How close is too close for a brake caliper

[PeteH]

there is about 5mm missing of the end of the stud.

Hi,

So the other 4 nuts are relying on 5mm of thread, or about 3 turns give or take.....that is certainly not enough thread engagement....especially for a vehicle you about to punt around a race track.

Be safe and call it a day.

Pete

[RobertoX]

With a 5 mm spacer you'd already have lost the location from the hub spigot to the wheel right?
As a general rule you should also have at least 1 full thread visible above the top of the nuts, the thread sometimes tapers in a little at the top. Assuming open top nuts.
For your clearance you should only need a 1.5-2mm spacer anyway.

[Cuzzo]

put the street wheels on and go have fun

[PeteH]

Hi,

+1 for cuzzo's idea. Go home get standard wheels and enjoy

Pete

[YLD-16L]

Ditto the standard wheels/tyres. Far safer than the other option.

You'll get booted too if any staff see you're only running 4 out of 5 wheel nuts. Other drivers may even report it if they saw.

[allencr]

dont really wanna shave them i have pretty supra brakes

So will 4 wheel nuts be enough?

I think some priorities need to be rearranged.

[1jz68u]

ok got it sorted. was having a chat to some of the mechanics that were with some of the porsche's that were there and we got some of the caliper shaved off as it was a better idea than any of the others i had at the time. worked perfectly no trouble at all.

thanks for all the advice guys. some of the things i was considering were very stupid, it was just the pressure of being there and the atmosphere.

[greywolf]

Goddamit, this was headed towards a Darwin Award !

Seriously though, good stuff choosing the smart and safe route mate. Wish more people changed their mind for the better more often like yourself.

[Lachie]

ok got it sorted. was having a chat to some of the mechanics that were with some of the porsche's that were there and we got some of the caliper shaved off as it was a better idea than any of the others i had at the time. worked perfectly no trouble at all.

thanks for all the advice guys. some of the things i was considering were very stupid, it was just the pressure of being there and the atmosphere.

So how much clearance did you end up having? And was there any rim to caliper interaction?

[JustenGT8]

With my previous R32 brake setup i had very close clearances, around 1mm. With street tyres this was fine but track rubber (semis and full slicks) would make them touch....dunno if it was the extra grip under brakes twisting the caliper more or lateral grip flexing the wheel/hub/whatever? Only touched enough to 'polish' the caliper but illustrated that things move more than you expect and eveything on there was very very solid and enginer approved.

[rsdeo]

If they are multi piston, meaning fixed calipers not floating there should be no worries. No matter how the pads wear. The caliper outside edge will never move.

[takai]

The caliper outside edge probably wont move (although the flex on the strut might cause it to) but the hub and therefore disc too will move, most certainly will move, and if the hub is moving ever so slightly then so is your wheel.
I have to run a 2mm spacer on the IPRA car because the caliper was self clearancing one of the wheels.

[1jz68u]

we cleared what we thought would be enough, but it does appear that there was some rubbing, nothing too major just taken a little more paint of the caliper and gave the back of the rim a bit of a polish.

i was told by several people that being a fixed caliper even 0.5mm of clearance would be enough, turns out they were wrong. i guess there are all sorts of things going on under load when on the track that don't normally happen.

Takai, did you get your 2mm spacer made up? i havent found any that are only 2mm.

i am getting new wheel studs that will be slightly longer as well.

[takai]

Nah, one of the guys i know just had some kicking around. I swapped a beer (1) for them.

[JustenGT8]

Easy to make, Linden could whip you up a set in no time