How to screw up your cars handling and ride - step by step!

[Racecomp Engineering]

Originally Posted by vignesh

If one where to run spacers. Do u recommend running the same size spacers all around, or running 20mm from and 25mm rear spacers have any adverse affect. This is on stock rims with Dunlop z2 tires

I have not done testing with different size spacers, but 5mm difference I wouldn't expect to have a noticeable adverse effect.

- Andy

[RFB]

Originally Posted by Racecomp Engineering

I have not done testing with different size spacers, but 5mm difference I wouldn't expect to have a noticeable adverse effect.

- Andy

I am running 16mm front and 20mm rear on arp studs, 225/40R18 Direzza 2's.
The slightly wider rear I thought was noticable on the track, the car seemed to have less oversteer and was easier to power through the corners, and seemed more stable.
Perhaps a placebo effect, perhaps not.



CERBERUS

[gramicci101]

I'm running 20/25mm spacers. The only thing I try to avoid is cranking my wheels around while sitting still, as that will put undo stress on the steering system because of the increased scrub radius.

For those who say spacers put additional load on the wheel bearings; they do. However, it's not that much. The OEM wheel, 17x7+48, has the centerline of the wheel located 40.9mm outwards from the hub mounting surface. So that's what the bearings are designed to support and that's the baseline that we'll use. Where the spokes mount to the barrel plays a part, but that varies by wheel design so I just use the centerline. The OEM wheel with a 20mm spacer moves the centerline of the wheel to 60.9mm out. A 25mm spacer is 65.9mm out. Seems like a major jump.

However, a wheel that is 17x9+42, the Mach V Awesome, which by all reports is an amazing wheel, has its centerline located 72.3mm outwards from the hub. An 18x9.5+40, which is a common size, has its centerline located 80.6mm from the hub. Plus, these wheels will have larger and heavier tires on them than the OEM wheels, so that's even more strain.

So yes, the load on the bearings does increase with the use of spacers, but no more than running wider wheels would anyways.

[Racecomp Engineering]

This could probably use a bump.

- Andy

[ATL BRZ]

Originally Posted by Racecomp Engineering

This could probably use a bump.

- Andy

It could definitely use a sticky

[SomeoneWhoIsntMe]

Originally Posted by gramicci101

I'm running 20/25mm spacers. The only thing I try to avoid is cranking my wheels around while sitting still, as that will put undo stress on the steering system because of the increased scrub radius.

For those who say spacers put additional load on the wheel bearings; they do. However, it's not that much. The OEM wheel, 17x7+48, has the centerline of the wheel located 40.9mm outwards from the hub mounting surface. So that's what the bearings are designed to support and that's the baseline that we'll use. Where the spokes mount to the barrel plays a part, but that varies by wheel design so I just use the centerline. The OEM wheel with a 20mm spacer moves the centerline of the wheel to 60.9mm out. A 25mm spacer is 65.9mm out. Seems like a major jump.

However, a wheel that is 17x9+42, the Mach V Awesome, which by all reports is an amazing wheel, has its centerline located 72.3mm outwards from the hub. An 18x9.5+40, which is a common size, has its centerline located 80.6mm from the hub. Plus, these wheels will have larger and heavier tires on them than the OEM wheels, so that's even more strain.

So yes, the load on the bearings does increase with the use of spacers, but no more than running wider wheels would anyways.

Please explain your math. Last I checked, the centerline of any +42 offset wheel would be 6mm away from any +48 wheel, regardless of the width of either. Maybe your arithmetic is expressing metric backspacing instead of offset or you made another incorrect assumption somewhere?

Either way the arithmetic is silly, it's not like you can directly correlate it into an expected service life for your wheel bearings, and they're easy to change anyway. And considering track use decreases wheel bearing life by an order of magnitude instead of by a percentage, this is one of the dumbest arguments against people building cars that look cool.

[dradernh]

Originally Posted by gramicci101

I'm running 20/25mm spacers.

...

the load on the bearings does increase with the use of spacers...

Depending on the car and how it's used (e.g., the race track), you may find that wheel bearings are wear items.

[ZionsWrath]

Looking into getting a 17x8 wheel in future for track use (HPDE) to clear AP sprint kit.

The wheel (Enkei PF01)comes in +35 and +45 offset. Right now I have stock suspension with -1.3 camber. I am planning to get AD08R in 215/45 to start and try the 225/45 after that (or should I just go straight to 225?).

My concern is inside clearance. At some point I'd like to do a little suspension mod whether strut/spring with camber plate (bilstein/RCE springs) or some bilsten coils.

First off how is the clearance of +45 with my -1.3 right now? Would I have problems when lowering with springs and adding camber? Also, I understand bilstein coilovers have wider springs than most, any clearance issues there? Any other advantages/disadvantages of +35 vs +45?

Sorry for questions, just don't want to have to pay twice for wheels.

[jdmblood]

in terms of spring rates for coilovers. i hear everyone throw out numbers followed by a k like 6k, 7k etc etc. with a 2 inch drop, what would be the reccomended spring rate to run on a coilover setup? does it become stiffer the higher the number goes or lower?

[STV3]

Anyone have any info as to whether the TRD lowering springs will have a positive or negative effect on handling and ride quality?

I love the way the stock setup feels but wouldn't mind reducing the gap between the tire and fender a little.

[jprice130]

Originally Posted by ZionsWrath

Looking into getting a 17x8 wheel in future for track use (HPDE) to clear AP sprint kit.

The wheel comes in +35 and +45 offset. Right now I have stock suspension with -1.3 camber. I am planning to get AD08R in 215/45 to start and try the 225/45 after that (or should I just go straight to 225?).

My concern is inside clearance. At some point I'd like to do a little suspension mod whether strut/spring with camber plate (bilstein/RCE springs) or some bilsten coils.

First off how is the clearance of +45 with my -1.3 right now? Would I have problems when lowering with springs and adding camber? Also, I understand bilstein coilovers have wider springs than most, any clearance issues there? Any other advantages/disadvantages of +35 vs +45?

Sorry for questions, just don't want to have to pay twice for wheels.

I autocrossed with 17x8 +45 wheels and 235/40/17 tires on the stock suspension and did not have any clearance issues. I also had the OEM crash bolts for about -1.2 degrees of camber in the front. The tires were within a couple millimeters of the spring perch in the front, but nothing to worry about and I never rubbed. A 225/45/17 tire on that size wheel would obviously give you a little more breathing room than my setup, so I wouldn't worry about getting a 225 wide tire to fit. Even if you add lowering springs with that setup, the clearance will still be fine since the front suspension doesn't gain much negative camber from lowering.

If you want 17x8 +35, that will obviously get the wheels further away from the spring perch and closer to the edge of the fender. Even though you'll be closer to the fender, it will still clear. You'll just have a little more poke that will sling dirt and mud on the side of your car...

So in short, a 17x8 wheel, a 225/45/17 tire, and the +45 and +35 offsets will work fine with your current setup and will still be good for lowering springs or coilovers (even the Bilsteins). I'd probably lean toward the +35 offset if all other things are equal (price, availability, etc), but it's not a big deal either way.

The thing that may ultimately swing your decision is whether the wheel and offsets you're looking at will clear the AP calipers in the front. Have you looked into that already? I still have the stock calipers, so I don't have any fitment experience there. Fender/strut clearance obviously won't matter if your wheel spokes are hitting your calipers!

[gramicci101]

Originally Posted by SomeoneWhoIsntMe

Please explain your math. Last I checked, the centerline of any +42 offset wheel would be 6mm away from any +48 wheel, regardless of the width of either. Maybe your arithmetic is expressing metric backspacing instead of offset or you made another incorrect assumption somewhere?

The centerline of the wheel is based on the width of the wheel, not the offset. So, the centerline of an 8" wheel is at 4", while the centerline of a 9" wheel is at 4.5".

Using the OEM wheel, 17x7+48, the wheel is 177.8 mm wide, with the center at 88.9 mm. It has a +48 offset, which places the hub surface at 48 mm from the inside edge, or 40.9 mm from the centerline. A 25 mm spacer would move the hub surface to 65.9 mm away from the centerline. The greater distance puts more leverage on the wheel bearings, which is what causes them to wear prematurely.

The Mach V Awesome, 17x9+42, is 228.6 mm wide, with the center at 114.3. The +42 offset places the hub surface at 42 mm in from the outside edge, or 72.3 mm away from the centerline.

The Mach V Very Awesome, 18x9.5+42, is 241.3 mm wide, center at 120.65, distance from center to hub surface is 78.65 mm. I chose Mach V's wheels because they're universally regarded as great wheels with the most effective measurements.

My point was that while spacers will cause additional wear on your bearings, it's no more than a larger aftermarket wheel would cause anyways. I've seen a number of people insist that spacers will destroy your wheel bearings, and it's just not true.

Originally Posted by dradernh

Depending on the car and how it's used (e.g., the race track), you may find that wheel bearings are wear items.

I agree completely. Especially coming from the four wheeling world, putting huge tires on low offset wheels can destroy your wheel bearings in short order. If you're racing, bearings should be one of those things you check periodically, because a failure could have catastrophic effects.

[Jyn]

Originally Posted by welllam

I come across a set of used Work emotions cr at 18 X 8.5 Et 38 and 18 X 9.5 Et 38 as well at a good price. This set is for form over functions as I have a prf 17*8 for tracks.
Reading this thread gave me some doubt because of the disadvantage on staggered set up. If I mount 245/35/18 on front and back will be still a squared setup and doesn't affect much the handling?

Still looking for input on this, as I have similarly sized tires (but more aggressive offset). Not a track car, but would like to know what kind of affects compared to stock handling it would have.

[SomeoneWhoIsntMe]

Originally Posted by gramicci101

The centerline of the wheel is based on the width of the wheel, not the offset. So, the centerline of an 8" wheel is at 4", while the centerline of a 9" wheel is at 4.5".

Using the OEM wheel, 17x7+48, the wheel is 177.8 mm wide, with the center at 88.9 mm. It has a +48 offset, which places the hub surface at 48 mm from the inside edge, or 40.9 mm from the centerline. A 25 mm spacer would move the hub surface to 65.9 mm away from the centerline. The greater distance puts more leverage on the wheel bearings, which is what causes them to wear prematurely.

The Mach V Awesome, 17x9+42, is 228.6 mm wide, with the center at 114.3. The +42 offset places the hub surface at 42 mm in from the outside edge, or 72.3 mm away from the centerline.

The Mach V Very Awesome, 18x9.5+42, is 241.3 mm wide, center at 120.65, distance from center to hub surface is 78.65 mm. I chose Mach V's wheels because they're universally regarded as great wheels with the most effective measurements.

Alright, now I see what you're doing. You think offset is the width minus the backspacing in metric. Frontspacing, I guess. Offset is the offset from the mounting pad to the centerline of the wheel. That's why they call it offset.

On your 17x9 +42 example, the inner bead is ( ( ( 9 * 25.4 ) / 2 ) + 42 ) = 156.3mm away from the mounting pad, the centerline of the wheel is ( 0 - 42 ) = 42mm away from the mounting pad, and the outer bead is ( ( ( 9 * 25.4 ) / 2 ) - 42 ) = 72.3mm away from the mounting pad.

Got it?