10 replies to this topic

[Jeffreypang911]

Hello y'all

Now Ive got a question about fitting wide rims on a Mini - 7x13, 8x13 even 7x10 seem extreme. Everyone says they ruin handling, puts wear on wheel bearings and other parts and all that stuff. But why do Minis that race run such extreme sizes and offsets?





Now we all know that 10s handle amazing (heck its what I am running) but you have to think why are these racing minis running such extreme sizes? Is it that they have completely different sub frames designed for this application? They would have to be lighter than your average street mini so the handling would be even worse (no weight on those wide tires?)

Ive always thought fitting wider tires for most cars would help the handling, but minis are a bit different...

So, anyone know the answer?

Edited by Jeffreypang911, 01 September 2010 - 06:07 AM.

[Bungle]

do the top 2 mini's you have pictured run with mini suspension ?

[samsfern]

the second one is a z-cars bike engined mini, which if im right arent normall standard mini suspension. And the top one looks more like a minus or something else.

Edited by samsfern, 01 September 2010 - 06:30 AM.

[Mr Joshua]

I run 16 x 7.5J on my mini with a 50/50 offset and the only component that has suffered has been a steering column, she will snap your spine if you corner to harshly.

Edited by Mr Joshua, 01 September 2010 - 12:18 PM.

[Danpolk]

im also keen to see what people say to this! I cant get my head around how people say 10x7s are good at handling and 13x7s so bad! As you said the offsets would be the same and the rolling radius isnt massively different either!

[Ethel]

Handling and road holding are different things. Tyre availability will be a factor with all those, but being racing tyres, they can at least have a soft enough compound to get to a decent operating temperature without having to worry about wearing the tread to below legal limits just nipping down to the shops.

First Mini looks like a mid engined space framer.

[minisilverbullet]

Like Ethel has stated, I wonder about the rubber compound. I.E on the cars pictured it will be very soft, compared to the tyres a road mini has. I read somewhere about the mini being too light, for wide wheels. and dont "push" the rubber onto the road.

I notice a huge difference between my summer wheels 13 x 7 and my winters (with soft rubber) 12 X 5. this being said even with the big wheels my mini still out handles most on the road.

And still puts a huge smile on my face - especially after driving my audi estate quattro which handles like a yacht.

[pikey7]

roadholding and grip. and race minis can have their wheel bearings changed every other weekend!

[travellering]

Also, racing cars are generally looking for the fastest way around a corner, not predictable straight line driving. If you drove most racecars on the street, with the usual distractions and surface imperfections, you'd probably pee your pants. They are twitchy, darty, and uncompromising.
The larger offsets help with weight transfer, i.e. they mean it takes more sideways cornering force to roll the car.

Streetcar handling is a compromise between predictability and performance. You'd probably like to be able to drive some of the time without a solid two-hand grip on the wheel, and if you are pushing the car you'd probably like it to give a bit of warning (tyre squeal, a bit of slip) before suddenly spinning out. As you maximise grip (turning into a racecar) you reduce that warning window.

Wide slick tyres on a smooth-paved race circuit allow for maximum grip, but on the street, they will tramline on any cracks or surface changes, and they will hydroplane if there is even mist in the air, let alone actual wetness on the ground.

[Ethel]

The car sits on the wheels, and is much much heavier than even the widest wheel, so big wheels have no effect on wheel bearings directly. Of course, you're probably fitting them to drive harder round corners which will put more strain on all the suspension. Heavy wheels won't move as quckly when pushed by the same suspension springs to try and keep contact with a bumpy road surface - something Minis are particularly adept at thanks to their iddy biddy wheels 'n lively spring rates.

[travellering]

The car sits on the wheels, and is much much heavier than even the widest wheel, so big wheels have no effect on wheel bearings directly. Of course, you're probably fitting them to drive harder round corners which will put more strain on all the suspension. Heavy wheels won't move as quckly when pushed by the same suspension springs to try and keep contact with a bumpy road surface - something Minis are particularly adept at thanks to their iddy biddy wheels 'n lively spring rates.

It's not the weight of the wheel that affects the wheel-bearing life. It's the width. The wheel bearing is designed to spin around one axis, while resisting motion in the other two. If you push the centerline of the wheel out (wider wheel, bigger offset, spacers, etc.), then you change the angle of the forces acting on the bearing to a side load instead of an inline axial load. Side loading kills bearings.