhere before! I nipped out and bought two new tubes this afternoon and they are 20-28c, put them in and the tyres are a touch harder but not by much. Maybe it is just me being used to the older tyres over the last few weeks (they had no give at all) and i'm worrying about nothing

 

[Gravity Aided]

There should be a certain amount of deflection when weight of the rider is put on a bike, but this should not exceed a few millimeters. Do you have presta or Schrader tubes and rims? It is my belief that prestas are more suited to the higher psi.