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MG MGB Technical - Body not centered over rear axle
| I just put new tires (185 70R 14's) on my 1972 BGT. I have twice noticed that when making a spirited left hand turn that the fender has made contact with the tire. So I measured from the edge of the tire(laterally) to the inside edge of the fender and the left side measurement is 1 inch, and the right side the measure is 1 5/8 inch. I also measured from the highest point of the fender arch down to the ground and the car appears to sit higher on the left by about 3/4 inch. (This I would have thought was a good thing that the left hand side sits higher, cause I wasn't expecting it to be hihger then the right side) Any suggestions on what I should do to correct these discrepencies. I have a 2 thounsand mile (round) trip planned in a month from now and the car will be loaded heavily(me my wife luggage tools and spares). I don't want to have the fender cut into my tire on left hand turns. Thanks for any advice, John Fraioli 1979 Inca Yellow MGB 1972 Teal Blue MGB-GT |
| John F |
| John- The eyes of new leaf spring bushings will suffer from less compression, and while that will help a bit, it really isn't a cure. If you know how to weld, you can cut off and relocate the mounts on the axle to proper spacingin order to get the rear axle properly centered, which will also help. The best cure is to install a Panhard rod to eliminate body sway over the rear axle. |
| Steve S. |
| Steve, Thanks for responding. I did check the archives and did hear about using a Panhard rod. I did not read however how this rod is attached. Can you explain how this attaches? Does it just bolt on or is welding required. I am not a welder. I do try to do all my own automotive work. So if it is a bolt on I can probably do it. I also read about hammering the fender lip up. Do you think I should do this also in the mean time. I think that will give me an extra 1/4 inch of clearance. John |
| John F |
| John, you don't mention leaf springs but if you've also installed a new set of springs this could be the problem. Some of the new springs are not straight which results in a lateral offset of the rear axle. Tom |
| Tom Custer |
| Pretty-well every MGB ever built has the axle offset to the left as you describe (both mine are), although I have read one person claim theirs is offset to the right. I've had two axles and three sets of springs on one of the cars, and two sets of springs on the other car (mostly for other reasons) and most of it made any difference to the offset except when I had RB roadster rear springs on the CB roadster which virtually eliminated except for extreme cornering fully laden. Some have moved the spring pads on the axle, which may well centralise the wheels in the arches, but almost certainly has offset the rear wheels relative to the front! The problem is in the original jigs used to align the outer wheel arch section, inner wheel arch section, inner wing etc. to the chassis rails. It has never been a problem with the correct axles, wheels and tyres but I had the same problem as you even unladen when using conversion hubs on the rear axle to change to wires. Eventually I fitted a proper wire-wheel axle and it was fine again. Wider wheels and tyres are also likely to have a problem, and 185s are quite a bit up from the original 155 and 165. The V8 had 175, but it also has higher and harder springs which also helps avoid it, as I found. |
| Paul Hunt 2 |
| John, As usual Paul is absolutely correct. On my 1973 MGB the axle is off center. When I put new tires on my car the fender rubbed a little on the tire. So after reading the archives I did as so many suggested and ground down the inside fender flange about .100" and I have never had another problem. Robert |
| Robert Browning |
| I think this has been compleley covered before and all you could want to know is in the archive. |
| Stan Best |
| John- You could increase clearance of the inner flange of the wheelwell by grinding the flange down somewhat, but do not eliminate it entirely as it is there to prevent the sheel metal around the wheelwell from cracking. However, this really won't eliminate your problem. It will merely allow you to corner a little bit harder before rubbing takes place. The only real cure is to limit body sway over the axle, and that requires the installation of a Panhard rod. The MGOC offers a good Panhard rod kit (MGOC Part # H150) that requires no welding, just some drilling for bolt holes, so you can put it in yourself. At a price of £347.49 it's not cheap, but it's probably the single best improvement to an MGB's handling that you can do. |
| Steve S. |
| John, You didn't mention which wheels you have on this car. I bought 6" Performance Superlites (AU) for my '73 B/GT and I have the new 8-leaf replacement rear springs made by John Twist, along with new rear shox. But with Cooper 185-70/14s I too get some rubbing on the left rear in spirited left turns, and not-so-spirited left turns with wife and luggage. In that case, a spirited right turn will set it to a bit of rubbing on the right side. This would be less of a problem with 5" Rostyles. I could also go to Superlites with a narrower offset. Indeed, if I find these wheels will work on my Magnette (so I don't waste 'em), I'll buy some narrower-offset wheels for this car. Or maybe I should look at that MGOC Panhard rod kit too. FWIW, Allen |
| Allen Bachelder |
| Can't speak of the mis-alignment yet, as I suffer from it too. As for the rubbing: I'm assuming I have a steel wheel axle with wires installed before I bought the car. I replaced the hubs and wires and put new 175's (as I recall) on it. Rubbed at most bumps. Measured the shackle length, and as I recall the bolts were 2 1/2" apart. I built a new set with bolts 4" apart and that helped a lot. Since then I replaced them with a set with bolts that are 5 1/2" apart. I have enough clearance now until I can re-attack the problem this summer. I just used 1 1/4" x 3/16" steel bars and 1/2" bolts and lock washers. Actually the car doesn't sit with much rake. Probably tells me the springs are in need of some TLC. Tom |
| T Lea |
| Thanks again for all the comments. My wheels are 6" rostyle. The springs have not been replaced. Today I took the left hand wheel off and rolled the fender lip up using a heavy hammer. This gained me about an additional 3/8 inch. Then on the advice of a local club member, I also used a narrow baseball bat wedged in between the fender edge and the tire and rolled the car by hand to flare out the fender a bit. All and all I gained about a 1/2 inch additional clearance. I guess I won't worry too much about the axle/body offset as I guess this is how they all are. I will work on acquiring a Panhard rod, and go about installing it. Apparently this is a good addition for improving the handling of all mgb's. So as long as no one has any contraindications to installing one I will go for it. Actually, this all happened because what I did was take the wheels and tires off of my '79 MGB (the 185's) because they are almost new Rain Force Michelins. I thought I would use them for the trip to Tucson. The ones that I took off the GT did not ever rub in the year that I have owned this BGT. They are rather old and a little dry. But have about 75 percent tread so I didn't want to buy new ones just yet. One of them has been plugged as I ran over a 3/8 inch bolt this past summer, the hole was so large I had to double up on the plug to patch it. So I was worried that on this long highway trip it might have come out. Anyway, once I get back from the trip I will swap the wheels again. But when it becomes time to purchase new tires for the GT, I think I should go with the 175's and not have to worry about clearance. One last question. If I go to the 175's do I still stick with the profile of 70 as in 175/70R 14 or should they be something else. John |
| John F |
| John- If you prefer to stay with 14” wheels, take a good look at P185/65R14 series tires. These have a rolling radius very close to that of the Original Equipment tires (Ever so slightly smaller by 3/8”), will fit into the wheelwells a little better, and will actually be closer to the original rolling radius than P185/70R14 tires. Being a more modern (read: advanced) design, not only will you end up with a smoother ride, but also P185/65R14 tires offer a wider range of traction/handling/wear combination possibilities. The P185/65R14 is now becoming an increasingly more common fit as it is more commonly available. The 65-series profile tire also has stiffer sidewalls than a 70-Series profile tire, so you may anticipate a further sharpening of the steering response and a corresponding increase in low speed steering effort as compared to that of the P185/70R14. Generally speaking, you should be able to come up with something that is superior in all categories to the old P185/70R14 designs. Why don’t more people use them on their MGBs? Because when the original tires became harder and harder to get, people switched to the P185/70R14 because they were what was available at the time that was closest to the original rolling radius. Since then it has become something of an Urban Myth that they are the way to go. Actually, the P185/65R14 is superior on almost every count and is in no way inferior to the older design. Unless you are substantially uprating the power output of your engine or modifying the suspension so you can drive very, very hard on curves, you do not need to go much larger. For most people, the P185/65R14 will do fine. |
| Steve S. |
| John, I have the same setup as you. 6" rims on Rostyles centres, rolled lip & eased out wheel arch. I'm using 195/65 Hankook tyres. No problems. Barrie E |
| Barrie Egerton |
| Steve - correct me if I'm wrong, but I believe you guys with the six-inch Rostyles are measuring them wrong. I don't think the 14" Rostyles were ever made wider than 5.5. FWIW, Allen |
| Allen Bachelder |
| I did a quick survey at a large MG meeting several years ago and quickly confirmed 8 out of 10 were offset left, one was centred, one was to the right. My '73 Roadster is offset left and I had a problem when fitting MG Club Hockenheim alloys. They are a beautiful wheel but the centre boss is much thicker than a Rostyle, of course. At the time I ended up peaning back the rear wing/wheel arch seam to ensure the tyre never touched metal. All been solved now by fitting new wing and wheel arch to cope with the rust god!! |
| Richard Coombs |
| Allen,the rims of my Rostyles were pitted & rusty. The centres were OK, so I just had the rims replaced with 6" rims except for the spare. The car is a GT,so I wouldn't have been able to close the boot cover if that was 6" as well. Barrie E |
| Barrie Egerton |
| Barrie, I didn't even know that was possible. Where would one get that kind of work done? In fact, I think I was exaggerating a bit. Rostyles may only be 5" wide. I haven't seen one without a tire on it in quite awhile, so I can't measure one here. |
| Allen Bachelder |
| Allen, I went to a shop that repairs & sells auto wheels. I had to get the whole rims replaced but a cheaper option is to have the rim split pretty much down the centre leaving the inner section still joined to the wheel centre. They then weld a new wider outer section to the original section of rim thus keeping the original wheel offset. There used to be quite a few places that carried out this sort of work in Sydney. I'm sure there must be something similar in MI. Barrie E |
| Barrie Egerton |
| Allen- I have 15" Dayton wire wheels, not Rostyle wheels. However, you are correct about the 14" Rostyle wheels that came on the MGB being 5" wide. |
| Steve S. |
| Allen, the U.S. company best known for rebuilding steel wheels with new rims on Rostyle centers is "Stockton" in California. They can work some real miracles too... like putting special 15" x 8" rims on 14" centers, as shown here: http://www.britishv8.org/MG/LeonardMarshall.htm Anyone interested in fitting a Panhard rod on an MGB - especially a home-made Panhard rod - would probably get a lot of good ideas from spending some time surfing the "British V8" website and photo gallery. Lots of different Panhard rods approaches! Here a few links off the top of my head: http://www.britishv8.org/Articles/MGBRearSuspension.htm http://www.britishv8.org/Articles/2007-TechSession3.htm |
| Curtis Jacobson |
Here are a few links to Panhard rod pictures: http://www.britishv8.org/MG/BrentLancaster/BrentLancaster-K.jpg http://www.britishv8.org/MG/CarlFloyd/CarlFloyd-F.jpg http://www.britishv8.org/MG/MartynHarvey2/MartynHarvey-M.jpg http://www.britishv8.org/MG/CurtisJacobson/CurtisJacobson-G.jpg |
| Curtis Jacobson |
| I've been following this thread with interest, as I am awaiting delivery of a 15x6" wheel from Stockton made by adding a new rim to the center of my old 14x4" original (roadster) disk wheel. I thought I would order one and see how it fits before I order the rest. The cost is $120 per wheel plus $29.50 for return shipping, so I want to make sure the wheel fits o.k. and is true and round before I ship the other four wheels to California. These wheels will go on my '67 BGT. I'm thinking a 185/65-15 tire will work best, but I have an old 195/60 lying around that I may mount on the wheel just to see if there is any clearance. The wheel I sent off was my spare, and I'm now using a Rostyle 14x5" wheel for the spare. With a 175/65 tire mounted on it, it just barely fits beneath the rear deck, so I'm not sure what I'll use for a spare if I go with 185/65 tires on 6" rims. Maybe deflate the spare somewhat and carry a bike pump? My other car is a Volvo P1800, and it has a very nice Panhard rod attached to the rear axle. I may try to find one of these to weld up to the MG if necessary to keep the axle in place. I believe they were also used on Volvo 120 and 140 series cars. -G. |
| Glenn G |
| I had the same problem several years ago after installing 185 size tires on my new Dayton wires. I finally solved it by installing red prothane rear spring kit. I didn't notice a harder ride, but the rubbing stopped. John |
| John Schroeder |
| Another source for a panhard rod I found via Doug Jackson's website: http://www.mantellmotorsport.com/ |
| Curtis Walker |
| Glenn, A little off topic, but how is the Volvo P 1800 compared with the MGB GT? A friend of mine has a P 1800, and it certainly is a very well built car. I have never driven it, though. Tore |
| Tore |
| The steering on the BGT is lighter and the springs are stiffer, making it a better handler than the Volvo. On the other hand, the Volvo seems more solidly built, although heavier, too. The Volvo interior is better-appointed. My '63 has a dealer-option air conditioner. The Volvo has double-wishbone front suspension and tube shocks all around, so it is a little easier to maintain than the MGB suspension. The 4-speed all-synchro Volvo gearbox has a much more sophisticated feel than the 3-synchro unit in my '67 BGT. They did share the same Laycock overdrive, when fitted. I think the difference can be summed up thus: The Volvo 1800 is essentially a small, sexy version of the 122 sedan, while the BGT is a more-comfortable rendition of a purpose-built sports car. After 20-odd years of P1800 ownership, I was amazed at the ready availability of parts for the MG. Patch panels for the 1800 have only recently become available, and if you need a new fender, forget it. -G. |
| Glenn G |
| A good trick I learnt many years ago is that if you get a piece of 2" x 1" wood approx 15"-18" long, place it in the lower part of the wheel arch and using a screw jack gently screw the jack out. The wood batten will bend as you apply pressure and should proved a gentle curve to the wheel arch and if done with the paint warm should not do any damage. I had the inner lips on my GT removed and the arches welded to gain additional clearance for 6" x 15" KN minilite style wheels with 195/65 x 15" Pirelli 6000 tyres and with the car (rubber bumper) lowered using reverse spring eye 2" lower springs. I have no rubbing problems although there is probably only 1/2" clearance on each side. I seem to be one of the lucky ones with the axle central to the body, and with the new springs which are much flatter you do not seem to get the lateral deflection as the bushes are not subjected to the same leverage as with the higher arched springs. I certainly would not bother with a Panhard rod, especially for a road car they are more trouble than there worth. They need very careful installation and setting up, and can still cause handling problems. Kevin. |
| Kevin Jackson |
| That sounds like a neat trick, Kevin. Does the base of the screw jack rest against the inner wheel well? I might try that trick, as my clearance on the drivers side is very slim (Canadian spec car), plus my axle is centred 13mm left of centre. Erick |
| Erick Vesterback |
| I still like my idea of longer shackles. worked for me. |
| Tom |
| Erick, Yes anywhere convenient on the inner wheel well so the jack is horizontal, you may need another piece of wood if the jack is too low. Tom, Thats fine to get more clearance, but the car will tride far too high unless your springs have sagged dramatically. Kevin. |
| Kevin Jackson |
| Unless the shackles raise the bottom of the arch above the top of the tyre when cornering, longer shackles will give more lateral movement of the axle than normal and so more likely to rub. If the arch *is* above the tyre, then it *will* be very high compared to normal. Harder springs on my 73 roadster did virtually eliminate rubbing, but that was as much down to the stiffer springs as raised ride height. Eventually I opted to put the correct axle/wheel/spring combination on the car as the harder springs gave an unpleasant ride. I did then extend the shackles but that was to reduce bottoming and grounding, and it hasn't re-introduced rubbing. |
| Paul Hunt 2 |
| I understand. I just bought another car with s real wire wheel axle under it. After I heal up I'll do the swap. Prolly get the springs attended to also. Tom |
| tom |
This thread was discussed between 26/01/2008 and 14/02/2008
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