Big Rear Discs

[Sidecar Man]

So after looking round and staring at the car the biggest let down on the V60 Polestar was the rear discs and calipers. I didn't want to go to the hassle of changing calipers as it's electronic hand brake. But thought some bigger discs would look better. It runs a 370mm front and 20" rims. So the rear 302mm discs looked a bit poultry. I spoke to Martin at reyland and we decided on a 350mm discs with 8mm less offset to allow for the bracket. Just need to get them fitted now. Bracket is machined ready and if it works I'll have one laser cut and plated.

[LTP]

So you're going to change the discs and risk upsetting the braking balance just because you think the rear discs look a little small? Really?

[Sidecar Man]

LTP said:

So you're going to change the discs and risk upsetting the braking balance just because you think the rear discs look a little small? Really?

That's correct. You think a 22% increase in swept area is going to upset the brake balance with a single pot caliper. It's a 2 ton car and has 370mm front discs with 6 pot calipers.(Compared to s standard 322mm disc on V60)
Explain to me how it's going to upset the brake balance!!!

[LTP]

Sidecar Man said:

Explain to me how it's going to upset the brake balance!!!

If you think the swept area is one of the determining characteristic of braking force then I don't think I can.

I can point you at this article though
https://www.sciencedirect.com/topics/engineering/d...
and invite you to consider whether increasing rear brake performance when you have weight transfer forward and the rear tyres are unloading under heavy braking is necessarily what you want to do, especially when the motivation is purely subjective aesthetics. I'll add that if your car initiates the anti-lock system you definitely want it to initiate on the front axle first to maintain straight line stability under braking.

Am I saying that it won't work? No. Does my post imply that it might not work out well? Yes. Your car and clearly your choice

[Sidecar Man]

LTP said:

If you think the swept area is one of the determining characteristic of braking force then I don't think I can.

I can point you at this article though
https://www.sciencedirect.com/topics/engineering/d...
and invite you to consider whether increasing rear brake performance when you have weight transfer forward and the rear tyres are unloading under heavy braking is necessarily what you want to do, especially when the motivation is purely subjective aesthetics. I'll add that if your car initiates the anti-lock system you definitely want it to initiate on the front axle first to maintain straight line stability under braking.

Am I saying that it won't work? No. Does my post imply that it might not work out well? Yes. Your car and clearly your choice

Thanks for the indepth reply. I will have more indepth read but it is interesting from what I can see. I haven't blindly go into it I have been talking to a company in the States that make a kit that's 350mm and a 4 pot caliper they've been testing and are now producing and selling the kit with no issues. Plus K sport said they could see no issues with my proposal.

[Sidecar Man]

Well all fitted and tested in both wet and dry plus tried Esp traction all works spot on