Grief Update - Yokohama AD08R tyres and geometry
Discussion
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.
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.
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 s
t. 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.
They do indeed stick like s
t. 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 said:
grippier than a grippy thing on a slippery day.
LOLI 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 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.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...
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 stripFFG
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.http://www.ebay.co.uk/itm/Infrared-Thermometer-Dig...
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.
That is big praise Nick, especially coming from you as I know you have a lot of power in your Chim and know how to drive. Surprising to hear you believe they are better than the R888s, they are supposed to the gold standard. Funnily enough when Ian drove my car at Bedford he commented on how he thought the AD08Rs felt as grippy as the R888s, I thought he was just being kind. Not a bad tyre then it would seem for what is essentially a compromise tyre. I wonder what Yoko's proper track tyre is like then, the A048-R.
mcosh said:
Where did you get the tyres. I cant find these sizes all from one supplier?
Front:http://ears.co.uk/tyres/yokohama-ad08-trackday-tyr...
Rear:
http://ears.co.uk/tyres/yokohama-ad08-trackday-tyr...
That did take a bit of searching. Tyre Leader had both sizes in stock when I bought mine. Same old issues with running the original Estorils, getting tyres are are nightmare!
HarryW said:
A little bit dearer perhaps, but F1 Autocentre has them in stock and the price is all inclusive. Time you pay shipping, fit, balance and carcass disposal it tends to balance itself out imhe.
Yes, agreed. I normally ask my local tyre shop to supply and fit as you are right in saying by the time they have charged for fitting disposal etc it normally isn't far off and I would rather give the money to a local business. In the case of the AD08Rs tyre leader had both in stock but the local tyre shop could only get the 15s in so I got the fronts from them and the rears I supplied and they fitted.
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