It's never bothered me before, rear – front, correct rotation – incorrect rotation, but now I've swapped the rotation of the rear RRalf tyre on my 26FS after it seemed "out of sorts" on tarmac sections and can report that yes, getting the direction correct has made a surprisingly noticeable difference (on tarmac).

I read somewhere that people run their NNick on the front wheel the "wrong" way deliberately to good effect. True or false?

Hire a professional and stop dicking around?

why else would they make it directional then

Hire a professional and stop dicking around?

A professional tyre swapper?

Tyres rotating the wrong way can only lead to a horrible and bloody death… 🙂

A professional tyre swapper?

All premium users get the use of one….sadly mine is Hora

I've always ran my rear Ralph the same as my front.

Tyres on the wrong way = incapable of negotiating switchbacks on man made trails.

Or so I've heard.

Straight line speed sonny jim, straight line speed.

The only tyre I've ever noticed a difference was a High roller on back to front on the rear, grippier but oh man, how draggy?

Might end up going backwards!

I think some tyres roll better better hence why they are directional and clear mud better.

With CAD design etc, its not a case of making a tyre look good anymore, but actually work better.

It was always to look good with M'cycle tyres! Looks before function.

On the XC routes it made no difference that I could detect, but something was not quite right on my 4hr road rides. Swapping it around and hey-presto it's good news again.

It's made no difference to the front.

Tyres with ramped blocks behave quite differently depending on tyre direction, e.g. High Rollers and Nevegals.

Tyre wrong way round? Thats my own ride excuse 1,004

Four hour road ride on a racing ralph? I'd say it'd be worth your while just investing in some more road going tyres. In answer to your question though, it depends on the tyre. Some are more directional than others. Bonty Mud X for example will make no difference whatsoever, something like a racing ralph, perhaps more so.