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Discussion Starter #1
Hi,

I wonder if anyone can please share what trackday tyres they may be using on a Giulia Saloon.

When preparing my own car I didn't undertake any 'tweeking' of the rear arch area apart from reducing the return horizontal flange as much as possible - it remains at about 10mm wide.

I have now driven the car a few times in UK Hillclimb events using a standard street tyre (175/60x15 Dunlop Street Response) and fancy trying something with a bit more grip!.

I'm using Classic Alfa's WH040 TZ/Ti 5.5x15 wheels ET36.

I bought a set of Toyo R1R 195/50x15 tyres which fit ok on the rims but just foul the inner section of the arch (outboard side). Worse on one side of the car.

I have some possible options if I stay with these tyres.
1) machine a smidge off the back of the wheel flange - say 2 or 3mm max.
2) machine the halfshaft flange a bit thinner - say again 2 or 3 mm.
A combination of these would pack the wheel/tyre inboard several mm (there's plenty of clearance against the inboard panelwork).
3) centralise the axle properly in the body - its a touch one way.

Other options.
1) try other tyres , but without buying a load its a lottery - the size on the carcass does not match the actual size when fitted so comparisons are not great!
2) go back to the road tyres:thumbdown:

In 15 inch sizes the only other options I can see are 165/50R15 Toyo R888 (this is my short term fix for a meeting this weekend - they look stupid!!) , 185/55R15 Kumho V70a and 185/70R15 Kumho V70a , everything else is at least 195 + wide , so will probably not help.

Any ideas would be most welcome guys!.

Thanks
Simon.
 

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Avon CRZ66 tires. Expensive but good. They also come in a variety of sizes to fit your Super without requiring further modification.
 

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Option 1 and 2, or any combination are very dangerous. Do not thin these areas!!

More likely you have an incorrect offset on your rims, putting the tires too far out.

Also, most high performance cars end up rolling the inner fender lip up to flatten the area where you are getting rubbing. More than 10 mm of room here.

Robert
 

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Richard Jemison
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Tire issue

As 60`s said, I wouldnt machine the axle flanges,

You can simply roll the fenders "Lip" to create space. (the old baseball bat trick)
Which will solve your clearance issues! They actually make a tool for doing the inner lip "roll) but it works far less effectively than the baseball bat or steel tubing a bit smaller in diameter to create just enough clearance. And the mod isn`t really noticable.

I wouldn`t think using narrow section tires would make a fun drive!

Toyo makes this size(195-50-15) in the R1R which I run as a race tire on the Duetto in 225-45-15 size. UTQG rating is 140 and tread pattern works for wet or dry. Wet being a major consideration in your country where umbrellas are a fixture of daily apparel.
 

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There is a 3mm at rotor flanges. Alfa uses 8mm rotor flanges, e.g. Mercedes use 5mm rotor flanges with 290mm rotors in 300hp 2ton weight cars. So I think you are safe after machining 3mm off.

Re locating rear axle is worth of doing, there is a 4,5mm more space at drivers side in my car when axles are lined up. so with some fine adjusting there is 2,25mm available.
 

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Make sure your axle is centered. Then limit sideways movement if you are using a trunnion. Thirdly machine discs.

If you use the Pace/Alfaholics trunnion the one with a Heim-joint is preferred.

If you use a standard trunnion, use Belleville washers between the Body and the outer bushes and a Heim-joint where the trunnion attaches to the axle.

Then machine rear discs as suggested above by Gasolina.

Rolling fenders does not make much of a difference on a Giulia Sedan as the tires rub up higher in the wheel well - cutting back the lip is more effective but tires will still rub up higher in the wheel well.

If you get more serious you can narrow the rear axle - as is done on a well known West Coast car that runs 7x14's or you have to do serious bodywork and bring out the whole fender a bit as has been done on a variety of cars. It might be worthwhile to ask Alfaholics how they stuff their 7x15 wheels with wide rubber in the back of their TI - though they proclaim that they work with out modifications which is not what I have seen.

Re: Avon CR6ZZ. The 185/70-14 work well but are a tight fit on Alfaholics 6x14 wheels 33mm offset wheels - they will rub ever so slightly on a lowered car with a perfectly set trunnion modified as above unless you modifiy the brake discs.

175/70-15 CR6ZZ are a bit skinny for maximal lateral acceleration but are much less likely to have issues with clearance.

Toyo 888 are available in 195/50-15 that will fit. Some find that they go off to quickly for track use.

If you can get a set of Yokohama A050 - they are not DOT: they are available in 185/60-14 and 195/50-15 and have been proclaimed by some to be the cat's meow.

205/60-14 can fit with extensive fender modification though not necessarily noticeable by the casual observer.
 

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My car has 195/60-14 Falken on 6" Bosch Spider wheels, no interference on the inner or outer side. A fair number of cars have mildly stretched outer fenders for clearance.

Andrew
 

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Bosch Spider wheels have I believe a 38mm offset like orginal GTA wheels which is the best offset for 6x14 on a Giulia Sedan.

My car has 195/60-14 Falken on 6" Bosch Spider wheels, no interference on the inner or outer side. A fair number of cars have mildly stretched outer fenders for clearance.

Andrew
 

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Discussion Starter #9
Thanks for the later replies , some of the earlier ones are somewhat random!.

Yes, As Alleggerita rightly says its not the actual 'lip' of the arch that's the contact point , its higher up on the inner fender panel above the centreline of the wheel / tyre.

The wheels are not wrong! they are the TZ / Ti replica and are perfect.

I will try the disc flange idea and get the axle more central - perhaps doing the alloy T bar modification at the same time.

I used the 195/50x15 R1R Toyo on the front and the 165/50x15 R888 Toyo on the rear at the weekend. Looked a bit strange but actually worked really well. I'm thinking with my limited power (150bhp) the 195 may actually be a bit too much. Knocked over 3 seconds off my previous best time at the hillclimb event I was doing and got a class win!

Using the 165/50x15 '888's all round will perhaps look a bit strange - kind of modern touring car look as they are very lower profile - but it gets the car a lot closer to the ground & lowers the gearing in a very useful way.

Thanks for the replies - its much appreciated.
Simon.
 

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Aside from all this, it is still my opinion that a 195 tire is too wide for a 105. At the rear too low wheel pressure, at the front very bad for the steering box. Also, and i have been involved in racing 105s for 15 years, i have never seen the profit in lap times. On a full race car yes, on a track day car never. 195 is too wide.
then again, i do not know what is available in 185/65/14 or, for the tz wheel, say 185/60/15.
For a trackday car i'd like a smaller diameter tire, the Avon is great, but then stick to the 175/70/15.
This tire is the very best for the road, but not necessarily the best for the track, aside from being rather expensive. The soft one will be consumed VERY quickly at the track.

And yes, machine off 3 mm from the rear brake discs.
 

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I run 205/50/15 Toyo RA-1's. If you roll the rear fenders and trim the rear inner fender and run a rim with a lot of negative offset they fit.

The rims I use are the Alfaholics Superleggera with the 35 mm offset. It is a little tricky getting the wheels off the rear axle with the long ARP studs but it works.

For the track they work very well.

Here a picture of this setup on my car at Sebring.
 

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