Mixing run-flats and normal tyres!

Mixing run-flats and normal tyres!

Author
Discussion

Emeye

Original Poster:

9,780 posts

238 months

Monday 22nd August 2011
quotequote all
My mate has just announced that he has put non-runflats on the rear of his 3.0 Z4 but the fronts are still runflats.

I've always been a bit obsessive about having my performance cars with a full set of matched tyres, so obviously I don't think this is a good idea.

Then again some of the WRC boys were running a mix of hard compound front, soft rear at the weekend, so may be my mate is a driving god?

What da ya fink?


ETA - I think he plans to put non-runflats on the front when the runflats have worn out. Tight arse.

Edited by Emeye on Monday 22 August 14:04

OwenK

3,472 posts

210 months

Monday 22nd August 2011
quotequote all
I suppose looking at it logically the only thing changed is that the front will have slightly different properties to the rear tyres. If you're prepared for it and appreciate it then no reason not to?

John D.

19,234 posts

224 months

Monday 22nd August 2011
quotequote all
Why have a 3 litre rear drive sports car and mis-match tyres? Be understeer city will it not? Not to mention the front will ride much harder than the rear (from what I understand a common trait of run-flats is a harsher ride).

Carl_Spackler

2,899 posts

203 months

Monday 22nd August 2011
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GHW

1,294 posts

236 months

Monday 22nd August 2011
quotequote all
IMHO, not an issue as long as both sets are legal tyres from a decent manufacturer.

I used to deliberately run my road rally cars on completely different tyres front and back to alter the balance of the car, but even then the difference was only very slight, and only when you were driving on the ragged edge.

On a modern daily driver with ABS and traction control it really shouldn't be an issue.

rich_vw

814 posts

207 months

Monday 22nd August 2011
quotequote all
I've done this (not through choice but necessity) and had no issue at all, although it was on a 118d. Changed the front to non RFT a month or so after.

c7xlg

900 posts

247 months

Monday 22nd August 2011
quotequote all
I ran my 4.8l rwd 360bhp car for a while with run flat on rear and real tyres on the front. Unless you drive like the stig on a power lap run you won't have any issues.

pembo

1,226 posts

208 months

Monday 22nd August 2011
quotequote all
He shouldn't have a problem, I ran my 220bhp MINI Cooper S with RF's on the back for a bit including a couple of track days and never had any problems.

Running full RF's is horrible so it's probably a good idea to work towards getting a full set of normals but he'll have to carry about a can of tyre weld somewhere because I'm guessing he won't have a spare!

Ozzie Osmond

21,189 posts

261 months

Monday 22nd August 2011
quotequote all
Personally I think it's completely bonkers to put runflats on one end of a car and conventional tyres on the other.

I've owned a car wich came with runflats and then I changed them all to conventionals. The change in ride and handling was considerable and I would NOT want to have that much difference between the front axle and back axle of my car.

Just because it's not illegal doesn't mean it's a good idea.

jon-

16,533 posts

231 months

Monday 22nd August 2011
quotequote all
Not ideal, but not the end of the world.

If you ever take note of tyres in a car park it's a wonder how some people stay on the road at all, so as long as he has decent tyres on there he'll be in a better situation than 90% of the population.

(did you know the UK is the biggest buyer of budgets in Europe with over 60% of our sales going that way)

honest_delboy

1,611 posts

215 months

Monday 22nd August 2011
quotequote all
3.0 Z4 with bridgestones on the front and yokos on the rear (both RFT though)

no problems so far...

steve_bmw

1,590 posts

190 months

Monday 22nd August 2011
quotequote all
Does anyone know the law on this one?

I have a z4 and want to swap to non runflats, the front tyres have 6mm and are runflat, the rear ones are getting low and will need doing soon.
I will be getting the bridgestone potenza re050 but the non runflat version so all the tyres have the same tread pattern.

Will it realy cause any problems on my daily commute?

c7xlg

900 posts

247 months

Monday 22nd August 2011
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No

rallycross

13,516 posts

252 months

Monday 22nd August 2011
quotequote all
Should be fine for a bit till he changes the others have tried all sorts of mixed tyre combos and running this really is no big deal - have tried much more odd mixes and still haven't fallen of the road or track.

CaptainSensib1e

1,473 posts

236 months

Monday 22nd August 2011
quotequote all
Will it not cause traction control problems, as you'll have different levels of grip at each end of the car? Heard plenty of stories along these lines when compounds have been mixed on front and rear along the lines of 'my car just tried to kill me'.

jon-

16,533 posts

231 months

Monday 22nd August 2011
quotequote all
CaptainSensib1e said:
Will it not cause traction control problems, as you'll have different levels of grip at each end of the car? Heard plenty of stories along these lines when compounds have been mixed on front and rear along the lines of 'my car just tried to kill me'.
No. No different from 2 pairs of tyres, one new and one at the end of their life or 2 different brands.

Providing you're not using a sensitive AWD system it will be fine.

c7xlg

900 posts

247 months

Monday 22nd August 2011
quotequote all
No.






Anyone getting the point I'm trying to make yet ????

Fat Albert

1,459 posts

196 months

Monday 22nd August 2011
quotequote all
Despite what the doom-mongers say there is no issue, it is like me running nice Falkens on the back of my Porker whilst I wait for the P6000s on the front to wear out....

At the last Service my Wife's 535D M Sport Touring needed 3 new tyres, the BMW dealer initially quoted us £960, but after haggling came down to £765, but then we did a deal on 4 non-RF Bridgestones for £804.

The car has been transformed! much nicer to travel in, compliant and smooth whilst retaining great handling. my only complaint is that the steering is lighter and a bid dead in teh centre...but my Wife sees that as a bonus!

Urban Sports

11,321 posts

218 months

Monday 22nd August 2011
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Same tyres on an individual axle and premium brands I don't see an issue.

Mr Whippy

31,052 posts

256 months

Monday 22nd August 2011
quotequote all
Problem is, the Z4 driving characteristics change so much going from OE RFT (RE050) to non-RFT, that I'd not be keen on mixing the axles.

It'll probably be fine 99.99% of the time, if you like a car that just drives badly in a different way to OE RFT's, but it'll be the time you need to lean on the ABS, ESP or TCS that you find out the different tyre properties at each end might cost you some stability or something.


I just don't get the reason for skimping either. The fronts are cheap vs the rears, and last for years too. Why bother?

Dave