When do larger tires require larger brakes ?

[MrZappo]

I have a Mojave with 33's from the factory ... I am considering 35's and would shy away from larger as it is a daily driver for me and I am looking for something in the middle ...


In any event, I always see people putting larger tires on jeeps but I have to imagine that it would severly limit your braking power as the tire diameter increases ...

So, just because I want to learn, is this a thing ? And if so, when does it become a concern ?

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[DaleG]

Larger (taller and wider)tires will actually give you a bigger contact patch if proper air pressures are used and may actually increase braking ability. More rubber on the ground, better stopping. There are LOTS of variables that affect braking and traction.

 

[MrZappo]

Larger (taller and wider)tires will actually give you a bigger contact patch if proper air pressures are used and may actually increase braking ability. More rubber on the ground, better stopping. There are LOTS of variables that affect braking and traction.

I am more referring to the brake disk and pads and their surface area ... I assume that they were designed for the stock tire size ... At some point the larger tire will overwhelm the brake systems ability to stop the tire I would think ?

 

[DaleG]

I am more referring to the brake disk and pads and their surface area ... I assume that they were designed for the stock tire size ... At some point the larger tire will overwhelm the brake systems ability to stop the tire I would think ?

Vehicle weight would play a much bigger part in overwhelming the current brake system. Now, that all said, you can go to bigger brake rotors and performance pads and INCREASE braking, but its completely unnecessary with 35 to 37 inch tires.

 

[Mac]

Larger tires increase the braking distance due to the increased leverage because of the larger diameter, tire weight also plays a part. 35s are probably okay but stopping distance would definitely be longer than with stock tires, larger than 35s upgrading the brakes should definitely be considered.

 

[Front Runner]

They have moved to the two piston calipers on the front and larger rotors which was the big brake kit and an upgrade from the past JKs. Plenty of stoping power there already.

 

[Mac]

They have moved to the two piston calipers on the front and larger rotors which was the big brake kit and an upgrade from the past JKs. Plenty of stoping power there already.

For stock JTs.... if you don’t believe the stopping distance increases when you add larger tires your kidding yourself.

 

[ShadowsPapa]

I have a Mojave with 33's from the factory ... I am considering 35's and would shy away from larger as it is a daily driver for me and I am looking for something in the middle ...


In any event, I always see people putting larger tires on jeeps but I have to imagine that it would severly limit your braking power as the tire diameter increases ...

So, just because I want to learn, is this a thing ? And if so, when does it become a concern ?

Nothing to do with tire size. It's vehicle weight. MASS is what you are stopping, not tire size.

 

[Silvertruck]

There’s not a braking deficiency on the gladiator. I have 37’s and heavy ones at that. The trans does a great job of engine braking by downshifting in hard stops. I am sure if i repeatedly jammed the breaks they’d fade fast but there is nothing dangerous about the factory braking power with bigger tires etc.

 

[ShadowsPapa]

For stock JTs.... if you don’t believe the stopping distance increases when you add larger tires your kidding yourself.

Just curious - do you have stats on that, a study? Or seat-of-the-pants measure?

32 vs 33 vs 35, I'd be shocked to see a difference. There's so very little difference in the leverage the road has over the brakes until you get much larger.
Jeep assumed you'd be changing things - I'd bet they have it all figured in up to a point.

 

[ShadowsPapa]

There’s not a braking deficiency on the gladiator. I have 37’s and heavy ones at that. The trans does a great job of driveline breaking by downshifting in hard stops. I am sure if i repeatedly jammed the breaks they’d fade fast but there is nothing dangerous about the factory braking power with bigger tires etc.

That's the other thing - that transmission downshifts and applies engine braking under harder stops. I've shown that in another thread where I went down hill and hit the brakes and let up and the thing downshifted and slowed me down even after letting up on the brakes.

 

[Renegade]

People, meet Physics. Physics says that as the radius of the tire increases, braking power decreases. That being a fact, the JT does pretty darn well with 37” tires.

 

[ShadowsPapa]

People, meet Physics. Physics says that as the radius of the tire increases, stopping power decreases. That being a fact, the JT does pretty darn well with 37” tires.

Yes, leverage - but it would take a fair amount of difference to feel any deficiency. A 33 to a 35 for example is a 2 inch diameter, 1 inch radius, so it's only got 1" difference in leverage. Not much.
The hub center is the fulcrum, the brakes only a few inches from the fulcrum while where the tire meets the road is much farther out. The stock brakes are more than enough - in fact, among the best brakes I've ever had on ANY vehicle. Mine can stop far better and FASTER than even my wife's Grand Cherokee. So I doubt anything less than a 40 would have much impact.
And then you are adding MASS to the thing to be stopped........

 

[Mac]

Just curious - do you have stats on that, a study? Or seat-of-the-pants measure?

32 vs 33 vs 35, I'd be shocked to see a difference. There's so very little difference in the leverage the road has over the brakes until you get much larger.
Jeep assumed you'd be changing things - I'd bet they have it all figured in up to a point.

Physics... the JT has decent brakes but they are nothing great for a vehicle of it’s size. Increase tire diameter increase braking distance.

 

[ShadowsPapa]

Physics... the JT has decent brakes but they are nothing great for a vehicle of it’s size. Increase tire diameter increase braking distance.

I'd argue against 'they are nothing great' - they are BETTER than my prior trucks had, better than any other Jeep we've ever owned. I thought I was going through the windshield first time I hit them even moderately hard.

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