psyg

I want to order an AP kit, with grooved discs, for my Scoob MY99.
Normally I drive with the 17" P1-wheels; but I go every 1 or 2 months to Nürburgring and prefer to drive there with the original 16" with RE010 tyres (on the dry circuit this tyres gives me more grip than the 17" S02-PP's; and also it feels better to 'finish' some almost worn 16"-oldies my friendly dealer gives me for free).

So when I buy the 16" braking kit I can use both sizes wheels/tyres (and Stef was so enthousiastic about his 16"kit...).
Now my question, is there really much difference in the braking performance compared to the 17" kit?
Or, is there another reason to prefer a 17" AP kit above a 16"?

grts Geert

Hoppy

I've just agonised over the same decision. Having wasted a lot of time and money on trying to improve the standard brakes I was determined to get the best I could, ie AP 6-pots and 330mm discs for 17in wheels. But that's not what I've ended up ordering!

The first things to change were the 6-pot calipers. In theory of course they're better but how much? The 4-pots are extremely powerful so probably not that much and, more importantly, you can only get a limited range of pads for the 6-pots (no Ferodo DS2000 I'm told) and they're about £200 a set!

The second decision was over the disc size. There's no doubt that bigger discs are better by simple virtue of the substantial extra mechanical leverage they give. There must be a formula for working this out. (Anyone know what it is?) But, bigger discs, wheels and tyres also have significantly more unsprung weight. About four kilos over 17in?

Moving up from 16in to 17in wheels is also expensive and there are lots of other little niggles that need to be sorted out. In particular, getting wheels that clear the brakes, have the right off-set and don't foul the wheel arches with both road tyres and slicks (I've found a source for 17in slicks - apparently they're not as hard to get as I'd been led to believe). All this takes a lot of time and trouble as the only way to be sure of everything is to actually fit stuff to the car and see if it's all okay.

So, in the end, I've opted for the 4-pots to fit 16in wheels. This gives me an easy and instant fix to a brake problem which is driving me mad. Over winter, I'm going to see if the 16in set-up is as good as it's said to be, and check the various 17in wheel and tyre combinations I want to use.

If I ultimately decide to go for the bigger brakes I'll just have to buy new discs, bells and caliper mounting brackets. About £400, I think.

Sorry to ramble. Hope this helps.

Hoppy

PS Your experience with 17in wheels and tyres over the standard 16in equipment contradicts both theory and practise expressed on this Board. Especially the tyres. Are you sure the difference isn't that the 16in tyres you're using are nearly worn out and therefore don't over-heat like new rubber?

psyg

Hi Hop

Thanks for reaction;

I wonder how many more people have or had to go through the same proces of choise-making between AP 16" and 17"?
16" has the weight-advantage (you really think 4 kg over 17"??; Stef said AP 16" has 3 kg less than the standard 2-pot my98-brakecombination a CORNER);
But also you can use both 16 AND 17in wheels; the 17" (with f.e. S02-pp) for better handling and overall-wet-use; 16" for snowtires, slicks & eating-up oldies on tracks.

You were wondering about my 16-17" experiencing: for me it was just the TYRES (I really prefer 17" wheels for handling/steering precision); I was also surprised that 16" RE010 gave me more GRIP on the DRY TRACK than 17" S02-pp (although before on the road I felt that 16" RE010 gave more grip/'rock'-feeling in fast bends than 16" S02-pp; in every other way S02-pp's were better). I think, as you do suggest, the S02's are softer compound, and when becoming really hot, they melting...
Wasn't it Pete Croney who said, after 20 rounds Donington S02-pp's are destroyed??

But again our question: AP 16" or 17"???

I guess ScoobyMania-Mike knows more...
and who else?

grt Geert

PS When you like 17" wheels, go for the OZ-P1 wheels!
They have the good ET (52 mm), not to heavy (9.2 kg; almost all the other 17"s are above 10 kg), with 215-40-17 S02-PP (plm 8,5 kg) total combination is just under 18 kg (not much more than 16" standards with RE010: plm 16,5 kg). And a nice colour, specially with a silver-gray and blue car, brake-dust no more problem...
In Holland you can buy/order this wheels with the 215/40 S02-pp's at the Subaru-dealer for plm 1050 pounds!

Hoppy

Thanks for the advice about the OZ wheels. From what you've said, it seems like the off-set is just right and the weight saving a nice bonus. Also, they're a top brand and look good. I'll start saving!

The 16 vs 17in weight saving I mentioned was just a guess at how much more unsprung weight a 17in wheel, tyre and 330mm disc might carry. I've heard ScoobyMania Mike talk about a saving of 3 kilos per corner with his 16in AP kit. It sounds a lot to me but as I'm having them fitted this afternoon, we'll see!

Take it steady around that Nurburgring!

Hoppy

Mike Tuckwood

17" kit will provide more braking power than the 16" kit, if only for purely mechanical reasons.

Whether your car is capable of making use of that then becomes the point, slicks will help, and obviously 17" kit means you could use slightly larger slicks, hence get better braking.

Brake feel, obviously where the 16" kit is working at 85% the 17" kit will only be working at 70%.

This will make a difference to progressiveness, bite, feel Etc.

Cosmetically the 16" kit looks a bit lonely in with a 17" wheel fitted.

Not sure if that has helped or not?


Mike.

psyg

Hoppy, thanks again for reply.
And Nürburg: come & try by yourself, you will enjoy it!!
The weekend 14/15 october there will be a lot of scoobs, from holland/belgium ànd from your country.

Back to the topic: AP 16" or 17", nobody else some comments???
Mike???

grt Geert

[This message has been edited by psyg (edited 27 September 2000).]

psyg

Mike

thanks for reply

you also have the answer on the weight question:
difference in weight between AP 16", 17" and OEM-brake kit my99/00?

grt Geert

CharliePsycho

Hoppy, you mentioned you could get 17" Slicks easily? Where?

I've got a P1, and yes the 17" anthracite wheels look good, but now the 18" ones are out, a mate of mine raved that you could actually feel the handling improvement (and they look even cooler )

So if 17" slicks are easy to get hold of I'll get the 17" ap kit and the 18" wheels for the road (when I have the money) otherwise I'll go and get some 2nd hand 16" wheels cos I <I>know</I> I can get slicks for those and the 16" kit...

[This message has been edited by CharliePsycho (edited 29 September 2000).]

Hoppy

Guys. The difference in weight between the standard 4-pot 16in brake set up and the equivalent APs is 1.6 kilos (16%). Weighed them myself. The 3 kilos saving sometimes mentioned applies to the old 2-potters, I believe. Most of the weight saving is in the alloy calipers, obviously. They're gorgeous lumps of quality engineering with new-look AP Racing logo picked out in yellow, like the six potters. Check the ScoobyMania site for pics.

For a set of 17in slicks dial 07974-156646. Alternatively, run a search here on 'slicks' and you'll find everything you've ever wanted to know about tyres, and a bit more besides. Checking the classified ads in Motoring News seems to be a popular source.

Hoppy