# Ever wonder what happens when you put a tire on the wrong way?

I’d heard the tread on a GP5000 is for aerodynamics. Contis are supposed to test well in the wind tunnel and to do that you need a small amount of tread on the shoulder

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Came here to say this.

Yep that makes sense boundary layer tripping on the front tyre will drop drag. Rear tyre is already in turbulent air. The location of the Conti “thread” is in precisely the right location, just where the air pressure gradient will start to change direction and risk premature separation.

Oh I do take that statement from Jobst with a good pinch of salt. I have a background as a amateur automotive engineer myself. In Uni my combustion lab was located in the automotive block. I got much incidental education on vehicle dynamics from my drinking buddies. Including a run down on the “Magic Formula” which is now lost in the mists of time. One of them was working for Benetton F1 in the active suspension days. His job was simulating the vehicle dynamics for every track in the championship and programming the car setup changes around the course. I asked if he needed the driver at all: “Not really”.

Anyway… Aquaplaning. I suspect that is like cold welding. Something that definitely does happen but more often than not doesn’t and is confused with something else. Back then a buddy of mine ran slicks on his MTB when commuting on it and we got into this very argument. Beer was taken as was umbridge: calculations ensued and my friend was proved to be correct. The force generated by a road bike tyre was an order of magnitude below that needed to aquaplane. Thus defeating the only possible reason for justifying a reduction in the contact patch by using a thread pattern.

Also it is worth stating that the grip in the wet is also a function of the tyre compound. Operating temperatures blah blah blah.

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I follow KTM in the moto GP. One of their riders won recently when he stayed out in the wet and everyone else pitted for treaded tyres. He might have saved time and won the race but it was a b@llsy decision, he was all over the place and the other who lost definitely benefited from tread by not having brown trouser moments

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Not sure how much there is behind it but I know ENVE were saying the tread serves for Aero purposes; conveniently optimal aero needs to say Enve though (though to be fair I think Enve say that the Conti 5000’s are a touch more so). From the old Bike Radar article: Enve enters road tyre market with aero-optimised tubeless rubber - BikeRadar

“Enve claims the tread pattern (which is made up of parts of Enve’s brand logo) has been specifically designed to improve aerodynamic efficiency. It says the tread acts as a ‘trip edge’ that energises the airflow, helping it to remain attached over the transition between the rim and tyre.
It also claims this effect works at the rear wheel too, where the tread helps to close the wake of the airflow as it transitions off the tyre, leading to a smaller low pressure wake behind the wheel.”

I installed these the wrong way, but truthfully wouldn’t know the difference. Been on all sorts of gravel, road, single track with these bad boys. I guess I’ll find out when I need to replace sealant, but it was such a pain to install, there was no turning back.

That was one advantage of rim brakes over disks. With a rim braked front wheel you could of just rotated it

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The real reason is that there’s an overlapping joint in the casing. You want it to get tighter, not looser. It doesn’t really make a difference though. The direction of the tread is pretty meaningless - the tire presses down and comes up, it’d need to be slipping to be pumping anything.

Someone mentioned kart/racecar tires, these tend to get a set shape to them as you heat can cool them repeatedly. Anything you’re doing this to won’t be making competitive traction past 5-10 heat cycles, so those would be practice tires you’re trying to extend the life of.

"The real reason is that there’s an overlapping joint in the casing. You want it to get tighter, not looser. " - do you have a source for that as it relates to bike tires? I can see a similar issue with that type of slip being an issue with the direction that one installs tubeless tape on a rim for example, but in a tire it all seems locked in by the actual rubber compound that is coating everything and calendered in.

FFS I literally posted on this very thread explaining which way round these go earlier this week 🤦

I’ll swap it round when it’s stretched a bit - they’re a right pain fitting when they’re new.

Don’t bother. It’s fine.

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Until I get to a coffee shop

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Learned from my dad a long time ago: Tractor tires have the chevrons pointing forward on the top, so that they are pointing backward where they contact the ground. If the wheel spins in mud, it pushes the mud to the side so that it can contact firmer ground. I’ve always thought that MTB tires use the same logic, but if my MTB wheel spins, I usually need to unclip. Also note that the front tire is used for braking, so you may want it reversed (but I don’t). I can’t say anything about road bike tires.