Rough roads - what difference would these these tyres make?

[Clintpistol17]

Hi

I'm looking for a new (used) car. Needs to tick several boxes, one of which is that I live in the mountains where the roads are poor quality with loads of rough patches, potholes, etc.

The cars I've short listed have the following spec tyres:

- 205/55 R16.
- 205/60 R16.
- 215/65 R16.

I've been told that the higher the side wall of a tyre, the more it will protect the suspension of the car and save frequent trips to the garage for new drop links, bushes, shocks, etc. I seem to have to have these sorts of things changed a lot at the moment!

With that in mind, how much difference would the above size wheels/tyres make?

Also. is it possible to easily change a car's tyre size, say from 205/55 R16 to 215/65 R16? Or would that be a real pain both practically and when it comes to insurance etc?

Many thanks

[danb79]

Clintpistol17 said:

Hi

I'm looking for a new (used) car. Needs to tick several boxes, one of which is that I live in the mountains where the roads are poor quality with loads of rough patches, potholes, etc.

The cars I've short listed have the following spec tyres:

- 205/55 R16.
- 205/60 R16.
- 215/65 R16.

I've been told that the higher the side wall of a tyre, the more it will protect the suspension of the car and save frequent trips to the garage for new drop links, bushes, shocks, etc. I seem to have to have these sorts of things changed a lot at the moment!

With that in mind, how much difference would the above size wheels/tyres make?

Also. is it possible to easily change a car's tyre size, say from 205/55 R16 to 215/65 R16? Or would that be a real pain both practically and when it comes to insurance etc?

Many thanks

Which car are you thinking of? Would a 4x4 not be a better choice?

What issues have you had so far if you're looking to change tyres?

And use this calculator to ensure you're still within specs of what your car needs; needs to stay within 2.5% +/- for it not to affect speedo/diff etc

https://www.willtheyfit.com/

If it's an xDrive BMW; stick with OEM sized tyres

[Bill]

It would also be useful to know what your current car and tyre size is.

[kambites]

Clintpistol17 said:

Also. is it possible to easily change a car's tyre size, say from 205/55 R16 to 215/65 R16? Or would that be a real pain both practically and when it comes to insurance etc?

It would obviously depend on the car, but that's a nearly 2cm difference in rolling radius. On most cars I suspect going from the former to the latter would foul something. The usual approach would be to drop to 15 inch wheels to allow more sidewall without increasing the rolling radius significantly.

As for the difference it will make - it depends hugely on both the exact car and the exact tyres in question. They all have a reasonable amount of sidewall by modern road-car standards.

[Davie]

kambites said:

As for the difference it will make - it depends hugely on both the exact car and the exact tyres in question. They all have a reasonable amount of sidewall by modern road-car standards.

This!

I'd stick my neck out and say if you took those three tyres sizes, send car, same brand, same roads, same pressures... you're average driver probably would be hard pushed to notice a significant difference.

But on that note, different brands, different pressures, suffering cars, different ratings...

The fact all are 16's with reasonable sidewall is enough, I wouldn't be getting too hung up on the exact size - there's too many variables beyond the size alone.

I'm also not convinced higher sidewalls make a significant savings on wear and tear, the suspension will still be taking bigger hits with a rutted road... the saving grace is higher sidewalls offer a bit more compliancy and protection, so maybe less likely to crack / bend a rim.

My car came with 18's as standard with 225/45/18 tyres (I think...) and I changed it a whole back to 205/55/16's and it does drive much nicer, less jiggly but it still goes through drop links and ball joints... and springs... at the same rate.

I also had 215/70/17 commercial rated Continentals on my van and it was horrible... it's now on 235/65/17 SUV spec tyres, ie without a reinforced sidewall and it's like night and day, hence the actual size is only part of the equation.

Edited by Davie on Sunday 10th November 19:10

[Clintpistol17]

Hi

Many thanks for the quick and helpful replies. To answer some of the questions...

danb79 said:

Which car are you thinking of? Would a 4x4 not be a better choice?

We're looking at Dacias mainly - Duster, Jogger and Logan Stepway. Possible the Vauxhall Combo Life. We've always been ok without 4x4 so thinking to stay away from that as it is extra money and something else to go wrong. Also, I was told in the past that a 2x4 with decent all season or winter tyres is better than a 4x4 with standard tyres?

danb79 said:

What issues have you had so far if you're looking to change tyres?

Various over the years. Our current car is an inherited Vauxhall Corsa D (195/55 R16 tyres), and before that we had a Skoda Fabia estate (185/60 R14). I'd have to look over old invoices to see what work we had done in the past, if I've still got them. But from memory it always seemed to be suspension related things like drop links, bushes, wishbones (?), shocks, shock mounts, CV joints.

I'm not looking to change tyres as such. But more looking for cars which will have better tyres (and protection of suspension parts) than our current Corsa and previous Fabia. I asked about changing tyres as the Logan Stepway has 205/55 R16, while the Jogger and Duster have better tyre sizes at 205/60 R16 and 215/65 R16 respectively. So I was wondering whether, if we went for a Logan, we might be able to change the tyres/wheels for a better size and side wall height.

Bill said:

It would also be useful to know what your current car and tyre size is.

kambites said:

As for the difference it will make - it depends hugely on both the exact car and the exact tyres in question.

Details above, if they help? In terms of the exact tyres, I guess make/model is something I can look into when the time comes to change them... Happy to spend extra for better and have used Cross Climates in the past. For now though, all I know is the potential tyre sizes for each model.

kambites said:

The usual approach would be to drop to 15 inch wheels to allow more sidewall without increasing the rolling radius significantly.

Ah, ok, thanks for explaining. That makes total sense.


@Davie - thanks for that. Lots to chew on there.


And thanks to everyone for taking the time to help, much appreciated.

[rallycross]

I’ve done this on many cars and you will find smaller wheels with higher profile tyres can transform how a car rides. Does not affect insurance and often you will find wheel size and tyre options from lesser models in the range will be an improvement on a standard car with larger wheels and lower profile tyres.

Eg have owned dozens of BMWs and have played around changing wheel sizes and tyre profiles to improve the ride eg a Mini Cooper on 15 inch wheels rather than big 17 inch can be so much better riding and more fun - using wheels from a base model. Same thing for bmw 3 series have swapped around from 19 to 18 to 17 to 16 inch wheels on things like 330, 335, 130 and you can improve to suit your needs / local bumpy roads same thing for Ford smax have changed them from 18 to 17 to 16” the differences can be huge all still perfectly safe and not a problem for insurance as long as these are OE wheels from the manufacture make and model range. .

[Davie]

I honestly think you're overthinking it... I've run various cars with various "sensible' tyres sizes (16's and 17's) and brands etc over rough rural roads for a long time and never had any real issues. The only car I exercised extreme caution with was a Volvo V70R on 18" alloys but it was very stiffly sprung and the alloys were made of unobtainium.

Everything else just got driven, little regard for what tyres whatever car was on however one of the best at soaking up ruts and portraying general good manners on crap surfaces was a 2008 Volvo XC70 with 235/65/17 all seasons. It never had any suspension parts replaced in over 40,000 miles and took a few big hits without any problems. And yes, FWD on all season is better than 4x4 on summers in low grip... but 4x4 on all seasons, winters or AT tyres is better still.

You can go slightly up on tyre sizes... or go one narrower but with a more generous sidewall and the rolling radius will be negligible. As for the tyre size dictating your decision, I honestly think the model of the car will be more of a factor... and you'll be replacing suspension parts more often regardless of tyre sizes, I think until you get into the realms of 33" AT tyres running 10PSi, then ultimately the suspension parts will be working overtime on rough, rutted tracks.

Plus does a Jogger, a Logan and whatever else share the same components...? One may have beefier parts. A Dacia Duster sounds like it could be worth a look?

[samoht]

Clintpistol17 said:

The cars I've short listed have the following spec tyres:

- 205/55 R16.
- 205/60 R16.
- 215/65 R16.

In case anyone is unaware, the actual sidewall height in mm is the first number (width) multiplied by the second number (aspect ratio) divided by 100.

So
205/55 = 205 x 55 / 100 = 112.75mm
205/60 = 205 x 60 / 100 = 123mm
215/65 = 215 x 65 / 100 = 139.75mm

So the last one has 19% more sidewall depth than the first.

As has been said, for rough roads there are generally benefits from picking the smallest OEM wheel which will fit over your car's brakes, with the corresponding OEM tyre size which goes with that wheel on your car. Or just buy the base model that comes with the smallest wheels to start with.

[trickywoo]

I regularly back to back the same make and model one has 205/45/17 and the other 215/45/17. The stock size is 195/45/17 which I drove on a lot before switching.

I prefer the 205 option. I can feel the weight of the 215 which I think affects the ride adversely.

The 205 option rides a lot better than 195 and I can’t feel any negatives on the road.

Tyre brand can make a difference too with some feeling softer than others.

[danb79]

Clintpistol17 said:

Hi

Many thanks for the quick and helpful replies. To answer some of the questions...

danb79 said:

Which car are you thinking of? Would a 4x4 not be a better choice?

We're looking at Dacias mainly - Duster, Jogger and Logan Stepway. Possible the Vauxhall Combo Life. We've always been ok without 4x4 so thinking to stay away from that as it is extra money and something else to go wrong. Also, I was told in the past that a 2x4 with decent all season or winter tyres is better than a 4x4 with standard tyres?

danb79 said:

What issues have you had so far if you're looking to change tyres?

Various over the years. Our current car is an inherited Vauxhall Corsa D (195/55 R16 tyres), and before that we had a Skoda Fabia estate (185/60 R14). I'd have to look over old invoices to see what work we had done in the past, if I've still got them. But from memory it always seemed to be suspension related things like drop links, bushes, wishbones (?), shocks, shock mounts, CV joints.

I'm not looking to change tyres as such. But more looking for cars which will have better tyres (and protection of suspension parts) than our current Corsa and previous Fabia. I asked about changing tyres as the Logan Stepway has 205/55 R16, while the Jogger and Duster have better tyre sizes at 205/60 R16 and 215/65 R16 respectively. So I was wondering whether, if we went for a Logan, we might be able to change the tyres/wheels for a better size and side wall height.

Bill said:

It would also be useful to know what your current car and tyre size is.

kambites said:

As for the difference it will make - it depends hugely on both the exact car and the exact tyres in question.

Details above, if they help? In terms of the exact tyres, I guess make/model is something I can look into when the time comes to change them... Happy to spend extra for better and have used Cross Climates in the past. For now though, all I know is the potential tyre sizes for each model.

kambites said:

The usual approach would be to drop to 15 inch wheels to allow more sidewall without increasing the rolling radius significantly.

Ah, ok, thanks for explaining. That makes total sense.


@Davie - thanks for that. Lots to chew on there.


And thanks to everyone for taking the time to help, much appreciated.

Fair enough

As others have said it could be that you're making this more complicated that it needs to be

Decent all-season or winter tyres in the size the vehicle needs will be more than sufficient

My folks have property in the Highlands and I've never had any issues with snow (been to the Cairngorms with no issues, across to Braemar via Glennshee etc); my BMWs have all been on winter tyres (up until recently, I now use all-season as they're better suited to the UK climate and where I lived in Lancashire)

Winters:

On 16s:
On 17s:
On 18s:

Our current cars on all-seasons:

On 18s (Goodyear Vector Gen3 4Seasons):
On 18s: (Michelin CrossClimate 2s):

[E-bmw]

As others have said the (real world) difference is relatively small in those sizes, having said that if it were me with that limited brief I would go with whatever car suits best & then after checking the (real world) speedo accuracy consider going up in sidewall sizes.

On top of that another thing to consider is the quality of parts used, so if you change anything subsequently on the suspension use the best brands you can & hopefully they last at least as well as the OE components.

[stevieturbo]

Clintpistol17 said:

Also. is it possible to easily change a car's tyre size, say from 205/55 R16 to 215/65 R16? Or would that be a real pain both practically and when it comes to insurance etc?

Many thanks

Many things are possible, but that's a pretty huge change, from 25" diameter to 27" diameter, which could cause clearance issues, as well as the slight width increase.

So really depends how high the car sits, how much clearance there is in the arches and wheel wells etc etc.

Although even 205/55 is hardly low profile these days. But if the terrain really is that bad, maybe a 195/65x16 might be somewhat of a safer compromise ?

On the door jam sticker about tyre pressures etc, what range of tyres does it list that the car might have came with ? ( or owners manual )

[MustangGT]

stevieturbo said:

Clintpistol17 said:

Also. is it possible to easily change a car's tyre size, say from 205/55 R16 to 215/65 R16? Or would that be a real pain both practically and when it comes to insurance etc?

Many thanks

Many things are possible, but that's a pretty huge change, from 25" diameter to 27" diameter, which could cause clearance issues, as well as the slight width increase.

So really depends how high the car sits, how much clearance there is in the arches and wheel wells etc etc.

Although even 205/55 is hardly low profile these days. But if the terrain really is that bad, maybe a 195/65x16 might be somewhat of a safer compromise ?

On the door jam sticker about tyre pressures etc, what range of tyres does it list that the car might have came with ? ( or owners manual )

Another thing to note is that the gearing will also be different by the same amount. According to an online tyre size calculator the difference in rolling circumference between 205/55 and 215/65 is 8.4%. Based on speedometer speed an indicated 70mph would have been indicated as 76mph with the smaller tyres. In the UK it is illegal for a speedo to under-read. I would not consider a change of more than 2-3% to be acceptable.

[croyde]

I had a Duster for 3 years. Couldn't fault it and the standard big sidewall tyres with bouncy suspension were fine at motorway speeds and a god send on our awful roads.

You could take speed bumps at full speed in it and was comfy roaming around the Highlands up to Skye.

Previously I had an e36 1998 BMW on its standard 15s. Sporty handling yet not bothered by rubbish roads or speed bumps.

[Tommo87]

trickywoo said:

I regularly back to back the same make and model one has 205/45/17 and the other 215/45/17. The stock size is 195/45/17 which I drove on a lot before switching.

I prefer the 205 option. I can feel the weight of the 215 which I think affects the ride adversely.

The 205 option rides a lot better than 195 and I can’t feel any negatives on the road.

Tyre brand can make a difference too with some feeling softer than others.

Those increases in tyre circumference/tyre wall must make a huge different in Speedo readings?

A 6% difference just between the 205/45/17 and the 215/45/17 according to online calculators.

[Panamax]

rallycross said:

I’ve done this on many cars and you will find smaller wheels with higher profile tyres can transform how a car rides. Does not affect insurance and often you will find wheel size and tyre options from lesser models in the range will be an improvement on a standard car with larger wheels and lower profile tyres.

^^^ Exactly this. Highly recommended.

Having been through the same process I will never, ever buy any ordinary car with a so-called "sport" designation. The Germans are particularly guilty in this regard - simply because their cars are designed for European roads in much better condition than UK. Getting a bit of extra sidewall onto the car makes a world of difference. Yes, handling will be affected but anything worth changing tends to have a price.

[Pica-Pica]

croyde said:

Previously I had an e36 1998 BMW on its standard 15s. Sporty handling yet not bothered by rubbish roads or speed bumps.

Agreed. Me too. 205/60 x R15. They were never an issue.