12 replies to this topic

[woodley miniman]

Hi all, I thinking changing the size my wheels from 5.5 x 12 to 6 x 12 how much of a difference will it make to the braking and handling to my mini. Cheers all.

[tiger99]

It will not noticeably improve the braking or handling, in fact both will be slightly worse in the wet (and how much of the time is it wet in the UK?), if the tyres have basically the same design. That applies to all cars, not just Minis, so once a tyre and wheel combination is sufficient, there is no point in going wider. You may gain a very slight amount of dry grip, that is all.

 

Actually, the handling could be worse, possibly much worse, even in dry conditions, if the wheels do not have the correct offset to maintain the scrub radius as originally designed, but if you buy the wheels from a reputable Mini supplier, that should have been taken care of already.

 

It it really worth changing them to get an extra 1/2" width? The changes will alll be small. If I was spending money, I would want a larger improvement.

 

Minis actually handle best on 10" wheels, but that would, depending on what you currently have, probably need the brakes downsizing.

 

The other consideration, of course, is bodywork, and you may need new arches, depending on what you currently have and how they cover the wheels.

[HarrysMini]

Why would it make braking/handling worse in wet? You'd be using the same size tyres so surely the only noticeable difference would be the offset.

Edited by HarrysMini, 15 February 2014 - 10:03 PM.

[Cooperman]

To be absolutely hones, on a road mini going up 1/2" in width will make virtually no noticeable difference so long as the datum offset of the wheels is the same. The tyres will still be 165 section.

Minis handle best on 4.5" wheels with 145 section tyres, especially in the wet, but best overall road-holding is on 4.5" or 5" wheel with 165 tyres.

However, for racing or sprints using 165 x 12 tyres a 6" wheel is better, especially when running higher tyre pressures as on a smooth track firmer tyre sidewalls, which high pressures give, are better.

[tiger99]

I never thought that anyone would make the wheels 1/2" wider without changing the tyres, and assumed that the tyres would be changing too. (Note to self, NEVER ASSUME.)  Actually, in that case, as long as the tyres are of a width compatible with the wheels, the difference will indeed be utterly negligible. The tread will be the same, the only difference is that the sidewall stiffness will change slightly, by fitting the tyre to a wider wheel. Again, why bother? I would suggest spending the money on a solid subframe mount kit, if not already fitted, and some adjustable dampers, both of which will very significantly enhance the handling.

 

My comment on wet weather grip is generally always true, based on tyre width, as there is less pressure per square inch in the contact patch, and so less capability of expelling water from the tyre/road interface. And, larger tyre diameter also means a larger contact patch, so less pressure. Some modern cars have 22" wheels, so I am told, and the marketeers brag about it. When I was somewhat younger, it was the fashion for wheels to become smaller, to reduce unsprung weight (which genuinely does improve roadholding, handling, braking and, within limits, ride quality). That trend was completely successful. Yet now, driven by idiots in marketing departments, not competent engineers, the industry is flying in the face of the laws of physics. My daily driver is my first car with alloy wheels (not by choice), and they are also by far the heaviest wheels that I have ever had, all because the poor fatigue properties of alloy need a far greater static safety factor than was ever needed by a steel wheel, and they are still less safe, with a very finite fatigue life.

 

It is time that control of car design returned to competent engineers, and we saw the end of stupidly large and expensive wheels. (That gives a cIue as to why we have stupid wheels forced upon us, it is all a way to make the cars more expensive, and so more profitable.) I will accept that 10" is not really feasible for most Minis nowadays, due to the difficulty of fitting in standard size disc brakes, and 12", with lower profile tyres, to get the same rolling radius, is a viable alternative. 13" is rather pointless.

[Cooperman]

Quite right. My daily driver has 19" wheels with 275/40 x 19 tyres on the back and 245/45 x 19 on the front. Absolutely unnecessary and they tend to spoil the ride smoothness.

I did drive a 1997 Cooper SPI recently with 4.5" x 12" wheels and 145 width tyres and I thought how nice it felt in general handling terms. true it may not have had the optimum dry road-holding, but it really did feel as a classic Mini should feel. The steering was light and accurate and it just felt, well, RIGHT somehow. 

What those silly 13" wheels are meant to achieve is anyone's guess, but really they were not engineered, they were inspired by the Rover marketing idiots.

[Ethel]

The tyre contact area is mostly a function of tyre pressure and vehicle weight. What differs is the shape of the contact patch. Lower profile tyres have proportionally less sidewall to deform with side loads and higher rpm. I wouldn't say it's entirely down to the stylists. If production saloon racers want lower profile rubber and bigger brakes their only option is bigger wheels. The boy racers want to emulate their racetrack heroes & the marketeers oblige.

[Tamworthbay]

Quite right. My daily driver has 19" wheels with 275/40 x 19 tyres on the back and 245/45 x 19 on the front. Absolutely unnecessary and they tend to spoil the ride smoothness.
I did drive a 1997 Cooper SPI recently with 4.5" x 12" wheels and 145 width tyres and I thought how nice it felt in general handling terms. true it may not have had the optimum dry road-holding, but it really did feel as a classic Mini should feel. The steering was light and accurate and it just felt, well, RIGHT somehow. 
What those silly 13" wheels are meant to achieve is anyone's guess, but really they were not engineered, they were inspired by the Rover marketing idiots.

Not to mention cost, I bet those 275/40x19s aren't cheap. I was in my local backstreet tyre place last year (Tamworth tyres, always do a deal if you haggle ).The car in front was a BMW x5, the owner was bragging to the shop owner how he got it for a bargain price as all it needed was a complete set of tyres and he had knocked £700 off the asking price. His face when the tyre guy told him a full set of tyres as originally fitted was £1200 was priceless. He was much less cocky while they were being fitted.

[rally1380]

Hi all, I thinking changing the size my wheels from 5.5 x 12 to 6 x 12 how much of a difference will it make to the braking and handling to my mini. Cheers all.

 

To bring it back on topic......You won't see (or feel) that much of a difference assuming you'll still be using 165 wide tyres.  But as others have said earlier...why bother adding 1/2" width?  If your current wheels are shot then i understand, but if it's for aesthetics and you are bein suckered into following the 'stance' fashion of daft width wheels purely for looks then don't bother.

 

At least you don't own a BMW X5 tho with tyres at that price.....ouch!!!!!

[HarrysMini]

If you're purely going for the slightly wider wheels for a wider 'stance', it would be much cheaper to fit ½" spacers. Then you can spend the rest of the saved money on components that will actually improve your handling (adjustable dampers, solid front subframe mounts, adjustable arms etc.)

 

If it's because your set of 5.5" wheels are knackered, and you are replacing with 6" wheels because they're more readily available in different styles, then go ahead. You'll notice almost no difference at all as you will still be using 165 section tyres. The only difference could be the offset and weight of the wheel. Depending on the offset, you might need wider arch extensions. 

[rally1380]

echo...echo.....echo....

[woodley miniman]

Hi all, thank you all for your input, much appricated, I think I'll stick to my 5.5's the wheels are in good shape and the tyres are all less then a year old. I'm going to put the money to better use, not sure what I'll decided over the next couple of week's. One thing I do need is a new windscreen so I'll be heading off to W&p for that and a new screen rubber and insert while I'm at it. w&p are doing the green tint windscreen for Just over 40 quid so a good price.
Thanks again to you all for your input.

[Cooperman]

Hi all, thank you all for your input, much appricated, I think I'll stick to my 5.5's the wheels are in good shape and the tyres are all less then a year old. I'm going to put the money to better use, not sure what I'll decided over the next couple of week's. One thing I do need is a new windscreen so I'll be heading off to W&p for that and a new screen rubber and insert while I'm at it. w&p are doing the green tint windscreen for Just over 40 quid so a good price.
Thanks again to you all for your input.

Spend the saved cash on getting the complete suspension accurately set-up and if it has not been done, solid sub-frame mountings on the front. then you'll really see the difference in overall performance.