Metric M12x1.5 Stud Conversion Inc. nuts for sprint alloys.

[CallanH]

Thought I would share the information and parts I gathered as well as detailing the work involved the a metric Freelander stud conversion for our cars.

This is a common conversion done on small chassis cars but seeing as our cars share the same stud splines it can be done on a dolomite also.

My post a few weeks ago on Faceache generated some comments asking why would I do such a thing?

My car is now nearly 50 years old with similar age studs, I'm not particularly fond of 50 year old hardware especially the alloy wheel nuts. I had a wheel depart on my 1500HL a few years ago down to pants hardware..

I also intend on fitting spacers as well as pushing the car quite hard so definitely don't want to rely on standard hardware.

Anyhow, the parts I've used are as follows.

Metric M12x1.5mm studs to fit land rover Freelander x16
12x1.5mm Flat 35mm, Thread 21mm Hex Chrome wheel nuts x16
18.5mm HSS Small Shank Drill bit.

The studs are available for roughly £35 for a set of 20 on eBay, nuts are £1.50 each on wheel parts direct. Drill bit cost £10 also off eBay. All in all though sub £80 in my case and cost less than 8!new sprint standard nuts!

The studs cannot be fit to the front hubs without removing them from the car and separating them from the disc, this is due to the extra length of the studs otherwise assembly is as normal. You can leave the disc on the car in order to do this.

The rear is slightly more difficult, I was unable to fit the studs due to the length and proximity to the backing plate for the drum. The course of action I undertook was to drill an appropriately sized hole in the backing plate with a rubber grommet to seal the hole afterwards. This enables the studs to be fitted in to the hub from the rear. You could alternatively pull the half shafts out somewhat.

Now for the drill bit, I spent a fairly long time searching supplies for wheel nuts close to the dimension of the original nuts. I was unable to find a wheel nut the same dimensions as the original nuts, they had a shank too small generally or were sleeve nuts with a significantly smaller flat than factory. After a few sample nuts were delivered I chose the best out the lot with a larger flat face then the factory nuts and a 21mm Hex in chrome finish.

The factory mounting holes in my wheels measured at approximately 17.5mm in diameter, the shank on the nuts I've used was 18.4mm approx hence the drill bit simply used in a plug in drill. Enlargement of the mounting holes may sound concerning to some but this is practice in some car circles and there is still significant engagement of the nuts due to the larger flat size.

With the above work done your sprint alloys should mount on your hubs and jobs done. For a tidier finish some may want to invest in an adjustable reamer to finish the holes in the wheels to a slightly higher standard.

I dont have too many photos showing the work done but I've attached one showing the difference between my studs and a Freelander stud as well the result of crap hardware on my old 1500HL.

Note, I also done this conversion on my 1500HL successfully following my wheel departure.

[new to this]

Ford escort use 7/16 studs also Triumph Stag also use 7/16 studs, Stag wheel nuts need modifying to fit Sprint wheels and there steel, im not a fan of alloy wheel nuts

Dave

[SprintV8]

Grayston Enginerring can supply studs nuts etc in Metric or Imperial.
Based in Chessington Surrey.
They only usually supply to the trade but have supplied to me if the order is big enough.

http://www.grayston.biz/wheelnutmenu.htm

[xvivalve]

One of Ted's anecdotes from conversations held 'back in the day' with Canley employees concerns the Sprint being the first production car fitted with alloy wheels. Seemingly, one of the reasons alloy nuts were used was to ensure that the nut was 'softer' than the wheel as early development testing had apparently shown the propensity for the holes in the wheel to become oval with continued heavy braking and acceleration accentuating minute movements! As wheel technology advanced this was overcome with devices such as wheel inserts to allow the use of taper seat nuts and changes to the alloy composition used for wheels...but we still have shanked nuts and the original alloy!

I too once lost a wheel from my '74 Sprint at speed on the M3, thankfully a rear, but it wasn't due to failure of the nut, it was the studs that had 'necked' from continued over tightening. A common phenomena apparently, this is why Sprint studs (and nuts) were changed in production cars from 3/8" threads to the more robust 7/16" threads, though there was never a recall to change the earlier 'series 1' cars to the revised specification. The flange on the Sprint nut being perpendicular to the thread apparently can put more stress on the stud than a taper seat nut does.

If you do this modification, or indeed use replica steel 'OE' style nuts, I'd recommend that the introduction of regular examination and checking of the wheel holes for circular accuracy.

[Carledo]

What he said ^^^^^^^

Modern alloy wheel technology lets you do pretty much whatever you want. Not so much the case with our "old school" Sprint alloys, which were designed and produced when the tech was in it's infancy.

I'd recommend the 12mm studs if you are swapping to a more modern alloy wheel. If you are sticking to the Sprint alloys i'd upgrade to the Escort (early MKI) 7/16" studs, if you don't already have 7/16" studs and use the later fit 7/16" alloy nuts that fit them. The later nuts are not nearly as hard to get or expensive as the earlier 3/8" nuts.

The reason for using Ford studs is that the original UKC 5475 studs are now pure unobtanium!

Steve