Replacement Tyre Sizes on a 120

Gary Stockton

Super Moderator
Supporter
Joined
Sep 10, 2012
Messages
3,924
Garage
Country Flag
zimbabwe
Hi all,

A quick question for those that know how this lot works ('coz I don't, really ... yet :x )

The 120 comes standard with 265/65x17 tyres on a 7J (I think) rim. No idea what, if any, offset that equates to - I think 0 ?

I put 265/70x17 Cooper STTs on as replacements - they fit perfectly, but the side lugs rubbed a bit on the front inner mudguard on full lock under compression (e.g. driving over the small bump going into my driveway). They also caught a little on the front mudflap after we trimmed it to fit the sliders - that's been fixed by cable tie-ing the sticky-out bit of the mudflap back to the body mount location :cool:

I solved the front rubbing by putting on 30mm spacers on all 4 corners - no more rubbing.

The tyres do the trick, and work well, but I suspect that after the 35mm suspension lift going in, on top of the 40mm body lift already there, that they're going to look a little lost in the wheel arches - the rear's already do.

So assuming I stick with Cooper STTs (which I most likely will do because I like them and they're not stupidly priced and do what they say on the tin), I plan to go up another size.

The current size gives me an OD of 802.8mm, or 31.6 inches. I can go to 285/70x17, which I think will fit OK, which give an OD of 830.8mm, or 32.7 inches.

I can also, for about £1.50 more each tyre, got to 33/12.5R17, which, clearly, is a 33 inch tyre. For quite a bit more I can go to 33x12.5R17 tyre - so up 2 inches but no wider.

So my questions are these:

  • Can I fit either the 285/70x17 or 33/70x17 without having to get new spacers or rims?
    Is there anything else I should consider (assuming they fit in the wheel arch etc. etc.?
    What are the issues (if any) around fitting the 35 inch tyres? (and remember, this is NOT a daily drive, but will be focussed towards overlanding and 'mild' laning :shifty: :whistle: so I'm not too concerned about changes in fuel consumption etc. )
    What, if anything, do I need to do to reset the speedo?
    What, if anything, do I need to do to the rear diff? :shock:
    What, if anything, do I need to tell my insurers? :roll:

Any thoughts / comments welcomed. The 35 inch tyres are significantly more expensive and will put too much stress on the drivetrain I suspect, so I've already mostly ruled them out - and they're getting into the 'stupid price' territory.

I've also thought about 'replaceability' in remote locations' which tends to rule out the 35 inch jobbies.

I'm leaning towards the 33/12.5R17, which are described as 'high-flotation' on the Cooper website - what the heck does that mean? They don't have quite the same load-rating as the 285/70x17, (which has the same as the 265/70x17). But maybe they're a bit more specialised and I should go with the 285/70x17's?? Sigh - decisions, decisions ... :think: :think:

Sorry for the long-winded posting :?
 

Jon Wildsmith

Super Moderator
Supporter
Guru
Joined
Feb 24, 2010
Messages
6,733
Garage
Country Flag
england
Width is as much an issue as height when looking at tyre clearance. If you put a 12.5" wide tyre on you won't be able to go as tall as with a narrower size. I would aim for 285 width tops if 31.6" tyres with a 265 width rubbed without spacers. You might find even the 285x70x17's give you issues and need to look at something narrower.

I can't see a 35"x12.5" fitting on a 120 and still be able to go round corners without a lot of work BTW ;)
 

Graham

Well-Known Member
Joined
Mar 22, 2010
Messages
3,935
Garage
Country Flag
uk
Gary Stockton said:
The 120 comes standard with 265/65x17 tyres on a 7J (I think) rim. No idea what, if any, offset that equates to - I think 0 ?

Hi Gary,

I read some where that the standard Toyota rims are 30mm off set.

I seem to remember this because the black rims I have are 5mm offset, and this essentially pushes the wheels out 25mm.

STP80070.jpg

.
STP80086.jpg

.
black.jpg


I have since painted them all black.

As a foot note, I have just remover the black rims, which I think were 8J.

Graham
 

Graham

Well-Known Member
Joined
Mar 22, 2010
Messages
3,935
Garage
Country Flag
uk
Jon Wildsmith said:
I can't see a 35"x12.5" fitting on a 120 and still be able to go round corners without a lot of work BTW ;)

I have 35 x 12,5 x R15 on my recent 70 SWB.
When I stand the spare next to the BFG A/T 265 x 70 x R17 on my 120, the BFG A/T is totally dwarfed by the 35 inch.
I can never believe a 35 inch will go on a 120, without almost removing the wing :o
 
Don't like the adverts?  Click here to remove them

Gary Stockton

Super Moderator
Supporter
Joined
Sep 10, 2012
Messages
3,924
Garage
Country Flag
zimbabwe
Looking at the 285/70R17 STT from Cooper, the recommended rim width is 7.5 - 9.5". I think the standard 120 rim is a 7" rim - will the tyres fit properly on a narrower rim, and would there be any inherent safety issues?

The 265/60R17 is specified for a 7 - 8.5" rim, and fit fine on the 120.

Cheers
 

Lorin

Well-Known Member
Joined
Mar 28, 2010
Messages
1,318
No idea if I'm right but I'd worry that squeezing a wide tyre on to a narrow rim would cause the sidewall to bulge out more. If going overlanding that might be a real issue when running lower tyre pressures.
 

Jon Wildsmith

Super Moderator
Supporter
Guru
Joined
Feb 24, 2010
Messages
6,733
Garage
Country Flag
england
I think Lorin is right, the narrower wheel will just give you a bit more side wall bulge but I'm not sure the 1/2" narrower than recommended will be a problem in the real world and 7" doesn't seem too unreasonable even if not ideal. Saying that, IIRC mr rubie got some 17" steels for the red car at a reasonable price so maybe that's the way forwards.
 

Gary Stockton

Super Moderator
Supporter
Joined
Sep 10, 2012
Messages
3,924
Garage
Country Flag
zimbabwe
Hmmm - now that's interesting! I've been looking for steel wheels for ages!! I'll chat to Ian

Cheers
 

Gary Stockton

Super Moderator
Supporter
Joined
Sep 10, 2012
Messages
3,924
Garage
Country Flag
zimbabwe
quite like these from Arctic:

getfile.aspx


or
getfile.aspx


marginally different, 17 x 10 alloy

Would look good in black with 35" coopers :cool: :drool:

Bet they cost a bomb though :?
 
Top