How much spacer is safe on stock rear studs?
 

What's generally safe to run with the stock rear studs? I'm considering 10mm spacers but don't want to bother if I have to replace the studs.

It seems most of the 10mm kits come with studs, so I wouldn't do it.

What is the rule? isn't it "seven threads engaged in the lugs minimum"? Don't quote me on that but I remember hearing something like that, so if you can't get them that far on the stud they should be replaced.

I've heard only 3mm on factory studs with spacers.


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This.

Yup 3mm is fine but anything over that needs extended studs.



Size of Bolt or Stud Mininum Number of Turns

14x1.5mm 7.5
12x1.5mm 6.5
12x1.25mm 8
1/2"e; 8
9/16"e; 8

Found here http://adaptitusa.com/wheellugnuttorquing.aspx

That's what I figured, thanks guys! I'll wait until I'm doing something more drastic to replace the studs (like when putting in adjustable UCA's maybe).

I'm running 5mm spacers onto the rear without problems.

I wouldn't use any spacer that is not hubcentric or does not have a hubcentric ring.

You do realize that no one sells a 5mm hubcentric spacer, right? It's because the depth of the hub flange is more than 5mm so the spacer would need to have a different center bore or be thicker than the flange to be hubcentric on its own.

At 5mm the wheel (if it's hub centric) would still be centered by the actual hub.

That is why I would never use a spacer that is not hub centric. That means no 3mm no 5mm etc...

I especially would never use those 3mm stamped / cast spacers

Any spacer must be hub centric to the wheel as well.

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This^ replacing studs is an easy job. Don't do it at all if you're not gonna do it right :thumbsup:

That's simply not facts, sorry. I'd agree with not using cheap stamped spacers, but a thin spacer is plenty safe.

The flange on the hub is usually around 10-12mm on most cars, which means with a 5mm spacer the wheel is still centric on the hub itself. That's also the reason why you only see hub centric spacers in > 10mm thicknesses for most vehicles.

HUH? I've been using an aluminum slip-on 5mm spacer for my work equips on my mr2 for the last 7 years. All is fine and dandy and absolutely no vibration issues or whatever.

Stop spreading misinformation.

Good to hear that your wheels haven't fallen off... yet. How much thread engagement do you have with those spacers? The required minimum of 12mm or more likely, less than 10mm. Why risk it?

If you really want to run spacers with the stock wheel studs you should be using ET lug nuts. The extended shank design provides additional thread engagement to compensate for the spacers and also helps with wheel centering. Gorilla makes them in several different styles.

Good I am glad you personally have not had any issues.

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It make more than a year i'm running my 5mm spacers at the back and I tried to retight my wheels the other day just to check if something was loose but I could not move my nuts at all.

No vibrations at all me either.

I used real 5x100 spacers with the same hub centric in the middle so the spacer sit perfectly there and this is much better than a universal spacer by the way.

Again, good to hear that your wheel nuts haven't come loose due to insufficient thread interference or from the threads pulling out of the nut due to insufficient thread engagement.

So, how much thread engagement do you have left with those spacers installed? Remove a wheel nut and then count the number of revolutions it makes as you thread it on until tight. Multiply that number by 1.25 (thread pitch) and you have your thread engagement. With 12mm studs you should have a minimum of 12mm TE. You're looking for 10 full turns.

Doesn't it suck when you come in, offer sound advice and schmucks that didn't bother even digesting what you typed chime in with "well i did it and my shit ain't broke yet"

Keep fighting the good fight, and remember you can't fix stupid.



The minimum recommended thread engagement for similar strength materials is 1.5x the pitch diameter of the thread. this is why thread inserts are measured in multiples of diameter instead of length.

People don't realize this is a long term not short term issue, the threads are fatiguing with the low thread engagement scenario they created for themselves. eventually the threads will stretch or shear, either causing them to gall or break.

That has NOTHING to do with spacers being hub centric or not, which is what the post you quoted was about.

I don't disagree that you want lots of thread engagement on the lugs, but that isn't related to hub centricity in the slightest.

How much spacer is safe on stock rear studs?

Apparently you've moved on to another subject mid-thread but the above is what I was discussing with Nofear99. My point here is that just because he hasn't lost a wheel yet in no way means that it is safe to run 5mm spacers (hubcentric or not) with the stock rear studs.

Good luck, later.

The general rule for minimum thread engagement in most bolted applications is at least 3 full threads. So since the thread pitch is 1.25mm don't go less than 3.75mm. I would recommend at least 4 threads or 5.0mm to have a little safety margin.

Here you go ;)

http://www.rhdjapan.com/night-pager-...acers-5mm.html