Do brake calipers expand with heat?

[ecs0set]

I have larger brakes on my car and even with bigger wheels the clearance is tight. I've just had new tyres fitted and the clearance between the brake calipers and the lead wheel weights is about 3 Rizla papers (maybe 1-2mm in reality).

I could go back to the tyre fitters and ask them to move the weights back. However there is definitely clearance at the moment so as long as the brake calipers don't expand it will be fine.

I'd rather not give them another opportunity to scratch the wheels.

Thoughts?

[bimsb6]

Are the calipers on sliding pins ? Sounds a bit close to me , a rizla is about 1/1000 of an inch so 3 are nowhere near a mm .

[Chris32345]

If they move the weights back it quite easily could then not be balanced soi Doubt moving a weight back is a solution

[ecs0set]

bimsb6 said:

Are the calipers on sliding pins ? Sounds a bit close to me , a rizla is about 1/1000 of an inch so 3 are nowhere near a mm .

Don't think so, 4 pot calipers. Rizla papers were a comedic exaggeration, looks around a mil by eye, maybe 2.

[kambites]

1mm is plenty of clearance. Steel expands to roughly 1.000011 times its size for every degree rise in temperature so for a 100mm piece of steel (from mounting point to rim) to expand 1mm would require a change in temperature of roughly 1000 degrees, which would come pretty close to melting the caliper.

Edited by kambites on Monday 29th March 19:20

[stevieturbo]

All metals expand with heat. Various metals will move when under load too, including wheels, calipers etc etc

[GreenV8S]

Caliper expansion is unlikely to be a problem. Bearing flex could very easily be a problem, especially when the bearings are hot.

[Dave Brand]

I had a similar problem with balance weights catching on the calipers (not sure which car, probably the Alfa 145) after having tyres fitted by a mobile fitter. Didn't spot it straight away, as I didn't move the car until a few hours after he'd gone.

When the fitter came back he said there was nothing he could do! The solution, obvious to me but not to him, was:

1. use lead rather than steel weights

2. check the thickness of the new weights against the old

3. lay the new weights on a flat surface & hammer them down to reduce thickness

Guess which tyre company I've never used again?

[ecs0set]

Thanks for all the comments. Based on the above, I'll leave it and keep an eye on it.

[Krikkit]

Dave Brand said:

I had a similar problem with balance weights catching on the calipers (not sure which car, probably the Alfa 145) after having tyres fitted by a mobile fitter. Didn't spot it straight away, as I didn't move the car until a few hours after he'd gone.

When the fitter came back he said there was nothing he could do! The solution, obvious to me but not to him, was:

1. use lead rather than steel weights

2. check the thickness of the new weights against the old

3. lay the new weights on a flat surface & hammer them down to reduce thickness

Guess which tyre company I've never used again?

Sounds like a pain in the arse for the fitter at what, £10/wheel?

[Dave Brand]

Krikkit said:

Sounds like a pain in the arse for the fitter at what, £10/wheel?

His problem, not mine! If he'd just taken the simple precaution of turning the wheels before dropping the car off the jack he would have avoided having to come back. I t was the "nothing I can do" attitude that amazed me.

[thebraketester]

I get my front wheels static balanced so the weights avoid the caliper. Small increase in wheel vibration but only above speed which are irrelevant for 99% of use.

[Matt_E_Mulsion]

If they are not hitting the caliper then I wouldn't worry about it.

[The Wookie]

If they’re a cheap Chinese aftermarket caliper I’d worry more about caliper flex under high pressure but a few mm is unlikely to cause you a problem

[TEKNOPUG]

I fitted AP Racing calipers and bigger discs on my WRX with maybe 1mm clearance between the caliper and inside of the wheel spokes. Ran it for 60k without any issues.