Dangerous Toyo's?

[Chown]

Hi all,

I've just had a pair of Toyo TR-1's fitted to the rear of my Griff and they are scary!!!

I have read threads on here about soft walls, higher tyre pressures and riding like jelly, but these are all amplified on my car.

I have run them in for 100 miles so far but the deformation in the tyre while cornering is huge! Tramlining is terrible and grip quite poor.

I can understand scrubbing them in may help the grip come along but how can this affect the jelly like road holding???

Seriously when on the motorway the rear of the cars "squirms" about, when accelerating the rear squirms and when i try adding a slight amount of throttle while exiting a corner the thing shifts laterally! This is gonna put me in a ditch!!! All this at really quite slow speeds!

I had S03's fitted before which were a tad low on grip but displayed non of the scary traits listed!

My car does sit fairly low and hence about 2 degrees negative camber but with no problems S03's

I have upped the pressure to 29psi but it isn't helping enough.

Help!!!

Thanks all.

[2Munkys]

Chown said:

I have upped the pressure to 29psi but it isn't helping enough.

Help!!!

Thanks all.

You've upped the pressures to 29PSI from what? If they were too high from the start you may be misinterpreting your symptoms and it's actually the ballooning out of the centre tread that's causing the squirming and not movement in the sidewalls. I'm due to replace my rear Toyo's which I've run at 24PSI throughout their life. Looking at the wear pattern would suggest that this in itself is just a tad too high as there's slightly more tread toward the shoulders. I understand most people run them at about 23PSI and I'd consider that to be about right.

[97octane]

Yoiks! I also have new Toyos at the rear, now done all of 29 miles on them, but they do feel a bit lively don't they? Likewise was on SO3s before.
Will check the pressures at lunchtime. I'll have a search this morning if I have time, but there was a thread about this before

Alan

[Paul V]

29 seems very high for a TVR, most tyre fitters pump the tyres up to 28 psi plus, when I got the Tuscan back from having new tyres I had told them 25 psi they still had 35 psi in. The car was all over the place.

[clive f]

mine were very scary at first, but after a coupple of hundred miles they are great, running on 26 psi on the rears.

[Argent]

I have TR1's on my 500, they are well worn in now and handle fine, 22f & 24r.

A.

[tvr4ever]

Had mine for several thousand miles and 2 trackdays, excellent tyre, can't make any comments how long they will last compared to the S03, but things are looking good so far. Maybe your allignment is a bit off from what it should be.

Fred

[Chown]

Thanks for replies all.

I have upped the pressure from 26 to 29, it felt better I think, but obviously unless i tread the exact same roads its hard to tell.

I can't stress enough how scary these are. When i first fitted them i thought wow turn is excellant, when in fact it was the rears shifting giving 4 wheel steering!

Driving down the M6 last night i had to grab hold of the wheel with 2 hands at 70mph! I overtook a Scooby and felt the rear squirm and thought if i hit a ripple in the road the two effects could compound and put me off the road. Ok TVR's are "livley" cars, but not dangereous surely!!

I shall try dropping the pressures to 23, but surely if these tyres have soft walls this will worsen the symptoms.

I'll put some more miles on them too, but i'd rather bin 'em before they bin me!

[dumbfunk]

I replace my S03s with Toyos all round (17's) on my Griff and it took nearer 500 miles to fully rid the rubber of the slippery release agent. I run them at the factory spec 22F/22R pressures - I can't imagine running them at a pressure as high as 29PSI!

Try putting the pressures WAY down, give it another couple of hundred miles and see whether, like me, you end up with more grip in the wet than you used to have in the dry with the S03s!


dumbfunk

[spend]

Its worth doing some research on how to get the tyres cured. Its not just driving around that does it, its about getting them though a couple of heat cycles - not as easy as it sounds unless you are very aggressive

Dave

[V8 GRF]

29psi is way too high. I was running 26/28 on mine and the handling was twitchy. I dropped them to 23/24 and the car is spot on.

[Chown]

Thanks,

I'll do some research, failing that a few burn outs!

I can't see how heat cycles will affect the side walls tho? If at 70mph on a motorway the car squirms then surely it must be the side walls as there is definitely no issue with grip. Similarly if the tyres are over pressured and running on a small patch on the centreline of the tyre, there would still be no grip issue?

We've all had loads of tyres on loads of fast cars, but this is the first time i personally have experienced this!

[Paul V]

Can you be sure it's the side walls flexing and not a grip problem?

[dumbfunk]

Yup. Squirm = slipping I reckon!

[S4CJO]

Also have TR1's on mine, they have twelve months use and handle fine. They are currently set to front 22psi and rear 24psi. The chances are I won't be using Toyo next time.

[Chown]

70mph, steady throttle, admittedly worn tracks in road from where thousands of lorries have passed and having to put 2 hands on the wheel! Summit wrong somewhere. Has happened just on change of tyres so i've ruled out suspension bushes etc.

Combo of low Griff, lots of camber and new Toyo's?

[DarkMatter]

Chown,

My guess is that you now have SO2/3s on the front and T1-Rs - that combination made my Griff scary too, just as you've described.

The solution for me was simple, I changed the front SO3s for T1-Rs (though only 'V' rated available in 15&quot - I was amazed at how much more stable and 'safe' the car felt.

Andrew.

[GreenV8S]

Raising the pressure is exactly the wrong thing to do.

The problem is that the tread blocks are squirming under load. This is caused partially because the new rubber is a soft compound made even softer by being only semi-cured, partially by the fact that the tread blocks are so tall.

You need to cure the tyres, and when you've done that drop the tyre pressure to a more sensible level (probably nearer 22/24 psi).

To cure the tyres you need to work the tyres hard enough to feel them squirm but not actually slide them, and you need to keep this load up by firm acceleration/cornering/braking for 10-15 minutes. By the end of this the tyres should be up to around 50C, which is painfully hot to the touch but not hot enough to burn. Once they've up to temperature, let them cool down naturally over an hour or so. You can repeat the exercise if you like. Each time you do it the effect will be smaller - it's the first one that matter.

29 PSI is way over the top for these tyres and certainly contributing to the problem, but you will find the tyres distort more and heat up more with this excessive pressure in so you may want to leave them where they are until you've cured them. In the winter this can be the only way to get enough heat into the tyres to cure them, but in the summer you should have no trouble getting them up to temperature even if you run the correct pressure.

Edited by GreenV8S on Monday 13th August 13:36

[Else]

I fitted T1-Rs (17" Cerbera wheels) all round and it was as you described, not nice. I found they had been inflated to 35 psi. I dropped them to 20 front 22 rear and it is now very good. No tram-lining at all and a very good compliant ride on the road. haven't tried them on the track yet though.

Andy

[eff eff]

I ran T1 S's with no problems, had a set of T1 R's fitted, car felt like it was on casters. After any sharp direction change the car would give a big shimmy. Checked the pressures 30psi all round courtesy of the tyre fitter!! Reduced to 22 front 24 rear car now stable, turns in and doesn't weav about.