19 replies to this topic

[Ollie36]

Hi all,

 

After a little guidance and help, I have a 94 reg that has been converted from a Mayfair to a Sportspack Cooper.  Had the car up on the ramp at a garage over the weekend and the rear subframe needs replacing. I have two things to ask/ need help with.

 

1) What are the differences in buying a genuine and non - genuine sub? I've also been told to look at second hand ones but I think it would be best to steer away from that option.  

 

2) By the looks of the sub I would believe it is the original from when it was a Mayfair and that the mechanic that built it for the last owner didn't change it when converting it into the sportspack.  I've noticed on Minispares etc that you can get specific subframes for sportspack cars but how vital is it to have one of these over a standard one?  I'm not sure what there is for it to make a difference, he may of just put the aches on with the wider wheels, whether or not that makes it viable to get the sportspack subframe or if its something else, i'm not sure.

 

Thanks in advance for any help/guidance/information!

[Steve220]

Non genuine subframes usually have less spot welds from what i've seen. They're slightly different to the eye, not sure on fitment though as i've always gone for genuine.

 

With regards to the sportspack subframe, there are a supports between cone mounting plate and the subframe itself. Whether this actually makes any difference is debatable. I've seen my new genuine one vs a non sportspack and from just a quick glance there didn't seem to be much different (apart from the little support plates).

[ukcooper]

another qyestion is do you want a 13" sportspack subframe or a !2" standad subrame wheels that is yes there are two types 

 

http://www.minispare...rames.aspx|Back to shop

 

http://www.minispare...10024.aspx|Back to

[mab01uk]

For Minis fitted with 13" wheels and Sportspack models KHB100590 subframe.

This subframe is strengthened and has the late type exhaust hanger rods as used on 1991 onwards Mini models.

[Ollie36]

Thanks for the info guys.

 

In regards to the sportspack frame, I've currently got 13"s fitted, however if I were to get the sportspack frame and then sometime in the future go down wheels smaller than 13" would it cause an issue? 

[Steve220]

Absolutely none!

[tiger99]

But going the other way could be catastrophic.Using the reinforced subframe retains flexibility for the future.

If the extra welds in the Sportpack frame are necessary (And Rover were not known for spending money without due cause!) a non-genuine frame with skimped welds would be woefully inadequate.

My preference in any case would be to seam weld the critical areas before fitting.

[Ollie36]

So going sportspack subframe is the best option, gives me more stability in keeping the 13"s and perfectly fine if I downgrade to a smaller rim.   Are minispares and minisport the best places to get them from or are there any other good suppliers?

 

Thanks again. 

[tiger99]

If it is the same genuine frame the cheapest supplier is the best. Try some Googling. But remember TMF+ membership for £10 will get a discount at Minispares and some others.

[Steve220]

Some of the heritage prices have gone up recently, so keep an eye out. Spend £5 on TMF+ discount and you get 7.5% off at minispares.

 

http://www.minispare...px|Back to shop

 

£442 x 0.925 = £408.85. A saving of £33.15!

[tiger99]

So I was wrong and overstated the cost of TMF+. Overall saving of £28.15 even if it is the only thing you ever buy.

Still pricey, like most bits now, but TMF+ is a real bargain.

[Cooperman]

For an 'as original' restoration with minimal additional work, a Heritage sub-frame is the best option.

However, if building a competition car, where the rear frame will have additional welding and preparation, even on a Heritage one, it is more economical to buy a pattern one, then do the seam welding and subsequently adjust for more accurate suspension settings afterwards.

It is hard to see why a modified frame was needed for a car running on 13" wheels when one considers the abuse the original frames had to take in race & rally cars over the years, with or without additional welding and reinforcing. Maybe the later frames were just not as good in terms of quality, either genuine or non-genuine.

[old original]

It is curious that the strengthened one came out in 1996, where ERAs with 13" wheels had appeared in 1989, but as I will be in the market for one before the next mot, I suspect I'll go for it anyway!

A bit of history..
I do remember that when I first had a rear subby done, it was in a Rover dealers and there was a '87 city/mayfair being done at the same time. The workshop ordered up the approprate sub frame for each with the standard one being about £110 and mine being £130. When they were delivered the next day, we lined them up next to each other and after 15 mins counting welds and measuring bits, the only difference found was an extra hole for the mounting for the fuel pump, for £20 I would have drilled it myself!

[tiger99]

There must be an interesting tale behind the subframe strengthening. But at least 2 of my Minis were quite seriously abused, with heavy stuff in the boot and bumpy roads, with no sign of distress to any part of the structure.

 

I have thought about this since I first saw mention of strengthened frames on the forum. I can't see where the extra subframe loads are coming from. The 13 inch tyre is lower profile than 12 inch so has about the same rolling radius as 10 or 12 inch, so sideways cornering loads will exert much the same bending loads on the radius arms. Now the later cars did get a bit heavier, so the rubber cone spring loads increased, and also the tension in the subframe side members (which I prefer to seam weld to the crossmembers, just because extra strength does no harm), but the cone spring has an outer and fairly stiff metal cone which spreads the load over the full diameter of the seating in the subframe. If the seats flex slightly at the outside edges, the middle which connects to the subframe web should just take more of the load, so why the extra bracing?

 

Yet we do hear tales of the cone seats failing, and even the ends of the pivot pins failing, the latter would only happen at well above the original design load as it appears to be plastic deformation, which implies a stress significantly above the fatigue threshold.

 

So I still can't fathom out the extra load. Or did Rover switch to metric steel sheet because it had become cheaper, and it was slightly thinner than the original? Beefing it up because the metal was slightly thinner would make sense.

[GraemeC]

The unsprung weight of the Sportspack also increased substantially, and given the wheel is on the end of a quite long lever I presume that would put significant force increase through the spring?