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MG MGB GT V8 Factory Originals Technical - What tires will fit

Well I figured I'd post up on the V-8 board cuz odds are more of you guys are running big meats than us 4cyl. guys. I just got a screamin deal on some 14x7 alloys. I want to throw a 215 or 205 series tire on if possible. I'm not sure what the offset is, but do you know what the widest tire you can squeeze under the stock fender is? If I can't fit it, I'm gonna get out the old baseball bat and make some subtle flares.
Thanks
Bill
69 B-GT
Bill Mertz

I think it's likely flares are in order, but first, go to a well staffed persponable rubber guy and ask him if you could measure your potential purchase. The
salespeople love to help you <$>~<$>, and will likely shadow you about, spouting all sorts of intersting technoflap on all the different tire company's procucts and a he may even have a quike-list which gives the various company's different tire dimensions and compunds. Or, pack a tapemeasure around rubbernecking small/med cars with fat tires and take measurements in the field. Fist, I take it your '69 is less that pristine/stock if your going to bend it. The '69s are beautiful. I ran 185/65/14 under my '71 GT with stock steel rims and on fast wet wet wet roads with no problems. There was about 1/2" clearance from rear outer fender wall to the tire sidewall at rest and it never scrubbed over bumps nor when driven hard. The fronts were'nt close, to anything. However, with more than slight tread wear, I'd experience 0 lateral G's for several scarey seconds on the wet long before 60 MPH. Lots of sunny days where you are but be aware and slow down in the rain. If your suspesion is stock, fat heavy tires may stess the components, make make the steering less sure. There is some refference to a phenominon called "skuttle shake" on the GT which invoves lateral vibration of the bulkhead with over-rubbering. I had no such problems with my slightly wider 185's and a very tired front end. Lots of guys run fatties and have on-rails handling, just look at some race set ups with Sebring flares.Now that's alot of meat, though the tires and rims are very light and most drivers preffer dry roads. Now your spending money again! If you have success I'd be inerest to hear about it. Narrow the rearend?
Angus
Angus Davies

Bill,
I have 205/70's R14 on the back of my 'GT right now. I don't know if they will scrape around a corner yet because I haven't had the car on the road yet. They are just there to make the car roll easily. I but know they phically fit under the fenders.

I want to eventually fit 215/60 R14; or if I can, 225/50 R15. This would probably require some "under the fender adjustments"
Hope this was some sort of help to you.

Wally
Wally Jonker

By the way Bill, it's a '68 GT with crome bumper springs.
Wally
Wally Jonker

Well hopefully I can just crush the lip of the fenders for a little extra clearance to fit the 205's. I'm not sure of the rim offset yet, so I don't know where my tire rub problems are gonna be. I hear that the inside of the rear is where tire clearance tends to be an issue.
Yes my B-GT is on the "whooptie side" but If I do flares, I will do a clean job on them. I wanna keep the body work as stock looking as possible. I've seen a 68 roadster running around at the local autocross running some large meats, and he simply bent the fenders out and up only so slightly, it looks good.
If you have any more info on the "skuttle shake" phenom, I'm interested. ON a side note, the car is going to be lowered about an inch, and will be fitted with negative camber wish-bones up front which may help for clearance. I guess I'll just have to go with the trial and error method.
Thanks for all the input. I'll keep you all posted. And you never know, with my hankering for power I may be back asking for V-8 swap advice.
Bill Mertz

I am running 195/65 - 14 Yokohamas on my lowered '79BV8. No clearance problems at all, they look pretty good and handle well for street use.
Martyn

I am using toyota camry aluminium wheels with 205 70R14 tires with no problems with clearence.
Les Biglands

Wally,
I am running 245/50-15 on rear and 225/50-15 front. Wheels are Panasports 6"-front, 7"-rear with "MG offset" from K-Speed. 51" rear end width and rear fenders "baseball bat rolled" as far as humanly possible, and panhard rod to be installed. The car is not on the road yet, but I was coached by a guy I met in Atlanta and viewed his car with that setup. Tires are Goodrich TA ZR-1.

Mark
Mark Marchbanks

Hey, Les,
How'd you solve the bolt pattern missmatch? The allum rims on my Corolla (14s) would look good and let lots of air through. I've found them forgiving with curb brushes and not terribly expensive to replace--I know a guy...
Angus Davies

For all those interested in converting to different rims on your MG, there was an excellent conversion chart about which rims interchange on various cars with both 4 and 5 bolt, in a Summer 99 issue of Grassroots Motorsports (a great publication) Not sure what month it is, but it had a porsche 911 on the cover, and was talking about how to become a pro race car driver.. It also mentioned offsets. Those camry rims sound great. How do the 205s handle?
Angus, I know the early RWD corolla rims fit the MGB 4 bolt pattern which I think is a 113.5 MM bolt circle.
Bill Mertz

you might find the cross-reference at
http://mr2.com/TEXT/WheelBoltPatterns.txt
very useful....
HTH
David Smith

To sort out replacement rims you need to go to tyre shop and get the Pitch Circle Diameter (PCD is the spacing of the wheel studs). You are after a stud pattern the same as a Datsun/Nissan 240Z or 260Z. Have run these type 7inch mags on my ex-racing MGA for 26 years now ..no dramas..ever!!!. By the way you can easily convert a set of stuffed spline hubs to discs real cheaply and safely without replacing cases etc. Contact me for details/photos if interested.
regards
mark
mark mathiesen

Like I said above, I believe the MGB bolt circle is 113.5MM. Meaning that any rim with this bolt circle will fit on the hub, offset will affect clearance. I know that early Z cars and datsun 510's will fit. I'm also fairly certain that first gen. RX-7 rims will fit. That grassroots motorsports article has all you need to know.
Bill Mertz

And like I said, you don't *have* to think or believe :-)
You can go look at http://mr2.com/TEXT/WheelBoltPatterns.txt and get the facts, it's quite simple really. The MGB is 4-bolt on a 4.5 inch PCD. It is not quite true to say 'any other wheel with this spacing will fit' as the angle (taper) of the lug nut seating is all-important. Use an incompatible lug nut and wheel combination and you have an accident which is looking for someplace to happen.....
David Smith

I ran 205/60/14's on 7" Shelby wheels for years. The wheels were aftermarket for a Datson 260 Z. Front wheel clearance is no problem, the "rub" is at the rear. I solved the problem by using a wire wheel axle with steel wheel hubs & 1/4" spacers. Note that all brands of 205/60/14's are not equal. There is more than an inch of varience between the extremes of several brands checked. Old Yoko Avids fit, new ones didn't.

Jim
Jim Stuart

Jim
Is your car a cusion bumper car with the extra inch ride height?
Wally Jonker

I run 205/60/14 on 6" wheels 3" back spacing aftermarket Datsun Z wheels, in my MGB. They also fit my 1963 Buick Skylark convertable, and my 1963 buick special. Also try Plymounth sapporo/ Dodge chalanger late 70s. Or 6 cilinder Mustangs late 60S. Or early 70s Mavericks/commets. Toyota wheels must have the center hole machined to fit MGB hubs.
I must mention that my MGB's rear axel is an MGC unit wire wheel, which is narrower than mgb disk wheel
Romney
romney

This thread was discussed between 14/02/2000 and 28/02/2000

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