Outbraked by a Ford Focus...
Discussion
We spent some of today in the Tamora at CAT driver training at Millbrook. We had rearranged our performance driving day from earlier this month when snow stopped play, and today we had perfect dry weather.
Millbrook is a great place with an impressive variety of facilities. The driver training day uses the mile straight for braking and brake / swerve, the high-speed bowl, the handling circuit, the Alpine route, and a big skid-pan with lots of coloured circles of different diameters to follow.
It might use other parts too, but our day ended sooner than we would have liked.
As the TVR doesn't have ABS, we used a Ford Focus to practice some ABS braking / brake & swerve techniques before doing some threshold braking. We then swapped to the TVR which, until now, I have always driven fairly steadily and have not locked up the brakes.
The first stop resulted in a big cloud of tyre smoke as the rear brakes locked up, and the fronts did not. Same tyres front and back, running the same pressure. Further stops over 3 passes down the straight produced exactly the same problem and I was having to limit the braking force to avoid having the rears lock up. The deceleration the TVR could manage without the rears locking was less than the Ford Focus
This is not a stable car setup, and the brake test is a good thing to get done early in the day to check that aspect of the cars handling.
Colin discussed whether we wanted to continue with a car that was not handling properly, or postpone the day until we have the car fixed and then carry on from where we left off. This is very good of him, since it effectively writes-off 2 days of his time for our one day of training.
Before finishing, we went onto the 40m circle, and in both directions increased speed until the car started to lose traction. In this respect the TVR is set-up very well (thanks TrackVRoad) - it goes into very mild understeer when pushed, that can turn into slight lift-off oversteer, or can be balanced out with a bit more throttle.
On our way back we popped into TVR Power and had a chat with Jason. He noted that the rear pads were EBC Greenstuff, and it wasn't clear what the fronts were since the back of the pads is not visible. A mismatched set of pads seems the most likely reason for the brake issues, given the calipers all look in good condition, as do the disks and tyres.
We also discussed the coolant dripping problem and, given its location and a quick examination, he was fairly sure it was the plastic ends to the radiator...
I now have a to-do list of new pads, new tyres, and new radiator before I return to complete my driver training. Based on what we have done so far, I am really looking forward to returning to Millbrook, and am grateful to CAT for being so helpful.
There were lots of interesting development vehicles going round Millbrook. My photo from the day is here.
Millbrook is a great place with an impressive variety of facilities. The driver training day uses the mile straight for braking and brake / swerve, the high-speed bowl, the handling circuit, the Alpine route, and a big skid-pan with lots of coloured circles of different diameters to follow.
It might use other parts too, but our day ended sooner than we would have liked.
As the TVR doesn't have ABS, we used a Ford Focus to practice some ABS braking / brake & swerve techniques before doing some threshold braking. We then swapped to the TVR which, until now, I have always driven fairly steadily and have not locked up the brakes.
The first stop resulted in a big cloud of tyre smoke as the rear brakes locked up, and the fronts did not. Same tyres front and back, running the same pressure. Further stops over 3 passes down the straight produced exactly the same problem and I was having to limit the braking force to avoid having the rears lock up. The deceleration the TVR could manage without the rears locking was less than the Ford Focus
This is not a stable car setup, and the brake test is a good thing to get done early in the day to check that aspect of the cars handling.
Colin discussed whether we wanted to continue with a car that was not handling properly, or postpone the day until we have the car fixed and then carry on from where we left off. This is very good of him, since it effectively writes-off 2 days of his time for our one day of training.
Before finishing, we went onto the 40m circle, and in both directions increased speed until the car started to lose traction. In this respect the TVR is set-up very well (thanks TrackVRoad) - it goes into very mild understeer when pushed, that can turn into slight lift-off oversteer, or can be balanced out with a bit more throttle.
On our way back we popped into TVR Power and had a chat with Jason. He noted that the rear pads were EBC Greenstuff, and it wasn't clear what the fronts were since the back of the pads is not visible. A mismatched set of pads seems the most likely reason for the brake issues, given the calipers all look in good condition, as do the disks and tyres.
We also discussed the coolant dripping problem and, given its location and a quick examination, he was fairly sure it was the plastic ends to the radiator...
I now have a to-do list of new pads, new tyres, and new radiator before I return to complete my driver training. Based on what we have done so far, I am really looking forward to returning to Millbrook, and am grateful to CAT for being so helpful.
There were lots of interesting development vehicles going round Millbrook. My photo from the day is here.
king awesome! )BCA said:
Something sounds amiss?? Our T350 locks the fronts waaay before the rears, there is if anything, too much front bias... the Cerb used to brake better, but it could also lock all four wheels pretty easily if it was slippy. 
+1 from me. Fronts always lock up first on my tam in wet or dry.BCA said:
Something sounds amiss?? Our T350 locks the fronts waaay before the rears, there is if anything, too much front bias... the Cerb used to brake better, but it could also lock all four wheels pretty easily if it was slippy.
I agree that something is seriously amiss. Very annoying to find my Tamora has dangerous on-limit brake performance during the first session of a driving day that we have gone to a lot of effort to attend.If the calipers are all in good condition, and the disks are all in good condition, hopefully new pads all round will correct the imbalance. The tyres are the same all round (Toyo T1-S), a little bit old, but I would rather change those after the brake pads to give me a good chance to test the brakes without smoking a new set of tyres.
Those stops where the rears locked up, despite quickly releasing some pressure and re-applying, made an impressive cloud of smoke
It will be interesting to know what pads are on the front as I don't associate the Greenstuffs on the back with massive performance, but maybe they are just working well on the back and the front pads are not good.
softtop said:
I have Ferodo DS 2500 on the front and EBC yellow stuff on the back and on road tyres can lock the rear in the Tuscan
Normally best to have the same pads all round so the brakes can work to the efficiency ratio front to rear as designed.Sounds like the OP may have a similar set-up.
gruffalo said:
softtop said:
I have Ferodo DS 2500 on the front and EBC yellow stuff on the back and on road tyres can lock the rear in the Tuscan
Normally best to have the same pads all round so the brakes can work to the efficiency ratio front to rear as designed.Sounds like the OP may have a similar set-up.
OP - At least you found out about your problem in a controlled emergency situation rather than out on the road....
I have the yellowstuff all round on the tuscan and although i have barely used it it seems to lock up the fronts a lot easier than the old pads (unsure what they were) did.
I have read comments about the yellowstuff locking easier which i'm not sure is a good thing.
Maybe its just the ebc pads then?
I have read comments about the yellowstuff locking easier which i'm not sure is a good thing.
Maybe its just the ebc pads then?
Zippee said:
I agree. I run DS2500's all round and have never managed to lock the rears, done the fronts a couple of times but the balance and stopping power is awesome.
OP - At least you found out about your problem in a controlled emergency situation rather than out on the road....
I agree. Much better now than in an on-road emergency situation. Or at the start of an expensive trackday. That said the driver training was way more £ than a trackday, but they were kind enough to allow us to postpone the training until it is fixed.OP - At least you found out about your problem in a controlled emergency situation rather than out on the road....
bobd said:
Get the car corner weighted and ride height sorted. I have seen this a lot on Tamoras and Tuscans light at the back end under heavy braking. Obviously check pads and lines, but usually a weight transfer issue due to poor suspension set up.
I would hope it isn't this. Thanks to the previous owner the car is on a 6 month old Gaz Gold Pro setup (yes, I know it isn't on Nitrons...). This was set up by TrackVRoad, and then the ride hights tweaked less than a month ago when I brought the car back to TrackVRoad at the end of its warranty.The handling in corners seems to be spot on, the ride heights are correct, and all the suspension components have been checked very recently. Unless there is a big fundamental failing of GGPs (yes, I know they aren't Nitrons), the weight transfer should not be the cause of the issue.
Further update...
Before I went on a 3000 mile road trip, TVR Power had a look at the brake set up, and changed the EBC Greenstuff on the rear for AP Racing pads which match the front.
They have had plenty of time to bed-in, and I avoided threshold braking on the road trip as that is best saved for track, just sticking to brisk driving.
I took the car out early this morning to find some quiet wide roads (M50...) to test the brakes.
Rears still lock up before fronts resulting in a little wiggle and a puff of smoke (I come back off the brakes as quickly as I can). Certainly the driver's side rear does as that was most obvious in the wing mirror. Not sure about passenger side rear. I assume if they both locked, the engine would be stalled and then bump-start when I came off the brakes. I don't think that happened.
Suspension set up should be ok. Gaz Gold Pros all round, damping still set to firm (12 from soft on front and back was selected for road trip with luggage).
The Tamora is going back to Track V Road in 2 weeks for its annual service and I really need to get this sorted since I have a driver training day finish when the brake balance is correct.
Track V Road say they often use good pads on the front (e.g. DS2500 which I like and have used on previous cars) and cheap pads on the back with less bite.
This sounds like a good option to me. More expensive options could be to use Red Rose front disks (£££) or do something with the suspension, but that should be fine, and since I only understand the basic of suspension, I am not sure what would be done to fix such a problem.
Any advice or experience welcome.
Before I went on a 3000 mile road trip, TVR Power had a look at the brake set up, and changed the EBC Greenstuff on the rear for AP Racing pads which match the front.
They have had plenty of time to bed-in, and I avoided threshold braking on the road trip as that is best saved for track, just sticking to brisk driving.
I took the car out early this morning to find some quiet wide roads (M50...) to test the brakes.
Rears still lock up before fronts resulting in a little wiggle and a puff of smoke (I come back off the brakes as quickly as I can). Certainly the driver's side rear does as that was most obvious in the wing mirror. Not sure about passenger side rear. I assume if they both locked, the engine would be stalled and then bump-start when I came off the brakes. I don't think that happened.
Suspension set up should be ok. Gaz Gold Pros all round, damping still set to firm (12 from soft on front and back was selected for road trip with luggage).
The Tamora is going back to Track V Road in 2 weeks for its annual service and I really need to get this sorted since I have a driver training day finish when the brake balance is correct.
Track V Road say they often use good pads on the front (e.g. DS2500 which I like and have used on previous cars) and cheap pads on the back with less bite.
This sounds like a good option to me. More expensive options could be to use Red Rose front disks (£££) or do something with the suspension, but that should be fine, and since I only understand the basic of suspension, I am not sure what would be done to fix such a problem.
Any advice or experience welcome.
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