Run flats ok?

jifl

Active Member
Jun 8, 2017
3
0
Hi all,

I have a 2016 Alhambra with TPMS. I understand that the sort of TPMS fitted works by uses the ABS wheel speed sensors to measure the rolling radius of the wheel to detect punctures (so-called indirect TPMS), rather than measuring the actual pressure at the valve (direct TPMS).

I needed new front tyres, and given the absence of a spare or even space-saver wheel, I ordered Bridgestone DriveGuard runflats. The reputation of the pathetic puncture repair kits is notorious, and in particular don't help with sidewall damage.

But the tyre co I usually used in the past are saying they don't think they're right for the Alhambra because it doesn't have direct TPMS and they claim it is unsafe if not. I get that direct TPMS is more accurate, but from all I've read, the only requirement is that it has some form of TPMS. The tyre guy thinks that run flats hold the shape of the tyre so perfectly that the rotation speed won't change. From what I've read with people testing run flats, I'm not convinced.

The Alhambra manual even says: "If replacing tyres, make sure the new ones have an emergency ride system (Conti-Seal / Run flat)".

So is the tyre guy misguided? Can you use run flats on an Alhambra? This company is normally good, and as they said to me themselves, they could have just gone ahead and taken my money and fitted them. That's noble, but that doesn't make them right :D

BTW, I also rang Seat, and they said it's fine, but I'm wondering if I'm going to have to get them to put it in writing for him to believe me (his words were "Although you have contacted Seat with regards to the fitment of the tyre I do not understand how they can say that this is safe. You do not have runflat sensors on the vehicle and as such you will not know that the tyres are punctured and you will then run the risk of further damage to the wheel and vehicle. Furthermore I am still not convinced that the rim would be strong enough for the tyre either.", and when pointing out the car did have TPMS, he said indirect isn't good enough).

Anyway, any info appreciated, thanks!
 

baba_metca

Active Member
May 4, 2016
32
0
The TPMS is, as you mentioned, is an ABS TPMS. So it will only sence if the radius is changed. If the tyre radius does not change at all, then this system is useless for that specific tyre.

On the other hand the tyres on the Alhambra are marked as an XL tyres, also the Alhambra is quite a heavy vehicle. Ours with the 4Drive is stated to be 1930kg not loaded. Loaded should be around 2600kg. So the rims, should be good enough.

There are some aftermarket TPMS that are tyre pressure based. They are installed on your wheels inside the air valve nozzle, or replacing the air valve nozzle. They are expensive, but do the job ok, also some of them are bluetooth enabled to comunicate with a smartphone. This could be a good workaroundon the problem.

The ContySeal tyres are too a good alternative but still does not protect the sides, only the protector.
Your tyre company is realy good if they are stating these problems, as they are real problems. You should be glad and this is a big PLUS to you. Do not get angry with them.

On the question, are the Runflats OK? Well if they are allready fitted,then just deflate one of them and ride it for a fiew miles in a safe evirenment to check the TPMS responce to it. Otherwise install an aftermarket tyre pressure TPMS to be 100% sure (depending on the TPMS). It will be good if you post some of your experionce on the matter
 

jifl

Active Member
Jun 8, 2017
3
0
Hi,

At the time I initially posted I hadn't had the run flats fitted, but after getting written assurance from SEAT that Bridgestone Driveguards should be okay, I decided to go for it and get the run flats installed.

So now I have them I have also now done the test by deflating one tyre and going on a quiet local road. I'm pleased to say the TPMS noticed after driving for only 2 minutes about a third of mile, and didn't drive above 50 obviously. The handling was also noticeably different as well.

So I'm happy with the run flats. You mentioned about XL tyres, and just for the avoidance of doubt, the Driveguards I chose are also rated XL; so if anyone reading this is thinking any and all run flats are okay, if they are not XL then there might be a difference on an Alhambra.

Out of interest, a week after, I took the car to my local SEAT main dealer for a minor service, and they wrote a warning that the new tyres aren't ContiSeal so I run the risk of flats if punctured. They evidently neglected to notice the big RFT letters on the sidewall!
 

Gerico1000

Active Member
Sep 7, 2014
46
0
The difference is that a run flat will do just that but will more than likely need replacing when you get to where your going etc.

ContiSeal will potentially repair itself when reflated. This is what mine did, therefore, where tyres are concerned I nearly always replace like for like using the original equipment. Having said all that I still have a full size spare in the garage at home!
 
Genuine SEAT Parts and Accessories.