road bike tyres and tubes

paddyb

ok, this may be a really stupid question but ive spent a while googling it and im none the wiser!
I got a road bike recently (Giant SCR 3), I want to pick up a couple of spare tubes and maybe a tyre but im finding the tyre/tube sizes confusing?

the tyres on my bike say 700 x 26 but when I look for tyres, most are 700 X 25 or 23.

Do these different sizes make much for a difference? Does a certain size tyre need the same size tube?

Membrane

paddyb wrote: »

I got a road bike recently (Giant SCR 3), I want to pick up a couple of spare tubes and maybe a tyre but im finding the tyre/tube sizes confusing?

It's worse than you think: http://www.sheldonbrown.com/tyre-sizing.html

the tyres on my bike say 700 x 26 but when I look for tyres, most are 700 X 25 or 23.

Do these different sizes make much for a difference?

700 x 26 vs 700 x 25 shouldn't result in a noticable difference, IF the indicated widths are correct, see the linked article for more on that.

Does a certain size tyre need the same size tube?

Tubes are specified to suite a range of widths, for example these tubes: http://www.cycleways.com/store/product/9577/Sp.-Pv-700X28-38/ are specified to suit 700 - 28 to 700 - 38 tyres.

Mr. Skeffington

Just get 700 x 25c tyres with tubes to suit, there will be no noticible difference between the 25c and the 26c that you have on your Giant at the mo.

Explanation on the sizing:
{700 x 25c} - 700 is the diameter of the wheel, and 25 is the tyre width ( both in mm)

Usually racing bikes use tyres with width between 19 and 23c tyres
Sport Bikes and Hybrid's usually use tyres between 23c and 32c

Personally I use 23c tyres on my road bike and I use 25c on my commuting bike. If you are buying new tyres I would reccomend Continental Gator Skins, they have a kevlar layer and are very puncture resistant.

The other very important point is to keep your tyres at the maximum pressure range indicated on the tyre wall, I reccomend buying a good track pump with pressure guage and that you check your tyre pressure each week. Even if you have no punctures your tubes will loose pressure over time.

paddyb

thanks lads, ill go for the 700 by 25 but just to clarify - in theory I could put any size on (eg. 700 x 23 or whatever) and it would be fine?

Ghost Rider

If you mean the tyres, then yes: all 700 tyres will fit all 700 wheels.

As for tubes, they have to fit the tyre as well as the wheel. (That said, you have a certain latitude e.g. a tube designed for 700x25 tyre may also fit a 700x26 tyre.)

paddyb wrote: »

thanks lads, ill go for the 700 by 25 but just to clarify - in theory I could put any size on (eg. 700 x 23 or whatever) and it would be fine?

Membrane

Ghost Rider wrote: »

all 700 tyres will fit all 700 wheels

No the inner rim width will limit what width tyres you can fit. See the Sheldon Brown link for a guide.

blorg

Membrane wrote: »

No the inner rim width will limit what width tyres you can fit. See the Sheldon Brown link for a guide.

Also, the frame, brakes, and mudguards (if you have them) will put an upper limit on how wide you can go.

Wheelworx

paddyb wrote: »

thanks lads, ill go for the 700 by 25 but just to clarify - in theory I could put any size on (eg. 700 x 23 or whatever) and it would be fine?

A giant scr3 or4,2 or 1 for that matter either will take 700x19, 700x23, 700x25, 700x 26 tyres. Decent branded (Michelin, Vittoria, Schwalbe etc) 700x19-23/25 tubes will fit no problem.
The 700 refers to the diameter of the wheel the 19/23/25/26 is the width of the tyre in mm so a 23mm tube will stretch to 26 no problem.
Rob

Home:Ballyhoura

I have a hybrid Dawes Discovey 201 like this from a few years ago. The rims have no markings (sizing or branding) on them but they just look like a cheap set of ordinary wheels which kind of look like the ones in this picture. My question is, at the moment there are 700 x 38c tyres on it (with a small thread pattern) and I was just wondering if something like a Continental Ultra Gator Duraskin Tyre in the 28c width size would fit ok or even work on a rim like this or would they be too narrow? I will be giving it to a friend for the W100 and want him to have the best chance possible of actually finishing it (considering his partner will be on a full road bike).

Would this tyre change make much difference to the resistance and therefore power needed or is there any other relatively cheap changes you would recommend making to help? It will probably be used as someone's first kind of road bike for longer distance "keep-fit" spins so I would like to make it the most enjoyable experience I can for them without turning them off the sport or buying a new proper road bike (which will probably come soon afterwards!). Alright, let me know what ye think. Cheers!

blorg

700x28s should work fine I imagine.