Run Flat Tyres without TPMS

[Truckosaurus]

I have just ordered some discounted winter tyres from a leading online tyre retailer.

As I used my number plate to identify the tyres sizes they know what my car is.

I received an email shortly after ordering telling me I had selected run-flat tyres and my car doesn't have a tyre pressure warning system (which is correct) - and they don't recommend such things.

I understand the theory, they don't want some dimwit driving around with a big hole in their tyre as the sidewall looks ok.

On low profile non-run flats you can barely tell if there's a flat, so I do regularly check my pressures manually anyway.

So, other than being a fool for going for run flats anyway, is it a big deal or is it just back side covering from the retailer?

(Also, I'm changing tyres to get the car back onto its stock wheels in advance of selling it before next summer, and thought I'd give winter tyres a try, so not a long term ownership proposition)

[Scrump]

If you regularly check tyre pressures then you should be fine, except…

I am sure I read that runflat tyres require a different rim profile then normal tyres. I recall normal tyres can be fitted on wheels meant for run flats but not vice versa. I may be wrong but worth checking.

[Stick Legs]

My 2010 BMW 530d had run flat tyres & a TPMS that worked from the ABS sensors rather than valve pressure sensors.

So there are forms of TPMS.

However Run Flat tyres require specific rims I think?

Alternatively try these:




A friend uses them on his trailer & reckons they are good.

[Mr Tidy]

Why not save a few quid by getting non-runflats seeing as you plan to sell?

I'm pretty sure some sort of TPMS was compulsory for (hateful) run-flats.

[Truckosaurus]

Mr Tidy said:

Why not save a few quid by getting non-runflats seeing as you plan to sell?

They were the cheapest in the size I needed (Kumhos) as there didn't seem to be any cheapo unknown brands doing winters.

I've cancelled the order now anyway.

It would be interesting to know more about the claims that you need different rims for run flats, googling doesn't seem to provide a conclusive answer - results all seem to be about going the other way (RFT to normal).

[stevemcs]

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

[Truckosaurus]

stevemcs said:

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

Very good. That's not something I'd ever heard and you'd think that would be what they'd flag up on the various tyre sites....

[MustangGT]

IIRC correctly a standard wheel for normal tyres is a J rim, for a run-flat tyre I think it is JJ. The area where the rim bead goes is kind of doubled to hold the bead even when the tyre is flat.

[E-bmw]

stevemcs said:

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

[mmm-five]

E-bmw said:

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

The pedant in me says you can fit it safely but it may not stay safely fitted

[stevemcs]

E-bmw said:

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

Kind of, yes you can fit the tyre, but as you say if it went flat it would go horribly wrong.

Having said that we have seen some cars with the wrong tyres on, usually hackneys that have a summer, winter, runflat and another summer.

There are also self seal tyres, they have a sticky substance inside, almost tar like thats designed to seal when they get a puncture.

[Pica-Pica]

E-bmw said:

stevemcs said:

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

You can physically fit a run-flat to a J rim but it won’t be safely fitted.
JJ rim profiles for runflats (but can also take non-runflats)
J rims are not safely suitable for run-flats.

[E-bmw]

mmm-five said:

E-bmw said:

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

The pedant in me says you can fit it safely but it may not stay safely fitted

There's an echo in here..... in here.....

[E-bmw]

Pica-Pica said:

E-bmw said:

stevemcs said:

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

You can physically fit a run-flat to a J rim but it won’t be safely fitted.
JJ rim profiles for runflats (but can also take non-runflats)
J rims are not safely suitable for run-flats.

in here..... in here....

[Pica-Pica]

E-bmw said:

Pica-Pica said:

E-bmw said:

stevemcs said:

The rim is slightly different for runflats, so you can put standard tyres on a runflat rim but you cannot (safely) fit a runflat tyre on a standard rim.

The pedant in me says AFAIK you can safely fit it but the tyre will not be retained on the rim when flat if that is what you meant.

You can physically fit a run-flat to a J rim but it won’t be safely fitted.
JJ rim profiles for runflats (but can also take non-runflats)
J rims are not safely suitable for run-flats.

in here..... in here....

But more precise, to be precise.