Alternative Tyre Size

Lord Rover

Lord Rover

New Member
Now summer season is nearly at an end I want to start sorting a few jobs out over winter including replacing all the odd tyres on my car.

At the minute on the P6 V8 it sits on 185 14 tyres a size apparantly it seems you can only get at exorbarant prices and they are in 8 ply only.

is there an alternative size anyone can recoment that is close to it in an easy to obtain modern size???
 
185/70 x 14" is quite a bit lower profile than standard. I have always been fond of 195/70 x 14" as they are slightly wider, slightly lower profile but have that nice 'wide oval' look to them. 195/75 or 205/70 are pretty close to standard height though you can start to get clearance issues with the 205s (on some cars.) That said, my 3500S had 215/65 x 14 on the back when I got it and they seemed to fit OK on the SD1 alloys.
 
There are three issues at play here.

First is the rolling diameter of the tyre / wheel combination. This affects the overall gearing of the car - how fussy or relaxed it is at any given speed - and of course whether the speedo reads correctly. Only real way to understand what is going on is to play with one of the tyre calculators. My favourite is on the Dutch SD1 site - http://www.roversd1.nl/sd1web/ - then go to "bodyshell" then "driveline calc".

Next is the width of tyre chosen suitable for the width of wheel you have on the car. For V8 standard steel wheels 195 is getting quite chubby, 205 is definitely too wide. The issue here is how vertical the sidewalls of the tyre are. Too wide a tyre on too narrow a rim and the sidewalls slope inwards and when you corner the car there is a tendency for the tyre to roll off the rim (!).

Finally does the new width of tyre foul anything on the body / chassis. You should be OK with standard steels wearing 195, I would have thought things would get difficult at 205 as the steels are offset towards the inside of the wheelarch. I say should because individual cars vary in the production tolerences in the rear wheelarch area - I found this out the hard way with "Lucky", the offside is markedly different to the nearside!

So what is the paractical outcome of all that? 195/75 X14 !

There is one other solution and that is to fit SD1 Vitesse 15" wheels. If you are lucky with the bodyshell tolerences on your car you may be able to fit them with 205/65 X 15 tyres without any clearance problems. Most people will need to skim around 3.5mm off the rear mating face of the wheel though.

Chris
 
KiwiRover said:
185/70 x 14" is quite a bit lower profile than standard. I have always been fond of 195/70 x 14" as they are slightly wider, slightly lower profile but have that nice 'wide oval' look to them. 195/75 or 205/70 are pretty close to standard height though you can start to get clearance issues with the 205s (on some cars.) That said, my 3500S had 215/65 x 14 on the back when I got it and they seemed to fit OK on the SD1 alloys.
Click to expand...

I can only go by the cars I've got, but the tyres on all mine, including my old 3500s, were the same height/rolling diameter as 185/70/12, 195/65/14, 205/55/15 and 225/50/15 tyres. My first rover (the blue project one) definately had the correct tyres on it when I got it because it was put in a barn when only eight years old, and the tyres were that badly perished.

Simon
 
The book "Rover 3500 1968 to 1977" published by Brooklands Books, there is an article on the Dunlop Denevo tyres. Quote..the tyres for the Rover are 205/65-375 whereas 185-14s are standard. The 65 indicates the aspect ratio, while the rim diameter of 14.8" or 375mm is not interchangeable in any way with standard wheels." Unquote. Further it states...the low aspect ratio of the Denevo means that the tread is wider than normal,..approximately one inch wider than the 80% aspect ratio tyres currently fitted as standard to the Rover 3500!

There you have it...the 185-14 tyres fitted as standard to the Rover 3500/S were 80 series tyres. The current alternatives as has been correctly indicated by KiwiRover and Chris are either 195/75 -HR14 or 205/70 -HR14. The rolling diameter of the original 185-14 tyres with their 80% aspect ratio are very close to the aforementioned sizes.

I am sorry Simon, but the 3500S was never fitted with 185/70 -14 tyres as standard equipment. The correct size for 15" wheels is 205/65 assuming clearance at the rear. The smaller diameter tyres that you listed will see greater engine revs per 1000rpm out on the road than when fitted with tyres close the correct original size.

Ron.
 
So, are the tyres on 2000's smaller than the v8's then? I'm not bothered in any way as I've got a higher final drive than the v8 anyway, and the tyres I have fitted now match the tyres it came with, and it looks so much better for it though.

Simon
 
Simon,

the 185/70/14 tyres that you mention (and i have fitted to my 2000 TC) are the correct replacement for the 165/80/14 factory fitted tyres for the 4 cylinder cars.
 
Although at the moment i have the 185's fitted in minilites that are wider than the standard 4 cyl wheels, when i bought the car, it was also on 185's on its standard rims. In my opinion it was looking just OK. Perhaps this is the limit for the standard 4 cyl rims.
 
This is an interesting thread, my 3500P6 (when purchased) has 215/65R14's on it which look nice and wide and a bit chubby (if thats the correct technical description!) and I was going to put the spare from my parts car (as it is unused and still on original unused steel rim) into my road car but was quite amazed at the difference in OD between the 215's and what is the factory standard 185HR14 spare I have, 665mm OD (unladen) compared to 625mm OD (laden, on car) 215 Bridgestone Turanza's. Interestingly the parts car has 195/75 14's which measure up OD wise (laden) the approx same as the 215's, and interestingly again is the spare in my road going car which is a Goodyear G800+S, ER78-14 which has on the sidewall "replaces 185-14" and is 640mm OD, its all rather confusing really! so my spare would give me a bit of a lopsided stance if I had to change a flat tyre. So I'm obviously doing more revs at constant speed than I should be doing, conversly doing less than the actual speedo reading, Is this correct, so then I should have either 195/75 -HR14 or 205/70 -HR14 then to maintain the correct OD as per standard (665mm)? so how much out will my speedo reading be with the 215's on it?

Thanks in advance,

Regards,
 
Hi Scott

Well you've hit on the reason you can get 215's under your rear wheelarch - they are under-diameter! If they were the correct rolling radius then they would foul the D posts. Maximum size you can get under the rear wheelarch (on the base unit - not the rear wings) is 205, as used by the Denovo clad cars, and then only with exactly the correct offset wheel (which the standard steel isn't). Only wheel which is readily available (in the UK) which works is the SD1 Vitesse wheel and even then you need to skim 3 mm off the back face. Modifying the base unit to take wider tyres is possible but not for the faint hearted - have a look at Simon Owens project car thread for some food for thought.

To work out the speedo error have a look at the DutchSD1 site that I identified earlier in this thread. This also allows you to play tyre sizes and get a comparison of their effects on rolling diameter, gearing and speedo error. Put 185 X 14 X 80 in the left hand calculator and then use the right hand calculator to asses your alternative tyre size. If you're using 14" standard wheels I'd guess you'd finish up going for 195 X 14 X 75. How easy is that to get where you are?

Another alternative might be to stick with your 215 X 14 X 65 tyres (as you presumeably know that they clear the rear arches) and compensate for the undergearing with a new overdrive gearbox - BL LT77 or R 380 or Toyota Supra if a manual or ZF HP22 / HP24 if an auto. That still leaves the speedo in a pickle but you could get that recalibrated. (PS the tyre calculator says that 100kph on your speedo is an actual 97.46 with the 215's)

Chris
 
Try this link:

http://www.camskill.co.uk/products.php?plid=m4b0s384p0

I have got a price from a local dealer in Bristol for the Falken tyres of £220 for five fitted and balanced. If you look at the tyre manufacturers own web pages, they usually give a list of local dealers.

These tyres are all 185/80/14 and are T rated. These are OK for the 3500 and are as close as you can get to originals. The H rated tyres only seem to be supplied by specialists and can cost as much for one as I paid for five!

Hope this helps.
 
So what's the narrowest tyre I can put on a 15" vitesse wheel?
I've picked up a 'spare' wheel but I can't be bothered getting it machined to fit under rear arches. I had 4mm took off the other four with 205's fitted. It's only to be used as a spare so I'm not too fussed about a couple of % rolling diameter difference.
 
tantus pedis said:
So what's the narrowest tyre I can put on a 15" vitesse wheel?
I've picked up a 'spare' wheel but I can't be bothered getting it machined to fit under rear arches. I had 4mm took off the other four with 205's fitted. It's only to be used as a spare so I'm not too fussed about a couple of % rolling diameter difference.
Click to expand...

I'm running 205/65 15s on mine without any machining.

The original 185 14 tyres were around 80 profile which gave a radius of about 650mm ( I say 'about' because they varied).

The 205/65 15s are 647mm.

195/70 15 would give you 654mm.

All about the same
 
I think you are unusually lucky Quattro! Lucky's unrepaired and as factory offside wheelarch is at least 6mm narrower than his nearside one and won't even take a machined Vitesse wheel! I'm about to set to with bottle jack and lump hammer next week! It does seem that this area of the base unit was not a high priority for dimensional accuracy!

Chris
 
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