How fast is too fast?

[NutBucket]

Originally posted by: DaiShan
I will check again when it is light outside, maybe I missed something with the flashlight, it is an accord v6 btw (I know I know, but really I just want to know if there is a chance the tires will explode on me) Also the more you do it, does it wear the tires down more?

In most cases a car can go as fast on stock tires as the speedo indicated. I highly doubt you run the risk of blowout unless you sustain the speed for an extended amount of time. The wear factor shouldn't be an issue.

That said, I strongly advise against such an exercise.

 

[DaiShan]

Originally posted by: Heisenberg

Originally posted by: DaiShan
I will check again when it is light outside, maybe I missed something with the flashlight, it is an accord v6 btw (I know I know, but really I just want to know if there is a chance the tires will explode on me) Also the more you do it, does it wear the tires down more?

Umm...no offense, but I seriously doubt if it will get close to 140. Especially if it's stock. Manufacturers usually will put tires that have speed ratings appropriate to what the car is capable of or in most cases limited to. If the limiter is set to 130, then H (rated at 130) rated tires are used. Even if you can, I would not recommend exceeding the speed rating for the tire, unless they are high-performance to begin with and you only do it under certain circumstances. The speed rating is really a measure of the tire's ability to dissipate heat. My tire's are H-rated (Comp T/A's), and I wouldn't have a problem doing 140-150 on them for a short period of time on a cool day. I wouldn't try that on tires from Wal-Mart, though.

I have done it twice, once a year ago, and once just now, I have read that the speedo is a little off at those speeds, but going back down hill it went past 140 (the last listed number) I do not do it regularly because it is incredibly stupid, and I would never do it when anyone else was around. From what I am hearing though, it is even less safe to do with these tires. BTW my car is only drag limited, no governor of any type.

 

[Blayze]

just follow the speed limit. at least then u won't have to worry about speeding tickets

 

[Jerboy]

Tires:

Q 99 mph
S 112 mph
T 118 mph
U 124 mph
H 130 mph
V 149 mph
W 168 mph
Y 186 mph
Z Above 149 mph

 

[Heisenberg]

Hmm...I didn't know those sedans would get up that far. Guess I was wrong. Anyway, without knowing the speed rating of the tire I can only say that if the tires are in good shape, you will probably be okay for very short runs, but I really wouldn't make a habit of it if it were me.

 

[mellondust]

This is too fast.

Edit: Click on JATO.

 

[DaiShan]

No, it is not something I do often, and isn't even something I would LIKE to do (I know Hondas are not safe at higher speeds), thanks for your help.

 

[SuperTool]

If I don't see CHP for a few miles, I like to go about 90-100 mph cruising speed if traffic is light. Sometimes I go faster, but only in bursts, and never about 120 mph. I have Maxima, which is about same class as your accord v6. In CA, if you go abouve 100 mph, that's reckless driving, which I believe is misdomenor. So it's not worth the risk usually. Sometimes I get carried away though and look down at the speedo, and see 115 mph or something.

 

[OS]

You can sustain the tire rated speeds for extended periods of time without a tire failure. I used to have T rated michelins on an accord, they are rated for 118 mph and I've done ~115 on them for 15-20 minutes at a time. Once made it between SD and LA in less than 50 minutes. Average just under 100.

You can also burst substantially above the tire ratings for a couple minutes without a tire failure. I've done over 125 on the same tires w/o a problem. I've never tried extended runs significantly over the tire rating.

That being said, be really really careful, bad sh*t can happen when you are going substantially over 100. When braking, do it very gradually, any sudden actions is serious bad news at high speeds. You don't want to lock the tires at high speeds. I like to nibble away my speed until I'm under 100 and then brake harder. If you see a pack of cars far ahead, brake early, it's never too early to slow down at triple digit speeds. Plus you never know if that pack of cars is following a cop. Same for turns, back off the speed on even moderate turns. If you hit a piece of wood that fell off some truck at over 100, God help you. Remember to look far far ahead when driving fast. And if you are using crappy tires, I wouldn't even try any of this.

Also, if you are going to drive really fast, don't do around other cars. Personally, I don't care how many laws are broken when people are by themselves, but I think it's really bad stuff to drive fast around other cars.

Finally, I've wrecked one car at high speeds. I walked away from the kind of accident that most people die from. I never drive triple digit speeds now. There is no such thing as 'safe' and 'unsafe' speeds, only shades of grey. In some situations, even the posted speed limit is unsafe. That is what your situational judgement is for. Think carefully and pick your poison.

 

[Nefrodite]

depends if you want to turn u forgot the exact speed but f1 cars have downforce of twice their weight at very low speeds already

 

[Turkey]

Do you have aftermarket tires or a sport package or something? 50 series tires are usually pretty "sporty," and I couldn't find any reference to 205/50R16 tires on a stock v6 Accord on google. It'd be more useful to have the manufacturer & model name than just the size if the rating isn't printed on the tire.

A few things about going fast:
1. You're going to have to stop eventually, and stopping takes much much longer at those speeds than they do at regular highway speeds. Chances are you will horribly underestimate the amount of time and distance it takes to slow down & stop when you are going 140 mph.
2. Different cars have different aerodynamics... most cars "lift" at high speeds. It could be as few as 10 lbs at 140 mph or more than 100lbs on both the front and back. This is a bad thing, because you lose some downforce that gives you traction when turning, but you still have to turn the same amount of weight. So you will lose control more easily. If you have a rear spoiler, it will probably create a negative lift on the rear tires but dramatically increase lift on the front tires, so you will have even less control.

The good thing about street tires is that you will be more likely to slide than roll if you lose control, because most don't have sticky-tire traction. But if you slide and hit even a small bump sideways at 100 mph, you will likely roll the car. If you are sliding at 100 mph and hit a moderate pothole, you are screwed. You might even be screwed if you hit a moderate pothole going straight at 140 mph.

I wouldn't hit top speed in most cars on the road today, especially the family sedans. They just aren't made for it. The power is for acceleration, not top speed.

 

[CocaCola5]

At high speeds, cars tend to have BOTH understeer and oversteer, front tires sorta stops working and the rear gets all unstable, due to lift. Lift is the main reason its dangerous to drive fast.

 

[Kadarin]

DaiShan: If you just see something like "205/50R16" on the sidewall of your tire, just look a bit to the right, where you will see the numbers relating to the load rating and the speed rating. It'll say something like "85H" or Z or V or whatever the speed rating is.

However, do NOT assume that just because your tire is rated to, say, 149mph, that it's safe to drive on it at that speed. A lot depends on the car, on the proper inflation of the tires (i.e. if they're underinflated, they're more likely to go kaboom on you), and driver skill.

Be safe. If you plan on eliminating yourself from the gene pool, please do not take anyone else with you.

 

[chickendinner]

Also speedometer error is on your side
after 100mph its anywhere from 5-10% incorrect
I know its 10% on motorcycles but not sure on cars.

 

[sharkeeper]

When the speedometer needle matches the same position as the hour hand of my watch at dinner time. (160 mph speedo)

Actually, stupid speed governor WILL cut in and light up LIM lamp on dash at 157 +/- 2mph...

Cheers!

 

Tire Guide

 

[IGBT]

The ones I worry about are the lowriders leaning to one side with bullet holes in the doors and dried barf trails on the sides of the thing. Are those guys really having a good time??

 

[LAUST]

N=87 MPH, 140km/h, Spare Tires
P=93 MPH, 150km/h
Q=99 MPH, 160km/h, Winter, LT Tires
R=106 MPH, 170km/h, LT Tires
S=112 MPH, 180km/h
T=118 MPH, 190km/h
U=124 MPH, 200km/h
H=130 MPH, 210km/h, Sport Sedans
V=149 MPH, 240km/h, Sports Cars
Z=149 MPH, 240km/h and over, Sports Cars
W=168 MPH, 270km/h, Exotic Sport Cars
Y=186 MPH, 300km/h, Exotic Sport Cars

 

[ATLien247]

Several years ago, my GF at the time had Q rated tires on her Escort GT. We were on a road trip, and while she was napping in the passenger seat, I decided I would see what this little car could do. Going down hill, I estimate we were going a little over 100mph. I couldn't really tell because the speedometer didn't register at that speed. The needle was almost all the way around to zero, but it would also fluctuate rapidly.

Anyhow, I finally slowed down to regular speeds. Shortly thereafter one of the tires blew. That was the last time I ever went that fast, in any car...

 

[skyking]

Your car is not just "drag limited".
Aerodynamic stability, or the "lift and down forces" produced at different speeds, can combine with small variations in the pavement, to completely ruin your day.
The interstate freeways are speed rated also, and large, gradual bumps and hollows exist. These defects are well within the specifications at 90MPH, and are not very noticeable at 70.
If encountered at 140-150, the unweighting effect of crossing from a low to a high spot may just get you airborne, or light enough on either end to completely lose control. I tried this maximum speed manuever with a lowered '66 mustang, but no spoilers. Luckily, I did not lose control, but it was not a good feeling.

 

[Carl Uman]

My diesel only does 95

 

[GermyBoy]

Haha, I thought you were going to ask a question about your relationship with a girl. However, you're talking about useless crap.