Wheel downsize means brake downsize - Good Idea?

I'm 99% finished with my track car (MK2 Golf PD150) and having trouble getting good tyres at decent money for the 16's it's on at the minute, plus there isn't much side wall room to play with to avoid contact with the arch either.

My idea is, drop down to 15" wheels (I already have the wheels) so I can get good track tyres without breaking the bank or causing contact from the tyre to arch.

The problem I have is it currently has 312mm TT high carbon discs & Porsche 4 pot calipers with EBC redstuff pads which will need downgrading to fit the 15's.

If I run 15's I was thinking of fitting VR6 288's as it already has 5 stud wide track, these should also be cheaper to replace the discs & pads which will also keep track day costs down too. (Discs & pads for the current set up were around 300)


My question is, does this sound like a good idea? I hate the idea of downgrading the brakes but if not the costs of track days may make it a very costly day out, even if nothing breaks.

Please let me know your thoughts and recommendations for discs & pads to swap to.

Thanks

 

It's all about compromising I suppose. I'm having the same issue, with tyres. Do I use 185/60R13 which are affordable, or do I go for 225/45R13, which are 200 Pounds per tyre. I think that in the end, the hobby is all about having fun. If the running costs of your car are to high for you to be comfortable with it, the fun will be a lot less as well I suppose.

 

Try to source `part worn` 16" tyres ... call http://steve-harkness-competition-tyres-bristol.b4r-uk.com/

Is the extra weight of the PD the reason for the current set up ?

 

Yea that's the thing, if it's potentially going to cost a small fortune to go on every track day it will soon become less pleasurable. Especially as I'm currently in the early stages of restoring our new house.

A few of my mates have built MK4 Ibiza track cars that have been built for relatively cheap track fun, they have TT 312's & 17" wheels with Nankang NS2R tyres which we can get a very reasonable money. These parts that will probably changing quite often will be far cheaper than mine so this is the route I think I may take.

 

No I already had these brakes on my old MK2 Caddy so it seemed to make sense when I sold it to keep them for this build, they were awesome on my Caddy and are awesome on the Golf but after going to a few track days (Not with my current car) I have since thought I need to keep running costs to a minimum.

The MK2 has a decent spec list so the Porsche set up suited it perfectly but I now have different thoughts.

We can get the Nankang in 15's cheap enough and they seem to work on the road pretty good too so this is one of the things that is swaying me.

 

If you go for the 15s my dad had some part worn yokohama track tyres if your interested? I'll find out what size they are tonight.

 

Have you lightened the front much?

 

Yea find out and let me know, Might be worth a punt

Cheers

 

The front of the car? The chassis is standard, no weight saving done other than getting rid of unused interior parts.

Why do you ask?

 

This is the car.

Pics are old, it's gone pink again.













I know it makes no difference to this thread but pictures are always good to see.

 

I standardized on 15's for my tarmac rally car(s), same reason tyre costs and only buying one size. 15" brakes will get hot and wear quickly, but providing you duct air properly are quite livable with.
300 for discs and pads would be beyond me also
Jon

 

Looking at how and what you have spent so far I would try some part worn 16" (even road tyres) and see how things `wear` ... prior to deciding to change.

 

Probably agree, another issue is gearing. Trackday gearing is always lower than road gearing..
Jon

 

I only asked as less weight would make it easier for your brakes.

 

Fact of the matter is a lot of wheel and brake size is down to fashion at sprint level. It is actually possible to fit a really good 270x19 system under a 13" wheel and it is good to 250kph on a downforce car pulling -2.5G. OK that is not a parts bin set up but it is still able to be done for a 1000 using second had F3 bits

My advice is go smaller wheels as your tyres are the most important thing anyway
Get your ducting right, so it blows into the centre and all of the air is pushed outwards, make a backing plate to suit, not just a lose bit of tube pointed in the general direction of the disc surface - you are aiming for the vanes
Don't try and use the same brake pads driving to the track as you use on the track
Job done

 

Like others have said ducting is key, you must also remember though that VW 288 discs are front vented which is really annoying.

I'm upsizing to 15's for the same reason as you, availability of cheap track tyres. But rather than using mk3 288 discs I've fitted mk4 288's as they have more offset meaning it should be easier to switch to a 2 piece disc setup easier in the future (using rotors intended for the Elise)

 

In racing series that are on 15`s are 295 mm discs the norm, altough that is with aftermarket calipers and with the right wheels that offer enough clearance
With the right setup ...brake performance is great.... but a larger disc ( diameter and thickness) is more temperature stable.... and you need performance brake pads that operate in the temperature window you need..... Brake ducting and decent brake fluid are key ....
Altough when doing track days... you can keep temperature more or less under control.... by pushing for a couple of laps...and then doing a few slow laps of to let things cool down...

 

Mickey, what have you done to fit the MK4 288's as the disc fouls on the hub where the caliper bolts up due to the disc offset?

I have some at work and tried them with a spare VR6 hub I have.

 

My idea with the ducting was to make something like this:



Iv'e tried the 15's I have over the 288's are there seems to be loads of room too which is a bonus.

Thanks for your advice.