rob_bell

rob_bell

Well-Known Member
I can't find this question addressed in the forum, but wondering about what tyre widths are acceptable on particular rim widths. And yes, this is another one of those tyre questions!!!

Doing a google search, the maximum tyre width for a 7J would be 225 - which if one is looking for AT tyres, one is quite limited for tyre profiles - and for what I was thinking about, 235 would be a better option.

So my very targeted question would be can I actually fit a 235 on a 7J rim, or should I keep to the maximum as quoted on the internet of 225?
 
You should be able squeeze a 235 tyre on there, and it'll give you some added sidewall protection.

Incidentally, I'm up your neck of the woods on Tuesday. We're staying at the Holiday Inn on the A40, Gypsy Corner for a couple of days.
 
If it's for a Freelander Rob, I would just check the tyre to strut clearance.

I have 225/65 x 17. About 0.25 inch gap between tyre and strut. A 235/65 or 70 is 0.4 inch wider so 0.2 each side. Bit tight!!!
 
Both the FL1 and the DS.

I’ve got 16s on the FL - and yes, I can see that the lower spring pan is the limiting factor for width/height of tyre. ive not worked out the tallest tyre i can use (the clearest instructions are for 17s as you’ve written :))

For the DS, it’s on 20s currently, but I have a set of 17” 7J rims from an Evoque. Hoping to get 235/65 R17 for these as these seem a pretty popular tyre size and available in an appropriate load and speed rating. Probably General Grabber AT3s - no Yokos in that size.
 
Nodge68 said:
Incidentally, I'm up your neck of the woods on Tuesday. We're staying at the Holiday Inn on the A40, Gypsy Corner for a couple of days.
Click to expand...

Great - give me a shout when you’re free. Evenings good for me when I get off work :D
 
rob_bell said:
I’ve got 16s on the FL - and yes, I can see that the lower spring pan is the limiting factor for width/height of tyre. ive not worked out the tallest tyre i can use
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29.5" in diameter is considered the maximum tyre diameter, on standard rims. ;)
rob_bell said:
but I have a set of 17” 7J rims from an Evoque. Hoping to get 235/65 R17 for these as these seem a pretty popular tyre size and available in an appropriate load and speed rating.
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My FL2 has 235/65/17 tyres, which seem a good comfortable size.
 
Yes, definitely! If you're around Wednesday, I should be around late afternoon if that works better?

Regarding 17" on FL1/FL2 - are they also 7J rims?
 
rob_bell said:
Yes, definitely! If you're around Wednesday, I should be around late afternoon if that works better?
Click to expand...
West London or Cornwall?
If London, then we'll be out taking the kids to places. If Cornwall, well we'll be in London. ;)
rob_bell said:
Regarding 17" on FL1/FL2 - are they also 7J rims?
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7½ inches for the FL2 17" alloy rims, which use 235/65/17 tyres, and 7 inches for the steel 17" rim, often used as a spare, which is fitted with 225/65/17 tyres.
;)
 
Haha - no worries - am in London, but if there’s a spare moment (probably not - I know how these things work!!!)…

235 is the stated max width of the 7.5J, so probably a bit cheeky to stick a 235 on a 7J!
 
Another numpty question - does anyone know of a tyre expert who can advise on tyres and tyre fitments? Would be good to discuss options rather than what a particular retailer wants to sell me...
 
That’s a nicely researched page, but their suggested alternate tyre sizes don’t appear to take into account the maximum tyre width for a particular rim width - so that particular section was more theoretical.
Things also get more challenging because although a particular tyre profile might be theoretically appropriate, certain sizes are more popular than others - with some simply unavailable - and then you need to ensure that the tyre has the appropriate weight rating and speed rating… which tends to limit choice even further!

Fortunately the FL1 is comparatively light and slow compared to more modern SUVs - so these factors shouldn’t rule out too many options :)
 
rob_bell said:
Another numpty question - does anyone know of a tyre expert who can advise on tyres and tyre fitments? Would be good to discuss options rather than what a particular retailer wants to sell me...
Click to expand...
The majority of 'tyre' experts will be retailers. Or people being sponsored by a tyre maker. The rest are just individuals with opinions, such as myself.

That said, tyres are not really all that difficult to understand. And there are plenty of online aids to help you figure out the size differences.

As for which tyre on which rim. It depends a lot on other factors. Rim width and tyre width do not have a 1:1 relationship. As the sidewall height will also impact what is suitable. Also the type and construction of the tyre can effect this.

The BFG (US site) has some good info on their tyres and recommended rim sizes per tyre size: https://www.bfgoodrichtires.com/auto/tires/all-terrain-t-a-ko2
Screenshot 2021-09-03 at 11.18.19 am.png


It tells you the tyre section on a recommended rim width and their their recommended range of rim widths.

I do not believe it is law to follow this, but obviously when you exceed manufacture recommended specs, it is always more of a grey area.

For off road use you might want to deliberately go to the narrow spectrum of the rim width range, as this will make the tyre bulge more and protect the bead area more so, although it may also run more risk of sidewall damage. The reverse and stretching a tyre might also result in more sidewall damage and more damage to the rim.


On most cars you can normally go up and down a couple of sizes with no real ill effect. It might alter your speedo a bit, but would depend on what % difference you go. Bigger or smaller might also impact acceleration and/or cruising rpms.

Likewise you can often alter the width of the tyre a bit too, although at some point you are likely to find they will rub and/or stick out of the arches. It really depends what you are trying to achieve overall.
 
Typical rule of thumb for a road car is to add one to the rim width in inches and convert to mm and thats your max-ish width, for an off road vehicle add two to the rim width, so for example, on my 16x7j stock hippo wheels, I'm using 235/70/16 on one set, the 235 is roughly nine inches so gives you an idea. As for the mini meet, why don't rob and nodge both take their missuses to evening thing, make it dinner and a couple of beers? That way the girls can talk hand bags while the hippo-driving-hubbies talk hairdriers :p
 
300bhp/ton said:
The majority of 'tyre' experts will be retailers. Or people being sponsored by a tyre maker. The rest are just individuals with opinions, such as myself.

That said, tyres are not really all that difficult to understand. And there are plenty of online aids to help you figure out the size differences.

As for which tyre on which rim. It depends a lot on other factors. Rim width and tyre width do not have a 1:1 relationship. As the sidewall height will also impact what is suitable. Also the type and construction of the tyre can effect this.

The BFG (US site) has some good info on their tyres and recommended rim sizes per tyre size: https://www.bfgoodrichtires.com/auto/tires/all-terrain-t-a-ko2
View attachment 247163

It tells you the tyre section on a recommended rim width and their their recommended range of rim widths.

I do not believe it is law to follow this, but obviously when you exceed manufacture recommended specs, it is always more of a grey area.

For off road use you might want to deliberately go to the narrow spectrum of the rim width range, as this will make the tyre bulge more and protect the bead area more so, although it may also run more risk of sidewall damage. The reverse and stretching a tyre might also result in more sidewall damage and more damage to the rim.


On most cars you can normally go up and down a couple of sizes with no real ill effect. It might alter your speedo a bit, but would depend on what % difference you go. Bigger or smaller might also impact acceleration and/or cruising rpms.

Likewise you can often alter the width of the tyre a bit too, although at some point you are likely to find they will rub and/or stick out of the arches. It really depends what you are trying to achieve overall.
Click to expand...
Really helpful, thanks! :D

Yes, I agree - and I'd go narrower if I could, but I think I'll end up having to wider just for availability... I may actually be better off getting a wider 7.5J rim to be honest, but it is annoying when I managed to score a set of 17" rims that will work on the car to be kyboshed by the 7J rim width. My fault for not foreseeing that pitfall...!

What does the section titled "Section width" mean by 8" on 6"? An 8" wide tyre on a 6J rim? Rim width range is self-explanatory - exactly the information needed! :D

Jayridium said:
Typical rule of thumb for a road car is to add one to the rim width in inches and convert to mm and thats your max-ish width, for an off road vehicle add two to the rim width, so for example, on my 16x7j stock hippo wheels, I'm using 235/70/16 on one set, the 235 is roughly nine inches so gives you an idea. As for the mini meet, why don't rob and nodge both take their missuses to evening thing, make it dinner and a couple of beers? That way the girls can talk hand bags while the hippo-driving-hubbies talk hairdriers :p
Click to expand...

Great rule of thumb and brilliant idea regarding distracting the significant other halves... LOL
 
rob_bell said:
Really helpful, thanks! :D
What does the section titled "Section width" mean by 8" on 6"? An 8" wide tyre on a 6J rim? Rim width range is self-explanatory - exactly the information needed! :D
Click to expand...

I'm guessing that's talking a bout a 205 tyre on a 6J rim, such as a 205/80/16, which slots nicely into my rule of thumb. Like 300bhp said, rubbing will become a problem if you go nuts with tyre width, but I don't think you're planning to go 285 50 17. Typically by the time you've limited the overall tyre diameter to the macig 29.5" nodge mentioned, youre in narrowe off road tyres anyway, 255 max width if your lucky. If you go that wide, you'd need to have a think about clearance from the inside sidewall vs the strut, or get spacers. Spacers also buy you more room for taller overall tyres, but you need to make sure your new wider tyre isn't shoved out of the arches by the spacers. how agressive an offroad tyre are you looking for?
 
Not quite - its for my Disco Sport - I have 7J ET45 17" rims for an Evoque to replace the 20" ones on the car currently, purchased so I can take the Disco off the tarmac. 235 section tyres with a slight increase in height and rolling diameter would work really well (and available in suitable speed and load ratings), but the web would suggest that 235mm wide tyres would be too much for a 7J rim, but would have been fine on a 7.5J...

I think I may have made a school-boy error, drat :(
 
If you are thinking of putting 17s on a car with 20s on then make sure you have clearance around the calipers.

We only went from 20s to 19s (winter wheels) on the L322 and some styles failed the caliper.

No idea what the Disco sport is like but sounds a huge difference.

J
 
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