Grief Update - Yokohama AD08R tyres and geometry

Grief Update - Yokohama AD08R tyres and geometry

Author
Discussion

MPoxon

Original Poster:

5,329 posts

172 months

Tuesday 23rd June 2015
quotequote all
Since enjoying Griff on the track as well as the road I have found that the Toyo T1R tyres do not seem to perform very well on the track. I really rate the Toyos as an all round tyre on the road but unfortunately they overheat and melt when exposed to constant cornering forces.



I did not want the hassle of having another set of wheels for the car for track day use only as I only do around 2-3 track days a year. After doing some research online two tyres seemed to get continue praise, the Toyo R1R and the Yokohama AD08R. I noted that the Toyo R1R only starts off life with 6mm of tread and the AD08s start with the full 8mm, I am not keen on the idea of paying for a tyre that does not have a full 8mm of tread so I went for the AD08Rs.

I could not get the AD08Rs in the same sizes I had on the car originally so using an online tool I calculated the rolling radius of the wheel before and after to get as close as possible to the original. I ended up with the following sizes which so I am lead to believe were the sizes used on some of the early non-PAS Griffiths.

Front – 205/50 R15
Rear – 225/50 R16



I had the tyres fitted at my local garage an immediately after driving out I noticed how much better the car felt on turn in, I was always a bit disappointed when I swapped from the OEM Bridgestone SO1/SO2 tyres to Toyos as the sidewalls did not feel as stiff and reading up this is a common complaint. The AD08Rs have a Kevlar reinforced sidewall and this for me was reminiscent of the feel of the old Bridgestones. The feel of the car and grip was also very encouraging, I normally hate having new tyres as the car feels a bit squirmy and unsettled on new thicker tread, I tend to prefer tyres once they are half worn, these new tyres did not feel too bad at all.

My only compliant was that I could feel the geo needed to be addressed as the car was not pulling straight on acceleration and had a tendency to wander to the right on a trailing throttle.

I booked a session with Super Tyres in Maldon for a 4 wheel alignment and geometry.



The initial read out from the hunter system showed that the geometry was in need of some attention.



I provided my own settings which I found on the PistonHeads forums many years ago and I have used ever since:

TVR Geo – Neill Anderson
Front & rear camber 0.75 to 1.25deg negative, as equal as possible side to side
Front tracking (toe) 10 to 20 minutes TOTAL ACROSS AXLE (5 to 10 minutes each wheel)
Rear tracking (toe) 4 to 6 minutes EACH WHEEL (as equal as possible side to side)
Front castor 4.75 to 5.25deg Positive (more important that each side is within 0.5deg of the other)

NOTE: As the front and rear wheel alignment are adjustable independently, but only the front wheels are connected to each other (by the rack) it is important that the pair of rear wheels are aligned to the nominal centreline of the car and not just to each other. The castor is not usually adjusted, the spacer at the upper ball joint is simply to ensure adequate clearance at the full extents of negative camber adjustment.

A couple of hours later the car was dialled in and the final read out looked good.



I took the car for a spirited drive and what an improvement, car pulls straight on acceleration, the tyres stick very well once they have some heat in them, turn is much improved. At the recent track day at Bedford the tyres were epic and the car felt really well balanced.

FlipFlopGriff

7,144 posts

246 months

Tuesday 23rd June 2015
quotequote all
Good news Matt.
I have the same size R1R's now on the precat and they stick like st to a shovel. I think the original pre cat sizes were 205/55/15 on the front but were 225/50/16 rear.
Just need to get on the drag strip to see if my times improve.
FFG

carsy

3,018 posts

164 months

Tuesday 23rd June 2015
quotequote all
Nice one Matthew thats good to know thumbup. I certainly could do with something stickier than my Continentals now i have the 5 litre.

MPoxon

Original Poster:

5,329 posts

172 months

Tuesday 23rd June 2015
quotequote all
They are very good indeed - Paul your drag times should increase by a fair bit if you can get enough heat in them from the burnout.

They do indeed stick like st. This is a frame from my recent track day. 3rd gear flat out the long corner, tacho is coming up to 6k so just short of 100MPH pulling 0.8G- iPhone GPS lags a bit.

The tyres pull 1.1G all day long. 1.2G they loose traction as I found out.


HarryW

15,150 posts

268 months

Tuesday 23rd June 2015
quotequote all
Great to hear the positive report. I've just fitted a set to the Cerbera, albeit 235/40/17 & 255/40/17.
Like you I really like stiff sidewalls and hark back to when Bridgestones were the road tyre for that. I even binned an almost new set of Goodyear F1's for another set of B's on my old V8S at one stage as I felt them dangerously wobbly, tucking under even at slow speed.
On the Cerb I found that Falkens had a good sidewall, if not the ultimate grip and was happy as that was the most important aspect to me, hate it when you can feel the tyre tucking under even on road driving.
I'm unlikely to track the Cerbera in the foreseeable, but again like you, I was pleasantly surprised at how good these AD08R's are out of the box, virtually squirm free after a few miles and grippier than a grippy thing on a slippery day.

MPoxon

Original Poster:

5,329 posts

172 months

Tuesday 23rd June 2015
quotequote all
HarryW said:
grippier than a grippy thing on a slippery day.
LOL

I think it might actually been one of your posts that I read that sealed the deal on the AD08s. There does not seem to be many people in the TVR world running these tyres, most I know in the market for fast road / occasional track day tyre seem to go for the Toyo R1Rs. I remember reading a post from a guy with a Cerb who had fitted AD08s saying how good they were.

You will be even more impressed if you take you cerb to the track - get some heat into them and they are epic! I put my hand on the tyre when I came into the pits and they were actually sticky. Love these tyres and if it was your post I read then thanks for posting as I am more than happy with my purchase!

leerdam23

606 posts

260 months

Wednesday 24th June 2015
quotequote all
Hi Matt

Next time you are out on track, check the tyre temperature distribution, ie are they hotter on the outside or the inside... I still think you have too much camber on the back (hot on the inside?) and not enough on the front (hot on the outside?)... IMHO

Have you got pic's of the tyres after the day on track...? Can tell a lot from that too...

Edited by leerdam23 on Wednesday 24th June 11:42

flipflopgriff

7,144 posts

246 months

Wednesday 24th June 2015
quotequote all
Bit cheaper than the R1R and more availability. The treadwear is 180 as opposed to the softer 140 R1R. Matt - they are V rated so you need to tell the insurer, which i'm sure you already have.
FFG

QBee

20,904 posts

143 months

Wednesday 24th June 2015
quotequote all
leerdam23 said:
Hi Matt

Next time you are out on track, check the tyre temperature distribution, ie are they hotter on the outside or the inside... I still think you have too much camber on the back (hot on the inside?) and not enough on the front (hot on the outside?)... IMHO

Have you got pic's of the tyres after the day on track...? Can tell a lot from that too...

Edited by leerdam23 on Wednesday 24th June 11:42
Matt, if you don't have a digital thermometer either borrow mine at the next TD, or get one off Ebay. I bought one like this one - there are two types, and the cooler ones (mostly up to 320C) don't go hot enough for all applications.

http://www.ebay.co.uk/itm/Infrared-Thermometer-Dig...

MPoxon

Original Poster:

5,329 posts

172 months

Wednesday 24th June 2015
quotequote all
leerdam23 said:
Hi Matt

Next time you are out on track, check the tyre temperature distribution, ie are they hotter on the outside or the inside... I still think you have too much camber on the back (hot on the inside?) and not enough on the front (hot on the outside?)... IMHO

Have you got pic's of the tyres after the day on track...? Can tell a lot from that too...
Hello sir, yes I will check that at the next track day, thanks for the advice. The camber on the back it quite severe so I may get them to dial it back to about 1 degree next time.


flipflopgriff said:
Bit cheaper than the R1R and more availability. The treadwear is 180 as opposed to the softer 140 R1R. Matt - they are V rated so you need to tell the insurer, which i'm sure you already have.
FFG
Yes insurance company notified, thanks for the heads up always good to have these things in writing. So in theory then your R1Rs should be grippier still if they are softer. I would be interesting to hear how you get on with then at the strip

QBee said:
Matt, if you don't have a digital thermometer either borrow mine at the next TD, or get one off Ebay. I bought one like this one - there are two types, and the cooler ones (mostly up to 320C) don't go hot enough for all applications.

http://www.ebay.co.uk/itm/Infrared-Thermometer-Dig...
Good shout I will keep my eye open for one of those. I have been meaning to get one for a while to go in the tool box, also good for troubleshooting a misfire and identifying which cylinder is not firing so I have heard.

HarryW

15,150 posts

268 months

Wednesday 24th June 2015
quotequote all
Not for me to say, but I agree about the camber, it's almost if you need the reverse the front and rear readings IMHO.

HarryW

15,150 posts

268 months

Wednesday 24th June 2015
quotequote all
Out of interest was that picture of your previous tyre the front left?

MPoxon

Original Poster:

5,329 posts

172 months

Wednesday 24th June 2015
quotequote all
Afternoon Harry, yes that first picture is the front left (passenger side) after a few laps at Bedford.

HarryW

15,150 posts

268 months

Wednesday 24th June 2015
quotequote all
Being Bedford complicates it, as its counterclockwise no? normally the outside edge takes the battering on cornering, I assumed a normal clockwise track with lots of right handlers! it looks like it's overheated though, what was the front right like?
I'm no expert by a long chalk but hot outside tread of front tyre normally means add negative camber as the dynamic is probably nearer positive. Obviously you have to compromise between road and track driving if you don't want to change it every week or kill the inner edge just with pottling about with lots of camber everyday. If it were me, I'd be inclined to be nearer 2* on the front and around 1* at the rear. If the rear is too low with little or no front to rear rake, as set by adjustable ride height you may have to raise the rear a bit, you may find the rear camber relaxes just with that.
Again all IMHO etc .....

Hoover.

5,988 posts

241 months

Wednesday 24th June 2015
quotequote all
try the Kumho V70A as run by Steve Howard ...... look at his times

HarryW

15,150 posts

268 months

Wednesday 24th June 2015
quotequote all
Hoover. said:
try the Kumho V70A as run by Steve Howard ...... look at his times
I think they start with less than 5mm of tread depth, have a wear rating of something like 50 and slightly less grip in the wet than R888's. I'm sure they are a great track tyre, but the AD08R's are more of a fast road tyre IMHO.

QBee

20,904 posts

143 months

Thursday 25th June 2015
quotequote all
Guys like Matt and me do a few track days a year, but 80-95% of our miles are done on the road.
Good tyre choice Matt. I like Federal 595 RSRs for all the same reasons.

450Nick

4,027 posts

211 months

Thursday 25th June 2015
quotequote all
I've got AD08Rs on my car now - 225/17 on the front and 255/18 on the rear and I have to say they are the best tyres I've ever had - so much better than even R888s, with much less tramlining.

HarryW

15,150 posts

268 months

Thursday 25th June 2015
quotequote all
450Nick said:
I've got AD08Rs on my car now - 225/17 on the front and 255/18 on the rear and I have to say they are the best tyres I've ever had - so much better than even R888s, with much less tramlining.
More goodness for the 08R's...How much power is the SC putting down and have you found they tame the wheel spin of a heavy right foot a lot better too?

450Nick

4,027 posts

211 months

Thursday 25th June 2015
quotequote all
Mine puts down around 400bhp but its very progressive... Wheelspin isn't really a problem and it rarely spins up the wheels, but then again I can quite easily make it break traction if I give it a hoof, but even in spirited driving it pretty much never would without me really wanting to so I'd say they stick very nicely indeed. If you do give it a hoof, an interesting side-effect is that they produce quite a lot of smoke! More than other tyres I've abused smile