Different front & rear tyre width on racing bikes: benefits?

buckles

Looking at Continental's 24mm rear Force and 22mm front Attack tyre combination and wondering if anyone on here uses different tyre widths on the same bike and what the benefits are.

I'd imagine that due to the fact that a higher percentage of the rider's weight is on the rear wheel, the increased air volume of a slightly wider rear tyre makes sense and would be better for preventing pinch flats on pot-holed courses. But why have a narrower front tyre other than to save weight? Given that front wheel grip is really important for fast cornering, wouldn't a wider front tyre (that can be run at a lower pressure than a narrow one) be better for the increased contact patch? Or would this just feel squirmy when turning?

jibberjim

Buckles wrote:

Looking at Continental's 24mm rear Force and 22mm front Attack tyre combination and wondering if anyone on here uses different tyre widths on the same bike and what the benefits are.

It's aerodynamic, because the front isn't protected by the frame, it's fully into the wind and a wide tyre, particularly if it's wider than the rim then it's a fair old penalty.

buckles

How does tyre width affect cornering stability and grip? Would a 28mm front tyre feel stable through a hard and fast turn (e.g. during a crit) or is it best to stick to 25 or lower?

markhewitt1978

The wider the tyre the more grip and cornering ability it will have, also the wider the tyre the lower the rolling resistance so wider tyres are faster in general. However; you pay a penalty with weight (wider = more rubber), and aero.

A balance has to be struck between grip and rolling resistance in favour of the wide and weight and aero in favour of the narow. In the past narrow was king, some pro riders using e.g. 18mm, this has been changing recently with 24mm not being uncommon in the Tour de France.

mamba80

jibberjim wrote:

Buckles wrote:

Looking at Continental's 24mm rear Force and 22mm front Attack tyre combination and wondering if anyone on here uses different tyre widths on the same bike and what the benefits are.

It's aerodynamic, because the front isn't protected by the frame, it's fully into the wind and a wide tyre, particularly if it's wider than the rim then it's a fair old penalty.

how does say, going from a 23mm tire to a 22mm decrease air resistance ? we r not talking about putting a Maxxis 2.35 mtb tire on the front
There is a 75kg > rider in the wind here and a 1mm drop in tire width will make diddly squat - surely its marketing and nothing more ?
the attack tire does use a very sticky compound and has great grip and the extra volume of the rear tire does increase comfort slightly, this is the main advantage of different size tires.

maryka

mamba80 wrote:

how does say, going from a 23mm tire to a 22mm decrease air resistance ? we r not talking about putting a Maxxis 2.35 mtb tire on the front

It's about getting tire width to be the same as rim width. If you're riding a typical narrow rim with 23mm tires, they have the profile of a lightbulb which is less aero. Narrow rims should be ridden with 18mm or 20mm tires to be most aero, but of course next to nobody would race on those around here! So if your preference is 23mm rims, then pick 23mm rims like Hed C2 or Velocity A23.

Tom Dean

Buckles wrote:

How does tyre width affect cornering stability and grip? Would a 28mm front tyre feel stable through a hard and fast turn (e.g. during a crit) or is it best to stick to 25 or lower?

I found racing on 25s that even though the grip is probably better, the feel is rather vague in fast bends. The front felt very soft when out of the saddle on hills. I prefer the sharper feel of 23s at higher pressure.

buckles

Was that on standard (~13mm internal) width rims though?

Tom Dean

Not sure of the of the exact widths but yes, standard fulcrums. How do normal narrow tyres (22-23) perform on the wider rims?

kajjal

Tom Dean wrote:

Buckles wrote:

How does tyre width affect cornering stability and grip? Would a 28mm front tyre feel stable through a hard and fast turn (e.g. during a crit) or is it best to stick to 25 or lower?

I found racing on 25s that even though the grip is probably better, the feel is rather vague in fast bends. The front felt very soft when out of the saddle on hills. I prefer the sharper feel of 23s at higher pressure.

I find the same, just a personal preference.

buckles

Tom Dean wrote:

Not sure of the of the exact widths but yes, standard fulcrums. How do normal narrow tyres (22-23) perform on the wider rims?

No idea myself but you're not supposed to use narrower than 25mm tyres on them from what I've read. You can supposedly get away with using 23mm but apparently there's a risk of damaging the rim if you hit a pothole and the tyre bottoms out. However 23's supposedly spread out to about 25mm on the wider rims so not sure how true that is

Tom Dean

Makes sense. Is anyone routinely using bigger than 25s for road racing?

buckles

I take that as a 'no'... ;-)

Have got 23mm wide rims now but unsure whether to stick with the 23mm tyres I've already got or try 2 x 25mm, or even try a combination of 25mm front and 28 rear. Would be an expensive experiment.

ozzzyosborn206

i would be surprised if many are using 25s for normal racing let alone bigger...?

ozzzyosborn206

madasahattersley wrote:

ozzzyosborn206 wrote:

i would be surprised if many are using 25s for normal racing let alone bigger...?

You'd be quite surprised

What race was this from? i know 25s are used fairly often as lots of new wheels are now wider eg zipp firecrest so they probably fit better. But even then on a forum of amateurs i still doubt many people would be running them unless doing something like Rutland or a race with some pave

maryka

madasahattersley wrote:

ozzzyosborn206 wrote:

madasahattersley wrote:

ozzzyosborn206 wrote:

i would be surprised if many are using 25s for normal racing let alone bigger...?

You'd be quite surprised

What race was this from? i know 25s are used fairly often as lots of new wheels are now wider eg zipp firecrest so they probably fit better. But even then on a forum of amateurs i still doubt many people would be running them unless doing something like Rutland or a race with some pave

I think that was Amstel Gold, but pretty sure most of Orica-GE have them as a permanent fixture

Nothing that steep on the Amstel Gold course! Notice the Garmin guy walking at the bottom. It's Porto Sant'Elpidio I think http://inrng.com/2013/03/sant-elpidio-al-mare-climb/

More on 25 mm tires, http://inrng.com/2013/04/reinventing-the-wheel-25mm/