[IntProst]

I've been looking/searching around the forum and I can't seem to find a clear answer to this question - well, three questions really.

I'm thinking about putting a larger tire size onto my 2012 TDI Touareg. On one site (1010tires, tire size calculator) there is a warning:

Warning! When changing tire sizes, we recommend staying within 3% of the diameter of the original tire. Any more than this and you face the risk of brake failure.

I see many people on this forum are running tires that are more than 3% larger than the original equipment tire size.

So finally my questions:

1. What are Touareg owners doing, if anything, to address this problem?
2. Where can we get upgraded brakes for our Touaregs?
3. What is the largest brake upgrade that can be accomplished with 18" OE wheels and swapping out just the brake rotors (i.e., using existing calipers, with some sort of mounting plate to relocate for the larger diameter)?

I think I'll simply stay within the 3% diameter of OE size and avoid all the potential trouble... but I am interested in your answers.

 

[noobytoogy]

Well there are loads of folk who have gone up to nearly 10% bigger from the standard 29.0 inches O/D to 31.5 inches O/D, the maximum that will fit in the wheel arch.

No one has reported brake failure.

But then again, perhaps they had brake failure, died and haven't been able to log in from heaven or hell!!

 

[IntProst]

Yea, I hope we don't have any of those "died trying" members around.

 

[nickm]

I'm not understanding the relationship between wanting bigger tires and brake size? The only risks you face with a larger overall diameter tire is rubbing your fenders, slowing your vehicle down (due to gearing) and throwing your speedo/odo off.

 

[Traillab]

The larger the tire the harder the brakes are going to have to work to slow the vehicle. Imagine the old lesson about a longer leaver or a cheater bar. The axle is further from the road surface and so is the brake disc. Of course I'm stretching back to my ******* days of putting 44s under a toyota. It was harder to stop.
i think this is more theoretical than real life. What is it like a one and a half a percent larger radius on the Egg?

 

[Yeti]

The larger the tire the harder the brakes are going to have to work to slow the vehicle. Imagine the old lesson about a longer leaver or a cheater bar. The axle is further from the road surface and so is the brake disc. Of course I'm stretching back to my ******* days of putting 44s under a toyota. It was harder to stop.
i think this is more theoretical than real life. What is it like a one and a half a percent larger radius on the Egg?

Yeah, you are not putting anything that big on a Treg unless you are mating the whole body to a truck chassis for true ******* modifications. The biggest diameter I believe you can do on a non TDI is 32" and pretty much 30.5" on a TDI due to rubbing the intercooler vents inside the front fender wells.
To the OP, the stock brakes will be fine, don't sweat it. I have oversized tires on mine and it brakes just fine.

 

[IntProst]

Traillab - going from the OE size of 29" diameter up to a 30" diameter is a 3.4% increase. Going to 30.5" is a 5.2% increase. I'm sure the 1010tire (and presumably other tire sites) warning is fairly generic, and they've picked 3% for liability reasons. That's probably a safe number for most (all?) vehicles, while many could go beyond that.

Yeti - Have you noticed any increase in brake pad wear or other mechanical items with your oversized tires compared to before you got them?

 

[Yeti]

Yeti - Have you noticed any increase in brake pad wear or other mechanical items with your oversized tires compared to before you got them?

No, I have been running oversized tires since I have owned a Treg. It stops just as well as the stock diameter tire. It does make the speedo dead on accurate as well as making the odometer slower. Beyond that no issues at all.

 

[Traillab]

x2 Yeti
Still a very small # indeed. That's diameter (5.2), it only the radius, the length of the axle to the ground, that is the increase, so its half of that or 2.6%.
I've looked at Hawk pads after some reviews gave good results.
Most of us here are running around on larger/taller tires.

But I think folks We've strayed from the original questions of the thread. One of which should be straight forward, "#2 Where can we get upgraded brakes for our Touaregs?

 

[nickm]

The larger the tire the harder the brakes are going to have to work to slow the vehicle. Imagine the old lesson about a longer leaver or a cheater bar. The axle is further from the road surface and so is the brake disc. Of course I'm stretching back to my ******* days of putting 44s under a toyota. It was harder to stop.
i think this is more theoretical than real life. What is it like a one and a half a percent larger radius on the Egg?

That would assume the Treg was built with brake that are borderline...the Brembos are anything BUT that.

You could swap out Cayenne Turbo brakes...

In any case any significant upgrade that would improve over the stock braking system would be in the multiple thousands of $$. The Cayenne Turbo Calipers/Rotors would run you around $4K, the next size up Brembos would run you about $6K out of their aftermarket catalogue..

IMO I don't think you'll be out-braking the stock Brembos enough that you need to upgrade them, Its not like the Treg comes with ****ty brakes....unless you have a few thou burning a hole in your pocket

 

[IntProst]

Regardless of using the Diameter or Radius of the tire, you get the same percentage increase when moving to a new size. You can't take the percentage from the diameter calculation and then divide by 2. You must do it all as diameter or all as radius.

With the number of members here that have increased their tire sizes, and the comments from Traillab and Yeti that they (and presumably others) have had no increase in wear on their brakes, perhaps there isn't need for an upgraded brakes/big brakes discussion.
Dead Horse

I was told when buying my 2012 that one of the changes from the previous model was the switch to a a four-piston caliper (I presume on the front). Maybe the rotor is a smaller diameter or not as wide... in order to save weight.

I suppose if someone wanted to upgrade their brakes, they could switch things to a previous model, or even move to Audi Q7 or Porsche Cayenne brake parts - rotors and maybe calipers. My previous car, a Pontiac G6, was terrible for brake repairs. A few people on the G6 forum upgraded rotors and calipers from other GM (and Saab) vehicles.

 

[nickm]

The brakes are the same in the Treg as on the Q7/Cayenne on all but the Cayenne Turbo. I'm not sure about the euro only TDI V8...

They moved to 4 piston in 09..I can't notice a difference between the 6 piston calipers in the 3 tregs I had before that and the 4 piston in the 09...there is no difference in size of caliper or rotor when the moved from 6 piston to 4 piston.

The brakes are engineered to provide high performance stopping for a 3 ton vehicle than can also tow an additional 4 tons...so it gan easily generate enough force to stop 7 tons very safely and very quickly. It a bit ambitious to assume a small increase in rolling diameter would require new brakes to deal with it...

 

[Yeti]

The four piston front calipers started to appear in late 06 I believe. I think Treggin in CO has them on his 06 v6. The rotor size did not change at all and the calipers look to be the same size, more then likely they went with larger pistons instead of smaller ones in the 6 piston.

As with Nick I noticed no appreciable difference in braking over the older 6 piston other then they appear to have went to a different material pad up front since they are no where nere as grabby as the OEM pad on the T1's.