First test of Yokohama's A052

[JB21]

I've been dying to get my hands on a set of these given all the rave reviews, and claims of the 'fastest road legal semi slick on the market'.

First impression when the tyres were delivered is they have very soft sidewalls for a semi slick, not much firmer than the Rainsport 5 XL's they replaced on my OE wheels.

Below is the first session of the day at Aintree and they are so, so different from the A048's on my other wheels. Albeit they are different size wheels and tyres on the rear. A048's are 225/50/15 and A052's are 225/50/16.

Its the turn in at the rear which is completely different, you can really feel the sidewall moving laterally which is such an odd feeling as once they set they are very, very grippy.

I only got this session on them so need more seat time with them, I'm going to try and up pressures at Oulton in a few weeks to see if that helps with turn in.

 

[Mr Underhill]

I've been dying to get my hands on a set of these given all the rave reviews, and claims of the 'fastest road legal semi slick on the market'.

First impression when the tyres were delivered is they have very soft sidewalls for a semi slick, not much firmer than the Rainsport 5 XL's they replaced on my OE wheels.

Below is the first session of the day at Aintree and they are so, so different from the A048's on my other wheels. Albeit they are different size wheels and tyres on the rear. A048's are 225/50/15 and A052's are 225/50/16.

Its the turn in at the rear which is completely different, you can really feel the sidewall moving laterally which is such an odd feeling as once they set they are very, very grippy.

I only got this session on them so need more seat time with them, I'm going to try and up pressures at Oulton in a few weeks to see if that helps with turn in.

I used to be a big fan of the A050's until I used the 52s. My first outing was at Cadwell and i hadn't adjusted tyre pressures and camber, resulting in this. That's one trackday. They don't have a reinforced carcass like the 50's so as soon as they hit the wear indicators, they fall to bits.

I got in touch with Darkside Developments who supplied me, who then put me in touch with Yokohama. Essentially i was running about -3.5 negative camber and 30 psi front and rear.

I adjusted the camber to - 2.5 and upped the pressures to 35psi hot as suggested. What a difference. A set used to last me about 3 track days after that and i knocked 2 seconds off my fasted times at Croft. My mates running A050's in the Trackday Trophy currently but tested a set of 52s recently and he was very impressed. Definitely my go-to tyre after that, although 50's are much cheaper, but limited if the track is damp. Good all round tyre.

 

[JB21]

I used to be a big fan of the A050's until I used the 52s. My first outing was at Cadwell and i hadn't adjusted tyre pressures and camber, resulting in this. That's one trackday. They don't have a reinforced carcass like the 50's so as soon as they hit the wear indicators, they fall to bits.

I got in touch with Darkside Developments who supplied me, who then put me in touch with Yokohama. Essentially i was running about -3.5 negative camber and 30 psi front and rear.

I adjusted the camber to - 2.5 and upped the pressures to 35psi hot as suggested. What a difference. A set used to last me about 3 track days after that and i knocked 2 seconds off my fasted times at Croft. My mates running A050's in the Trackday Trophy currently but tested a set of 52s recently and he was very impressed. Definitely my go-to tyre after that, although 50's are much cheaper, but limited if the track is damp. Good all round tyre.

View attachment 1609228

Yeah only ran them 30psi hot as that's what I've always ran my semi's and slicks. I'll up them to 35psi like you say, and see how I get on. Camber is -3 all round so not to aggressive.

 

[shiftspark]

Looked to be going well at Aintree, we didnt realise it was you until after lunch but i left soon after.

 

[andybond]

Yeah only ran them 30psi hot as that's what I've always ran my semi's and slicks. I'll up them to 35psi like you say, and see how I get on. Camber is -3 all round so not to aggressive.

That seems high to me. I run 2bar front 2.2bar rear.

Your better off using thermals on this. The sweet spot is between 40-44 degC on this tyre.

 

[JamesBryan]

That seems high to me. I run 2bar front 2.2bar rear.

Your better off using thermals on this. The sweet spot is between 40-44 degC on this tyre.

That sort of temp must be hard to manage on any normal day surely?

Most track tyres operate in the 60-90c range.

On a hot day you're looking at 30+ track temps alone.

My AR1's are in the 40-50's even after a cooldown lap, measured with a longacre pyrometer.

Not saying you're wrong by the way.

 

[Mr Underhill]

Apologise for giving the wrong info yesterday I said 35psi when it was actually 32 psi.

This is from Yokohama themselves.

"If suspension is adjustable front and rear, then no need to run higher pressure in rear tyres , Maybe try a bit more in the front – 32 psi [2.2 bar] hot, bit less in the rear hot 32 psi same as front."

I would usually run 30psi hot in the fronts and 35psi rear when using A50's.

"When checking tyre tread temperatures hottest should be on the inside, and total difference of inside, middle, outside should be around 15 -20 degrees C. if inside shoulder is too hot it will just wear out quicker – same as you have seen before with the outside [rolling over]."

Simon at Yokohama

 

[andybond]

That sort of temp must be hard to manage on any normal day surely?

Most track tyres operate in the 60-90c range.

On a hot day you're looking at 30+ track temps alone.

My AR1's are in the 40-50's even after a cooldown lap, measured with a longacre pyrometer.

Not saying you're wrong by the way.

Funny you should mention it - I thought exactly the same. I used a pyrometer too and aimed for 40-44 deg C.

Info I got was from here: https://www.adamsandpage.co.uk/moto...working' tyre temperature,is 1.4 bar or 20lbs.

 

[JB21]

That seems high to me. I run 2bar front 2.2bar rear.

Your better off using thermals on this. The sweet spot is between 40-44 degC on this tyre.

I've ran 40psi with Rainsports just to they don't roll over a piss themselves. This is what I'm trying to achieve here, obviously not that high but I'll certainly be aiming higher than 30. Not to worried about tread temps as they've always been spot with the current set-up running various track and race tyres. James has been kind enough to lend me his pyrometer in the past.

40-44 is nowhere near hot enough for proper track tyres, especially full slicks. A052's are an exception as they are very soft and dont really have R rated charatariscts.

 

[andybond]

40-44 is nowhere near hot enough for proper track tyres, especially full slicks. A052's are an exception as they are very soft and dont really have R rated charatariscts.

I agree as a general rule, but as your thread title was FIRST TEST OF YOKOHAMA A052 I thought the information was both relevant and factual in regards to the Yokohama AD052 and not the plethora of other tyres that are not Yohohama A052.

I have always gone for pressure over temp but on these AD052 both pressure and temp are mentioned.

 

[JB21]

I agree as a general rule, but as your thread title was FIRST TEST OF YOKOHAMA A052 I thought the information was both relevant and factual in regards to the Yokohama AD052 and not the plethora of other tyres that are not Yohohama A052.

I have always gone for pressure over temp but on these AD052 both pressure and temp are mentioned.

I get a bit carried away when it comes to tyres 😆