Wheel and tyre size options

[Paul.H]

Anyone using these wheels ? Advertised to fit TR7 https://www.performancealloys.com/wheel ... load=False If so are you using the 25mm ET or the 15mm ET . Also which tyre width and profile would suit the original wheel arches.

[lancsman]

Paul, you have a PM.
Lancsman

[Beans]

What size are you thinking about? Not using this specific wheel but a 7Jx15" wheel (which I think is the maximum you should use on a TR7) with an ET of 15 mm will move the outside rim 34 mm outwards compared to the original 5,5J rims. So I'd say stick to the original 25 mm ET.
As for tyres either 195/55 R15 or 205/50 R15 should fit. Or just not! The panel tolerances on these cars can be fairly wide. So measure first before you order the tyres!
Some more info ... http://tr7beans.blogspot.nl/search/label/Wheels%20%26%20Tyres
Of course if you want to cut out the wings you can ignore the above

[Paul.H]

Thanks for the reply's guys.
Beans, I was thinking of 7x15 wheels and a 205 55 tyre.

I intend to remove the current 3.9 engine and install a 4.6 with a Cosworth T5 box with the quaife close ratio gear set. The rolling radius of the 205 55 tyre and a 3.45:1 diff is just about right for this gearbox and engine.

Thanks for the info on the ET. Need to go for the 25mm off set then. I don't intend to cut out the wheel archs, however don't mind rolling the the returns on the arches or even cutting them off and welding the inner and outer wings together.

Do you know if the 205 55 x15 will clear using a 25mm et wheel without cutting?

[Beans]

There's a fair chance you'll get problems at the front with such tall tyres.
And with problems I mean scrubbing of the tyres on the lower parts of the arches.
The correct castor angle is pretty important here (as in wheel centred perfectly inside the wings arch)

I would have loved the attachment function to show the affected area, but that doesn't seem to work for me

[Hasbeen]

I have 195 55 15s on the front, & 205 50 15s on the back of the 8.

It is lowered about an inch, & this is about as big as I can go with just rolled guard returns.

This balances quite well, but applying the full 300 BHP from the 4.6L will push the front into terminal understeer out of slow hairpins. Otherwise the handling is good.

You can kick the tail, & power slide out of the slow stuff, but although fun, I think it is slower than driving to the limit of the front grip in the really slow stuff.

I was loaned some 205 60 15s to try on the front. They rubbed on both the chassis & guard on full lock, & hit on the vertical stiffening angle on the underside of the guard on full bump on wavy roads.

Hasbeen

[prackers]

Running 205/50/15 and 205/45/15 on my two 8's, that is on MGF rims, the 50's needed very slight relieving of the front lower inner wing to avoid rubbing and that is using 5mm wheel spacers all round.

[frankman]

Hi All

There is a very good tool to see how the rim width and the offset depth are related to the radius of the rim tires !

You can also immediately see how the roll-off difference affects the speed deviation

It is of course specific to the country how much tolerance I have in the rolling circumference and in the wheel spacers (with us a maximum of 2% is allowed - TR7 1.410 / 1.405 = 14.05mm)

And finally, Beans said the theory is the one - test in practice

http://www.tire-size-calculator.info