Hi all,
I’d like to apologise for the length of this post, you can jump straight to the questions but you may miss out on context.
I’ve recently acquired a 2019 Insignia Sports Tourer with 20 inch wheels. Whilst I’m enjoying the car, I am regretting the wheel size since I need to travel across Europe this winter and I need either all-season or winter tyres to avoid getting hefty fines in countries like Germany. At 245/35 R20 they are not cheap and there isn’t much changed from £750! So, I’ve looked into alternatives but I’m being met with a ton of information, some of which is contradictory. I would be very grateful for your advice.
Since the car comes with a baseline option of 18 inch wheels (tyres are 245/45 R18) I decided that another set of cheap 18 inch wheels plus winter tyres would be a good solution and not that much more expensive than the tyres for the 20inch wheels. However, I have not been able to find cheap steel rims at 18 inches. I can find all sorts of alloys but their rim widths do vary from 7.5J to 8.5J, I’m unable to confirm the current rim width but I think it is 8.5J.
I have TPMS on the current wheels, I’ve been told a whole variety of contradictory things about what I should and shouldn’t do. Some tell me I must install additional TMPS sensors in the additional wheels, whilst others say that it shouldn’t be an issue if they are not present. Some say that I can only get new sensors to work by taking them to a specialist to get working, whilst the handbook seems to suggest that I only need to drive the car for about 20-30 mins at no more 60mph.
At my local Vauxhall Dealership, the service manager told me that by putting smaller 18 inch wheels on the car that the ABS would start raising faults. I quizzed him about why this should be and he told me that the diameter would change and therefore the circumference would change. I challenged him, stating that difference between wheel and tyre combination of 245/35 R20 and 245/45 R18 is about 2mm across the diameter. I also pointed out that this is well within the error produced by tyre wear over the lifetime of the tyre, if you have say 6mm of tread depth you can take that below 2mm before needing to change the tyre, that’s a loss of 8mm across the diameter. He adamantly stuck to his position despite my reasoning, I left confused and with a distinct loss in confidence in their ability to help.
Because I couldn’t get a decent answer out of my local dealer I decided to call Vauxhall’s own customer service line. They said that they knew nothing about what the local dealer had said about the ABS, but instead offered that they didn’t recommend changing the wheel size. When I asked them why, they told me that it would invalidate my warranty (my car still has 29 months to run). I pointed out that this model in its basic form comes with 18 inch wheels, the wheels I have are optional extras. They then dropped the claim about the warranty but still insisted that they don’t recommend fitting 18 inch wheels because it could affect the handling. I gave up at this point but not before I tried another dealer in a nearby town. The guy from the other dealership sounded a bit more clued up but he was noncommittal when it came to the TPMS.
Speaking to a variety of wheel and tyre specialists I’ve come to the conclusion that there is no issue in changing the wheels, why would there be? But the jury is still out on what would happen to the TPMS if I either get new sensors or don’t bother at all.
So, questions on the above:
1. Why am I not able to locate 18 inch steel rims?
2. What issues would I encounter if I acquired 18 inch rims with 8.0J width instead of the 8.5J width that I think the current 20 inch wheels have?
3. If there somewhere where I can verify the other parameters of my wheel setup such as offset and centre bore, etc? (I’ve found my local dealership useless)
4. If I go for additional TMPS sensors, will they work out of the box or will I have to get someone to fettle them to work with my car?
5. Am I wrong about my encounter with my local dealer?
Anyway, thanks for struggling this far, I hope you can find the time to give me an answer.
Cheers,
Sean.
I’d like to apologise for the length of this post, you can jump straight to the questions but you may miss out on context.
I’ve recently acquired a 2019 Insignia Sports Tourer with 20 inch wheels. Whilst I’m enjoying the car, I am regretting the wheel size since I need to travel across Europe this winter and I need either all-season or winter tyres to avoid getting hefty fines in countries like Germany. At 245/35 R20 they are not cheap and there isn’t much changed from £750! So, I’ve looked into alternatives but I’m being met with a ton of information, some of which is contradictory. I would be very grateful for your advice.
Since the car comes with a baseline option of 18 inch wheels (tyres are 245/45 R18) I decided that another set of cheap 18 inch wheels plus winter tyres would be a good solution and not that much more expensive than the tyres for the 20inch wheels. However, I have not been able to find cheap steel rims at 18 inches. I can find all sorts of alloys but their rim widths do vary from 7.5J to 8.5J, I’m unable to confirm the current rim width but I think it is 8.5J.
I have TPMS on the current wheels, I’ve been told a whole variety of contradictory things about what I should and shouldn’t do. Some tell me I must install additional TMPS sensors in the additional wheels, whilst others say that it shouldn’t be an issue if they are not present. Some say that I can only get new sensors to work by taking them to a specialist to get working, whilst the handbook seems to suggest that I only need to drive the car for about 20-30 mins at no more 60mph.
At my local Vauxhall Dealership, the service manager told me that by putting smaller 18 inch wheels on the car that the ABS would start raising faults. I quizzed him about why this should be and he told me that the diameter would change and therefore the circumference would change. I challenged him, stating that difference between wheel and tyre combination of 245/35 R20 and 245/45 R18 is about 2mm across the diameter. I also pointed out that this is well within the error produced by tyre wear over the lifetime of the tyre, if you have say 6mm of tread depth you can take that below 2mm before needing to change the tyre, that’s a loss of 8mm across the diameter. He adamantly stuck to his position despite my reasoning, I left confused and with a distinct loss in confidence in their ability to help.
Because I couldn’t get a decent answer out of my local dealer I decided to call Vauxhall’s own customer service line. They said that they knew nothing about what the local dealer had said about the ABS, but instead offered that they didn’t recommend changing the wheel size. When I asked them why, they told me that it would invalidate my warranty (my car still has 29 months to run). I pointed out that this model in its basic form comes with 18 inch wheels, the wheels I have are optional extras. They then dropped the claim about the warranty but still insisted that they don’t recommend fitting 18 inch wheels because it could affect the handling. I gave up at this point but not before I tried another dealer in a nearby town. The guy from the other dealership sounded a bit more clued up but he was noncommittal when it came to the TPMS.
Speaking to a variety of wheel and tyre specialists I’ve come to the conclusion that there is no issue in changing the wheels, why would there be? But the jury is still out on what would happen to the TPMS if I either get new sensors or don’t bother at all.
So, questions on the above:
1. Why am I not able to locate 18 inch steel rims?
2. What issues would I encounter if I acquired 18 inch rims with 8.0J width instead of the 8.5J width that I think the current 20 inch wheels have?
3. If there somewhere where I can verify the other parameters of my wheel setup such as offset and centre bore, etc? (I’ve found my local dealership useless)
4. If I go for additional TMPS sensors, will they work out of the box or will I have to get someone to fettle them to work with my car?
5. Am I wrong about my encounter with my local dealer?
Anyway, thanks for struggling this far, I hope you can find the time to give me an answer.
Cheers,
Sean.
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