17 inch wheels but which tyres sizes for front and rear ???
Discussion
Garlick said:
Serious Q.
What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
Griff owners tend to fit larger wheels so larger discs can be fitted to enhance the faster car What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
Chimp owners fit them for.....
Del 203 said:
Garlick said:
Serious Q.
What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
Griff owners tend to fit larger wheels so larger discs can be fitted to enhance the faster car What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
Chimp owners fit them for.....
k are you asking about bigger wheels 
Grey Ghost said:
Garlick said:
Serious Q.
What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
No idea to be honest. It is a private sale I am buying and the wheels are on the car already. The suspension feels a little firmer than others I have tried but not seriously so, in fact it is softer than my prevous Cayman S with the sport chrono setting on. The car has some Spax yellow springs fitted to it which is probably where the firmness comes from but the car handles well and I just want to make sure I get the right sized tyres fitted to it before I begin to learn how it handles.What's with the wheel size upgrade? Does it offer a handling improvement or is it purely cosmetic?
As I say, I'm being serious as I always thought bigger wheels ruined the ride/ handling on smaller cars?
On the plus side 17" do allow very large discs and IIRC the fitment of 888s.
JR said:
Upgrade is a dubious choice of word, esp if they are 7" rims and you're fitting 235s onto them.
On the plus side 17" do allow very large discs and IIRC the fitment of 888s.
JR, could you expand on this. I'm new to TVR's and am looking for any input before I put new rubber on the car. The 235's are on the rears only, the fronts have 215's fitted.On the plus side 17" do allow very large discs and IIRC the fitment of 888s.
Cheers
Grey Ghost said:
JR said:
Upgrade is a dubious choice of word, esp if they are 7" rims and you're fitting 235s onto them.
On the plus side 17" do allow very large discs and IIRC the fitment of 888s.
JR, could you expand on this. I'm new to TVR's and am looking for any input before I put new rubber on the car. The 235's are on the rears only, the fronts have 215's fitted.On the plus side 17" do allow very large discs and IIRC the fitment of 888s.
Cheers
JR said:
Requirements vary: looks, comfort, or performance? (Remember that the T-series cars were designed to run on 16” wheels.)
Assuming that you keep the rolling radius the same then larger wheels will:
Downside: - cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the unsprung weight, produce a harsher ride, increase the rotating unsprung weight (second moment of inertia) and be more liable to scuffing on kerbs when parking.
On the plus side they should: - prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel and control, have less tyre wall flex (thus reducing both heat and fatigue and be better for long high speed journeys) and they should look good. Perhaps most of all they allow you to use top quality (UHP) rubber.
Larger wheels will effectively increase the spring rates and fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. There are advantages to tyre wall flex when cornering too; this flex gives a lot of feedback and enables more progressive oversteer. Reducing this flex gives more ultimate grip but when it reaches the limit there is less opportunity to control it.
If a car was set up for one wheel size then by increasing the wheel diameter, keeping the same rim the same tyre widths the same rolling radius and the same tyre model then the mathematical advantages are not as much as the disadvantages, even after minimising them by adjusting the suspension set-up. Check whether the weight and the cornering speed of the car are not enough to mean that the tyre rolls onto its sidewall causing sidewall scrub during cornering.
Tyres for 14” wheels are a low point for performance rubber. From there the larger the wheel diameter the better the quality of rubber that is available.
Wheels have a mounting offset from centre known as ET (German = Einpress Tiefe, literally meaning "push in depth,"). The Pitch Circle Diameter (PCD) and Centrebore needs to be considered. Wheel spacers can only reduce this ET value, irrespective of the wheel diameter.
Also consider whether you think that very large wheels will look appropriate on a car that was designed with more modest wheels.
16” all round is probably the best combination for performance. The real choice should be from the roads which you use, your driving style and your preferences.
Cheers, Jonathan
Specifically for you have a look at tyre manufacturers's tables such as this: http://www.toyo.co.uk/productdetail.php?identity=p... if you really have got 7" riims all round then that's too much of a stretch IMO and dubious to say the least insurance wise. If you drive relatively low miles in generally dry weather then 888? http://www.toyo.co.uk/productdetail.php?identity=p... will fit on your rims. Your problem is (if the 7" report is correct) that the car really needs 7/7.5f and 8/8.5/9 rear rims. Trying to economise by having the same size wheel all round compromises the car; have a look at stuff like this: http://www.comp.co.uk/Assuming that you keep the rolling radius the same then larger wheels will:
Downside: - cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the unsprung weight, produce a harsher ride, increase the rotating unsprung weight (second moment of inertia) and be more liable to scuffing on kerbs when parking.
On the plus side they should: - prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel and control, have less tyre wall flex (thus reducing both heat and fatigue and be better for long high speed journeys) and they should look good. Perhaps most of all they allow you to use top quality (UHP) rubber.
Larger wheels will effectively increase the spring rates and fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. There are advantages to tyre wall flex when cornering too; this flex gives a lot of feedback and enables more progressive oversteer. Reducing this flex gives more ultimate grip but when it reaches the limit there is less opportunity to control it.
If a car was set up for one wheel size then by increasing the wheel diameter, keeping the same rim the same tyre widths the same rolling radius and the same tyre model then the mathematical advantages are not as much as the disadvantages, even after minimising them by adjusting the suspension set-up. Check whether the weight and the cornering speed of the car are not enough to mean that the tyre rolls onto its sidewall causing sidewall scrub during cornering.
Tyres for 14” wheels are a low point for performance rubber. From there the larger the wheel diameter the better the quality of rubber that is available.
Wheels have a mounting offset from centre known as ET (German = Einpress Tiefe, literally meaning "push in depth,"). The Pitch Circle Diameter (PCD) and Centrebore needs to be considered. Wheel spacers can only reduce this ET value, irrespective of the wheel diameter.
Also consider whether you think that very large wheels will look appropriate on a car that was designed with more modest wheels.
16” all round is probably the best combination for performance. The real choice should be from the roads which you use, your driving style and your preferences.
Cheers, Jonathan
Cheers, J
PS your use of the car and requirements will affect the best choice for you. There's no one answer that is best for everyone.
Gay Ghost said:
The car has a set of 17" Estorils on it currently shod with 215/40/17 on the front and 235/40/17 on the rear. The rears have about 5mm of tread left and I was considering getting two new tyres in the 235/40/17 size and putting these on the rear of the car and moving the current rear wheels and tyres to the front, that way having all 4 wheels shod with the same size of rubber. That was until I noticed the slightly different sizes and thought that the slightly wider rubber on the front might rub.
So is this plan going to work if I get two new tyres in 235/40/17 size or should I replace all 4, if so what are the recommended sizes for front and rear.
If it is of any consequence the car is running on Spax yellow springs and looks slightly lower than other 450's and 500's I looked at.
An excuse to post pictures of a far better looking car So is this plan going to work if I get two new tyres in 235/40/17 size or should I replace all 4, if so what are the recommended sizes for front and rear.
If it is of any consequence the car is running on Spax yellow springs and looks slightly lower than other 450's and 500's I looked at.
swanny71 said:
17" Ford RS soft spokes
swanny71 said:
No clearence issues with 215/40/17 and 245/40/17
Swanny posted this on another thread & as i said earlier i believe you have the same wheels 
I would've thought you could go 225 up front without clearance issues but not sure... Or why not try your rear 235's for clearance
Then go 245 rear I've asked another Griff owner (BlairOut) who i think has 17's to pop in as well
If you want real grip
The toyo site gives you dimensions for different sizes R888 & T1R
Have you Chimp owners noticed its always the Griff boys helping you lot out
Edited by Del 203 on Sunday 7th March 14:47
Jonathan, Del many thanks for the info so far.
I'll wait until I get the car home here next week and then get the rim sizes off of the wheels themselves. Once I have these I'll post back and get an opinion on the right tyre sizes to fit front and rear. Hopefully they are slightly larger at the back and I can get 235/245 on them and 205/215 on the front. If I am lucky and they are the right width for front and rear they will be sent off to be refinished as per Swanny's set
Failing that it's off to a wheel shop with recommended sizes and offsets from you guys and a wallet bashing session shall ensue
Please keep the feedback coming as it is all useful.
I'll wait until I get the car home here next week and then get the rim sizes off of the wheels themselves. Once I have these I'll post back and get an opinion on the right tyre sizes to fit front and rear. Hopefully they are slightly larger at the back and I can get 235/245 on them and 205/215 on the front. If I am lucky and they are the right width for front and rear they will be sent off to be refinished as per Swanny's set
Failing that it's off to a wheel shop with recommended sizes and offsets from you guys and a wallet bashing session shall ensue
Please keep the feedback coming as it is all useful.
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