Impossible to say as it's obviously going to depend on the circuit and hope all the cars handle exactly the same left to right.

 

If you are talking about a two-lane plastic track you can "do the math" to find out how much of a difference there is between the two lanes. Usually a single crossover in a layout will improve lane length equality. Also, if the cars and drivers are equal, as you state, then the shorter (inside) lane will be quicker simply due to the fact that it is shorter in length.

The whole quandary around lane lengths and how to get them equal is to implement lane rotation. That way every driver gets to race in every lane.

 

I think it is generaly assumed that the outside lane is the fastest way around.

I respectfully disagree.
While it's not universal due to a laundry list of reasons for things to be different, I've found that most tracks with uneven lanes get faster laps on the inside (shorter) lane, when the car is properly prepared and the driver of sufficient skill. This is based on my personal experience as well as observations of racing on a variety of tracks.

Since one cannot prepare a track for all combinations of cars and drivers, it's my opinion that the best planning includes at least an attempt to make the lanes of equal length. At the very least, don't make them even MORE uneven than they would be without any specific elements to make them even, which is what you're suggesting.

I've seen tracks where the outside lane is given some shortcuts where it's on the inside of a turn, but I've never seen a track where the outside lane is made even longer. I'm sure they exist, though, and we'll see them soon, since I just said they don't exist.

 

The most accurate way to measure the difference is with a timer....adjust...test...repeat

 

I have sort of covered this several times in my thread such as here. Lane lengths are 37.96', 39.80', 41.66' and 43.50'. With a few cars...

Lane 1 | Lanes 2 | Lane 3 | Lane 4 | Total Time
4.127 + 4.137 + 4.295 + 4.387 = 16.946 | Black Ford GT
4.069 + 4.186 + 4.321 + 4.425 = 17.001 | Red Audi - 0.03% slower
4.236 + 4.216 + 4.354 + 4.436 = 17.209 | Red Ford GT - 1.55% slower
4.290 + 4.200 + 4.350 + 4.404 = 17.244 | Black Audi - 1.75% slower

Accumulated to...

Lane 1 | Lane 2 | Lane 3 | Lane 4
16.722 | 16.739 | 17.320 | 17.652 | Total time per lane
0.0% | 0.001% | 3.6% | 5.5% - Percentage slower than lane 1

To make two lanes equal time you would either increase the faster or decrease the slower lane's length by the distance traveled by the time difference? I also think you have to define the fastest as my Lane 1 is fastest for one lap however if the race was 10 laps I'd take Lane 2 as it's easier to drive. The consistency would more than likely make up for the additional distance. And don't forget two cars won't handle the same in all lanes. Again in my thread running three cars one car won in four lanes and another won in four lanes (going both directions on the track).

 

I have two lane Policar track and the faaster lane by around 1/2 - 1 second is the one with more inside corners so is shorter

 

As I've never seen two really equal cars yet alone drivers does it really matter that much and as said above just rotate the lanes during the race.

 

I’m currently undertaking a substantial modification to ‘Loch Downs’ due to the inside lane being too much faster. The outside lane is a faster average speed but even with some extra banking to make it even faster i’ve come to the conclusion that an overpass to make the track a figure 8 is now my best option.
if you’re club racing I don’t think it matters as you’re getting on each lane for an equal length of time, and for social racing I put the slower drivers in the quicker lanes. The problem is my main opposition and I are very well matched and he felt I was being unsportsmanlike when I put further work into my car to help it keep up, whereas I felt it was essential for me to do this if I was going to win ANY dice.

 

I think one good approach is voltage. With separate power supplies (or CU settings for cars) you should be able to even out the lanes with no problem. From above the cars are averaging around two tenth from Lane 1 to Lane 4. A little drop or increase in voltage (based on lane) would hardly even be noticeable when driving.

 

I have a 4 lane extended figure 8 track. The two inner lanes were always just a bit faster than the two lanes with the longest and tightest curves. I put buck converters under the control panel for each lane (thanks Paul chappyman). I thoroughly clean the track and take a great handling car and run one lane at a time. I adjust the power level for each lane till I can run consistent 4 second laps. I do this by myself with nobody else there. I clean tires after 10 laps or so. I end up with a little more power on th 2 outside lanes. I can use the same car and run laps within .05 on every lane. Being a figure 8 style track, the center lanes run about even with each other and the outer lanes fall behind when they are running the outside curve, but pull back even when they have the inside curve. We limit cars to a fast lap time of 4 seconds and have a few races rotation or just sprints every week where sometimes you can't tell which car wins. There are deniers but this is sure an easy way to make lanes even and it actually works.

 

I think it is generaly assumed that the outside lane is the fastest way around.

It depends on the characteristics of the car and the relative lengths of straights to corners.

In the simplest case, take a circle with two lanes. Any car will lap quicker on the inside lane if it develops the same g force on both lanes. In that case the outside lane is not the quickest. The difference becomes more marked as the bend radius tightens, given constant lane spacings.

If we now look at a simple “oval” with the circle split and two straights linking the halves, the outer lane has a temporary advantage as the car will exit the bend at a higher speed and therefore spend less time and distance before reaching maximum speed. The straights will therefore be covered quicker in the outer lane.

Whether the time saved on the straights is greater than the time lost on the bends depends on how quick the car accelerates (and brakes), and whether it reaches its maximum speed or not.

Every track and car combination will be different in this respect. That’s the theoretical side as posed in the o.p. In practice of course, most drivers find the wider radii easier to drive. Hairpins can be very quick but you have to get the braking and cornering spot on every time to realise the advantage.

 

Inside lane isn't fastest otherwise we'd see F1 drivers sticking to it...they don't, they stick to the widest curve possible through a bend.

 

Inside lane isn't fastest otherwise we'd see F1 drivers sticking to it...they don't, they stick to the widest curve possible through a bend.

Sigh. Yet another example of your simplistic nonsense, Kevan. You might like this one too:

Outside lane isn't fastest, otherwise we'd see 1500m runners sticking to the outside lane of a 400m athletics track. They don't, they stick to the tightest curve possible through a bend.

 

If only the forum had a Faceplant emoji...
Neither view is applicable to slot car racing.
The racing line is not an applicable principle here.

Both Dave and Kev have oversimplified the racing-line principle.

Kev : the widest route (biggest circle radius) only applies if you can enter the corner wide, clip the apex, then exit wide doing so while at high speed and on the limit of adhesion. Can't do that with a slot car.

Dave : 1500 metre runners WOULD take a racing line ,clipping fhe apex , if they were running at race car speeds. Once speeds increase toward the limit of adhesion, "sticking to the inside"( to shorten the distance ) requires a drop in speed in order to get around the corner.

Generally in multi lane (4 or more) slot car racing, the edge lanes are slower because they have a combination of the smallest turns (requiring the car to slow down more) and the largest turns (requiring the car to cover more distance)

 

I tried varying the voltage with minimal benefit. I have found a .15v variation lane to lane is optimal and still the best I can get is 1/10th difference. I have tried stupid levels of voltage and have found a plateau due to wheelspin/sliding.

 

I tried varying the voltage with minimal benefit.

A similar (less likely) approach is "cementing" controller settings. I can alter a car's performance in very small increments via sensitivity and traction control. Admittedly not easy to audit or control... oops I don't know how it moved from 8 to 10.

 

Recently helped a friend set up a short oval track, with the same voltage on all lanes the inside lane was lapping the outside lanes every couple of laps. Added some diodes to drop the volts a little, I think I added 5 to lane 1, 3 to lane 2 and left the outside lane at 12 volts, and that evened out the lap times.

 

On my 4 lane oval the inside lane is the quickest.
It might seem like your going faster on the outside lane but the times tell the tale.
From out to in your times are faster, but for me it makes no difference as I run 4 lane digital.

 

Well I guess I was wrong! I was thinking that if you are in the outer lane you will be traveling a little faster due to wider radius. You would be faster exiting the turn and would reach maximum speed on the strait first. But as been proven there is more to it than that.

 

I've noticed that new/intermediate drivers often find that is the case. This is also often connected to driving with cars that use traction magnets but that have poor actual traction. but that's probably more coincidence than anything else.
Once you learn how to navigate the tighter turns better, the shorter distance more than makes up for the need to slow down a little more.

 

my track is a 3 lane set up with a length of 100 ft. (33 meters )with a crossover making the lanes equal in length. lane 1 ,has the tightest curves ( 2 ) as compared to lane 3
both can usually get the same times ,with most cars ,however the centre lane can be a tad faster ,but not much ,
but after saying that ,some of my cars cannot get anywhere near the times they do when on either of the 2 other lanes
a very few cars actually out perform their times of lanes 1&3
so it all come down to car specifics ,c of g , tyre s ,responsiveness to throttle ,braking ,and the track layout as well

 

For my posts above I am talking about times from the same car and driver on each lane, so as to remove as many variables as possible other than the lane configuration.

 

me too

 

Boys and their toys 🤗

 

True, but my post did generate 3 hahas, so I'll award myself a C- for effort.

Whatever, it's an amusing thread, particularly considering that at post 12, Gripping Pneus explained it perfectly and there didn't really need to be much/any discussion after that, yet here we are at post #32. 🤣

And as for the outside lanes usually being slower on multi-lane circuits because they have a combination of the largest and smallest turns, that's a whole other debate. Outside lanes on Ninco, for example, are slow because the cars frequently slide onto the track borders which have a slightly less grippy texture than the track proper, plus car-unsettling raised kerbs on the outside 50% of the border. Molesey's wood track definitely isn't slower in the outside lanes.

 

The sarcasm was so obvious a dumb foreigner like me got it, and I am not even blessed with that world famous "British sense of humour" Whatever that is.

To get back on topic, when I drew the first SSRC layout, the brief was: No bridge. But the difference between lane 1 and lane 4 was 3m (around 10% of the lap length), so we had to include a bridge to even the lanes out.


Joel

 

I'm not sure if it sounds too easy to be true or if it is too complicated for guys to understand, but the variable voltage to each lane actually creates equal lap times on all lanes no matter what configuration your track is. The buck converters are very easy to install. This is just inline on the power feed to the controller. Wire in and wire out. You can buy them from Amazon for $5 each or so. Very simply, if a corner is slower for one lane over another, a slight power boost will allow a bit more speed on the straights and that makes up for the slower speed in the corner and the lap times come out even for good drivers.

 

Apologies for any misunderstanding but I thought that your point was that the wider radius was the fastest - as per your post #13