Hre r40 for track

[FunnyK]

Hey guys, im looking for getting a set of "18 R40 as a separate set for track. Everything as far as brakes on the car is stock, so my question is would they fit alright? What about the width, is that something that is based on the tyres i will put on them or i have to specify it when im going to order? Also i would appreciate if someone used them and has anything to share in terms of it being a good choice or not, thanks.

[Protocav]

Excellent wheels, I have the R43. These wheels were originally designed specifically for the BMW M3 and then adapted to other cars. I have a 9.5/10.5 setup because I originally started with 275/295 tires to keep the balance and diameters similar to stock...this was completely wrong. I now run a square tire setup on these different width rims and the car handles like a dream.

If this is a track only set then (in my opinion) there is only one option: 18 X 10 with a 25 offset, Nitto NT-01 tires in 275/35-18 all the way around. No rubbing, no issues with the computer, just pure fun. These are probably the grippiest tires that will still allow you to drive to the track. The only thing better would be full slicks (40 treadwear).

[Porschefile]

Originally Posted by Protocav

If this is a track only set then (in my opinion) there is only one option: 18 X 10 with a 25 offset, Nitto NT-01 tires in 275/35-18 all the way around. No rubbing, no issues with the computer, just pure fun. These are probably the grippiest tires that will still allow you to drive to the track. The only thing better would be full slicks (40 treadwear).

.

[FunnyK]

So is 25mm ofset is something that has to do with the wheel itself or is that something people use spacers for?

[Car54]

That's the offset of the wheel itself...distance from the center point of the wheel to the mounting surface.

I have a sweet Nutek (HRE founders company) 19" setup for sale if you're interested...really cheap!

[Richard@M-World]

Originally Posted by FunnyK

Hey guys, im looking for getting a set of "18 R40 as a separate set for track. Everything as far as brakes on the car is stock, so my question is would they fit alright? What about the width, is that something that is based on the tyres i will put on them or i have to specify it when im going to order? Also i would appreciate if someone used them and has anything to share in terms of it being a good choice or not, thanks.

As far as I know, HRE custom makes its wheels, so you can spec it to whatever works on your car. They've also done a ton of wheels for the M3 and will have no problem building you a set that works.

Originally Posted by Protocav

If this is a track only set then (in my opinion) there is only one option: 18 X 10 with a 25 offset, Nitto NT-01 tires in 275/35-18 all the way around. No rubbing, no issues with the computer, just pure fun. These are probably the grippiest tires that will still allow you to drive to the track. The only thing better would be full slicks (40 treadwear).

+1 on the wheel set up. You may want a 5-10 mm spacer to push the rear wheels out a little, but not required.

This 18x10 ET25 set up also works because of tire availability. One of the most common tires to use is 275/35/18 (check tirerack)... from street tires to DOT-R.

[M3SQRD]

I have a set of R40 and R43 wheels.

Richard is correct, HRE can manufacture the R4x wheels to pretty much any offset you want within the range of widths they offer.

The wheels work, and look, fine with stock brakes.

Are you interested in running a square or staggered setup? Biggest advantage to a square setup is it gives you the ability to rotate/move wheels front to rear. However, with some aftermarket suspensions a 10"et25 wheel might rub with a 265/275 tire on the front suspension, spring or lower spring seat/collar. Because of the suspension I was running I had to go with a 9.5"et23 F wheel so I'm running 9.5/10 staggered setups.

[Porschefile]

Originally Posted by M3SQRD

I have a set of R40 and R43 wheels.

Richard is correct, HRE can manufacture the R4x wheels to pretty much any offset you want within the range of widths they offer.

The wheels work, and look, fine with stock brakes.

Are you interested in running a square or staggered setup? Biggest advantage to a square setup is it gives you the ability to rotate/move wheels front to rear. However, with some aftermarket suspensions a 10"et25 wheel might rub with a 265/275 tire on the front suspension, spring or lower spring seat/collar. Because of the suspension I was running I had to go with a 9.5"et23 F wheel so I'm running 9.5/10 staggered setups.

Is there a list of what suspensions rub? I have KW Clubsport and just got some 18x10 et25 but haven't tried them yet.

[Richard@M-World]

Originally Posted by Porschefile

Is there a list of what suspensions rub? I have KW Clubsport and just got some 18x10 et25 but haven't tried them yet.

On KW Clubsport, you will most likely need a spacer in the front to prevent the tire from rubbing the lower spring perch.

[Porschefile]

Originally Posted by Richard@M-World

On KW Clubsport, you will most likely need a spacer in the front to prevent the tire from rubbing the lower spring perch.

uh oh, I have a track event next week. 10mm or so?

[FunnyK]

I was actually thinking about trying michellin sport cup as a track set, but the closest size they have are either 295/30 or 265/35. Would any of these fit right?

[bigjae1976]

Originally Posted by Richard@M-World

On KW Clubsport, you will most likely need a spacer in the front to prevent the tire from rubbing the lower spring perch.

Can you ditch the helper spring and then get the clearance?

[M3SQRD]

Originally Posted by FunnyK

I was actually thinking about trying michellin sport cup as a track set, but the closest size they have are either 295/30 or 265/35. Would any of these fit right?

Depending on your wheel widths (staggered or square) and offsets as well as your driving style, suspension setup, etc, you could run either 265/265, 265/285, 265/295, 285/285 or 285/295 - the F 285 may result in rubbing on fender liner or suspension.

What are your wheel specs? Are you running stock or aftermarket suspension? Stock camber? The PSCs like a lot of camber otherwise you may experience excessive wear on the outer tread block and tire sidewall...

[M3SQRD]

Originally Posted by Porschefile

uh oh, I have a track event next week. 10mm or so?

I don't have experience with the KW CS but a 5 mm spacer usually is enough; however, would that push your front wheel/tire out too far (too aggressive offset)?

To answer your previous, question...no, I do not know of a list of front struts that may/may not have tire clearance issues.

[bigjae1976]

Originally Posted by M3SQRD

I don't have experience with the KW CS but a 5 mm spacer usually is enough; however, would that push your front wheel/tire out too far (too aggressive offset)?

To answer your previous, question...no, I do not know of a list of front struts that may/may not have tire clearance issues.

I don't like 5mm spacers without hub extenders. If the back of the wheel bore is tapered then there is VERY little material in contact with the wheel and the hub. I know that APEX ARC8s with 5mm spacers leaves about 2mm of contact.

I think the clearance issue comes in when you have a helper spring which pushes the spring perch lower. I know KW had this issue. If you fit an 17x9 ET42 on a non-M E46s, the KWs would need a 5mm spacer whereas Bilstein and Koni (which didnot use a helper spring) would clear. I've heard of some people taking out the helper sping and then not having clearance issues...not sure how true that is or what the side effects were.

[M3SQRD]

Originally Posted by bigjae1976

I don't like 5mm spacers without hub extenders. If the back of the wheel bore is tapered then there is VERY little material in contact with the wheel and the hub. I know that APEX ARC8s with 5mm spacers leaves about 2mm of contact.

I think the clearance issue comes in when you have a helper spring which pushes the spring perch lower. I know KW had this issue. If you fit an 17x9 ET42 on a non-M E46s, the KWs would need a 5mm spacer whereas Bilstein and Koni (which didnot use a helper spring) would clear. I've heard of some people taking out the helper sping and then not having clearance issues...not sure how true that is or what the side effects were.

HRE uses a smaller wheel hub chamfer than OEM and other wheels so there is > 2 mm of hub engagement with a 5 mm spacer.

Yes, removing helper or tender springs and couplers helps clearance with some setups; however, with my Motons the issue wasn't due to a helper/tender spring or coupler and that's why I ended up going with a 9.5" F wheel.

[Porschefile]

Originally Posted by bigjae1976

Can you ditch the helper spring and then get the clearance?

Called Apex today and this is what they advised.

[bigjae1976]

Originally Posted by M3SQRD

HRE uses a smaller wheel hub chamfer than OEM and other wheels so there is > 2 mm of hub engagement with a 5 mm spacer.

Even then that's not a lot of material. Just went through a class at the track this past weekend about fatigue and parts breaking. I would imagine that as you have less contact between the inside of the wheel and hub lip that the load is transferred to the studs/lug bolts. Given the experiment we witnessed...the life of the wheel fasteners is greatly compromised.

I ran a 5mm space for awhile but I had a 3mm hub extender.

[M3SQRD]

Originally Posted by bigjae1976

Even then that's not a lot of material. Just went through a class at the track this past weekend about fatigue and parts breaking. I would imagine that as you have less contact between the inside of the wheel and hub lip that the load is transferred to the studs/lug bolts. Given the experiment we witnessed...the life of the wheel fasteners is greatly compromised.

I ran a 5mm space for awhile but I had a 3mm hub extender.

It's a simple "hollow-pin in socket analysis" under combined bending, lateral shear and axial load. Only the hub reacts a portion of the vertical shear - you'd be amazed at how much shear a lip with 80 mil of engagement with a 2.85"-diameter can carry. I'm comfortable with the > 3-4 mm of engagement I have with a 5 mm spacer. However, thanks for your concern

[bigjae1976]

Originally Posted by M3SQRD

It's a simple "hollow-pin in socket analysis" under combined bending, lateral shear and axial load. Only the hub reacts a portion of the vertical shear - you'd be amazed at how much shear a lip with 80 mil of engagement with a 2.85"-diameter can carry. I'm comfortable with the > 3-4 mm of engagement I have with a 5 mm spacer. However, thanks for your concern

Lol...anytime! Still, my apex and OEM wheels have a taper on the back, appears to be at least 3mm. So is 2mm of engagement fine? I'm not an engineer but I know enough to make me dangerous.

[M3SQRD]

Originally Posted by bigjae1976

Lol...anytime! Still, my apex and OEM wheels have a taper on the back, appears to be at least 3mm. So is 2mm of engagement fine? I'm not an engineer but I know enough to make me dangerous.

2 mm = ~80 mil...In actually, the shear load is only transferred over a very short distance (i.e., the entire hub length is not effective; the spacer acts like a non-structural "gap" which increases the bending stress at the hub root). The minimum distance required for the shear load to transfer from the wheel to hub, as a quick sizing rule-of-thumb, is when the effective bearing stress is equal to the bearing yield strength of the material. If you are afraid of 2 mm of lip engagement to transfer < 2-2.5k lbf then you don't want me to get started on the structural design (static, dynamic, fatigue and fracture) of aircraft and spacecraft

[bigjae1976]

Thanks for the detailed explanation. I've learned something on my day off!