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visits member for 1 year, 6 months
seen Apr 2 at 23:01

Recently entered the world of IT, I'm now learning to develop databases and build iOS apps.


Dec
10
comment Engine power specification at different rpm?
Great explanation. Do you prefer the peaky curve even just for street driving, or is it mainly because you track your car?
Dec
4
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@BobCross Yep I hope I portrayed that by showing that µ isn't constant. Ok to try make it really clear, I mean a braking system which is overpowered. The pads and pistons and all that have more than sufficient force to slow down the wheels as much as they want - so much so that they could lock the wheels, but due to the use of ABS they don't lock the wheels, they instead grip at the threshold. I don't get why you're saying the cornering grip and braking grip is completely unrelated - didn't you read the "Traction Budget" from The Physics of Racing?
Dec
4
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@mac Exactly, that's what I wanted the answer to contain. Check out the answer I wrote up, do you think it's reasonable?
Dec
4
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@BobCross Not a problem if you don't agree with the edits, I'll just draft up something myself.
Dec
4
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@BobCross I did some more research, and Wikipedia (en.wikipedia.org/wiki/Tyre_load_sensitivity) and other sites (technicalf1explained.blogspot.com.au/2012/10/…) explain that the coefficient of friction decreases slightly as load increases. This explains everything in my mind - your experience of higher mass resulting in slightly worse braking, and even the nose dipping doing likewise. I'm going to draft some edits on your answer incorporation this, hopefully we can come to an agreement.
Dec
3
comment When is EBD (Electronic Brakeforce Distribution) beneficial?
So how come my car claims to have ABS but not EBD?
Dec
3
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@BobCross Definitely, more weight is going to increase the rate of brake fade. However my premise is a one-off stop, so I'd build the experiment around that. This question may be left open for a while until I can actually test this. Also need to make sure I have cash to replace the brakes if need be - this doesn't sound like a healthy test for my brake pads!
Dec
2
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
@BobCross My biggest gripe with your answer is the assumption that the braking force will be the same as the mass of the car increases, even if the tires can still lock up. I also don't get why you recommend a set of articles and then disagree with it. Anyway it looks like we're in a bit of a stalemate until we have some numerical data. I would love to carry out that experiment, I'd have to think where and when I could do it. I'd change it so that weight is alternated each run, current experiment setup will make progressive brake fade skew the results.
Dec
2
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
Your core point is very true - there's a lot of factors that I'm now just realising that go beyond simple block physics. I've had a bit of a read through The Physics of Racing and it's quite interesting. He does say that "If a tyre can take one g before sliding, it can take it on a lightweight car as well as on a heavy car", which is in line with what I've been saying about mass, not what you've said above. However he does explain the challenge of keeping the tires in contact and under static not dynamic friction. If you change the bit about mass, I'll accept your answer.
Dec
2
comment How can I repair cracks in leather seat?
Wow those guys even have my obscure BMW leather colour "Indigo BMW228" - that's the first I've seen of it online. You're a hero, I may actually tackle this project some time and fix my driver's seat.
Dec
2
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
Ok also 3. Can a very skilled driver brake better without ABS than they would with ABS? I gave more detail to the scenario in my question.
Dec
2
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
2. Why is it worse to have the majority of the load on two tires instead of four? Does it increase propensity for the friction to be dynamic?
Dec
2
comment Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?
Wow, impressive answer! This is what I was looking for. Two questions/points: 1. Yep I know a = F/m, so assuming a constant negative F, an increase in m results in an inversely proportional decrease in a. However, static friction being proportional to the normal force is F = m * g * u (coef. of static friction). Substitute in for F, and you get a = (m * g * u)/(m) --> a = g * u. So assuming the same tires, and brakes that can hold the tires at that maximum static force, I don't see why mass would increase braking distance.
Oct
6
comment If my brakes overheat, do they need to be replaced?
Awesome, I'll give you the tick because you were so comprehensive with talking about each part. Is there anyway to know if you've boiled brake fluids, or check the caliper seals?
Oct
5
comment Causes of early clutch failure EXCLUDING driver style
@RoryAlsop I imagine if someone rode the clutch badly, particularly if in a hilly area, you might wear the clutch out in that time. Back when I was learning I did a great job of burning the clutch on some poorly executed hill starts!
Oct
5
comment Why are drum brakes still fitted on Ford's cars?
"Slotted and drilled rotors are a compromise between ..." - they're not really a compromise when you take in to account the full set up of much larger pads and rotors. Interesting point nonetheless.
Oct
5
comment If my brakes overheat, do they need to be replaced?
Wow you and Brian have both given great answers - I'm in a bit of a predicament in picking one! To me, Brian's answer is more comprehensive, but I see you've got a lot more up votes. Can someone else explain why this is so far the preferred answer?
Oct
4
comment If my brakes overheat, do they need to be replaced?
Interesting, so you reckon pads will actually return to a good state after cooling but the discs may not. Hopefully we can get some more input on this.
Mar
24
comment Does accelerating faster worsen fuel efficiency?
I've gone ahead and accepted your answer as I think it gives a more accurate explanation. Rather than suggesting that the slower you accelerate, the less fuel you'll use (not true given fuel consumption at idle), it suggests that there is a minima on the fuel efficiency curve. As Bob said, you do need to consider wind resistance, which is greater at higher speeds and thus favours lower acceleration, though I don't think it would stop there being a optimum point. But really what this requires is testing the OBDII port while driving - may do that some time.
Mar
16
comment Does accelerating faster worsen fuel efficiency?
Wow what an answer. I'm going to need some time to have a good look at this, but I think this information is what I've been looking for!