tyre size

hod65 said:

have currently 27mm tires on my bike getting bit worn if i change to 23mm firstly will it improve speed and would i have to get smaller tubes to suit ...thanks ...

Usually a narrower tire has less rolling resistance than a wider tire, but not always. There are a lot of other factors that effect the RR too, such as inflation pressure, threads per inch, etc. You can probably get away with using your current tubes since you are reducing the size rather than getting larger.

Check with your LBS for tires that have less rolling resitance and they can point you in the right direction. These tires are generally more expensive but they are worth it. Now if they will make you go faster.............😕.

kdelong said:

Usually a narrower tire has less rolling resistance than a wider tire, but not always. There are a lot of other factors that effect the RR too, such as inflation pressure, threads per inch, etc. You can probably get away with using your current tubes since you are reducing the size rather than getting larger.

Check with your LBS for tires that have less rolling resitance and they can point you in the right direction. These tires are generally more expensive but they are worth it. Now if they will make you go faster.............😕.

I would be very careful in using your original tubes previously on 27mm.
A 23mm tyre with say an average pressure 100psi with an oversize will be crowded with your old tubes and you will also have the potential to blow the tyre off the rim, there being too much surface area expanding and having no where to go, the result pushing the tyre off the rim and the tube will 'blow' as a result.
I would suggest based on the quality of the 23mm tyre you fit a quality 700cx20/23c tube the smaller diameter can easily expand and fit snuggly. Obviously if the tyre is of the quality say of a Panaracer Duro/closer, or a Michie Pro2/3 the pressures can be easily accommodated to 120 to 140psi. Again based on road surface conditions and rider weight.

If you can get the tubes to fit there is no problem. The only potential problem is if they are not designed for 23mm tyres then the chances of pinching under the tyre bead are increased. You just need to be more watchfull of this when mounting.

The tyre and its bead are what holds the air pressure. The tube has no structural role to play. A tube will never be responsible for a blow out as long as it is mounted correctly (ie: enclosed completely by the tyre and rim).

tafi said:

If you can get the tubes to fit there is no problem. The only potential problem is if they are not designed for 23mm tyres then the chances of pinching under the tyre bead are increased. You just need to be more watchfull of this when mounting.

The tyre and its bead are what holds the air pressure. The tube has no structural role to play. A tube will never be responsible for a blow out as long as it is mounted correctly (ie: enclosed completely by the tyre and rim).

thanks for info guys