RFTto Normal Tyres
RFTto Normal Tyres
Author
Discussion

kenyon

Original Poster:

1,269 posts

287 months

Tuesday 2nd February 2010
quotequote all
Guys,
Changed my RFT to normal non RFT and what a difference on my E92 Coupe (330DM Sport). The car handles 100% better not skittish on cornering and more grip and easier on the suspension too.

Tyres put on are 265/30/19/ZR on rear - Falken cost £270-oo a pair including fitting and vat.
235/35/19/ZR on Frint - Kalken cost £230-00 a pair including fitting and vat.

Same price if I was buying just two RFT for the rear, a real saving. I run the same tyres on my ferrari too.

Insurance okay with the change and does not effect BMW warranty as I have purchased the tyre pump inflator kit too.
The RFT on the rear have only lasted me 10K due to sides wearing badly and showing signs of a blow out due to bad wear on the inner sides. The car was purchased brand new 01st Feb 2009 and and has covered 45K in a year with 4 sets of tyres being replaced.

dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
Sounds good thumbup

I need to do this too. With the current state of the roads (ie cold, wet, snowy, greasy, full of pot holes) my RFTs are doing my head in. The only thing which might stop me is if the third generation RFTs appear - they are reportedly much easier riding than the current generation of RFTs...

kenyon

Original Poster:

1,269 posts

287 months

Tuesday 2nd February 2010
quotequote all
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.

dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
Aha - you obviously missed my really truly fascinating thread on this very subject

But in general I agree with your sentiment smile

abarber

1,711 posts

271 months

Tuesday 2nd February 2010
quotequote all
The difference junking the run flats makes, is just vast.

I changed the run flats on my 330i a few years ago, for F1 Asymmetrics, the difference in ride, comfort and grip was massive.

Just had a loaner 320i Coupe whilst in for servicing, couldn't believe how bad the ride was.

You do loose a little turn in response, due to the softer sidewalls. Hardly makes much difference on 18 or 19" wheels though.

Had three punctures on the RFTs, none since too. Very strange.

DSM2

3,624 posts

230 months

Tuesday 2nd February 2010
quotequote all
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.


dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
DSM2 - do you know anything about the third generation RFTs ? I recall you are involved in the tyre business so I wondered if you had any inside info ...

DSM2

3,624 posts

230 months

Tuesday 2nd February 2010
quotequote all
dibbly_dobbler said:
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
DSM2 - do you know anything about the third generation RFTs ? I recall you are involved in the tyre business so I wondered if you had any inside info ...
In what way? They are basically the same as earlier generations but developed to try to improve wear rate and ride.

In all honesty, the industry has basically accepted that RFTs will remain a niche market because the shortcomings seem inevitable for a SST type runflat. The PAX overcame the ride issue but was killed, to all intents and purposes because fo the difficulty in fitting and the need for unique rims. (Also didn't wear very weel.)

It's long been the grail for manufacturers to produce a practical RFT that performs as well as a 'normal' tyre but we are still a long way from that.

Conti are now moving back to regular tyres with OE installed sealants. nothing new there but seems as good a way to keep mobile, in most cases, as any.



dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
DSM2 said:
dibbly_dobbler said:
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
DSM2 - do you know anything about the third generation RFTs ? I recall you are involved in the tyre business so I wondered if you had any inside info ...
In what way? They are basically the same as earlier generations but developed to try to improve wear rate and ride.

In all honesty, the industry has basically accepted that RFTs will remain a niche market because the shortcomings seem inevitable for a SST type runflat. The PAX overcame the ride issue but was killed, to all intents and purposes because fo the difficulty in fitting and the need for unique rims. (Also didn't wear very weel.)

It's long been the grail for manufacturers to produce a practical RFT that performs as well as a 'normal' tyre but we are still a long way from that.

Conti are now moving back to regular tyres with OE installed sealants. nothing new there but seems as good a way to keep mobile, in most cases, as any.
Thanks. I had read on another thread that the new generation of RFTs were (reportedly) virtually indistinguishable from a normal tyre (5% more harsh than normal tyres as opposed to 15% in the current RFT) so I had wondered if/when they would be becoming available. I raised a topic here which linked to the original review but nobody seems to know anything about it ...

DSM2

3,624 posts

230 months

Tuesday 2nd February 2010
quotequote all
dibbly_dobbler said:
DSM2 said:
dibbly_dobbler said:
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
DSM2 - do you know anything about the third generation RFTs ? I recall you are involved in the tyre business so I wondered if you had any inside info ...
In what way? They are basically the same as earlier generations but developed to try to improve wear rate and ride.

In all honesty, the industry has basically accepted that RFTs will remain a niche market because the shortcomings seem inevitable for a SST type runflat. The PAX overcame the ride issue but was killed, to all intents and purposes because fo the difficulty in fitting and the need for unique rims. (Also didn't wear very weel.)

It's long been the grail for manufacturers to produce a practical RFT that performs as well as a 'normal' tyre but we are still a long way from that.

Conti are now moving back to regular tyres with OE installed sealants. nothing new there but seems as good a way to keep mobile, in most cases, as any.
Thanks. I had read on another thread that the new generation of RFTs were (reportedly) virtually indistinguishable from a normal tyre (5% more harsh than normal tyres as opposed to 15% in the current RFT) so I had wondered if/when they would be becoming available. I raised a topic here which linked to the original review but nobody seems to know anything about it ...
The thing is that a radial car tyre operates on the basis of a very stiff tread area and very flexible sidewalls. The Self Supporting Tyre type of RFT has a much stiffer sidewall and a heavily built up shoulder, which is the most highly stessed section. It's inevitable that if a tyre is going to support the wieght of the car witout inflation, then the sidewall needs to be pretty stiff and this compromises the basic design, affecting grip, ride and wear.

Compromises can be made in the suspension to compensate but, as many of us know, that is not a developed art yet, to say the least!


There are ways of enabling ' normal' tyres to run flat, eg the RAV 4 application, but these have yet to be taken up widely enough to make the equipment needed for fitting and removal interesting to most retailers.



dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
DSM2 said:
dibbly_dobbler said:
DSM2 said:
dibbly_dobbler said:
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
DSM2 - do you know anything about the third generation RFTs ? I recall you are involved in the tyre business so I wondered if you had any inside info ...
In what way? They are basically the same as earlier generations but developed to try to improve wear rate and ride.

In all honesty, the industry has basically accepted that RFTs will remain a niche market because the shortcomings seem inevitable for a SST type runflat. The PAX overcame the ride issue but was killed, to all intents and purposes because fo the difficulty in fitting and the need for unique rims. (Also didn't wear very weel.)

It's long been the grail for manufacturers to produce a practical RFT that performs as well as a 'normal' tyre but we are still a long way from that.

Conti are now moving back to regular tyres with OE installed sealants. nothing new there but seems as good a way to keep mobile, in most cases, as any.
Thanks. I had read on another thread that the new generation of RFTs were (reportedly) virtually indistinguishable from a normal tyre (5% more harsh than normal tyres as opposed to 15% in the current RFT) so I had wondered if/when they would be becoming available. I raised a topic here which linked to the original review but nobody seems to know anything about it ...
The thing is that a radial car tyre operates on the basis of a very stiff tread area and very flexible sidewalls. The Self Supporting Tyre type of RFT has a much stiffer sidewall and a heavily built up shoulder, which is the most highly stessed section. It's inevitable that if a tyre is going to support the wieght of the car witout inflation, then the sidewall needs to be pretty stiff and this compromises the basic design, affecting grip, ride and wear.

Compromises can be made in the suspension to compensate but, as many of us know, that is not a developed art yet, to say the least!


There are ways of enabling ' normal' tyres to run flat, eg the RAV 4 application, but these have yet to be taken up widely enough to make the equipment needed for fitting and removal interesting to most retailers.
Fascinating stuff thanks again thumbup

Silver993tt

9,064 posts

269 months

Tuesday 2nd February 2010
quotequote all
kenyon said:
All the M models do not have RFT.
My E91 330D M-Sport comes with RFTs

dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
Silver993tt said:
kenyon said:
All the M models do not have RFT.
My E91 330D M-Sport comes with RFTs
I think that is true for 'proper' M models - ie M3, M5, M6 etc (no disrespect to your 330 btw smile)

timwatsham

239 posts

280 months

Tuesday 2nd February 2010
quotequote all
By the way, someone mentioned tyres wearing really badly & unevenly - I've just switched from RFT on my Z4 which was tramlining and wandering all over the place. It had worn down the inside edges so I took it to Wheels in Motion in Chesham who popped it up on a jig and changed the camber of the wheels and reset the toe-in etc.

Drives like a new car now - simply lovely... Would recommend a visit there if anyone has problems of uneven wear...

ed335d

395 posts

206 months

Tuesday 2nd February 2010
quotequote all
I personally can't see the point of runflats, other than not having to stop if you have a puncture.

Deflated RFT = 50 miles at 50 mph? Non-RFT inflated with tyre weld = 50 miles at 50 mpg. Need a new tyre in either case

Blow-out on RFT, tow home. Blow out on non-RFT, tow home.

When was the last time you had a blow out?

Slow puncture on RFT, drive to get some air into it, maybe repairable. Slow puncture on non-RFT, fill it up with the compressor you keep on board when you changed to non-RFT's, maybe repairable (more likely to find someone who will)

Very harsh ride on RFT's, much smoother ride on non-RFT's

Full set of RFT's for me - £1100, non-RFT's (and slightly wider) - £650. Difference = two tows and a space saver for long journeys?

As long as you're prepared (mobility kit etc), non-RFT's are the sensible choice.


kenyon

Original Poster:

1,269 posts

287 months

Tuesday 2nd February 2010
quotequote all
DSM2 said:
kenyon said:
RFT are pointless as if you get a nail/screw in your tyre and they are no repairable and will need to buy a new tyre. Where on normal tyres they can be repaired and changed on the rims to ensure even wear and in turn last longer.

All the M models do not have RFT.
Total myth, of course RFTs are repairable.
Maybe so but I know of no garage that will repair them and Guarantee their safe to use, not like normal tyres. Anyway RFT are too expensive for what they are and deliver in performance and handling characteriscs.

kenyon

Original Poster:

1,269 posts

287 months

Tuesday 2nd February 2010
quotequote all
ed335d said:
I personally can't see the point of runflats, other than not having to stop if you have a puncture.

Deflated RFT = 50 miles at 50 mph? Non-RFT inflated with tyre weld = 50 miles at 50 mpg. Need a new tyre in either case

Blow-out on RFT, tow home. Blow out on non-RFT, tow home.

When was the last time you had a blow out?

Slow puncture on RFT, drive to get some air into it, maybe repairable. Slow puncture on non-RFT, fill it up with the compressor you keep on board when you changed to non-RFT's, maybe repairable (more likely to find someone who will)

Very harsh ride on RFT's, much smoother ride on non-RFT's

Full set of RFT's for me - £1100, non-RFT's (and slightly wider) - £650. Difference = two tows and a space saver for long journeys?

As long as you're prepared (mobility kit etc), non-RFT's are the sensible choice.
Totally Agree. BMW have balls uped

ed335d

395 posts

206 months

Tuesday 2nd February 2010
quotequote all
Your RFT's didn't last long! My original set lasted 24k miles.

At 18k miles (1st service), dealer said my rear tyres were illegal on the inside and needed replacing. Wasn't too happy, so did some research and found out that a common cause for inside wear is incorrect pressures and the agressive set up.

Admittedly, I didn't check the pressures very often, but started to and ran 0.2bar over the BMW pressures (as advised by the dealer). The rears lasted another 6k with even wear and the fronts are still legal (but sitting in the garage).

Changing no non-RFT's is one of the best 'mods' you can give your car

Edited by ed335d on Tuesday 2nd February 21:20

dibbly_dobbler

11,496 posts

227 months

Tuesday 2nd February 2010
quotequote all
ed335d said:
Admittedly, I didn't check the pressures very often, but started to and ran 0.2bar over the BMW pressures (as advised by the dealer). The rears lasted another 6k with even wear and the fronts are still legal (but sitting in the garage).
Ed - were you running on 18s ? Can you remember if it was 0.2 bar over the fully loaded recommended pressure or the normal recommended pressure ? I am running mine a bit hard at the moment (2.9 bar iirc) but I am concerned it's knackering the ride and reducing grip levels. What do you reckon ?


ed335d

395 posts

206 months

Tuesday 2nd February 2010
quotequote all
dibbly_dobbler said:
ed335d said:
Admittedly, I didn't check the pressures very often, but started to and ran 0.2bar over the BMW pressures (as advised by the dealer). The rears lasted another 6k with even wear and the fronts are still legal (but sitting in the garage).
Ed - were you running on 18s ? Can you remember if it was 0.2 bar over the fully loaded recommended pressure or the normal recommended pressure ? I am running mine a bit hard at the moment (2.9 bar iirc) but I am concerned it's knackering the ride and reducing grip levels. What do you reckon ?
This was on 19's, 255/30 and 225/35 if I remember correctly. 0.2bar over normal loads

I found that the compound was too hard in the cold and was all over the place below about 7 degrees C. Didn't rate the RFT's in the wet either.