19" Wheels to heavy for MK6 Stock brakes?

[RedRayne_GTI]

Hey all,

So, I finally got around to switching from my winters to my 19" wheels yesterday and I've notice today that under somewhat heavy braking it feels like my brakes are slipping slightly. Could my wheels be too heavy for my stock brakes? or are my brakes in need of a change? I'm still running the stock pads and I'm at 90K kms with no brake pad warning light yet.

I didn't notice the slipping with my stock steelies during the winter.

[toplessvw]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Should not make that much of a difference if any. Just think of it as driving with out a passenger then putting one in. The only thing I could think of is that with the bigger wheels the brakes are running cooler and not in optimum temp range.

[onceover]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Very doubtful you would notice a difference. Think of it this way, the car probably weighs 3000lbs, adding 50-100lbs in wheels wont change much.

[Fizzo20]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Wouldn't a larger wheel have a greater rotational mass as the wheel size/speed increases? I actually have no idea, just speculating because I was curious about the same thing.
Paging Mech_Engg

[RedRayne_GTI]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Thanks for the quick reply everyone.

I was thinking along the lines of what Fizzo said, but I really have no clue either.

[witchcraftz]

Re: 19" Wheels to heavy for MK6 Stock brakes?

ABS system maybe? Are you running a staggered setup? Or perhaps you dented a sensor ring installing hte new wheels?

[MechEngg]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Wouldn't a larger wheel have a greater rotational mass as the wheel size/speed increases? I actually have no idea, just speculating because I was curious about the same thing.
Paging Mech_Engg

Yes, but it is negligible compared to the inertia forces of the car travelling at the same speed that the brakes have to overcome. Good thinking but it wouldn't make a huge difference.
You are honestly probably just used to a higher profile tire and different ride conditions, going from a 16" winter to 19" summer makes your car have quite a different feel, especially if your winters are narrow and the summers are wider. You shouldn't be experiencing any brake fade or temperature related issues because of the change in weather either.
Also has a good chance of being purely psychological

[syncrovan]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Wouldn't a larger wheel have a greater rotational mass as the wheel size/speed increases? I actually have no idea, just speculating because I was curious about the same thing.
Paging Mech_Engg

Yes it would.

It might be nice to get the tire's size from your summer and winter tires to make sure.
How old are your summer tires (date is on it)? Are they at the right pressure?

At a smaller scale, weight of the rim-tires combo will have an effect too....

[RedRayne_GTI]

Re: 19" Wheels to heavy for MK6 Stock brakes?

ABS system maybe? Are you running a staggered setup? Or perhaps you dented a sensor ring installing hte new wheels?

I like to think I know what my ABS feels like when it kicks in, especially on dry pavement, I don't think it was that. And yes, I'm running a staggered setup.

Where would I find the sensor ring?

Yes it would.

It might be nice to get the tire's size from your summer and winter tires to make sure.
How old are your summer tires (date is on it)? Are they at the right pressure?

At a smaller scale, weight of the rim-tires combo will have an effect too....

Summers are 225/35/19 and they were brand new from UrbanExp last June.
Winters are 185/60/R15

[flipstah]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Hey all,

So, I finally got around to switching from my winters to my 19" wheels yesterday and I've notice today that under somewhat heavy braking it feels like my brakes are slipping slightly. Could my wheels be too heavy for my stock brakes? or are my brakes in need of a change? I'm still running the stock pads and I'm at 90K kms with no brake pad warning light yet.

I didn't notice the slipping with my stock steelies during the winter.

I had 19's on my Golf R and I didn't feel any difference in braking. Sounds to me like you need new brakes

[Natty54]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Bbk!

[bobkatkat]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Did you clean you 19" summers on the car after you did the swap? If so you may just have temporarily contaminated the pads.

[kujiwara]

Re: 19" Wheels to heavy for MK6 Stock brakes?

1lb rotational mass is equal to 15lb of mass on the chassis, basic racing knowledge, however most of the time this isn't very noticeable in daily driving, unless your 19s are significantly heavier than your winters such as 20% you really wouldn't feel the difference, or if your car does not make much power eg 2.0 8v you will notice, I doubt it is noticeable on a r32

[syncrovan]

Re: 19" Wheels to heavy for MK6 Stock brakes?

Summers are 225/35/19 and they were brand new from UrbanExp last June.
Winters are 185/60/R15

This is a little over 6% more, not really enough to make a problem like you described about braking.

1lb rotational mass is equal to 15lb of mass on the chassis, basic racing knowledge, however most of the time this isn't very noticeable in daily driving, unless your 19s are significantly heavier than your winters such as 20% you really wouldn't feel the difference, or if your car does not make much power eg 2.0 8v you will notice, I doubt it is noticeable on a r32

I didn't remember it would be that much, I always thought it was about 1 to 5 but I could be wrong.

It wouldn't take much to get 10lbs to 15lbs more per wheel with this setup, added the 6% more on the diameter difference, this could be significant ..... but with nowadays braking system you should be ok.....

To make sure about it, switch back to your winter set and you'll know right away!
At the same time, it would not hurt to check your brakes especially after 90k.....always more important to do first than any engine mod in my eyes!

[bobkatkat]

Re: 19" Wheels to heavy for MK6 Stock brakes?

1lb rotational mass is equal to 15lb of mass on the chassis, basic racing knowledge, however most of the time this isn't very noticeable in daily driving, unless your 19s are significantly heavier than your winters such as 20% you really wouldn't feel the difference, or if your car does not make much power eg 2.0 8v you will notice, I doubt it is noticeable on a r32

You are way to high here Jerry, more like 1lb of weigh is 2-3 lbs on the chassis. You would have to have most of the weight in the tire and very little in the rim to get a 1500% difference. Of course where the weight is makes a bigger of difference, the design of the rim does make a difference. I do notice a difference on the ACR between 19" street pigs and the 16" track tires but that would probably be blamed half on the weigh difference and half on where the weight is 23.5" diameter vs 25.7 inch. diameter.

Here is a good calculator that has all the math. For calculating rotational inertia and acceleration.