MX5 Racing - Achilles 123S - 205/40/ZR17 Review

[mx5racing]

At last Mondays club track day we were able to do some back to back testing of the Achilles tyres. I started the day with some well worn Toyo R888's. I've never been overly keen on the Toyo preferring the Kumho v700/v70A instead. That said for what we use our cars for the Toyo has been the best from a financial/wear perspective. Times on these have been Kumho 1.09:79 and 1.10:64 on the Toyos. These were also 2 different days so weather and track conditions need to be considered.

We began Monday with the worn R888's and over 2 sessions I managed a 1.11:4. We then fitted the Achilles for the afternoon sessions. Initially we started with 27 on the RH and 26 on the left. The 1st session ended with 32 on the LH, 30 on the RHR and 34 on the RHF. We adjusted the tyres to 32 all round and began the next session. The front end was very good but the rear a tad looser than I'd like. On the run adjustments via the EDFC managed to dial this to a minimum but the times did not reflect it. After feedback with David we did some more pressure adjustments and knocked them back to 31 front and 29 rear. This improved the balance even more. By this stage the track was not in the best condition and I did a 1.12:7. Time ran out and we packed up for the day.

Couple of interesting points is the rolling diameter of the tyres is less than the Kumho so we were able to use higher gears (5th down the straight, 3rd onto the straight, 4th across the top) and this took a few laps to get the balance and flow again. Under brakes they are not as grippy and therefore need an extra metre or so to retard the car enough to get the apex. Keep in mind they are a 205 not a 215 so a lot of the balance/drive issues could be related solely to this. They don’t have a very square edge (like the Kumho) so this also reduces the footprint. Additionally the side wall is stiffer than the other tyres so flexing and tread block movement is reduced which in turn reduces the heat transfer for short supersprint bursts. That said the 1st lap was a tad light in the bum but after that I was up it for the rent. In a race warmup the heat generated should be fine.

So from my point of view the conclusions are - I have no hesitation recommending them to anyone wanting an R spec tyre at a great budget price. They are nice and progressive so you will learn excellent car control with a forgiving tyre. From a cost vs performance they win hands down so much so I spoke to Mania and ordered enough for all our NC's. Although lacking the total grip of a Kumho or Toyo for our cars and my driving style I'd class them 90% there. At less than 35% of the price they'll do us. We are running all our cars on them at the MX5 Challenge events, including this weekend at W/Park. I'm confident that with some small set up tweaks we can get them into the 11's which will be competitive enough for us.

Time will tell what they are like with regards to wear and heat cycles, and wet weather grip but I look forward to a lot of on track fun with them!!

[hamx5ter]

Thanks for the fantastic review Chris... i was planning to drop the rear pressures for my next attempt on the track, to try and sort my tailyness and your feedback is perfectly timed...

For me, I found 30 hot felt just right, perhaps a little taily, but certainly a good start for me. This is with 195/50R15's anyway...

i was going to use 30F and 29R hot to see if the rear would stay down a bit more the next time around (chucking in my numbers to get some feedback from the experts )

Will find out how my experiments end, but having fun so far...

btw, the SE Tower Brace i picked up off you on monday fits perfectly on my NB8A....

Also, I'm a little bit more than drunk, so please ignore all the posts...

[mx5racing]

MX5 CHALLENGE 24/25 October Wakefield Park

Since the previous weekend we had fitted the Whiteline front bar and
set the rear bar to full stiff.

The Saturday was about 26 degrees and the start pressures were 24
psi. We set the front bar to full soft and ran the front shocks at 6
clicks. The rear bar was on hard. The first couple of laps were quite
good with the balance neutral. By the 3rd lap the pushing was back and
the rear very loose. Pressures were around 29 on the LH and 28 on the
RH. I set the rear bar back to the centre position and set the
pressures to 28 hot to try. The balance was much better and they
lasted for quite sometime before dropping off. 3rd race I set the EDFC
to 6 in the front and played round with the rear as the grip changed.
Sunday began much cooler and decided to drop the pressures
substantially. We ran at 24 hot front and rear. Front shocks were set
to full soft (zero) and rears to 6. Tyre squeal was almost non
existant and the car very consistent straight from the get go. I managed
a 1.12.5. What we have found with our testing is the tyres like a very stiff
set up and low tyre pressures. Wear has been excellent.