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MG MGB Technical - tyre sizes

I want to put alloys on my 'B (currently wires) and have been offered some Minators fitted with 185/70 R14 Federal Super Steel 731 tyres. I had considered fitting 165s if I had bought new. What difference will I notice between these two tyre sizes? Also anyone heard of these tyres?
Steve Church

At speedometer readings of 60 MPH and 100 MPH, a 165/80 will give 58.5 MPH and 97.4 MPH, respectively.

At speedometer readings of 60 MPH and 100 MPH, a 185/70 will give 58.9 MPH and 98.2 MPH, respectively.

All other factors being equal, the 185/70 should give a smoother ride and better grip. I thought Federal went out of business years ago!
Stephen Strange

I have 195's on my 1979 with Rostyle wheels

Rides fine


gary hansen

I just bought a set of new Minator wheels to replace the rusty wires that were on the car. I fitted 175/70-R14 General tires. They perform extremely well and the 185s will probably fit with no problem, if my car is a good example. RAY
rjm RAY

Thats reasurring then. Now I just need to decide if the Federal tyres that are fitted are actually any good (are they going to suprise me in the wet!). If I need to put new tyres on then the price the seller is asking is too high (UKP200) and I will get some new wheels and tyres from MGBHive. However I do believe that they are the KN Minators. The Minator copies I have on my Midget are pretty good though.

Does anyone know where the date code is on tyres and how it is coded?
Steve Church

If they were made after 2000 most -not all- have a 4 digit code. Stamped on the sidewall clockwise round from the size, after the DOT box. First 2 digits are the week, second 2 are the year. So 2806 is 28th week of 2006. Federal sound like a Budget brand. As for age look for small cracks around the perimeter edge -tyres perish!- and does the rubber have a shiny sheen to it. If so -it's old. If someone has put tyre dressing on it I wouldn't touch it- as its probably covering up its age!!!
Michael Beswick

Also, look in the tread itself. Small cracks will appear between the the raised treads levels showing age related problems, even if the sidewalls are still in good condition. RAY
rjm RAY

I spoke to the seller last night. Tyres are date coded 2009 so about 15 months old. I read mixed comments on Federal tyres but the majority are reasonably favourable for a budget tyre. I just need to be aware of possible clearance issues. Would rim size have an affect on this? I believe them to be 5 1/2 inch rims. How is this marked on a Minator?
Steve Church

The 14" Minator wheels, for the MGB, are 5.5" wide. I have no clearance issues with mine. I probably could have easily gone with 185 tires, but I played it safe and stuck with the 175 tires that I had on the car before fitting the new wheels. RAY
rjm RAY

I have 185/65 tyres on 14" x 5.5" Minator knock-ons on a 1970 GT with no clearance problems.

J Tait

This thread was discussed between 11/08/2010 and 15/08/2010

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