Downsizing wheels

[WJY]

Apologies if already covered elsewhere but I couldn't much specifically on this.  I have a 1996 Xflow supersprint with the large 16 inch HPC wheels (which I think are 8 inch rims, front and back).  I intend to do a lot more track going forwards and want to downsize the rims to 13 inch (likely Apollo) - for agility but need to retain some stability for longer road trips, etc.  On my 16 inch HPC's are currently a set of 205/45 all round.  What I am trying to decide is: 

1. should I go 6 inch front and 8 inch rear for the new 13 inch wheels - or 6 inch all round? 

2. what is the "standard" ZZS size that people normally run on the 13 inch wheels (assuming either 6 inch all round or 6/8)? 

3. I shall do more research on this one but if anyone has any tips about needing wheel spacers or anything to get from the old wheels to the new ones that would be appreciated! 

Many thanks, 

[Jonathan Kay]

What's the maximum power of the engine?

What's the clearance under the sump?

And do you care about appearance?

Jonathan

[Tiddy7]

I would go 6” all round unless you have over 200 bhp

[Paul Richards]

You’ll be lucky to find ZZS tyres as they have been discontinued. You’ll also find the 13 inch wheels and tyres will probably be a lot smaller resulting in speedo being inaccurate and front mudguards hardly filled. Also may find ground clearance reduced. Have you considered retaining 16inch wheels for road and a cheap set of second hand wheels and tyres for the track where ground clearance, mudguards and speedo are less likely to be a problem.

[7 wonders of the world]

or use 13" rims with 185/70x13 tyres which were of that period....

...or 185/60x14, either of these will fill the front arches

[Golf Juliet Tango]

I run a 1996 Crossflow (live axle) on 13" wheels.  I'd look for 185/60 tyres (70 profile if you can find them).  You might look at the Camskill site  https://www.camskill.co.uk/# which just lists tyres (those in stock) by size.  

Use a tyre size calculator to examine the difference. This is one of several https://tiresize.com/tyre-size-calculator/

It's a big difference but as 7WotW says, a 70 profile actually gives you a rolling radius which is only marginally smaller.  

[Wrightpayne]

If also using on the road you might want to consider the ground clearance given by the different wheel options with your suspension settings.

 

According to willtheyfit the tyre diameter drops from 596 to 552 on 185/60R13s so 21mm lower.

 

I think 8” rears will be over tyred based on reading threads over the years rather than personal experience. I’ve asked before and 200hp + seems to be the threshold where 8” rears are a benefit.

Edited May 26 by Wrightpayne

[Miker7]

Depending on required grip levels, I Believe you'll struggle to find something gripping in 13 x 185 x 70. If you do, please let us know. Most grippy tyres at 60 profile at this size.

[Golf Juliet Tango]

3 hours ago, Miker7 said:

Depending on required grip levels, I Believe you'll struggle to find something gripping in 13 x 185 x 70. If you do, please let us know. Most grippy tyres at 60 profile at this size.

Sadly that is true.

[DougBaker]

I switched from the 16" wheels to 13" using Uniroyal Rain Expert in 13 x 185 x 70, the same size as the Academy uses. The diameter of the tyres is almost unchanged between the two. My car has an unmodified base spec 1.6K

I am sure there are grippier options but I find these to be really well balanced on track and road. Grippy tyres just mean you go through the hedge faster when you run out of talent.

[Miker7]

I thought the general rain expert recommendations where for rain expert 3s and you can only buy rain expert 5s now.

Do you have 5s? If so how do the 5s compare to the 3s?

[Golf Juliet Tango]

I'm still on 3s. They last too long...

[DougBaker]

3s I believe, a bit of searching and I don't think the 5s are available in that specific size.

[Gridgway]

I've got 185/70 Academy tyres on my xflow.  There might still be availability - try BMTR.  They seem to work fine