new tires, new bushings, new sway bar... result?

[Nunyas]

I got my 'B's shoes resouled today (a full set of shoes would include wheels in my book) with 185/65 14's. Smaller in diameter than the 185/70s that I got her with, but within a half inch in diameter of the tire sizes The MGB Experience and British Motoring says to be the original stock tire size (165HR14). So, the speedo shouldn't be too far off, drive testing seems to verify this, as going 10MPH over the posted limit still has me passing people left and right.

First thing I noticed after she was shod with new rubber was that she no longer wiggle wobbles... YAY! The next thing I noticed was I KNOW when I hit an imperfection in the road. Meaning, cracks, "patches", and road reflectors are positively felt. It's almost "jarring", but not to the point of "brain rattling". I think this is mostly because of the tire store inflating the tires to the "maximum recommended inflation pressure" of the tire. Over all the ride quality is still comfortable but well within the realm of being sports car 'stiff'. I think the harshness can be lowered if I play with the tire pressures and make them closer to MG specs. Obivously, I can't use the exact MG recommended tire pressures due to the different tire tech, but I'm sure lowering the front tires by evan 5psi will produce noticable results.

Next up was how easy the steering wheel turned. It felt like I had power steering compared to before. I had to make a conscious effert to not crank the sterring wheel like I had gotten use to. I can now navigate a parking lot with 1 hand. In the past I had to use both hands in crowded parking lots.

The anti-sway bar that I installed a couple of weeks ago made a significant improvement in normal day to day driving with the old tires. Body roll in turns was reduced so much that it feel like an entirely different car. With the rain we recieved early this week, I definitely found that the car now tends to under steer while making a U-Turn. The fun of discovering this was using the gas pedal to change under-steer into mild over-steer /ubbthreads/images/graemlins/tongue.gif

The new tires took the already improved steering response (thanks to the anti-sway bar) and made it even better. I can definitely feel a huge difference with the new tires. The old tires (185/70s) had a lot of side wall flexing. How much flexing was going on I did not know until I got the new tires. The old tires gave the 'B a boat-like feel in turns, albeit a john boat, but a boatish feel none the less. At first I thought this might just be how the suspension was, but now I know it was the tires. The side wall flex of the old tires may well have been what I've been feeling at the rear of my car when I thought the axle was sliding around. Actually, I'm pretty sure that's what it was.

I took a spirited drive through a near-by canyon/mountian pass road (La Tuna Canyon). The turns aren't very sharp there. They're mostly long sweeping turns, but the road isn't perfectly flat, and the humps and bumps made the old tires flex a lot while driving the road. The flexing of the tires on this road while in the turns was so unnerving that I never went over 50MPH on it. With the new tires, I took it at 60 both down hill and up hill. Never once did I feel the sensation of the car wagging in the turns to be caught at the last second by the grip of the tires. A turn of the wheel instantly told me that the car is going to do exactly what I tell it and when I tell it.

To top it all off, the car is the flatest I've ever seen it in ANY turn now. There's some minor body roll still, but compared to what it use to be the current roll might as well not even exist.

The over all handling is almost exactly what I envision when I hear you folks talk about the 'B's great handling characteristics. It feels so good to drive a sports car that handles like one /ubbthreads/images/graemlins/laugh.gif It handles so good now, I think all the suspension "upgrades" I've been thinking of are no longer needed...

except one... And that is to lower the car an inch or two. I hate looking at my car next to others in the parking lot. I can see I have the same ground clearance, but given how much more narrow the 'B is compared to other cars; the 'B looks like it has a lift kit on it. /ubbthreads/images/graemlins/eek.gif

My labors over the summer are now beeing enjoyed. I think the last thing "bugging" me right now is the wiring harness under the dash. Hopefully, this weekend will cure the connection ailments under there. /ubbthreads/images/graemlins/smile.gif

 

[Steve_S]

Re: new tires, new bushings, new sway bar... resul

Good show! Your tire pressure is definately too high. Maximum pressure is for the heaviest vehicle the tires will support. An MGB with 165R14 tires should be running around 28F 26R. Run more for performance driving or slightly less for max comfort.

A stiffer sway bar will exaturate understeer. You can adjust the toe/caster/camber of the front wheels to counter this a little but the car may become a bit twitchy. You can also play with the front / rear tire pressure differences to increase / decrease over/understeer.

Lowering will definately help the handling greatly but will ride a bit more stiff. If you really want to make the handling crisp, you can install a panhard rod. Doug Jackson sells a kit.

 

[Dozuki]

Re: new tires, new bushings, new sway bar... resul

I Noticed that after about 250 miles, my new poly bushings finally set it. Bumps and road imperfections are not anywhere near nerve wracking as they were when I first installed them. Not sure how new your bushings are, but the ride may get less jarring as they break in a little.

 

[Phantomracer]

Re: new tires, new bushings, new sway bar... resul

[ QUOTE ]
Good show! Your tire pressure is definately too high. Maximum pressure is for the heaviest vehicle the tires will support. An MGB with 165R14 tires should be running around 28F 26R. Run more for performance driving or slightly less for max comfort.

A stiffer sway bar will exaturate understeer. You can adjust the toe/caster/camber of the front wheels to counter this a little but the car may become a bit twitchy. You can also play with the front / rear tire pressure differences to increase / decrease over/understeer.

Lowering will definately help the handling greatly but will ride a bit more stiff. If you really want to make the handling crisp, you can install a panhard rod. Doug Jackson sells a kit.

[/ QUOTE ]

How do you adjust camber and caster? Everything (should) be non-adjustable other than toe.

I have been autocrossing my B for a few years now. I personally don't see a need for a panhard bar. There is no tire rubbing, even with my wider 195 tires (or my stock ones either). The rear end seems located just fine. I don't think it would hurt anything, but, personally do not see a need for it.

Stock sway bars on later (77+) B's work well together. I wouldn't put a larger one on the front unless the car had uncontrollable oversteer, which is rare for a B...that is..that can't be corrected by other means (rebuild/rebush suspension, springs, lowering, tire pressure, etc). A thicker front bar, with the stock (or non-existant) rear bar will understeer/plow like a pig.

FWIW, I am running stock tire pressure (27/32 I believe) on my modern 185/70/14 tires with my 80B and it works well. Pretty neutral, with a hint of oversteer. Lowering the car 2" certainly helped out in the handling department.

Paul

 

[Nunyas]

Re: new tires, new bushings, new sway bar... resul

Well, my 'B is from '76. So, it had NO sway bars what so ever when I bought it. The bar I put on it is 5/8" I think. It's using what appears to be stock replacement rubber bushes. So, the bar could be stock from an older car, but it's still worlds better than none at all. I tried to get poly bushes for it, but the guy at Moss I spoke to said the poly bushes they had were for larger diameters like 3/4" and 7/8".

I haven't made any "changes" to the toe-in, but the under-steer is not bad at all. It's just noticeable on wet roads, but the car still goes where I tell it. Then again, when I noticed the under-steer it was on wet asphault with the old tires. The front right had a bad "bulge" in the tread area, and both fronts had badly receding hair lines that resembled bad comb overs... /ubbthreads/images/graemlins/eek.gif

I noticed about a month ago that Moss is selling RB Front and Rear sway bar kits. I might go with one of those kits if I think it necesary later on (after lowering).

I don't have too many miles on my poly bushings yet. I think I may have about 2 tanks of gas on them (when I was getting really crappy gas milage (low teens)). Which brings to mind, I think my new coil is giving me better gas milage. The old one (my avatar) was severely corroded, gave me "girlie-man" sparks, and after about 20 minutes of driving it would start 'missing' at random intervals. I've gone 2.5 days on this tank of gas and it's still between full and the first tick mark. With the old coil, I would have been just under 3/4 tank of gas left by now.

 

[DrEntropy]

Re: new tires, new bushings, new sway bar... resul

WOOHOO!!!! You're in up to yer neck! Great. If you have or can get a "gun barrel" style wire brush to fit inside the Lucar connectors you'll be fussin' with over the weekend, you've got it licked. "ScotchBrite" plastic scouring pads work well for the "bullet" ends.

IIRC the recommended tire pressures are 28 front, 32 rear. The pressure differential in any case should be 4~5 lb/psi. The backs at the higher pressure gives neutral to oversteer, the same or lower than the fronts and you'll likely start to find that "push" again. 28 should be the minimum T.P. at either end. Lower and you're just wallowin' about. Keep an eye on wear across the entire tread and you can judge if you're too low (both edges wearing faster) or too high (center wearing faster). Now go have a ball!

 

[Phantomracer]

Re: new tires, new bushings, new sway bar... resul

[ QUOTE ]
Well, my 'B is from '76. So, it had NO sway bars what so ever when I bought it. The bar I put on it is 5/8" I think. It's using what appears to be stock replacement rubber bushes. So, the bar could be stock from an older car, but it's still worlds better than none at all. I tried to get poly bushes for it, but the guy at Moss I spoke to said the poly bushes they had were for larger diameters like 3/4" and 7/8".

I haven't made any "changes" to the toe-in, but the under-steer is not bad at all. It's just noticeable on wet roads, but the car still goes where I tell it. Then again, when I noticed the under-steer it was on wet asphault with the old tires. The front right had a bad "bulge" in the tread area, and both fronts had badly receding hair lines that resembled bad comb overs... /ubbthreads/images/graemlins/eek.gif

I noticed about a month ago that Moss is selling RB Front and Rear sway bar kits. I might go with one of those kits if I think it necesary later on (after lowering).

I don't have too many miles on my poly bushings yet. I think I may have about 2 tanks of gas on them (when I was getting really crappy gas milage (low teens)). Which brings to mind, I think my new coil is giving me better gas milage. The old one (my avatar) was severely corroded, gave me "girlie-man" sparks, and after about 20 minutes of driving it would start 'missing' at random intervals. I've gone 2.5 days on this tank of gas and it's still between full and the first tick mark. With the old coil, I would have been just under 3/4 tank of gas left by now.

[/ QUOTE ]

My plan of attack on a 76 would be to lower it with 1" (2" if you dare)lowered (stiffer) springs and 1" lowered blocks in the rear, using original springs. This assumes the bushes are all in good shape. You might have to use CB rebound straps, and trim your bump stops a bit too.

Do one thing at a time. Lowering it will give the most bang for the buck, as it is easy, cheap, and reversible.

Once that is done...if you still feel like the car handles like crap (I doubt you will), then try the aftermarket sway bars. The way the rear attaches to the sheetmetal trunk, to me, leaves a lot to be desired. I would just leave well enough alone. Get good (poly) bushings in, lower it, play with tire pressures..get H-rated summer tires (hard to find) and you will be quite surprised how well it handles...without having to play jr-suspension-engineer. ..and potentially induce other undesirable handling characteristics.

If you do want to go balls out...at least do one thing at a time...see what change it did..before going on to the next mod.

Paul

 

[Steve_S]

Re: new tires, new bushings, new sway bar... resul

By joe you've caught me in a brain fart! THe stock suspension is not quite as adjustable as I was blabbing on about above. I was just talking with someone about a B with a coil-over conversion and I guess I mixed things up in my mind. On a coil-over car you could of course adjust everything. On a stock car you're fairly limited but honestly the need to adjust such things on a road-going MGB is quite low. The very first thing you should be doing is checking that tire pressure. Start with a known number like 26-28 F, 28-32 R and adjust from there. When I ran Michelin XZX 165R14, I found 28/30 to work well. With my setup now it's actually best at 30/30.

 

[Nunyas]

Re: new tires, new bushings, new sway bar... resul

Well Phantom, I already have poly bushes front and rear; I think they may need another tank of gas or two before they're "settled in". The next step is to change the front springs and add blocks to the rear. The car is amazingly flat in turns now, relative to how it was when I bought the car. I've yet to really push the car to the limits of traction with the new tires, but already I know it's doing much much better. Turns that had the tires talking to me before are begging for me to give it more gas. It's so much fun to drive now that I can't get enough...

The difference for me is about the same as the first time I removed the hard top from my car. It has a totally different personality now. I think the new 65 series tires are helping the poly bushings to set in a bit quicker than the squishy and flexi 70 series tires. Because, either I'm getting use to the ride, or it's actually becoming less "harsh" ever day I drive it. /ubbthreads/images/graemlins/smile.gif

Anyways, I was definitely planning on lowering the car before considering any other suspension modifications. As it is, all the work I've done so far was to get the suspension back into shape for daily driving. Well, except the front sway bar, but that had to be done. The mount points were already on the chassis, and all I had to do was change the lower front wish bones to put it on. Besides, I'm befuddled as to why they removed the bar when they raised the car and added more weight. It needed it in the worst way.

I may be a couple of months before I get around to lowering the car though. For now, it is most certianly an incredible amount of fun to drive. I may need to replace a couple more important suspension pieces relatively soon, but I've done it once already. So, next time won't be as much of a pain. Until I go getting greasy again, I'm going to enjoy every second behind the wheel of my 'B /ubbthreads/images/graemlins/laugh.gif

 

[Dozuki]

Re: new tires, new bushings, new sway bar... resul

When and if you do lower the car, I would suggest going with negative camber A arms in the front too (if you havn't already). Lowering an RB will tend to give a bit of positive camber (from what i've read) and this will correct that. I did this to my 75 when I did the front sus. (lowered 1 1/4"). I havn't done the lowering on the rear end yet. I also just got new tires yesterday. Toyo Proxies 185 60 R14. (had 185 70R14). The car is now a tad on the oversteer side, as I can hear more of the tires growling in the back on hard turns. Runs at a little heher revs with the smaller tires and sits another 1/2" lower all around.
Keep on diriving, the ride will get better and better as the bushing set =)