Hillclimb and Tyres

Sides Veteran Volks Folk

2,220 posts · joined May 2007 · 16 Oct 2007, 5:51 pm

#616827

Found out today that the classes at AHC are a bit different than what's normally run at Mt Cotton, and that Jezebel will need to meet the regs for Improved Production.

The main change I have to make is 15" rims rather than the 16" Fuchs I normally run... plus put some steel guards on the back... so should be able to get it done in the 2 weeks left.

Anyway I figured try find out what tyres, tread widths etc. other bugs run with in Improved Production... then I can start the ring round and see what the $$$ hurt is going to be...

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vassy66T1 Wow ... are U reading this?

2,120 posts · joined Jun 2003 · 19 Oct 2007, 8:13 pm

#617338

Tell us a bit more about the regs Dave.

I am at the beginning of building my beetle to do just this and don't want to do it twice if I don't have to 🙅

Appreciate your experience... I am also a Brisbane boy

vassy

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 · 19 Oct 2007, 9:10 pm

#617345

Dave, you will also need to put the original bumpers back on.

You can now run 50 series tyres in the class, which is worth about 1/2 to 1 sec quicker times per track.

Jump onto the CAMS website and then go to the "manual" section for all the regs

bat69 There is no status

791 posts · joined Apr 2005 · 19 Oct 2007, 10:23 pm

#617365

I would run either a 205 / 15 / 50
or a 195 / 50 / 15.

You can only run a 50 series tyre on 15 inch rims, other wise its 60 series on 14 inch. (max rim width is 7 inch).

dunlop, toyo, kumo, yokies, bridgestone are all good tyres. Have a look on the CAMS web site and have a look at the approved tyres for the imp pro class (for hillclimbs - the circuit regs are slightly different again).

White Knuckle Racing Team [/i]
"Drive it like dirt"

Sides Veteran Volks Folk

2,220 posts · joined May 2007 · 22 Oct 2007, 8:43 am

#617661

Thanks for comments guys - much appreciated.

After several re-reads of the Improved Production regs I think I'm getting there. The thing that caught me Vassy was that at Mt Cotton they normally run a Road Registered category where things aren't so controlled as imp pro - it's basically any Category 3 car that's properly road registered (I think club plates tho are excluded). I log booked as 3C Rally Car Other, so road reg suited me fine since I had wider guards up back, bigger rims and so on, and I was more out to have fun than be competitive anyhow. But for AHC they're running exactly by the CAMS categories, and to be honest I just don't want to miss out on 3 days of racing.

Thanks for the tip about bumpers Craig - have had that sorted for a while, but I definitely don't like the look of the car as much with them on. 🥲

I think 195/50 up front and 205/50 rears is what I'm going to go for - prolly just a mental thing, but I've always felt happier with slightly more rubber on the back. Looked at the measurements tho, and the 15's are going to end up being A LOT smaller OD than what I've been running up till now..."bring it on" for slightly better times, but might have to reset ride heights a bit first !!!

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BiX Veteran Volks Folk

2,499 posts · joined Sep 2002 · 22 Oct 2007, 9:22 am

#617667

I have a set of 205/60R15 on 7 inch steel rims if you need them.

Also once i get the 6 ich rims powder coated, will have a set of 195/55r15 in toyo r881 (got the tires if you have rims to run them on)

Looking at a set of 205/55r 15 for the hillcimb next year.....

I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!

fullnoise Fahrvergnugen

964 posts · joined Sep 2002 · 22 Oct 2007, 9:27 am

#617669

Changing tyre size changes your ride height, handling characteristics, gearing and speedo reeading.

A lower profile tyre usually gives you shaper turn-in and less flex in the tyre which translates into less body roll.

However lower profile tyres can give you less "feel" as they will let go more suddenly.

I'll list some overall diameters which may help the size choices:
560 - 15 cross ply =633mm (Standard beetle)
165R15 Michelin XZX = 646mm
205/60R15 = 627mm
195/55R15 = 595 mm My preference becasue Yokohama don't make a 195/60R15 anymore.
205/50R15 = 587mm
195/50R15 = 577mm
205/60R14 = 602mm
195/60R14 = 590mm

Now for road leglity and insurance requirements you normally have to keep the diameter within 15mm of the original equipment tyre. So the window for alteration is 618 - 648mm.

CT

But racing cars are quite different.

esratrams

BRUTUS Officially Full-On Dubber

255 posts · joined Feb 2006 · 22 Oct 2007, 10:10 am

#617673

Sides, you may have to run in Sports Sedans if you really want to leave the bumpers off. Brutus had no choice as he aleady had wider fibreglass guards. The positive side of being in sports sedans is you can almost do what you like as far as mod's go, with no questions from scrutineers, or complaints from other competitors. In Vic the sports sedans times are usually similar to those of the Imp. Production guys anyway. We don't regret being in S'Sedans, but if there were any other VW Bugs in Imp. Production (to date there aren't any) it maight have been a shame.

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Sides Veteran Volks Folk

2,220 posts · joined May 2007 · 22 Oct 2007, 12:10 pm

#617691

I'd thought about the road legality, but only very briefly as I don't plan on running these tyres + rims on the road. Here in QLD it's +15mm and -26mm on the overall diameter of the tyre, which my 16" rims fit within nicely (as do the road tyres that I'm going to have to take off my 15" rims incidentally).

Question though CT - is there a document or link that covers what sizes Yokohama do for their motorsport tyres ??? My thinking is that if I ever do any circuit racing I'm going to need A032 or A048's on, and since I don't really want FOUR sets of tyres might be easier to get Yoko's now and be done with it.

And yeah Brutus - I had thought about just going Sports Sedan, but the thing that knocks me there is the requirement for 2 anti intrusion bars each side in the cage... my cage only has single each side, and Qld Transport rules don't really allow for a second one cos it hampers entry/exit. Also no other beetles running at Mt Cotton regularly yet, but hopefully that's gonna change soon...

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'60 KG Coupe - resto kinda started
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vassy66T1 Wow ... are U reading this?

2,120 posts · joined Jun 2003 · 23 Oct 2007, 6:03 pm

#617874

Give it a year and there will be another beetle running at Mt Cotton. 😂
Not planning on registering mine at all though. Will be interested to work out all this class differentiation and settle on what I need to conform to.

Just got a nice 54 oval body to put on the BJ IRS chassis I already had. Lots of work to come but the excitement is building. I should be able to make it across for some of the racing and look forward to seeing you there.

I'll send a pm closer to the day when i confirm what day I will make it.

cheers

vassy

fullnoise Fahrvergnugen

964 posts · joined Sep 2002 · 24 Oct 2007, 8:52 am

#617951

Hi Sides,

R-spec tyres like the A032R and A048 are pretty versatile. They can be used for hillclimbs, supersprints and tarmac rallies and the Yokohama's are DOT approved and road legal.

So you could get away with one set of tyres for everything you do.

I've used my A032Rs in supersprints last year, the Dutton Rally this year and I even drove from Sydney to Warwick on the fronts.

The fact that they last quite a while on a light low powered car is a good thing but it's also a problem. It's really hard to get R-spec tyres up to their proper 60 degree operating temperature. Your car needs to be set up well with new shocks and the right spring rates to get the most out of the tyres.

I think the A032Rs are only available in a couple of sizes now. There are still some 195/55R15s and 205/60R15s in stock. The range has mostly been replaced by the A048. Unfortunately for those with light cars that do short events the A048 compounds are mostly one range harder than the A032R range and each size only comes in one compound.

I could crap on for ages about these things beacuse they're quite complicated to get to get rigt.

Some of the A048 sizes are:
185/60R14, 195/60R14, 185/55R14, 205/60R15, 195/55R15, 205/50R15, 225/50R15, 195/50R16, 205/50R16, 215/45R17 and 225/45R17.

These are available from Yokohama Motorsport Distributors listed at the bottom of this web page http://www.yokohama.com.au/motorsports/

They ain't cheap but the cost per kilometer is good.

Regards CT

esratrams

Sides Veteran Volks Folk

2,220 posts · joined May 2007 · 25 Oct 2007, 2:20 pm

#618118

Hey, i'd be great Vassy to see you there, and even better on the track as a regular thing !!! BiX is also Brizzy based, and has had his car in an "almost ready" state for a while now... hopefully he's going to run at the December round.

Thanks for the info CT - it's all good suff to know. I know what you mean about being complicated to get right - was stunned last time just out how big an effect 1psi difference in the starting pressures made. I'm tryin to be as thorough as I can and change only limited things at a time, record results etc., but I know I've got a fair way to go yet to get the most out of things !!!
🙂

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'70 Hillclimb Bug 'Jezebel' w/- Haltech EFI - http://bit.ly/VwTNtQ
'60 KG Coupe - resto kinda started
01 New Beetle - gf's car, but I turn the spanners

Sides Veteran Volks Folk

2,220 posts · joined May 2007 · 12 Nov 2007, 3:29 pm

#620607

Thought I should round this out with what I ended up doing tyre wise.

I checked out the pricing and availabilty on the Yoko's on your advice CT, and it was just going to be too tight on both timing and budget this time round. Ditto the Toyo's down in the 195/50/15 and 205/50/15, so on advice from some of the other regular hillclimbers up here I went with Kumho's at 185/55/15 and 205/50/15 in the medium compound. The Kumho's seem to be a bit softer than the Toyo's that I'm used to, and also seem to be able to run them at a lower pressure without getting that dreaded squirmy feeling when coming off the top of the first loop. That could just be warmer track and air temps too.

Craig was right on the gearing - big enough difference to be noticeable before even getting out of my driveway. Combination of changes improved my pb time by almost bang on a second - hard to say how much was down to the gearing change, but definitely had more pull going up into the loops.

Also finally got round to putting the 28mm torsion bars in the rear since had to reset the ride height anyway for the shorter tyres. I'm now getting mild oversteer, but really pretty controllable. Going to hoipefully stiffen the front up some before the next round to get back to neutral - I'm still re-learning how to drive volksy's quickly and am finding even little things make a big impact on my confidence levels, so we'll see what happens.

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Join a car club - get car peeps

My toys
'70 Hillclimb Bug 'Jezebel' w/- Haltech EFI - http://bit.ly/VwTNtQ
'60 KG Coupe - resto kinda started
01 New Beetle - gf's car, but I turn the spanners

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 · 12 Nov 2007, 7:48 pm

#620661

Sides wrote:Craig was right on the gearing - big enough difference to be noticeable before even getting out of my driveway. Combination of changes improved my pb time by almost bang on a second - hard to say how much was down to the gearing change, but definitely had more pull going up into the loops.

Also finally got round to putting the 28mm torsion bars in the rear since had to reset the ride height anyway for the shorter tyres. I'm now getting mild oversteer, but really pretty controllable.

I'm looking forward to running the 50 series tyres, I should be able to drop all my times by about 1sec as well.

Heath and Christine have been running the 50 series this year and they have lowered their times.........but then again they have also been using new tyres for nearly every event.... which helps !!

I think i will upgrade to the 28mm bars as well as the old t3 bars seem a tad soft.

Good to see that you are progressing.

Cheers
Craig t