Rear Spacer Question
#1
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Rear Spacer Question
I need to put a 10mm spacer in the rear of my 86 Carrera. It’s not hubcentric and I’d like to avoid purchasing a new set if I don’t have to.. Any experience/issues with flat spacers at the track? Say any vibrations?
Thanks
Thanks
#2
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It's not safe if your wheel center is not held by the hub flanges. Get hub centric spacers. Otherwise your wheel is only held by your wheel studs and they are not designed to take that load.
Edit: I have seen wheel studs fail on a car at Road Atlanta this year for just that reason.
Edit: I have seen wheel studs fail on a car at Road Atlanta this year for just that reason.
#3
It's not safe if your wheel center is not held by the hub flanges. Get hub centric spacers. Otherwise your wheel is only held by your wheel studs and they are not designed to take that load.
Edit: I have seen wheel studs fail on a car at Road Atlanta this year for just that reason.
Edit: I have seen wheel studs fail on a car at Road Atlanta this year for just that reason.
Failures still happen with spacers, but they are the result of improperly torqued bolts/crappy stud extensions, etc.
#4
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Originally Posted by Kevin Fennell
This isn't right. Your wheel is held to the hub by FRICTION between the hub and the wheel surface, or in this case between the hub, the spacer, and the wheel..
#5
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"Nearly all OEM Wheels are designed to be hub-centric. The automaker designs an OEM wheel to fit on a certain car or range of cars. The center bore of the wheel is sized to fit perfectly onto the axle of that car. This is a hub-centric connection, as the wheel is centered by its connection to the axle hub. The lugnuts hold the wheel firmly to the mounting plate, but it is the wheel-to-axle connection that actually holds the weight of the car. This is quite an important distinction, as the lugnuts are designed to handle lateral forces that push the wheel away from the mounting plate. The forces that the hub and center bore connection are designed to withstand – the weight of the car forcing downward and impacts forcing upward – are at right angles to the forces that the lugnuts are designed for."
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#6
I can't speak for Porsches or Lotus's , but on BMW's, 10mm spacers are problematic. They are typically too short to have hub extenders and too long to provide an adequate lip for the wheels. I run a 12mm in the front and 15 mm in the rear. Both spacers have hub extenders.
#7
Nope.
"Nearly all OEM Wheels are designed to be hub-centric. The automaker designs an OEM wheel to fit on a certain car or range of cars. The center bore of the wheel is sized to fit perfectly onto the axle of that car. This is a hub-centric connection, as the wheel is centered by its connection to the axle hub. The lugnuts hold the wheel firmly to the mounting plate, but it is the wheel-to-axle connection that actually holds the weight of the car. This is quite an important distinction, as the lugnuts are designed to handle lateral forces that push the wheel away from the mounting plate. The forces that the hub and center bore connection are designed to withstand – the weight of the car forcing downward and impacts forcing upward – are at right angles to the forces that the lugnuts are designed for."
"Nearly all OEM Wheels are designed to be hub-centric. The automaker designs an OEM wheel to fit on a certain car or range of cars. The center bore of the wheel is sized to fit perfectly onto the axle of that car. This is a hub-centric connection, as the wheel is centered by its connection to the axle hub. The lugnuts hold the wheel firmly to the mounting plate, but it is the wheel-to-axle connection that actually holds the weight of the car. This is quite an important distinction, as the lugnuts are designed to handle lateral forces that push the wheel away from the mounting plate. The forces that the hub and center bore connection are designed to withstand – the weight of the car forcing downward and impacts forcing upward – are at right angles to the forces that the lugnuts are designed for."
Think about this. 90% of all aftermarket wheels that you see driving around have PLASTIC hub centering rings. This is because they are only loaded when you are installing the wheel to keep it centered. Once you drive down the street these do not see ANY load.
If this was not the case answer this: How come I have completely intact PLASTIC hub centering rings on my car after doing 30+ sessions at COTA with A7 tires. The load is all held by the friction between surfaces while you are actually driving the car.
OEM's use hub centered wheels because they have a number of benefits, they are easier to install. They give you some backup if the studs come loose, and people expect it. Hubs DO NOT carry load while you are driving.
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#8
Another thought experiment. If the load is NOT held only by friction think about what happens when you hit the brakes. Do the wheels spin on the hub until they hit the stud, then go to the other end of the travel when you get on the gas, and over and over again? No... The studs are never loaded in anything but tension, and that tension creates a friction between the mating surfaces.
#9
Another thought experiment. If the load is NOT held only by friction think about what happens when you hit the brakes. Do the wheels spin on the hub until they hit the stud, then go to the other end of the travel when you get on the gas, and over and over again? No... The studs are never loaded in anything but tension, and that tension creates a friction between the mating surfaces.
#10
Has anyone ever seen a tolerance posted for the hub opening on an aftermarket wheel? If it's carrying such loads certainly it is a very very tight fit? The $100 wheels that every Miata in the world is racing on have that level of hub machining?