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Hi Martin,

I've been very interested in this since I came across this thread. What a great effort! It certainly looks like it pulls up well. First impressions on the braking behaviour?

 

Couple of questions for you if I may, and important ones for Aussie registration rules,

1) What is the overall track increase?

2) what are the caliper piston sizes.?

 

Really looking forward to seeing the CTIS set-up.

Ian.

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Hi Ian,

 

the setup has been calculated to give best results while retaining a) stock main brake cylinder and B) stock booster setup. The caliper volume fits into that regime. This setup has been dimensioned to remove the automatic 4wd/6wd engagement and still be able to stop a 4t car within legal limits. I am sure, that is where 99% of all other conversions will fail, because they have been devloped for use on light 4x4 trophy trucks and would in no way comply with any official regulations - even if their owners claim it. A simple excel sheet can easily proove the oposite here.

 

Secondly we have the overlander in mind, who relies on spare parts. While we were not able to do this with a cheap OEM caliper (the one that we had in mind went out of prodution before we were finished...), we are using IDENTICAL calipers all around. There is only a left/right difference in terms of differential piston setup, but overall you would be able to survive an emergency by simply taking a rear axle caliper and putting it in the front. That's the idea behind it.

 

The overall layout is identical to the Pinzgauer 718, which also uses 8 identical calipers on 6 identical discs. Best spare part availability in the outback ever ;) In terms of braking force we have dimensioned the setup around 10% above the Pinzgauer (even with 37" tires!), in terms of fading stability we should be miles ahead.

 

To answer your questions:

 

1) We use differential piston setup for even brake pad wear. So a caliper contains 2x38.6mm and 2x41.2mm pistons, resulting in an equivalent of a single ~80mm piston. For comparision: Pinzgauer would be at around 76mm.

 

2) I have drawn up a lenghty comparision between a stock standard Volvo on drums and the tigerexped setup with our own 9x17 wheels and 37x12.5R17 BFG MT KM2. Take a look and feel free to ask more questions if needed:

 

ZZ6BAA5643.png

 

Ciao,

 

.martin

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Looking at a total for the prices you listed this conversion will cost somewhere around 1000€ (+VAT) per wheel?

 

It has been a month since the video. Have the testing given you any more conclusions regarding the design?

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Hi Tamaz,

 

yes, we have been working on that stuff and fixed 2 problems that we have found during testing and also finally setteled on a thread size for the CTIS connection on the front face of the hub.

 

Front axle always costs more than a rear axle, because of the double caliper setup and I think you need to be realistic about complete conversion costs.

 

While you can source most of the parts needed yourself (in case of tires you will have to anyway, because we cannot supply them), I have roughly calculated what you will need to spend (not nessecarily on our parts, but in general) to complete a full conversion with all new bearings, tires, wheels, brake lines, bolts, hubs, calipers, pads, brackets and whatnot.

 

As I said, costs are not quite symmetrical for front ans rear wheels, but if you would simply divide total cost by 4 and 6 you would REALISTICALLY end up at around: ~1600 EUR per wheel plus VAT plus shipping to you. Spare wheel costs around 450 EUR plus VAT/shipping (tigerexped steel wheel + 37" tire, internet price).

 

I will try to get all parts up onto the website soon and also try to pack some sort of kits to give a littttle better pricing, but since this project will not make us rich anyway, there won't be too much discount possible.

 

We can only accept pre-paid orders, as we are not financially equipped to pay for all of your kits that you might not take in the end - this was atually just a private project to get a nice disc brake conversion for our own car... so it has evolved a little into something bigger due to public interest ;) I will push all sales through my girlfriend's online shop to help with logistics and be able to do proper VAT deduction for all of you outside of Germany, just in case you are wondering who is the billion dollar company behind all this :D

 

Hope this helps, I know I am slow.... I have a full time job besides all this ;)

 

.martin

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I've been waiting for a "real" disc conversion (ie: that doesn't need to destroy anything on the car) since I have my C303 and now, I'm in love 8)

This is definitively excellent work.

 

I've read you use 17" rims and 37" tires (with a 6x6).

 

With a 4x4, wouldn't it be better to use 35" tires (or 315/75R16 but this means 16" rims)?

Do you have any advice on this?

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Klug, Im not involved but from reading all the text i figure that when new rims were designed for the project, 17" was chosen since it is more common and therefore more tires to choose from on the market. I haven't had a look myself if that's the case but from what i read, that was the reason for the 17" rims.

 

 

Tiagra:

 

Yea, i totally forgot about the double calipers in front when making my calculations... Thanks for reminding me. :)

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@Tamaz, my question was more about tire size than rim size.

My understanding was that 17" was chosen to have enough room for the calipers.

 

I've read here and there that 315/75R16 or 35x12.5R16 was the "best" dimension for 4x4.

My C303 was fitted with 900x16 tires when I bought it, it was nice on (high speed) roads but they felt too tall (eating too much torque) on tracks (especially in the Alps). 

 

6x6 have a different ratio, that's why 37" sounds (to my knowledge) ok with them.

 

If I chose this way (this disc conversion), then I'll go with tiagra's rims.
So, with a 17" rim what would be the best size for "easily available in Europe" all terrain (not mud) tire on a 4x4?

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@Klug, i didn't think of the difference in gear reduction between the models.

Try looking at 315/70R17, that's just 0,6% difference from 315/75R16 in circumference and the same with.
 

post-9208-0-77815800-1465997958_thumb.jpg

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That's http://tiresize.com/, isn't it?
Just discovered it. It's great! Thanks.

 

It seems 35x12.5x17 exists too.

 

Now I just have to find out what is easily available in France...

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Hey guys, Tamaz is right, th 315/70R17 is basically the perfect 17" pendant for all 315/75R16 people. There is a wide range of tires available, even real winter tires etc. 37" is a little less common and mostly available in more aggressive threads usually. In Europe anyway. In the US the selection is much better...

 

About rim choice: The 17" steel is needed to clear the large brake system. Usually steel wheels are pretty narrow on the inside, that's why standard 16" steel wheels usually don't fit. I have tried 16" aluminium beadlock wheels from Tibus, which are basically flat inside and therefore have better clearance: They fit. TIght but no problem. SO if you really wanted to stay with 16" and have some spare cash, you can also go 8x16 aluminum double beadlock. I will also make a kit including those, but beware: These wheels cost a lot of money. Not quite as much as the (narrower!) Hutchinson wheel for the G wagon, but close. Anyway, it's an option and might be interesting if you take into account, that you can keep existing tires or whatever. There is also an 18" double beadlock wheel which I haven't tested, but it might also fit - costs even more than the 16" version, but if someone is interested, I will also try to find a solution for that. I personally think our 9x17" steel wheel is the perfect solution :)

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Martin,

 

tiny mistake (I think) in the 4x4 kit: "4x (actually 3 left and 3 right hand) 330x32mm vented brake discs by ATE." while it should be "2 left and 2 right".

 

About the wheel archs, you say there's a picture here (on the forum), maybe adding a link would be nice if anyone wants to see it?

 

Prices are with VAT, will you be able to sell ex-VAT (EU company buying)?

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Oh yes, mistake :) thanks for spotting it, will correct it tonight...

 

The 'here' actually is a link to the post with the width comparison above... The stupid shop template just doesn't show it. Will try to color it somehow...

 

Ex VAT: absolutely! That's one reason why we need to do this officially through tigerExped.

 

Ciao,

 

.martin

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YW.

 

I showed your solution to a friend of mine and he told me something like: "This is for a 6x6 that is much heavier, could it work with a single caliper for the front wheels on your 4x4?".

 

I obviously was not able to answer  :(

 

I told him about the double braking on front wheel but that was all I could think about to keep the two calipers.

 

Do you have any idea about this?

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Hi Klug,

 

yes I have an idea about this, because I calculate stuff before I build it ;)

 

Short answer to your friend would be: Counting calipers does not help and means exactly nothing.

 

I will try a medium answer for some more insight ;))

 

For one: Yes you need a brake dimensioned like ours "only" for cars up to 4 tons. That's what the calculation is based on. So on a 3.5t 4x4 you could go with a ~12.5% smaller setup.Since the difference is so small, we have not developed a second configuration for obvious reasons.

 

Secondly, the whole setup did not come out of the blue, but is a direct copy (in terms of overall dimensioning) of the Pinzgauer 716/718 disc brake setup that has been adapted for a) larger tires, B) only 4000kgs, c) the brake booster setup present on the Volvo and d) legal requirements of maxiumum pedal force for specific amount of brake force delivered.

 

d) has been calculated with the Pinzgauer setup aswell and it can be seen, that their setup also complies with this rule. (500N force on the pedal for a 50% braking procedure, here calculated at 4000kgs)

 

a) The pinzgauer tire size is pretty small, only around 430mm in diamater, we use 470mm diamater for 37" tires. That means just for the tires we need to come up with about 9% more braking power to be within legal limits.

 

B) is the compromise to make it possible at all, and to be on the safe side since most of us have down-rated their 6x6 to 3500kgs for various legal reasons.

 

c) the Volvo has a weirdo 2x7" booster setup, which gives more power to the brake system than the Pinzgauer 8" booster, so that is good. In case of failure of one booster, you would not be within legal limits anymore, but the pedal force needed to stop a 4000kgs truck with be well within humanly possible limits, so consider that a safety factor of the Volvo brake circuit.

 

Now let's see some OEM cars and their calipers:

 

* Sprinter 906 (4.6tons): Double piston brembo calipers, 52mm, wheel size pretty small but 9/10" Tandem booster (!)... piston diameter per wheel: 73mm

* Volkswagen T5 Multivan (2.8tons), single piston calipers, also 9/19" tandem booster and "small" wheels, 60mm piston per wheel

* Pinzgauer 718 (4500kgs), larger tires, 2 calipers with 54mm each, only 8" booster, equals 76mm piston per wheel.

 

Even though there are some factors that influence size of calipers etc., one thing should become pretty clear by now: The heaver the car, the larger the pistons/calipers needed. The big differences in booster size are due to the fact, that the overall setup nowadays is a little diffferent from back then: Now we optimize cars for comfort, so we use pretty large main cylinders, that in turn need huge boosters to give the same system pressure as we would have reached back then with smaller boosters and larger main brake cylinders. We gain very small brake leverages and the car therefore feels more sporty. The overall dimensioning stays the same: pedal force multiplied by booster must equal enough pressure to stop the car within legal limits.

 

Now let's see what we've got on the THE BRAKE:

 

* Volvo 303/304 (3500-4500kgs), double piston double caliper, with 38.6 an 41.2mm pistons, dual 7" booster (basically just like 7/7" tandem), equals piston diamater per wheel of 79.8mm.

 

Notice something? 79.8mm piston diameter and all the other parameters (disc diameter etc.) equals about 10% increase of system "performance" over a standard Pinzgauer setup.

 

So to sum it up: THE BRAKE is not some crazy lunatic setup, way oversized for the job, but it is VERY comparable to other OEM setups and calculated to stop a 4t Volvo on 37" tires within legal limits with a proper safety margin, as you would expect from a OEM setup aswell.

 

GIven that, I hope your friend can trust in the brake setup dimensioning of Magna Steyr, Volkswagen and Mercedes Benz, because THE BRAKE has been designed based on their existing setups. Not more, not less ;)

 

That was the medium length answer with no math involved, hopefully that will do it. I know THE BRAKE is expensive, but over-dimensioning is not the reason ;)

 

Ciao,

 

.martin

 

P.S.: Almost forgot to answer your question: YES, absolutely, you could get some calipers made, that are big enough to have a single caliper setup in the front. But: I don't know such a caliper from any OEM, one reason why Steyr also used TWO calipers on their car to get to the needed piston area. Secondly, even if i managed to get a 6 or 8 piston caliper manufactured that lead to the needed piston sizes, it would not be cheaper and huge as f*ck. Secondly I would introduce a second type of caliper on the whole car, since of course you would need a smaller variant on the rear axles. The result would have 2 major disadvantages: You would reduce the number of calipers manufactured for each type, thus raise manufavturing costs per caliper again. Secondly you would end up with 2 different types of calipers of your rig, thus totally undermining the concept of identical parts to enable emergency repairs and servicing on the road. In summary: Does not make sense. Unless... unless you raise the overall system pressure to a point, that would allow using a smaller piston caliper. E.g. by introducing a hydraulic brake booster or some 9/10" tandem booster setup with different diamater main brake cylinder and so on. That would basically lead to overall dimensioning of a whole system, which I did not want to do and which many of you wouldn't want, either. So instead we decided to keep as much of the stock system as possible, copy the best parts of the Pinzgauer and the Unimog (basically only the double caliper idea and overall dimensioning) and modify to suit our needs.

Ok, that should do it for now... Good night ;)

 

P.P.S.: Just for illustration's sake and to make you feel more comfortable with the double piston setup... we are not alone here:

 

Pinzgauer:

5775119.jpg

 

Unimog:

Grafik11.jpg

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I love your answer. Perfect. Thank you!

It does confirm me this is the good setup (keeping most of the stock system, same caliper all around, easy to install/manage).

 

How will the order process be handled?

Is it individual (anyone who wants the setup pass its own order) or will you "organize" some kind of "grouped order" (I think I read this on Vince's forum)?

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The orders will be individual with us, but we will wait until we have a certain number of orders until we order all parts. Reason is, that we need to meet minimum order quantities to reach a sensible price level for most of the parts. Good news is, that we basically have enough orders already, so there won't be further delays once we started. You can order now, but we will probably start with production process in about 6 weeks only, as i am still waiting for some feedback from German TÃœV regarding vehicles for German customers. Zhe earlier you come forward with your orders, the easier it is for us to plan.

 

We will NOT be able to stock conversion kits, as I am not a bank or a rich man ;))

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Presentation/transportation box done :) Will hopefully take it to some exibitions/meetings and also our local TÃœV guy to have a look :D

 

ZZ2A993056.jpg

 

ZZ49D11201.jpg

 

ZZ0ED80D37.jpg

 

Good night ;)

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Hello guys,

 

I have VERY good news: German registered cars will have the chance to get this setup legalized, we'll hold a special test session on Germn TÃœV proving grounds in late October this year. All calculations look good and we are good to go now.

 

This means: We will start taking orders NOW and all orders that have been paid by September 1st 2016 will be part of this production run. It is uncertain whether there will be future production runs, because we always need a minimum number of cars to make it feasable. So if you are thinking about it, now is the time. I will try to personally get back to people who voiced their interest in the past, but not sure I can catch all of them. Feel free to share among your friends, this might be the one and only chance.

 

See ya, I am EXTREMELY happy now ;)

 

.martin, just back from talks with TÃœV

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Does anyone know where/how to contact user 'hoss' other than PN in this forum? He was very eager to participate back then, but now seemingly impossible to make it happen for him, due to lack of contact :/ only about a week to go until we start the production run...

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Ok guys, last call for this production run: we'll close orders by tomorrow night. Next run, if at all, only in a few months from now.

 

See ya,

 

.martin

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Good luck! I am a bit curious on how many sets you will produce this time (and I do understand if you want to keep the production numbers secret for now).

 

It has been very interesting to follow the progression of the disc brake project, and this is the only option I would choose if I were to change to disc brakes on my C303. For my use, however, the drum brakes are good enough for now.

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It's not a secret: We'll probably do 9 vehicles in this production run. Scattered around the world from Australia, to France, the Netherlands, Ireland, Germany and Romania. Only 2 of the vehicles are actually registered in Germany, one of them being my own ;)) Let's hope everything works out as planned, otherwise this will be one expensive f*ck*p I will pay for the rest of my life :>

 

See ya,

 

.martin

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