I'm could in a possition to save 1.5KG of unsprung weight across the front axles. Question is. Would it be worth it?

Edited 6 April, 201016 yr by faboka vrs

All depends on the cost.

Is it brakes?

Is this unsprung or unsprung reciprocating mass?

All depends on the cost.

Is it brakes?

Sure is the brakes.

According to Brembo's site 312's weight 7.9Kg's each. 288's weigh 7.2Kg.

Its not certain but I could be looking for a new set of discs for my 312 setup. I think I still have my old 288 discs somewhere so all I need is to purchase some 288 carriers. Not going back to the standard fabia calipers as the feel was pants.

Pro's. Slightly cheaper than buying new disc. Can fit 15's and 1.5Kg weight saving.

Con's: not that much cheaper than just buying new 312 discs. Less stopping power.

Is this unsprung or unsprung reciprocating mass?

Had to google that But yes reciprocating mass.

Sure is the brakes.

According to Brembo's site 312's weight 7.9Kg's each. 288's weigh 7.2Kg.

Its not certain but I could be looking for a new set of discs for my 312 setup. I think I still have my old 288 discs somewhere so all I need is to purchase some 288 carriers. Not going back to the standard fabia calipers as the feel was pants.

Pro's. Slightly cheaper than buying new disc. Can fit 15's and 1.5Kg weight saving.

Con's: not that much cheaper than just buying new 312 discs. Less stopping power.

:no:

Don't do it unless you have some lightweight 15" rims your going to fit.

312mm discs aren't that bad,even genuine can be had for less than £100 a pair.

312mm discs aren't that bad,even genuine can be had for less than £100 a pair.

£72.20

Kind of the answer I was hoping for. One of my "lets try something different" ideas.

Edited 6 April, 201016 yr by faboka vrs

I know A.C is not part of unsprung etc

A.C removal is a big weight saver if your serious about power to weight ratio

If it's downgrading the disc size, I'd not bother. If you'd been thinking about lighter tyres or rims, that would be another story.

not worth it, it wouldnt even make a noticable difference.

A set of Pro Race 1.2 wheels would make more difference.

Been toying with the idea of Pro's on the Octavia and fabia, I've already gone down from 17's on the fabia to the standard 16s and though it does not have the same "grip" if feels better if that makes sense? It also means it does not catch the inner arch on full lock anymore.

There was a GB trying to be run on scoobynet for Pro's which had them at a very good price, not sure if its still on or if anyone can join it..........................hmmmmm maybe briskoda should have one?

Definately be worth it I think. Every kg saved of reciprocating weight is worth 8 so you'd save like 11.2kg or 22.4 depending on if you're doing all 4. I'm confusing myself now. But please somebody correct me if I'm wrong

Your formula is wrong, but the principle is correct - a saving in reciprocating mass is like saving mass^4*distance from shaft(m)*rotating speed/second. In this case, set speed to 600rpm (10rps), and we can fill in values of 1.5^4*(0.312-0.288)/2*10 for a saving in reciprocating inertia of ~0.6kg, then add the original 1.5kg lightness.

anyonne interested Halfords have got them on offer, 18's with budget tyres is around the £650 area.

Have you considered flywheel, wheelnuts or pulleys? At Least then the only downside is ££ lol.

Edited 16 April, 201016 yr by JLneonhug

Do you mean rotating instead of reciprocating? The brakes will reciprocate, because they move up and down with the suspension, but the formula above uses the rotational speed and not the reciprocating speed which will vary with the road surface.

I was always taught that the reciprocating mass is the effective mass (component mass plus inertial mass) of the components which reciprocate.

ok done a little more reading on lightweight pulleys for tubby cars...

http://www.seatcupra.net/forums/showthread.php?t=191620

seems like not a good idea..

Lightweight pulleys would reduce the total reciprocating mass of the engine. This does nothing for power, but does let it spin up and down faster when not under load (basically when in neutral and/or declutched) They would offer a slight gain in acceleration, but using the figures above for converting back from 312s to 288s as front brake rotors, you'd see gains of maybe 1.5/1500 or 0.01s on a 10 second acceleration run. Conclusio - lightweight engine pulleys are performance snakeoil, unless you're getting over-speed failures on the stock items.