Tyre & Wheel sizes

[Jools]

Hi all, just out of interest what is the largest wheel diameter & tyre width anyone has used on a Sierra based model?

[CosworthCabrioLee]

Re: Tyre & Wheel sizes

Hi jools I have used 17" with 205/50/17 also have done this on a previous v8 cabrio.
This is a very simlair rolling circumference as the std 15" and tires on most cabrios.
Having driven both cars with both wheels the 17" wheels give much better handling with no difference to ride comfort or noise.

[Mike]

Re: Tyre & Wheel sizes

Hi all, just out of interest what is the largest wheel diameter & tyre width anyone has used on a Sierra based model?

Hi Jools
Wheels and colour must be the two decisions that occupy the majority of any Marlin owner's thinking time!

I have always thought standard Sierra diameter tyres do not fill the wheel arches adequately, so wanted to increase the diameter. The biggest I am aware of are on Simon Gregory's Cabrio with 215/55/17 - he has 7J rims: These have a rolling diameter of 668mm.
.[IMG]
Marlin May 2010 by cabrio_simon, on Flickr[/IMG]


The availability of offsets of the wheels you choose will affect the projection of the tyres relative to the wing edges. Due to the prevalence of modern front wheel drive cars, you can find the offset you would chose is not available.
My tyre of choice would have been 205/60/16 (652mm dia), but this size is used almost exclusively on White Van Man's wheels, so have thicker side walls and additional ply, and do not have modern tread patterns, so I passed on these.
I finally chose 215/60/16 (643mm diameter). My alloys are 7J and I could only get ET-38 offsets, so had to fit 10mm spacers at the rear to clear the chassis adequately. I do not plan to fit them at the front.
In common with other 7J rim users and wide tyres I'll be pushing the limits of the tyre remaining under the wing profiles when I get the camber set correctly - see below.
I have dropped my rear wing 15mm lower than Marlin recommended both front and back, to get better door clearance over the front wing, and help with tyre/arch filling. I also deliberately profiled the top of the rear wing 5mm deeper than the sides to reduce the gap above the tyre.
Even with the rear spring adjusters wound fully up I am only just happy with the rear arch fill. However, Derek Jones (Cabrio Tech advisor) tells me he has had to wind his spring adjuster down every year as the springs continue to settle.


[IMG]
A bit of camber? by Mike's Marlin BMW Cabrio, on Flickr[/IMG]
This shot was taken the day I took my Cabrio off its build stands for the first time, and shows how much camber adjustment I will need to make!


[IMG]
First Drive! by Mike's Marlin BMW Cabrio, on Flickr[/IMG]

Chris Cunliffe chose 205/55/16 (632mm dia), but then chose to drop the rear wing around 60-70mm at the rear relative to the tub, in order to close the arch around the rear tyre.

Archive Photos 1036.jpg

Peter Morris chose 205/65/15 (648mm dia) and appears to have profiled the rear wing and fitted it exactly as Marlin suggested.

Peter Morris14.jpg

There are several other Cabrios on 7J rims.
So to answer your question - 17" rims are probably the biggest seen fitted, x 7J rims the widest, with tyres as big (in diameter) as 215/55/17 = 648mm diameter.

There are several websites which offer tyre size calculators which I found very useful, such as this one:

http://www.etyres.co.uk/tyre-size-calculator.htm

Hope this helps

Regards

Mike

[bryannewell]

Re: Tyre & Wheel sizes

Hi folks
I am also considering a change of size
At the mo I am running 205 x 65 x 15
If I were to go to 205 x 50 x 17 would that be a good match?
I think I would prefer 205 x 55 x 17 (slightly more forgiving over the potholes which we will all have shortly!!)
Measuring my rims from outside to outside they are 8", does that make them 8J or is the size taken from inside edges?
Lee
Can I ask where you got the minilites you put on your Roadster a while ago and would you know if they do them in 17"?
Regards
Bryan

[CABRIOBOB]

Re: Tyre & Wheel sizes

Try - Midland Wheels - Cornwood Farm - Napton Road - Stockton - Southam - Warwickshire - CV47 8HU - United Kingdom, MWS website.
I got 15" minilites from them for my old Roadster but you would need to ring them to check if they do 17".

[CosworthCabrioLee]

Re: Tyre & Wheel sizes

Hi Bryan as my mate say's try midland wheels but the bad news they dont do 17" 15" is the max size, otherwise I would of maybe gone this way with the cabrio. My wheels are 7J with et38 offset, but because my hubs are Granada I had to go for 5 stud wheels.

[Mike]

Re: Tyre & Wheel sizes

Hi folks
I am also considering a change of size
At the mo I am running 205 x 65 x 15
If I were to go to 205 x 50 x 17 would that be a good match?
I think I would prefer 205 x 55 x 17 (slightly more forgiving over the potholes which we will all have shortly!!)
Measuring my rims from outside to outside they are 8", does that make them 8J or is the size taken from inside edges?
Lee
Can I ask where you got the minilites you put on your Roadster a while ago and would you know if they do them in 17"?
Regards
Bryan

Hi Bryan
I would have liked to fit Minilites to my Cabrio.
If you look on MWS site, it only shows 15" under products, but if you look under their news section they are now making 16" Minilites (the original Minilite style), but they are very expensive.

http://www.minilite.co.uk/news.php

This is the picture of their 16"



Mike

[bryannewell]

Re: Tyre & Wheel sizes

Gents
You are correct, it seems nobody does minilite style larger than 15"
Guess I'll stick with what I've got for now then
Thanks for your help
Bryan

[bryannewell]

Re: Tyre & Wheel sizes

Hi mike
Missed your post as I was typing mine!
16" is getting there but not sure 1" gain would be worth the cost
Cheers
Bryan

[Mike]

Re: Tyre & Wheel sizes

Hi mike
Missed your post as I was typing mine!
16" is getting there but not sure 1" gain would be worth the cost
Cheers
Bryan

Hi Brian
Yes, I decided I could not justify £175 per rim for the Minilites, plus tyres on top, when there are reasonable alternatives at less than half that price.
Rim size is a very personal thing - for me 17", and low profile tyres are suited to a more modern look, whereas 16" with a little more rubber maintain the period look, which is what I wanted. In the end I chose 16" BK550 and 215/55/16 tyres.

IMG_0864.jpg

[bryannewell]

Re: Tyre & Wheel sizes

Hi Mike
I agree £175 is a bit steep!!
Yours do suit the car very well
I'll keep looking around for now and see what comes up!!
Regards
Bryan

[CABRIOBOB]

Re: Tyre & Wheel sizes

I am selling 4 Miglia 15" wheels and tyres to fit a a Cabrio. 195/65/15 Toyo tyres with approx 6mm tread, see attached picture.

[dave_kitson]

Re: Tyre & Wheel sizes

Hi - Before you all rush out and buy new wheels and tyres, bear in mind that, (1) you could reduce clearance under the rear wings so the wheels hit the underside when flying over hump back bridges, etc, (2) you could reduce clearance when on full lock and there isn't much to start with, (3) any tyre outside the wing will fail IVA (I had to force the front wings outwards even on std wheels/tyres), and (4) you may have to recalibrate the speedo. Do one job and create four more? Its up to you! Have fun - Dave

[pdm_engineer]

Re: Tyre & Wheel sizes

Peter Morris
I see my name has been mentioned but none of the pictures above are of the car I built.
So I thought I would provide one. (Hopefully attatched PC070088)
The car was built to the manual and the wings were only de-burred and not fettled in any way.
As othe members have pointed out the ground clearance is actually more important than the wheel arch clearance.
Don't worry about the look but do make sure you have a minimum of 4 inches ground clearance.

[CosworthCabrioLee]

Re: Tyre & Wheel sizes

Nice car Peter