8 x 15" Alloys?

[K9ng]

Anyone know if 8x15" alloys would be ok on my R?
Am in a dilema as I want a spare set of road wheels as I have 15" track alloys
And was looking to get some 15's for the road would 8x15 give any problems??
If I was to go to 16's would I need to get the alignment done every time I went back to 15's from 16's.

Any help is much apreciated ;-)


TIA

 

[Braveheart]

If I were you, I would stick with all 15" as you can mix and match for track and road.
I have no idea why you would fit 8X15" as your road wheel choice... what tyre would you stick on the rims.... 205+... ??? Give the car a rest. Run 205's on the track and drop down to 195's for the road. I would have a harder compound tyre for the road on the second set of rims and if need be use them on the track if need be. For example, if it's hot conditions, I would put harder compound tyres on the LHS at knockhill as they would soon heat up and work fine and save the soft when it's cooler. I would also run 205 rear and 195 front. But do not get 15" and 16"... then you will need more of both.

 

[GINGA]

I would also run 205 rear and 195 front.

And burn your centre diff out in no time :roll:

 

[K9ng]

I have no idea why you would fit 8X15" as your road wheel choice... what tyre would you stick on the rims.... 205+... ??? quote]

I was going to go with the 8x15" as they have more clearence for my brakes.
And it woud be different, I will stretch a 195 tyre over the rim ;-)
Still I don't know whether or not to go for 16's I don't mind having to get 2 different size of tyres as the 15" tyres are cheap anyway. But my main question was will I need to ge the car aligned going from 16" to 15"??

 

[Braveheart]

I do not think you would need to carry out wheel alignment when changing from 15" to 16" but still do not understand why you would want a set of 15's and a set of 16's.
Now I understand.
I have 2 sets of 15" wheels. Buddy Club 6.5x15" with Toyo R888's 205's and Team Dynamics Pro 1.2 7x15 with Toyo T1's 195's the Buddy club are ET42 and do not clear my wilwood 4 pots without 10mm spacers but the Team Dynamics are ET35 and clear the 4 pots without spacers. If the wheel's that you use for the track clear your setup, why not get another set of the same or something very similar and just put cheaper tyres on them or another good set of tyres then you can use them for road and track and you will have spare wheels at the track.

My configuration as it stands is not ideal. I bought the club first with R888's then the Team.
Ideally, I should have the wider tyres on the wider rims but I'll sort that out once I deplete the R888's

 

[K9ng]

Idealy I don't want 16's am hoping either the 8x15 will clear the brakes or maybe some 15" Rota slipstream with et28 should do the job.

 

[Braveheart]

Rota do have good clearance.
Having looked at the Team Dynamics web site, I think my rims must be et30.
I have 3mm clearance to spokes and 4mm to inside rim on wilwood 285mm kit.

 

[bracpan]

15" Rota slipstream clear Willwood Calipers on 310mm disks with a 5mm spacer.
dont go different tyres front to rear as the diameters are slightly different.
Phil

 

[K9ng]

I have ordered some Rota slipstream 15" with an
offset of 28 so should clear without the need for spacers.

 

[irishjohn]

ATS cup wheels are available in 15x8 and i think would look killer on a r

plus they are pretty light and strong too.

 

[Braveheart]

15" Rota slipstream clear Willwood Calipers on 310mm disks with a 5mm spacer.
dont go different tyres front to rear as the diameters are slightly different.
Phil

Keep us posted on the clearance that you get with the slipstream 15's please as there could be 6 pots available and I would upgrade if I can fit them under 15's.

With regards to different size tyres (width) front and rear, I'm still not convinced there would be a diameter difference. Incorrect / different tyre preasures would have an effect on diffs and transfer box. I'm not a fan of spacers but found a better degree of stability in the corners (on the track) after fitting 10mm spacers. Now that I have found a 15" wheel that will fit over my 4 pots without spacers I want to keep that lack of understear feeling and wish to try a few permutations with regards to the setup.
1. 15x205 all round with 10mm spacers on the rear.
2. 15x195 front / 15x205 rear with no spacers.
3. fit Ingalls fastcam camber adjusters to rear 2deg +ve camber.
4. 2deg +ve rear 1deg +ve front.
5. all of the above but all mixed up.... :doh:

This will all take up a lot of testing and I should really try to monitor transfer box temps to see what put's a strain on it. I will be messing about with other mods at the same time.

BTW, it's not uncommon for touring cars to use two, sometimes three different compound tyres at the same time on different axle hubs depending on the track.... complicated buisness. :shock:

 

[K9ng]

Will keep you posted, any ideas if I will need alignment doing
if I go from offset of et40 down to et 28?

 

[Braveheart]

Will keep you posted, any ideas if I will need alignment doing
if I go from offset of et40 down to et 28?

The smaller the offset the further the wheel is thrown out from the hub.
It should not affect wheel alignment but will have a very slight effect on camber.

 

[K9ng]

I have got the slipstreams on with about 15mm
clearence for the caliper in an offset of 28.

The handling is much better too

 

[bracpan]

You will find the different size tyres will give you different diameters I have been looking at these over the last few weeks, and they all differ, no matter what side wall ratio you try, and as they dont recomend doing this on the Pulsar ( and many other 4 wheel dive cars) you could be asking for problems with your diffs. Plus putting wider tyres on the rear than the front will only help to increase understeer.
As for spacers there is nothing wrong with a small/minimum well made spacer as its only making up for the slight alteration in offset/inset. But make sure you have enough thread on the studs.
Altering wheel sizes has nothing to do with settings like camber, caster toe/in etc, all that will stay the same, as you have not altered any settings, think about it !!! Not even the roll centre will alter to any measurable amount as the difference in diameter is so slight. ( not to be confused with centre of gravity)
You also want more camber on the front than the back,,,and its negative camber not possative camber...or it will handle like a jelly in a spin dryer.
Cheers
Phil

 

[Braveheart]

You will find the different size tyres will give you different diameters I have been looking at these over the last few weeks, and they all differ, no matter what side wall ratio you try, and as they dont recomend doing this on the Pulsar ( and many other 4 wheel dive cars) you could be asking for problems with your diffs. Plus putting wider tyres on the rear than the front will only help to increase understeer.
As for spacers there is nothing wrong with a small/minimum well made spacer as its only making up for the slight alteration in offset/inset. But make sure you have enough thread on the studs.
Altering wheel sizes has nothing to do with settings like camber, caster toe/in etc, all that will stay the same, as you have not altered any settings, think about it !!! Not even the roll centre will alter to any measurable amount as the difference in diameter is so slight. ( not to be confused with centre of gravity)
You also want more camber on the front than the back,,,and its negative camber not possative camber...or it will handle like a jelly in a spin dryer.
Cheers
Phil

Thanks Phil for correcting my guff..
Here's were I start back peddling but don't think I can get out this hole... :doh: :lol:

I did get mixed up with the camber +/- and to bring the struts out away from the car is -ve. As knockhill is primaraly right handers for example and my left hand tyres take a real hammering on the outer tread area regardless of added tyre pressure, adding (-ve) camber is what I want. +ve would have me rolling on the side walls and running on the rims..
When I mentioned a slight change in camber, as you have pointed out, that is incorrect of me as well... To fit wider wheels or spacers or both, it will give an effect similar to changing (adding -ve) camber. You will get the sensation of having added -ve camber (providing you have -ve to begin with) as the more tyre you present to the road, the outer part of the tyre will have less pressure to the road than the inner. (serious woffle or what.... ;-) )

Can't think of any more excuses for now....

 

[campbellju]

^^^^^^^^^^^

I'm still reading this with upside down and back-to-front o vision??

I think what you're trying to say is wider wheels give you more grip and more -ve camber gives you more grip. Ignoring the details of my statement, I still don't understand why you would put wider wheels on the back. Also, at the front top mount, if you move your strut away from the car (engine?) then you add +ve, not -ve camber. For the record, adding spacers or wider tyres changes track (distance between centre line of tyres) and still has nothing to do with camber. Tyre width vs alloy can have a dynamic affect on tyre profile and give a camber like affect that alters grip but I don't think you mean that?

Widening track has a similar (but slightly different) affect to lowering the car on weight transfer. You normally increase track at the heavy end to reduce weight transfer. This is why rear engineed cars have wider track at the rear and a GtiR like many other FWD cars has a wider track at the front.

I just tried to re-read your last post and I'm completely confused

mij