Different sized tyres.

[Adam4868]

I've some tyres I want to use in 28 sizes.I know my bikes won't take them on the rear as there isnt enough clearance, but the fronts are ok.So is there anything to stop putting 28 on front and 25 on rear ?

 

[Kajjal]

All you can really do is try it and see what you think. In theory you may go a bit slower but have more grip and cushioning.

 

[Salty seadog]

If they fit you'll be fine.

 

[Ajax Bay]

is there anything to stop putting 28 on front and 25 on rear ?

No. ETA: there's nothing to 'stop you' bar the clearance your frame/brakes offer/allow. But bear in mind that one manufacturer's 28 is not the same as another's. And even models differ from the same manufacturers. For example (on a 15mm inner rim width) GP 4 Seasons 28 measure less than 27mm and the GP4000s II in 28 measure as 29+mm wide (at the same pressure - eg 90psi).
Rollingresistance.com gives a steer on measured (actual) v quoted width for the many tyres they've tested.
Also bear in mind that the front tyre carries less load so, for the same width tyre, it will need less pressure (eg 15psi less for a 75kg rider).

 

[Tim Hall]

Put the smaller one on the front, then you'll be riding downhill all the time.

 

[Alfa GT]

I've done this loads of times when I've had tyres that need replacing and I cannot be bothered or afford to. I had a 35mm cyclocross tyre on the front and a 28mm GP4000 on the rear last week and it felt fine! Always prefer to have the grippier tyre on the front though as understeer on a bike is not fun.

 

[Ajax Bay]

Always prefer to have the grippier tyre on the front though as understeer on a bike is not fun.

What's grippiness got to do with understeer, please? On road (ie asphalt/tarmac), is a cyclocross tyre 'grippier' than a GP4000 (I think not)?

 

[Adam4868]

Thanks for the replies I had a 28 strada tyre which will only fit front and ive put a strada 25 on rear.Went out this morning and feck am I slow ! Putting it down to this

 

[Ajax Bay]

strada tyre

Don't know if it's this one:
https://www.bicyclerollingresistanc...-2017-vs-continental-grand-prix-4000s-ii-2014

 

[Adam4868]

Yea that's the one,I've had a pair of 25s on another bike that have been fine fora few years.Had a 28 gumwall one but will only fit front so bought 25 to match.Thanks