Changing from 3/8 to 7/16 wheel studs

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Bumpa
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Changing from 3/8 to 7/16 wheel studs

#1 Post by Bumpa »

I am about to get a Dolomite 1850HL and I have some Sprint wheels to put on it. It seems like a good idea to upgrade to the thicker studs, but I don't know whether this is an easy or difficult job. I assume that the studs are a press fit from behind the hub flanges. Do the bigger studs need the flanges to be drilled out or not? Or am I worrying about nothing and the 3/8 studs will be fine? I don't intend to do anything other than enjoy the car on the road.

Mike
Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
cliftyhanger
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Re: Changing from 3/8 to 7/16 wheel studs

#2 Post by cliftyhanger »

Which sprint nuts do you have? If none, the 7/16 are much easier (and cheaper)to source, plus far more reliable.
Swapping the front is easy,at worst you have to takethe hub off.The rears may be trickier. You either pull the hub (correct puller required) OR you can drill the backplate to feed the stud in, and then fit a grommet. Of course, this is when I fitted 12mm studs to my car, and they are a little longer too. So the "correct" 7/16 may be an easier fit.
But whatever, do upgrade. Honest.
Clive Senior
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Re: Changing from 3/8 to 7/16 wheel studs

#3 Post by SprintMWU773V »

Ironically you might find the correct 7/16" studs hard to find in the same way that genuine non-stripped thread 3/8" nuts are. The thicker ones obviously have their advantages but I wouldn't bother to change all the studs just for the sake of it, it's a lot of work.
Mark

1961 Chevrolet Corvair Greenbrier Sportswagon
1980 Dolomite Sprint project using brand new shell
2009 Mazda MX5 2.0 Sport
2018 Infiniti Q30
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Bumpa
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Re: Changing from 3/8 to 7/16 wheel studs

#4 Post by Bumpa »

Which sprint nuts do you have? If none, the 7/16 are much easier (and cheaper)to source, plus far more reliable.
I have no sprint wheel nuts at present, but according to Rimmer's web site both sizes are available in steel, although they are pricey.

Mike
Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
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tom16v
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Re: Changing from 3/8 to 7/16 wheel studs

#5 Post by tom16v »

If you are going to fit steel nuts then I would stick with the 3/8 studs.
The only Dolly stud I have ever snapped was a 7/16 one.
There aren't any new ones available that are a direct fit, so it would be a second hand unknown set that you would likely fit.
I think either can have manufacturing faults or have been badly treated over the years.
If your studs are good then I would stick with what you know and save the hassle.
:D
1979 Carmine Dolomite Sprint
1974 Saphire Dolomite Sprint (Soon to be tastefully modified)
2005 Mystic blue BMW M3
2004 Mystic Blue 330d
2001 Peugeot 206 Hdi180
rolf

Re: Changing from 3/8 to 7/16 wheel studs

#6 Post by rolf »

I've got the small ones at the front and the thicker ones at the rear.
Didn't bother to swap the front ones. Just have to pay attention when all the wheels are off.

Rolf
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Re: Changing from 3/8 to 7/16 wheel studs

#7 Post by MIG Wielder »

There is one other important difference listed on page 06-2 of the Sprint workshop manual.
The 3/8 in UNF nuts need a torque of 50 ft.lbs
The 7/16 UNF nuts need 70 ft.lbs.
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