Speedsterclub.nl

vet cool, Maik!

Hello together,

a great and friendly "Goede middag" to the nederland community

I´m a german Speedy-friend, perhaps some of you know me from Edersee or other nothern meetings. sorry for writing in english, but I don´t know anything of the dutch language (indeed of the english one not so much more )

I hope you can give me some more information about these fantastic (?) allibelled discs. Markv was so friendly to answer some questions before, thank you for this once more.

So, as you perhaps know, we have to go every two years to the german TÜV (mot) for a technical control. In the meantime one has to look after every technical modification, that is has been already proofed by the TÜV.

If this isn´t proofed in anyway before there is an opportunity to go as the first to the TÜV with all type of documents (dimensions, weights of the discs; certificate of the taken materials for the discs, bells, bolts; strengthcalculation - some kind of stability proof - structual or stress analysis). They will proof this and in best way, you get the official ok

All this is necessary for respecting the rules of the insurancecompanies... allinall very costly but in the opposite quite sure...

Sorry for the whole text in the beginning... now my questions:

The 10 sets, are they only used on tracks? I think, you have not a kind of TÜV in the early years, but in the following time? If so, has anybody checked this to get the discs through test?

How are your experiences with the discs? Has anybody before using them driven normal crossdrilled discs? Are there any differences in dry or wet conditions?

Thank you in advance, kind regards

Dag!

Hi,

the discs have no TUV approval as far as I know. We do have a yearly test for cars older then 3 years. But the rules are quite different from the german TUV.

I use the discs on street and on track. No issue's what so ever.

As the comparison to crossdrilled discs, I don't know what the purpose would be of the cross drilling other then looks? Main difference in wet/dry braking will probably be the pads you are using.

Cheers,

Mark

Same experience as Mark for me.
I inspected the discs everytime after a trackday and they still look as new

I would get in contact with the supplier and see what you can arrange with him. If they can get a TUV approval on them a whole new market could be in reach for them, and with you as their public relations man in Germany
Maybe they have TUV approval on the alu belled discs for the elise? As they have sold a lot more of those as for the speedster. The steel part is the same, the alu bell is different, but this might help a bit...

Good luck!
grtz,
Maik

Thanks or your answers.

Well, I´m in contact with geary. But he don´t has any documents or he doesn´t want to have any


Are there any marks, signs on the rotors, which tell something about the used material?


Yes, I want to try a groupbuy in germany... but for this I need some more specifications...



Maik: do you have weigh the complete discs too? Markv and Geary said something about 5kg, but I need it more precise


Kind regards

Hi Hasi,

I did some weight checks before they went on:

standaard rotor 7.35 kg
alu-bell rotor 5.45 kg

The thickness of standaard one was aprox. 1mm reduced. The weight differance should be more than 2kg on each wheel!!

I hope this helps.

note:
Thorney (UK) has got alubel replacement discs as well. They're AP approved which might help you to get them through TÜV technical control easier.
Here's the LINK buy 'em for 470,- each?

1mm disc thickness less means almost 0.3kg reduction in weight, so the standard brake disc would weigh around 7.65kg, so (on Dominique's scale) the alu belled discs from Geary are 2.2kg lighter each

Don.Hasi schreef:Well, I´m in contact with geary. But he don´t has any documents or he doesn´t want to have any

Usually he's pretty helpful, but you may want to be very specific about the exact information you need to be able to get some for of TUV approval. I suspect he would be worried that someone could copy the setup if he gave out a lot of detailed info.

As he sells most of his parts in the UK and to the USA he's probably reluctant to invest a lot of time and perhaps money in an approval process for road use in Germany where the market seems to be pretty well covered by local developers (eg. Moto-Concept and similar) for both the Elise and the Speedster.

Are there any marks, signs on the rotors, which tell something about the used material?

No. They are CNC machined, but no stamps or marks are on the product to identify the alloy type used.

BTW..

Is it legal under the TUV system to replace the outer steel part of the 2-piece brake disc and then keep using the center piece?

The reason I ask is that I have seen several 2-piece brake discs sold in Germany like these:



But these are only sold 'complete'. So you can not buy the steel part of the disc separately. The reason given by the manufacturer in this case was that this would void the TUV approval?

Bye, Arno.

@Dom: cool price isn´t it Yes, I know the discs of Thorney. But these have a greater outer diameter. So you have to use an extra bracket for the caliper...

The AP-System should be TÜV friendly, indeed...

We have weighed the stock ones with 7,43kg. So the difference would be "only" 1,98kg per corner...

I wonder how there is so much difference between the S2-Elise and the Speedy... Does anybody have a solution for this?

oh, btw we have also weighed the stock crossdrilled for the turbos. They weigh only 5,59


@Maik: We have weighed them different... but I will ask again in our community.


@arno: no question. Geary is supernatural friendly He answers any stupid question with a lot of humour, many informations and again and again and again. Because of his character I only want to help, selling a few sets of this lovely discs more, as there are greater circumstances for getting a TÜV-approval at all.

That there are perhaps some confidental infos may be... but the other way round, with our system it is not usefull to deal with not approved brakesystem... i wouldn´t declare, that all german Speedy are legal, or quite legal in the opposite but concerning the brakes there is no "easy way" In some views also right, for sure...

So, cause there aren´t any information on the discs, I couldn´t help him a step further. So we have to wait whether he got more informations or not.

Any other discs are much heavier. The ones of Sandtler too: the RS/A weighs 6,3kg Yes, they are tüv-approved. It was said, that the rotor could be changed. But how you have said, I haven´t seen any company, that delivers the rotors only.




Cheers

Don.Hasi schreef:oh, btw we have also weighed the stock crossdrilled for the turbos. They weigh only 5,59

Correct.

The cross-drilled brales for the Speedster are actually S2 Elise brake discs, but now with an 5-bolt setup.

If you compare them side-by-side then what causes the weight difference is clear: the air-gap is much bigger on the crossdrilled/Elise discs than on the normal plain Speedster (Vectra/SAAB) discs.

So there is much more metal on the normal discs than the Elise/crossdrilled ones.

Very useful to have extra heat capacity on a 1500+kg car.. Not so much on a 800kg car..

Bye, Arno.

Don.Hasi schreef:...

We have weighed the stock ones with 7,43kg. So the difference would be "only" 1,98kg per corner...

....

@Maik: We have weighed them different... but I will ask again in our community.

.....

Dominique has weighed both types of discs on the same scale (correct me if I'm wrong Dominique), so the difference quoted by him (and me ) should be quite accurate

Hope you can arrange something with Geary!

Arno schreef: So there is much more metal on the normal discs than the Elise/crossdrilled ones.

yes, I have seen this on the excellent pictures of Maik.

But how do you explain the differences between the S2-alli-belled-discs and your VX-discs regarding, that we have just one hole more?

Very useful to have extra heat capacity on a 1500+kg car.. Not so much on a 800kg car..

very interesting point. So, the material takes heat. But do you ever brake a 1500kg car like our 850, do you go with your your van on a track? I for my case would say no. I would also say, that I would drive nearly the half of the speed of my vx on streets like attached.

Wouldn´t it be better to have then more material in this case with the vx too? What do you think? Is lightweight in this case more counterproductive ?


@Maik: Oups. I didn´t wanted to offend someone. The discs we have weighed have been 3000km old on a turbo. So something must counted on the weight. But I don´t know how much. Did we have the km of the discs from Dom? Perhaps we can draw a line...

Thanks for your support

Cheers

Don't worry Don, I was far from offended

Arno meant that the drilled speedster discs have far thinner discs than the OEM non drilled. So the same as the Elise S2 brakes. So that is where the weight reduction can be found.

And don't worry with the discs from Geary, I gave them a lot of beating on Zandvoort last season and the whole combination of these discs in combination with the CL RC06 pads. After ten laps they felt as fresh as on lap 1! Really no difference. And I do not brake early so to say

Don.Hasi schreef: But how do you explain the differences between the S2-alli-belled-discs and your VX-discs regarding, that we have just one hole more?

Not sure I'm understanding right..

The plain Speedster discs are from the Vectra V6 and weigh about 7.5 Kg

The cross-drilled Speedster brake discs are identical to the original S2 Elise brake discs, except they are now 5x110 (and 63mm center bore) and not 4x100 like the Elise. They weigh about 5.5 Kg

The Eliseparts discs use the same design steel part as the cross-drilled discs, but using better steel types, and use an ali center and weigh about 5 Kg for both the Speedster and Elise version.

very interesting point. So, the material takes heat. But do you ever brake a 1500kg car like our 850, do you go with your your van on a track? I for my case would say no. I would also say, that I would drive nearly the half of the speed of my vx on streets like attached.

You need a tradeoff/compromise.

The thicker walled discs take longer to warm up and can 'store' more heat. So they take longer to get real hot and may resist warping better. But the tradeoff is that the smaller air-gap also reduces their capacity to transfer this heat to the air again and get rid of it.

The best situation is to find a brake disc that's thin enough to get up to good working temperature quickly (get the best braking performance) but not too thin so it overheats (warping, blue discoloration, burnt pads) during hard braking actions.

Also it should not be too thick/heavy, or the disc will slowly creep up in temperature as you keep adding energy to the disc, but it can not get rid of it fast enough. This will slowly boil your brake pads and fluid. Can also damage your hub bearings and driveshafts because the heat transfers from the brake disc to the hub.

It's a bit of a balancing act. The orignal Speedster discs from the Vectra V6 are perhaps a little over-dimensioned when it comes to material thickness.

The AP versions (290 and 295mm) are pretty similar to the cross-drilled and Elise versions when you look at them. Relatively thin walls and large air-gap. They are made from much tougher steel though.

Bye, Arno.

Maik: in every way fine So your description with the argumentation of geary and arno verify the decision for these discs I would take them at once, but our racemanagement would discover them as a tune up version at once... much risky... and as told above, any insurances are blown away without certification... ok, then we have to wait what Geary says


arno: If the allibelleddiscs from geary for the vx weigh like dom has proofed 5,45kg, then they are 0,5kg heavier than the s2-allibelleddiscs from geary which should weigh 4,95kg. That the design of the rotors should be nearly the same is obvious. But where comes the increase of 10% from ? Any ideas?


Cheers