Spitfire Spitfire wheel studs

[tktrain]

Just in the final phases of completing a full rebuild of the chassis of my '78 Spit during a full frame off restoration/mild modification for durability and performance. I have gone with the obligatory shorter and slightly stiffer front springs and a stiffer rear spring, urethane everything where available, ceramic pads and carbon metallic shoes plus 100% new brake parts and copper/brass brake lines. Also, I'm replacing all the bearings and seals along with new trunions and vertical links... well, basically new everything. The crown wheel and pinion were perfect so those stayed.

Here's my question: I'm concerned about the durability of the 3/8-24 wheel studs. I have a set of 7/16-20 studs for the Rover that are basically a direct fit in the existing flange/hub holes which would be significantly stronger. The question is, are they worth the effort to install? I intend to run 15x5.5 (+22mm offset) Minilites with 195/50-15 tires which would be the same outside diameter as the OEM installed tires.

 

[Don_R]

I have heard the autocross guys do it because of the hard cornering they do..

I'm not racing my Spit so the upgrade to the larger studs is not in my future

 

[This14u]

Paul Geithner has some good info on Spit stud upgrades on his site

https://auskellian.com/paul/links_files/upgrade_spitfire_wheel_studs.html

 

[Bob Claffie]

Raced Mk2 and Mk3 Spits for several years back in the day. Never a problem using the original studs. One change made was to use CYLINDER HEAD NUTS as replacements for the regular lug nuts. Much beefier. Bob

 

[Andrew Mace]

Raced Mk2 and Mk3 Spits for several years back in the day. Never a problem using the original studs. One change made was to use CYLINDER HEAD NUTS as replacements for the regular lug nuts. Much beefier. Bob

Fascinating, Bob! Equally fascinating is that I've heard the very opposite as well: lug nuts made for better cylinder head stud nuts! Maybe someone at Triumph mixed up the spec. sheets way back when.... :laugh:

 

[Bob Claffie]

Drats ! Caught again. That's what happens when you trust a forty year old memory.
Lying in bed this AM deciding to get up or not and this "goof" popped into my head and I couldn't wait to correct it. I guess that's why my friend Andy is a moderator and I am only a lowly contributor. Thanks Andy for setting the troops straight. Bob

 

[tr8todd]

I used to run 7/16 studs on the TR8 race car. I routinely snapped them, mostly changing wheels. My guess is they stretched under racing stresses and constant retorqueing. When I changed the bolt pattern to 4X100 and installed 1/2" studs with a larger knurled end, problem went away. No more snapped studs and cheap abundant wheels. Keep in mind, there is a huge difference in grip between 10 plus inch wide Hoosier slicks and normal street tires.