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MG MGB Technical - Accelerator pedal placement
I've been driving a '73 BGT, and the accelerator pedal is giving me some grief. over the last year or so, I've been learning to heel-and-toe in my mother's car (better than something I have to pay repair costs on) and I can do it fairly well. When I got into the B I found that I couldn't find the gas pedal with my heel, no matter where I put my foot on the brake pedal. The Accelerator is set back about 2 inches from the brake pedal. Is this the normal alignment for the two pedals, and if so, is my technique wrong? |
Dave Pothecary |
I personally have cut the height down to the minimum on my '77. You just pull the pedal out of the car, cut it off, then re-weld it down as low as it will go. Then lube up the shaft, and re-install it. Much better relationship to the brake pedal. That would be for heel and toeing of course. It is uncomfortable to drive, even for a short 5'8" guy. Now my leg is straighter. I also added a 'dead pedal' for my left leg, to help me brace my body, in competitive driving. Safety Fast Dwight McCullough |
Dwight McCullough |
You know, that's something I always wondered about. If this heel-n-toe tecnique is so helpful, why don't cars have the pedals designed for it? I'm not sure that any of the vehicles I've ever driven have ever been set up for it, as it seem an incredibly awkward position to put your foot in and then try to move it quickly. Assuming you could do it correctly does it even make a difference? The only time I even thought it might help to be able to hit the gas and brake at the same time was when I had the turbo on the car. Anybody here who really understands what this is all about? Do you have to be pigeon toed to do it correctly? Jim |
Jim Blackwood |
The factory pedal was eventually modified to make heel'n toe-ing easier, which is why people like Paddy Hopkirk made a fortune out of gizmos that clamped onto the standard pedal. But it is not so much heel and toe as the sides of the feet, or the ball of the foot on the brake and the arch on the accellerator, you just adopt whatever strategy fits your pedals the the flexibility of your ankles. When on a single-seat driving experience we were told to 'heel and toe' to blip the throttle on each down-change, even when going from 6th to 5th to 4th holding the clutch pedal down all the time, to make life easier for the gearbox. |
Paul Hunt |
The pedals In my mum's car (2000 Vauxhall astra) are about 1.5" apart, and the gas pedal is down maybe a half inch below the level of the brake. My friend James has a midget and the accelerator and brake are about half an inch apart and totally level. You need narrow shoes to not hit the brake and gas at the same time. I usually brake with my toes and tap the gas with my heel Which might well be the wrong way round. It's a bit tricky with the poor throttle response in modern cars, but pretty satisfying when you can change down without anybody noticing. Aside from avoiding damage to the gearbox, matching revs while changing down will reduce wear on the clutch, and also reduce the risk of shift lock. |
Dave Pothecary |
Heel & toeing in the B is acheived easily - just brake with the left side of the right foot and blip the accelerator with the right side of the same foot. The pedals level up with the brake applied - I do this all the time to keep the engine from stalling when cold. |
Chris at Octarine Services |
I have trouble with that, as I have to get the brake pushed quite a way through its travel before I can find the gas pedal. By quite a way, I mean the brakes are on really hard (a whole heap more than I normally use, and probably only a little away from locking the wheels). Is there any way of adjusting the pedal, or is this about normal for a B? |
Dave Pothecary |
Dave, Different year MGs are a bit different, I think, but in general you raise or lower the pedal by adjusting the cable stop at the carburretor. I set mine so that when the pedal is all the way to the floor, the throttle plates are fully open. That way I know that I get full throttle when I want, but there's no danger of over-stressing the cable and possibly pulling the cable stop loose. I seldom heel-and-toe. but I have on occasion and the pedal positions seem reasonable, if perhaps not ideal.... |
Rob Edwards |
Dave Its not so much the throttle as the brake pedal that would be the easiest thing to adjust. The 1980 pedal box is the best set up for heel toe and with some of those bolt on pedal sets, even better. I am going to make this a bit of a project when i have cleared the other MG tasks i have, but one thing you might like to attempt to do is set the brake pedal up, such that the the first movement is slack (i.e. pedal take-up with out operating brake) until it is level with or just past the first movement of the throttle. That way the two pedals will be level and you will be able to rock the foot back and forth over them more equally. I would imagine that the problem you are having no is you are over braking when trying to blip the throttle which rather knackers your technique!! Personally i find the acclerator too far over to the RHS to be comfortable to heel and toe - the 1980 is further to the left and as i have said above, a far better set up all-round. Jim FWIW, heel and to is a great aide to driving an MGB or other *older* or very powerful RWD car. It smooothes out the gear changes and settles the car better during spirited driving. I have found also that some modern cars work better for this technique to - the Peugeot 306 HDi being one of them, because the diesel engine seems to have such a steep torque curve and turbo spool, that down-changing under hard braking without a blip of throttle before the lower gear is selected can be rather jerky!!! People have developed different techniques to suit personally, and often the techniques are changed from car to car, but i personally, attempt to brake with the ball of my right foot and *roll* the outside of foot against the throttle, such that the 4th/5th toes are on the gas. So its not strictly heel-toe at all... The idea is to blip the throttle as the gearshift is moved through the gears on a downchange before the clutch is lifted up, to spin the next cog up faster and smoother. Not so much needed with synchromesh (some say it even knackers synchromeshes, but hmmm not sure on that!), but was part of every day driving-life yonks back!! If one was to attempt to drive point to point in something similar in set up to a B, i.e. RWD, no driver aides, and a bit brutal in driving experience, but say with a massively powerful engine - eg Bv8 or new TVR perhaps..? It would be a brave man who down changed hard on the brakes before a bend, without heel- toeing to smooth it all out!! Chances are the rear axle would lock up and spin the car! ~PHIL |
Phil |
Interesting. So what we're talking about here is mostly just a matter of timing then, trying to speed up the process of blipping the gas to smooth renegagement of the clutch in a lower gear just prior to exiting the turn. Possibly of some use while racing I would think, on a closed circuit where you have many repetitions to develop a line and timing through the corners but for spirited motoring on the backroads the attention might be better spent checking for potential road hazards and setting up the exit line. I can see why you might want to practice it though. Jim |
Jim Blackwood |
Jim Its one of those techniques that we are not taught nowadays and people think are redundant, until you have the priviledge of a spirited drive in the hands of a master.... THEN you understand what its all about. It depends on how you view your driving i suppose. If you can master it, its a good technique to use - in all conditions, EVEN on the road. Situations such as wet or icy conditions would benefit from this technique to smooth everything out, certainly. I don't have a problem with people using it on the road, if they are proficient in the technique. Most who do it all the time (of whch i am not - i am still perfecting the techniques), would do it without even thinking so, hazard awareness is not affected. I'd recommend if you do get the chance, to have a go at learning it! :-> ~PHIL |
Phil |
Jim I understand your hesitation to acknowledge the benefits of this practice. In reality the technique is only necessary to protect the weak synchromesh system used on early MG gearboxes (and others). If done correctly, especially on a down change, the gear lever engages the next gear with less pressure on the lever. This is an indication that you have matched the revs correctly and the synchromesh was hardly used to match the gear speeds. This is quite unnecessary on more modern gearboxes. It is also true that if incorrectly done you can increase the load on the synchros. cheers |
Ian Buckley |
In theory the pedal position is fixed. There should be a metal bracket on the toe-board that the pedal hits just as the carbs get to full travel so you are not stretching the cable or pulling on the shafts in the carb bodies. The amount of travel is controlled by the carbs, and the adjusting nut on the pedal bracket controls the amount of free-play in the cable as measured between the finger on the throttle spindle and the choke spindle. Without the bracket, and if the cable is adjusted so the pedal hits the floor, the pedal position will be a good couple of inches lower than it should be. |
Paul Hunt |
Jim, Heel and toe is important for the entry of corners. When driving hard, there is little traction to spare. A situation known as shift lock can develop, where the engine when thrown into a lower gear is enough, in combination with the braking, to lock the back wheels. This is obviously a bad situation, and heel and toe technique reduces the braking force of the engine to a negligable level, enabling you to select the correct gear for the corner whilst decelerating smoothly. This is the technique that racing drivers have to use to brake late and power on early. |
Dave Pothecary |
I don't know if Chris Betson has very big feet, or drives in wellies all the time, but in my '71 there is no way I can brake with the left side of my right foot and touch the accelerator with the right side. The gap is simply too big. Mind you, I do have small feet (UK size 7). If you read contemporary road tests of the MGB, one thing all testers moaned about was the impossibility of "heeling & toeing", a practice I used all the time when I drove a Midget. But then the Midget also has an organ pedal accelerator hinged on the floor which I love. I've never driven a late model B, which are supposed to be better. Mike |
Mike Howlett |
You know, I think I have one of those brackets in the parts bin, maybe I should search it out for a look. However, I'm afraid in my case it's going to take some work to set things up properly. Back about '81 or so when I did the conversion I used a shortened clutch fork and external slave but I still had to put a box under the gas pedal to clear the shift linkage and I've never put it back to original as it was only in the last rework that I went to the internal slave and I need that corner of the footwell off a parts car to do it up right. This meant I had to shorten the gas pedal about 2 inches. The box makes a handy footrest and I've gotten used to it over the years, though at first it was slightly akward. But this means the only way to press the gas is with the toes. This winter as the engine will be out might be a good time to rework that area, or maybe I should wait until I can buy a lift for the shop which hopefully won't be that far off. I really would like to take a ride sometime with someone who really has mastered the tecnique, as I've known of it for many years but was never really able to do it correctly. Maybe I could get some tips on correct pedal placement before reworking my car. Jim |
Jim Blackwood |
A reason why more manufacturers don't make it easy to heel and toe is liability; as the pedals are too close together and some ol' sot may hit the gas and not the brakes and crash his car or kill someone. Manufacturers make it very difficult by purposely putting the gas and brake pedals on very different heights. |
Mike MaGee |
Mike, No not big feet (size 8) Just put a little dogleg in the accelerator pedal to bring it closer to the brake and fit a pedal rubber which widens the pedal slightly. |
Chris at Octarine Services |
I use both a 68 and a 79 as daily drivers. As Chris notes, the proper technique is to use whatever part of the foot works to blip the throttle while using the ball of the foot on the brake. The force on the brake pedal should remain constant before, during and after blipping the throttle. The older form of double clutching (and why it is called "double clutching") was to brake, depress the clutch pedal, shift into neutral, let the clutch out, blip the throttle, depress the clutch pedal, go into the lower gear, then let the clutch out. When done correctly, and it takes some experience to do it, you will almost exactly match the engine speed and transmission/rear wheel speeds. The "modern" method of double clutching is to simply depress the clutch and blip the throttle while downshifting into the next lower gear. Not, in my experience, quite as effective, but easier to teach in driving schools which often have less experienced drivers attending. The point, in either method, is to allow a smooth transition from a higher gear to a lower gear while brakeing or decellerating. The purpose of going to the lower gear is to maintain the engine rpms in the best range for torque and performance, which allows better control of the car, especially in an emergency situation. Anyone who says that double clutching is without value during regular driving simply indicates that they are not competent at the technique and cannot drive at a high performance level. I do use the technique daily. It results in smoother driving and, by keeping the engine in the proper performance range, allows you to instantly take evasive action when necessary. Sufficiently practiced, it becomes second nature, just as steering the car does. If you objective is to learn to drive your car nearer to its limits, it is a must learn technique. Les |
Les Bengtson |
Good description Les. I had to learn to double-declutch on my first car back in 1965 as it had a straight cut gear set with no synchromesh on any gear. When I had the Midget 1275, I used to take pride in double-declutching into first gear noiselessly. Didn't always get it right. Ah Chris, you've bent the pedal. That explains it. Might try that on my project car. Mike |
Mike Howlett |
This thread was discussed between 21/12/2003 and 22/12/2003
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