Bicycle Mechanics - Different Tyre/Tire sizes back and front

Hi all,

Was going to get some nice "puncture proof" tires (http://www.wheelworxbikes.com/product_info.php?cPath=70_110&products_id=1065) for my Trek 7500 when I was taking down the tire sizes from my current ones and I noticed that I have a 700 x 35C on the back and a 700 x 38C on the front. The wheel was changed on the back last year and it's a different style rim on the back so I assume the different size comes from that.

Does this matter / make any difference?

What do you mean? Are you asking if the different sizes are a problem? Then no, that can be fine. Are you asking because you want to know what size tire to buy? Well, that is up to you and your rims. Rims can handle a variety of sizes. Here is a chart for recommended tire widths:
http://www.sheldonbrown.com/tire-sizing.html#width

Mainly wondering if different sizes were a problem, is the 35C and 38C parts referring to mm? If so I guess I should be okay getting two tires the same ie 700x 38C?

That's perfectly alright.

Go here and scroll down to Mixing/Matching Tires: http://sheldonbrown.com/tires.html#width

Thanks for that, interesting articles on there.


Wider Front, Narrower Rear
A wider front tire makes sense in many applications, however, when handling and ride comfort are considered. A wider tire will generally provide better cornering traction than a narrower one, assuming appropriate inflation pressure.

A wider tire also provides superior shock absorbency. I personally prefer a slightly wider tire in front, since I suffer from some wrist discomfort on occasion.

I think I'll stick with the slightly wider one I have on the front then.

I've been cycling for many years but only started to take more of an interest in maintenance etc. of my bike now, which may have something to do with the town I've moved to and the terrible road conditions! ;-) so thanks for answering the newbie questions.