So I bought some 10 mil v1 ichibas for the front but after some thinking, Ive decided that I would like to use 15mil instead. Assuming I can get my hands on some 15mil spacers (minus the studs), can I use 15 mil spacers on studs that were meant for 10 mil?

I realise you can run up to 5mils on oem studs. Will 5 mil make much of a difference when it comes to extended studs?

 

its your life at stake here...i wouldnt cheap out. studs break=you die, studs dont break=you live

 

Do not cheap out on this one. Don't risk it.

 

I doubt a spacer would ever break. It's a flat piece of aluminum/magnesium alloy or some other strong metal. The spacer doesn't take any load. Your using good studs that's the important thing. I assume they are the 40 mm extended ones. Which are 10mm longer than OEM. So you'll still lose about 1 to 1 1/2 turns if you go 15mm. It's up to whether you feel that's safe. Seems like some ppl have run 5mm spacers on stock studs just fine. There's a formula for how it's calculated. Something like the diameter of the stud = how long it should be or something like that. I personally would not go any wider than 5mm without longer studs or 15mm in your case and I'd be paranoid as hell for the first while and probably would be carrying a torque wrench in the car with me for the first while any way.

 

Or just get the right offset wheels. There is a thread here I posted a few years back with someone who had almost lost their life with failed spacers.