What tyre size dilemma

[300bhp/ton]

Got something to ponder here.

The car has 205/70R14 tyres on it at present. An odd size to say the least.

Optional tyres of the era for it were 215/70R14 or 225/60R15's.

Again all rather odd sizes.

The main issue here is, such sizes mean the tyres are 25.30 - 25.85" tall.


I'm quite happy to change rim size and I'd also like something a bit more chunky than a 205. The hub is actually a fairly common PCD of 4 x 108 with a centre bore of 63.3, these are the same as a Ford Fiesta, Puma, Focus MK1, Escort and so on.


I'd happily opt for 15, 16 or 17" rims. Maybe even 18's if it worked out better, although not sure I like the rubber band look.

But I'd like to try and preserve rolling radius.


So what would you opt for?

[falkster]

Which car is it for mate?

[300bhp/ton]

falkster said:

Which car is it for mate?

1986 T-Bird. Currently has pepper pot 14" alloys on it (standard alloy for them). I believe they are the same rim as found on a Fiesta of similar vintage. The main difference is the tyre diameter. I think if I drop down on the tyre size the arches will look empty.

[falkster]

300bhp/ton said:

1986 T-Bird. Currently has pepper pot 14" alloys on it (standard alloy for them). I believe they are the same rim as found on a Fiesta of similar vintage. The main difference is the tyre diameter. I think if I drop down on the tyre size the arches will look empty.

The pepper pots on fiestas are 13" though.
I think with it being an old car anything too big would look daft. What about some 15" Ford alloys?

[j44esd]

OP - PM me your address, and I will send you a book that covers all the conversion sizes - so within the ETRTO specs you can see what other tyres are a possible match. Hope that helps!

[falkster]

http://www.alloywheels.com/tyrecalc.asp

[parapaul]

Based on the original 205/70R14 size:

Tyre code   Diameter  Circumference  Difference
----------  --------  -------------  ----------
205/60 R15  627 mm    1970 mm        -2.43 %
215/60 R15  639 mm    2007 mm        -0.56 %
225/60 R15  651 mm    2045 mm         1.31 %
205/65 R15  648 mm    2036 mm         0.76 %
205/60 R16  652 mm    2048 mm         1.53 %

[JR]

falkster said:

http://www.alloywheels.com/tyrecalc.asp

Good shout. I'd go for the near universal 205/55/16 for great choice availability and value. 225/55/16 or 225/50/16 would be fine also.

[j44esd]

JR said:

falkster said:

http://www.alloywheels.com/tyrecalc.asp

Good shout. I'd go for the near universal 205/55/16 for great choice availability and value. 225/55/16 or 225/50/16 would be fine also.

205/55 R16 seems a good suggestion - it is at the maximum tolerance by ETRTO specs at -2% diameter (A 205/70 R14 books at 655mm overall diameter, so you can go to 640mm (Down 2%) or to 665mm (Up 1.5%)), but as stated it will open up a good selection of tyres at a good price - 205/55 R16 is the most popular size in the country - just make sure that the load/speed index is correct for the vehicle as well!

[300bhp/ton]

j44esd said:

205/55 R16 seems a good suggestion - it is at the maximum tolerance by ETRTO specs at -2% diameter (A 205/70 R14 books at 655mm overall diameter, so you can go to 640mm (Down 2%) or to 665mm (Up 1.5%)), but as stated it will open up a good selection of tyres at a good price - 205/55 R16 is the most popular size in the country - just make sure that the load/speed index is correct for the vehicle as well!

Thanks.

About 3/4" shorter.

Seems there's a fairly good choice of 225/60R16's too