Tyre Size - Poss expensive week ahead!
Discussion
ChrisPap said:
Don't forget that the front and rear rims are different, so you can't rotate the wheels front to back anyway.
And the rears are wider, as on many high powered RWD sports cars, to give more grip under traction and prevent bad handling that wants to throw you at the hedge. Look at any Porsche, Ferrari, McLaren, whatever, and any RWD racing car right up to F1.
The front and rears are not different widths, all the same.And the rears are wider, as on many high powered RWD sports cars, to give more grip under traction and prevent bad handling that wants to throw you at the hedge. Look at any Porsche, Ferrari, McLaren, whatever, and any RWD racing car right up to F1.
Different offsets , yes, but same widths.
mk1fan said:
I appreciate the comments re larger rear tyres don't see the necessity given Tamy is a 'basic' 3.6 and I'm not at the stage where I need more power nor do I drive [Tamy] that 'hard' that rear grip is an issue.
It may only be a basic 3.6 but still has over 280 bhp trying to go through the rear tyres.
mk1fan said:
If matching tyres were goos enough for the factory Sagaris then they're good enough for
They were good enough because they were a much wider profile and the suspension set up was engineered around this.The T cars were not and as a consequence you run the risk of upsetting the balance.
I really can't understand why you would ignore good advice from experienced owners with a consensus opinion.
I'm not ignoring advice. I have read the thread. The car came from the factory with same sized tyres front and rear in 16 inch version and the Sag (which in simple terms is the same basic underpinings but wider track) in 18 inch version. Why is it different for a Tamora or T350 on 18 inch wheels? It seems to be more of an 'owner' led requirement for wider rear tyres to look right rather than a dynamic requirement.
Can anyone demonstrate a significant improvement of grip between 225 and 235 tyres and by that I mean one that a regular driver is going to notice? I appreciate that this means time away from preparation for this weekends fun and games in Germany.
Can anyone demonstrate a significant improvement of grip between 225 and 235 tyres and by that I mean one that a regular driver is going to notice? I appreciate that this means time away from preparation for this weekends fun and games in Germany.
mk1fan said:
I'm not ignoring advice. I have read the thread. The car came from the factory with same sized tyres front and rear in 16 inch version and the Sag (which in simple terms is the same basic underpinings but wider track) in 18 inch version. Why is it different for a Tamora or T350 on 18 inch wheels? It seems to be more of an 'owner' led requirement for wider rear tyres to look right rather than a dynamic requirement.
Can anyone demonstrate a significant improvement of grip between 225 and 235 tyres and by that I mean one that a regular driver is going to notice? I appreciate that this means time away from preparation for this weekends fun and games in Germany.
The guidance about tyre sizes being given is based on what was the standard manufactures set up, not based on what an average driver under average driving would notice. The Tamora on 16 inch wheels did have matching 225 tyres, the Sagaris (and Tuscan S) had matching 255 tyres, but your car is neither. Your chassis is the same as the T350, that came with 18 inch wheels and that had 225 at the front and 235 to the rear. That's what your car would have been supplied with if the buyer had ticked the18 inch wheel option.Can anyone demonstrate a significant improvement of grip between 225 and 235 tyres and by that I mean one that a regular driver is going to notice? I appreciate that this means time away from preparation for this weekends fun and games in Germany.
Ultimately it's your car and fit what you like. I fitted tyres which are too big on the back of mine 255/40 to try and soften the rear on our rough North East roads, it's ruined the handling and with less than 500 miles on them, I'll be junking a few hundred pounds worth of Goodyear AS2's. The cars are sensitive to rubber choice.
Paul
I'm beginning to suspect that TVR fitted larger rear tyres on the rear 18 inch wheels for aesthetic reasons rather than dynamic.
If the 18 inch option was ticked on the order form they didn't change anything else on the car just bolted on different wheels.
It seems pretty well accepted that the 16 inch set up produced the best handling and fastest Tamora. If it was such a dynamic necessity to have wider rubber on the back then it would be even more so with the smaller rims. The manufacturer didn't feel it necessary to do so. Go up to 18 inch wheels and all of a sudden it is. I don't understand why and it would be nice if someone could explain this change if it is a dynamic requirement.
As I understand it, the Sag's track, geo, damping, springs and tyres were all the work of the external consultant and TVR adapted the body to suit. The consultant determined that, dynamically, matching tyre size was required although at 255 they are wider. Why didn't they stick with narrower tyres up front?
It seems very odd that the cars in between the 16 inch shod T chassis and the 18 inch shod Sag 'need' different sized tyres front and back.
At the end of the day it's more my curiosity as to 'why' rather than me going 'look at my tyres aren't I great'.
We all seem to want a balanced car and the two 'best' set ups from the factory had matching front and rear tyre sizes. To me, that's more than a coincidence. However, I am not a suspension guru so am happy and willing to learn.
If the 18 inch option was ticked on the order form they didn't change anything else on the car just bolted on different wheels.
It seems pretty well accepted that the 16 inch set up produced the best handling and fastest Tamora. If it was such a dynamic necessity to have wider rubber on the back then it would be even more so with the smaller rims. The manufacturer didn't feel it necessary to do so. Go up to 18 inch wheels and all of a sudden it is. I don't understand why and it would be nice if someone could explain this change if it is a dynamic requirement.
As I understand it, the Sag's track, geo, damping, springs and tyres were all the work of the external consultant and TVR adapted the body to suit. The consultant determined that, dynamically, matching tyre size was required although at 255 they are wider. Why didn't they stick with narrower tyres up front?
It seems very odd that the cars in between the 16 inch shod T chassis and the 18 inch shod Sag 'need' different sized tyres front and back.
At the end of the day it's more my curiosity as to 'why' rather than me going 'look at my tyres aren't I great'.
We all seem to want a balanced car and the two 'best' set ups from the factory had matching front and rear tyre sizes. To me, that's more than a coincidence. However, I am not a suspension guru so am happy and willing to learn.
Ant. said:
ChrisPap said:
Don't forget that the front and rear rims are different, so you can't rotate the wheels front to back anyway.
And the rears are wider, as on many high powered RWD sports cars, to give more grip under traction and prevent bad handling that wants to throw you at the hedge. Look at any Porsche, Ferrari, McLaren, whatever, and any RWD racing car right up to F1.
The front and rears are not different widths, all the same.And the rears are wider, as on many high powered RWD sports cars, to give more grip under traction and prevent bad handling that wants to throw you at the hedge. Look at any Porsche, Ferrari, McLaren, whatever, and any RWD racing car right up to F1.
Different offsets , yes, but same widths.
mk1fan said:
I'm beginning to suspect that TVR fitted larger rear tyres on the rear 18 inch wheels for aesthetic reasons rather than dynamic.
I think this is highly unlikely. TVR worked hard to produce dynamic sports cars. The mixture of high horsepower and short wheelbase makes the Tam and T cars susceptible to spinning. Wider / grippier rear tyres reduces this risk. To this day manufacturers offer larger wheel diameter options and the tyre selection will be based on the dynamics of the car which will of course change when larger wheels are fitted.A larger contact patch will always provide more grip (that is why F1 cars have wider rears).
Choice of tyre manufacturer may provide slightly different ride quality, and different performance under set conditions. Different sizes will change handling and it could be dramatically worse. Of course it is your car / your choice but why risk it when there are still plenty of good tyre manufacturers offering the original sizes of tyres?
OP, you seam to be trying to justify your tyre choice based on the 16 inch Tamora wheels and Sagaris, but the only reason I can see why anybody would put a smaller tyre than the manufacturers recommendation on the rear would be to save a few £'s.
Yes, they will look stretched on the rim (like the 225 fronts do) but disregarding that and assuming there's no insurance implication, put them on and let us know how you get on.
Paul
Yes, they will look stretched on the rim (like the 225 fronts do) but disregarding that and assuming there's no insurance implication, put them on and let us know how you get on.
Paul
The Surveyor said:
I fitted tyres which are too big on the back of mine 255/40 to try and soften the rear on our rough North East roads
Interesting. I put 255/35 on the rear of mine (which keeps the radius about the same) but will also be returning to 235/40 at the next tyre change.As I understand it the Toyo T1 Sports (which are not the same as the T1S) are available in the correct sizes - anyone tried these?
After too many buckles in my 18" spiders, and much trawling around these forums, I now run SP12s on my T350. These are 8" wide at the front and 9" for the rears. The tyres are 225/40 and 255/35 respectively. This is by far the best set up I have had on my car in over 6 years of ownership, and is better than on any other TVR I have driven in that time (including stock Sagaris). IMHO this is how the cars should have come out of the factory; good grip at the rear, good handling and minimal tramlining. I wouldn't willingly go back to the stock setup, let alone 225 sections front and rear.
Seriously, consider going wider at the rear not narrower.
Seriously, consider going wider at the rear not narrower.
mk1fan said:
It seems pretty well accepted that the 16 inch set up produced the best handling and fastest Tamora. If it was such a dynamic necessity to have wider rubber on the back then it would be even more so with the smaller rims. The manufacturer didn't feel it necessary to do so. Go up to 18 inch wheels and all of a sudden it is. I don't understand why and it would be nice if someone could explain this change if it is a dynamic requirement.
I think that you have a good basic point although AIUI you have your sizes back to front in that TVR would have liked to have fitted 235/40s all round on the 18" wheels due to the rim width but there were clearance issues on the front; front could have been 235/35 but that would have caused dymanic problems so they compromised by fitting 225 but keeping the 40 profile.All things considered why not just fit 235/40 to the rear? Is it that you want to take all four tyres of the rims half way through their life and swap front to rear tyres?
TA14 said:
I think that you have a good basic point although AIUI you have your sizes back to front in that TVR would have liked to have fitted 235/40s all round on the 18" wheels due to the rim width but there were clearance issues on the front;
I hadn't considered that the fronts may be undersized. Interesting. Thanks for actually reading my question.I have no intention of rotating tyres or swapping them round 'mid cycle'.
jev said:
Interesting. I put 255/35 on the rear of mine (which keeps the radius about the same) but will also be returning to 235/40 at the next tyre change.
As I understand it the Toyo T1 Sports (which are not the same as the T1S) are available in the correct sizes - anyone tried these?
I changed from Goodyear AS1 to Toyo T1 sports a couple of months ago. Read a few PH reports and other tyre reviews and was not happy with the AS2s. Found 225/35 and 235/40 on Openeo, based in Germany. Ordered Friday delivered to Glasgow on Monday all in for £440, tyres less than 12 months old from manufacture. So far have been very happy with the tyres - don't do track days but certainly great on the road in the dry but can't vouch for wet handling.As I understand it the Toyo T1 Sports (which are not the same as the T1S) are available in the correct sizes - anyone tried these?
Cammy71 - thanks for the info. That was the exact change I was contemplating. BTW, my understanding is that the Goodyear AS2 is not available in the 225/35 size and you get an AS1 instead.
RobertoBlanco - I just think the rear is a little hard which possibly makes it easier to slide. I was wondering if this was due to the lower profile and so the increased flexibility of the 40 profile would be better. This may all be in my imagination however!
RobertoBlanco - I just think the rear is a little hard which possibly makes it easier to slide. I was wondering if this was due to the lower profile and so the increased flexibility of the 40 profile would be better. This may all be in my imagination however!
Had the tyres fitted on Saturday.
Had been due to go to a meet on Sunday but didn't go. So, at this time, the only drive was the one back from the fitters.
Away to Scotland next weekend so it'll be the following weekend before a decent run.
Initial thoughts, seems more comfortable up front, less 'wandering' whilst going straight. A trip out to the Hot Rod Diner should be a good base comparison.
Now, just a suspension and geo check.
Had been due to go to a meet on Sunday but didn't go. So, at this time, the only drive was the one back from the fitters.
Away to Scotland next weekend so it'll be the following weekend before a decent run.
Initial thoughts, seems more comfortable up front, less 'wandering' whilst going straight. A trip out to the Hot Rod Diner should be a good base comparison.
Now, just a suspension and geo check.
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