Question for people with IForged Astras...

[Blue Batmobile]

Had my wheels installed yesterday, pics coming soon. I noticed ther is very little clearance between the brake caliper and wheel spoke, about 2 millimeters. This ok?

Bat™

 

[Fast Viper]

Yes it is OK, if anything you can get a 1/4" spacer, the brake caliper does not move, so its not as if it will get scratched by the rim. Unless there is some really major impact, you are perfectly fine! Dont worry

 

[MikeR]

Had my wheels installed yesterday, pics coming soon. I noticed ther is very little clearance between the brake caliper and wheel spoke, about 2 millimeters. This ok?

Bat™

Yes, its fine. To get that deep lip the center has to be moved inward. As long as it doesnt touch, you are just fine.

 

[Viper Specialty]

Do you happen to have the offsets on your build sheet? I can compare them to mine and see if maybe someone made an error?

Here are my wheel measurements:

Front:
-19"x11"
-1.5" Lip
-20mm from back of spoke to Caliper face

Rear:
-20"x13"
-3" Lip
-10mm from back of spoke to Caliper face.


You have to watch it if they are TOO close, and I would say 2mm is too close, unless you are wrong on that meaurement. The wheel can deflect a certain amount, especially during hard cornering and braking and rip the inside of the spokes to shreds along with the paint on the caliper. The other issue with excessingly close clearance is that you run the risk of even small road debrit chewing up all of the finishes as you are driving normally from being ground into the spokes and caliper as the wheels turn. Chances are, if you are excessively close, you will show signs of damage within the first 1-500 miles.

Anyone would need more exact information to really give you a definitive answer.

 

[plumcrazy]

2mm is really close. id be worried.

 

[2002_Viper_GTS_ACR]

Especially if you HEAT up the Caliper at a much higher temp then the wheel (heat expansion will put that caliper even closer to the rim at that point).

A hot lap on the track or some really hard street driving (and braking) will make that 2 mm gap even smaller. (Calipers and Rotors get a lot hoter and therefore expand more then the wheels will).

 

[2002_Viper_GTS_ACR]

Ps. If you are curious on how you can get an exact measurement. Use plado or silly puddy. put it inbetween the wheel and caliper and then install the wheel, bolt it down (not move/rotate the wheel at all). Then gently remove the wheel, and the plado/silly puddy and cut it in half, so you can then use the calipers to measure the plato's impresson and actually get the exact clearance you have.

Hope that helps. (Its how I used to do piston to Valve clearance checking on my old Chevy v8's.)

Jon

 

[Dawg2Snake]

My Iforged Aeros were that close and I never had any problem at all.

 

[Blue Batmobile]

I'll take a pic and post it up. Vince at IForged assured me the spacing is correct. I just wanted to see if you guys with Astras has the same gap. As far as put a spacer, dont know if thats the route I wanna take. The wheels go just a tad beyond the wheel well. Its perfect right now.

Bat™

 

[crayne hurst]

Yes its OK.I just put them on 2 FGTs.The trouble is i got 22s in the rear,Now pirelli is not going to make 335/25/22s no more.If someone knows of a place where i can find some
please give me a call.Love them on my vipers. 774 722 0532.

 

[Blue Batmobile]

fgt's?

Bat™

 

[MikeR]

fgt's?

Bat™

He's talking about a Ford GT.

Anyways, Bat dont worry. You probably have the 4" lip. If you had the 3.5" lip like on the HRE's, then to get same offset,they would bring the center hub out more and you would have more space between brake caliper.

Contrary to what others have said, I've seen race cars with just a few mm if that between wheel and brake caliper. And like mentioned by Dan, maybe your measurement is off just a little. Still, I wouldnt worry.

I went and looked at my build sheet.
19x10.5 2" lip, +49 offset about 20 mm between curve of spoke and caliper.
20x13 4" lip, +51 offset about 5mm between spoke and caliper.

 

[Fast1]

The tire and rubber / urethane components of the suspension will give long before the wheel distorts. I have seen this kind of tolerance several times on cars that went through the shop with custom wheels. At first I thought the same as you, but have never seen a problem.

 

[2000_Black_RT10]

2 mm to myself is beyond minimum clearance since I work in the OEM vehicle design / engineering world.. It'd never be that close due to build tolerances and accomodating future wear. Maybe it's ok while everything is fresh and new, but when the wheel bearings wear out a bit, there'll definitely be an interference issue. Race cars are a different breed, parts are routinely changed / maintained, tighter tolerances / adjustments, I wouldn't use them as a guidline of design for a street car.

 

[93Cobra]

I'll take a pic and post it up. Vince at IForged assured me the spacing is correct. I just wanted to see if you guys with Astras has the same gap. As far as put a spacer, dont know if thats the route I wanna take. The wheels go just a tad beyond the wheel well. Its perfect right now.

Bat™

Hey Bat,

That spacing you have is pretty close.

I sold my Astra's and bought some CCW's. To bad I didnt get to install them because they are pretty sweet.

 

[Nine Ball]

I've ran a few cars with hardly any gaps between the calipers and wheels. If they don't hit, they should be okay. Someone mentioned wheel bearing wear, but how many Vipers are ever driven 100K+ miles in their lifetime

If 100s of others are running those wheels without issue, I'd feel comfortable running them too.

 

[2000_Black_RT10]

Ya ya.. I've been here long enough to know how long Blue owns his cars.. I'm just sharing a view from the design world for what it's worth. You know it all depends how the car is driven, 100k doesn't apply in a general sense.. really.. there's probably nothing to worry about.. I'm just pointing out what dictates the wheel to caliper relationship.. there was talk about suspension components, etc.. but what do I know..

Blue's ride is very nice btw.

 

[2000_Black_RT10]

You have to watch it if they are TOO close, and I would say 2mm is too close, unless you are wrong on that meaurement. The wheel can deflect a certain amount, especially during hard cornering and braking and rip the inside of the spokes to shreds along with the paint on the caliper.

Yes.. hey there Viper Specialty. It was easy to demonstrate this below to support your valid concern, took about a 1/2 hour to model a wheel and run a quick analysis on it, to illustrate wheel deflection and stress. It obviously doesn't represent the wheel exactly, nor the material, in which I selected something similar to typical forged aluminum properties. I have more than 15 years of design in the automotive industry. Years at Chrysler (chassis, R&D, powertrain), as well as Ford Motor Company (body, chassis), heck I even worked in the Viper engineering group (chassis, powertrain) supporting them in CAD stuff.. now work at a company which caters to F1, Daytona, supercars, many of which I cannot chat about whatsoever due to strict corporate confidentiality.

This is the CAD model I just created at home using the pics in Blues other post of the wheels in the wrapper for quick reference.. (as pathetic as it is, I'm off sick today.. so this stuff is also fabricated with cold meds..), spokes are slightly wider, etc.. it's just a hand sketched 3D model..

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This image represent stress, red is the high stress regions under a hard side load, noting the wheel is in a randomly rotated / fixed position..

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This image illustrates the maximum deflection, note the max is on the inside lip.. the spokes twist near the middle height and deflect in at the bottom and out at the top, since the force is coming from the tire contact patch region, and the rim is fixed at the hub studs / wheel nuts.

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Here's a higher rez image of the displacement direction / results on the lower spoke nearest the ground.. there surely could be more than 2 mm of deflection, I can't give you a number because my model does not represent the wheel in discussion, this is just a demo of illustrations based on random values. Blue is least deflection, light blue then green is even more and red is highest.
http://www.wincom.net/mnllehti/Wheel_Example_3b.jpg

Here is a GIF / motion file showing how the stress is distributed in this model under a hard side load, of approximately 1000 lbs on the edge of the wheel (noting max moment takes place at the tire contact patch). Worse case could be PS2s or slicks on the track.. which results in alot of G force (vehicle mass / interia) that is put into the wheel around a hard corner..

The max deflection illustrated is not near the caliper position (the caliper is near the height of the spindle.. the middle of the wheel in respect to height, why you would never mount a caliper at top or bottom which is close to the max deflection of a rim), if you watch the rim closely, you can see the rim deflecting (w/a 0.05 ratio image exaggeration in deflection).
http://www.wincom.net/mnllehti/Demo_Wheel_Stress.gif

The comment that it works for 100s of others.. that argument has no value in the design / engineering world, because of the unique scenerios and parameters (and many more on top of this quick demo, fatige, different load cases, etc..), it takes much more than that to validate a design. So that's why I babbled about this.. just sharing my point of view for what it's worth whether it's disliked or not..

If anyone enjoys this stuff, that's cool, it's the only motive for demonstration.. that and being bored at the moment.. and the funny thing about this long winded reply is that I cannot say yes or no due to lack of info.

 

[Blue Batmobile]

Hey Bat,

That spacing you have is pretty close.

I sold my Astra's and bought some CCW's. To bad I didnt get to install them because they are pretty sweet.

Hey Noel, did you get what you wanted for your wheels? Cant wait to see the new ones .

Bat™

 

[2000_Black_RT10]

If you guys ever want any images, etc.. once I model the wheel in CAD (takes about 15 minutes to make a wheel, see ViperArry's 3D design post in the GTS RT/10 forum, it's easy to change the appearance / finish, here are some examples.. sorry for the sneaky pete for the SRT folks, I modeled the center cap in the other post..

There was a post about chrome appearance vs brushed aluminum appearance, I can emulate the difference a bit, see below..

That's it.. thanks for the self inflicted entertainment opportunity and my excessive babbling in your post Bat. I need to order some overlays from you one of these days..
Mike

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meow..

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[Nine Ball]

Pretty cool CAD illustrations! Which software are you using to model those? I've used CATIA and Pro-E in previous jobs (also a Mech Eng here).

Tony

 

[2000_Black_RT10]

Thanks Tony, aha you should be giving me a hard time then! Yes, that software from France.. CATIA, been on it since V3. I mostly do body surfacing stuff lately, yet ProE is great for solid modeling too, which I never really did get a chance to dig into, mostly CATIA, bit of UG in the past for GM stuff..
Mike

 

[Blue Batmobile]

pretty cool.

Bat™

 

[Malu59RT]

So pics of the car with the wheels yet?

 

[Blue Batmobile]

Soon .

Bat™