Rear end width?

[Travis104]

Hello,
I am going to be running a Speedtech torque arm rear with dse mini tubs. I want to run a 335 rear tire on an 18x12 rim. I have searched and have mound many different answers in older threads. What would be the best width for a 9" rear, and what kind of backspacing/offset should I look for in wheels.

Thanks

[slimjim]

I see you're building a 68, same as me.
well if you haven't already purchased wheels then it will be easy. I am running 19x12s with 325s with the speedtech torque arm and DSE tubs with room to spare for 335s no problem, my WMS to WMS is 53" and the backspace on my wheels is 5.25". If you are yet to buy it all then I highly advise you get the rear end narrowed by speedtech(dutchman) and have it all sent through together.
I thought it would be easier and cheaper to sort the narrowing and third member out myself and it ended costing a lot more than speedtech charge.

[Travis104]

I haven't ordered the wheels yet. I have been trying to plan everything so I don't end up buying something twice. What kind of wheels did you go with? I was also looking at other companies instread of going through Speedtech, but it seems like ordering everything through them may be the best option.

[TheJDMan]

Not trying to start an argument, but I have a hard time believing the 53" WMS dimension listed above is accurate. I suspect that is actually an axle housing flange width measurement. A lot of people confuse housing width with the Wheel Mount Surface. For example, I'm running 335s on 18x12 5.6" bs wheels and I am running a 57" WMS to WMS rear end width. I'm running a Moser 9" floater which has no housing flange and I ordered my rear end direct from Moser with the specified 57" WMS width. There are a lot of guys out there running 56" WMS rear ends which again makes me think the 53" is the axle housing flange width.

That said, don't trust anyone's measurements or dimensions because every car build is different. Buy your wheels/tires first then mock them up under the car. At that point it is a simple matter to measure the exact distance between the wheel mounting pads in order to determine the exact rear end width you need for your car.

[Schwartz Performance]

JDMan, yours doesn't make sense either lol.

Our standard is 56" WMS, and a 12" wheel uses 6.25" BS.

With that said, lip to lip of the wheels as I stated, will be 69.5".

Yours would be 71.8" which would likely stick out of the quarters a bit.

57" WMS should require around 6.75" BS.

-Dale

[TheJDMan]

I still have the reciept from Forgeline that specifies the 18x12 5.6" bs WC3 wheels and I have the receipt from Moser specifying a 57" WMS 9" floater. This is exactly the reason why I tell everyone to do their own measuring because there are so many conflicting measurements on different builds.

[Schwartz Performance]

Yeah no kidding lol.
Weird.

[slimjim]

Not trying to start an argument, but I have a hard time believing the 53" WMS dimension listed above is accurate. I suspect that is actually an axle housing flange width measurement. A lot of people confuse housing width with the Wheel Mount Surface. For example, I'm running 335s on 18x12 5.6" bs wheels and I am running a 57" WMS to WMS rear end width. I'm running a Moser 9" floater which has no housing flange and I ordered my rear end direct from Moser with the specified 57" WMS width. There are a lot of guys out there running 56" WMS rear ends which again makes me think the 53" is the axle housing flange width.

That said, don't trust anyone's measurements or dimensions because every car build is different. Buy your wheels/tires first then mock them up under the car. At that point it is a simple matter to measure the exact distance between the wheel mounting pads in order to determine the exact rear end width you need for your car.

yeah 53" overall is certain, here is my painful evidence lol. I know because the speed shop who narrowed the housing to 48"(53" overall with axles installed) said it was wrong by their measurements and that it needed to be 54" overall, so after "lengthening" the housing to 49" then installing the axles with their 2.5" offset, installing the brakes and wheels it became obvious it was too wide as the car couldn't be lowered to the ground. This expensive process became one I couldn't forget. My rears also have the deep lip if that counts for anything.

[jlay]

"Buy your wheels/tires first then mock them up under the car. At that point it is a simple matter to measure the exact distance between the wheel mounting pads in order to determine the exact rear end width you need for your car."

⬆️ This by experience. Especially on a 67-68 camaro

[Travis104]

Ok, sounds like I should order wheels/tires first. What offset or backspace should I get on the wheels?