Tyre sizes

[smarttim24]

Quite new to cycling have just brought a Trek 7.3fx which has 700 x 32 Race Lites hardcase tyres as standard. Could i fit thinner tyres on the same standard rims i.e 700 x 28 or 25

 

[John the Monkey]

Depends on the rim size.

Sheldon Brown has a chart about half way down this page;
http://www.sheldonbrown.com/tire_sizing.html
that lists safe combinations of rim width and tyre.

Looking at the chart, 28mm should fit whatever size the rim is - to be sure about other sizes, you'll need to find out the width of the rim (I did look, but no mention of this on the trek website).

 

[HJ]

The Trek website claims the wheels are Bontrager Nebula, 32-hole rims, but I can find nothing on the Bontrager website about them. I suspect that you can get away with 25mm tyres, but it would be best to check with a good LBS before buying...

 

[smarttim24]

Thanks for the advice. Do not know he this is of any significance just noticed is whilst having a closer look at the rims there is a sizing 622 x 15 does this 15 refer to the internal rim diameter

 

[TheDoctor]

I think it must do.