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MG MGF Technical - Why 16 inch ?

A good one to start the week...

I will be renewing the tires pretty soon, but is it worth to invest in 16 inch wheels before.

Which ones do you prefer ?
For what price will they be mine ?

Thanks for your input
Erik


I had this choice recently.

Surprisingly, I decided to stay with the 15" wheels but put good rubber on them.
This is mainly because I like to feel when the car is about to go.
When I tested a car with the 16" rims, the grip was definately better but
I couldn't feel when the car was about to spin out.
Amongst the racers/sprinters a trend for 195 rubber on 15" rims is starting.
Interesting!

Having said that, the 16" wheels give fantastic grip.
The supplied Eagle F1 tyres are very good indeed.
It's down to personal preference, but I'd go for either the multispokes or the
'square' spoked wheels. They look stunning.

Price?
Might want to bargain with a dealer. They can often have 'spare' sets.
Alternatively get a quote from Brown and Gammons.
Last time I looked they could do a set for £850.

Or to throw a real spanner in the works, you could get a suitable convertor from
Mike Satur and then chose from the aftermarket suppliers!

P.
Paul

I was about to ask the same questions.

anybody got more reasons NOT to get 16". i can think of plenty of reasons TO get them myself

thanks for your help
Matt

Just a quick question with regard to the increase in tyre size.
Will larger tyres on the fron rub on the inside when on full lock?

And is there any reason why not to change to 195's?

Thanks
Al :-?
alastair

I've upgraded to 16" (6 spoke "minilite") last week.
My first comments :
more grip, but as Paul said, the limit is less "sensitive".
I had, like Paul, Bridgestone S02's on 15" wheels before, and they were great.
This time I went for Toyo Proxes for 2 reasons : firstly, S02's don't exist in 215/40 (only 205/45 and they are damn expensive) and secondly, a friend recommend me the Toyo's and I hadn't much time to shop around as my rear tyres were really dead.

The ride with 16" is firmer, esp. on bad roads (like they are way to much in Belgium), but on a good surface, boy what a suction pad !
Also re. look : much better than standard 15".

Tyre rubbing inside wheel arches ?
Yes, but really slight (only at full lock). I have to sort this out (hairdryer ...)
I had the same rubbing, if not more, when I had 205 front tyres on my 15" wheels, before the S02's.

Keep also in mind that ideally, with 16" wheels, the "bump stop kit" is required.
Only useful in case of hydragas failure, bu as I already experienced 2 failures in the past, I do not trust anymore the Hydragas system ; the bump stop kit will come one day...
I've seen Powerflex makes polyurethane bump stops (different shapes and lenghs) : maybe a good alternative to Rover stops ?
Problem : it's difficult to resist ordering some other polyurethane bushes ;))

Conclusion : 16" wheels are not obligatory. The best impovement is their look.
If you're looking for a good grip and handling at a reasonable price, go for S02's (195 front, 205 rear).

Fabrice

Now, I have a spare set of 15" wheels and I don't know what to do of them.
Sell'em ? Keep'em for winter tyres ?

Fabrice

Fabrice, I totally agree with your summary.

I have, over the last week, the opportunity to try both 15" wheels shod with Brigdestone S-02s (195/50F 205/50R) and another car with 16" rims shod with Goodyear F1s (215/45s all round). My impression was that the 15" with Bridgestone tyre combination was superior in feel and feed back- exactly as Paul has already stated. Grip was marginally better with the S-02s, but there is remarkably little in it. Both are 100% better than standard Goodyear NCT3s!

Previously, my only 'performance' justification for buying a 16" wheel was for the tyres which would have a shorter sidewall height (and therefore less flex). However, as the performance tyres have such stiff side walls anyway, this advantage seems to be far less than I expected.

The other factor to consider is that running a car with 16" wheels is going to cost more than a car with 15" wheels. This is based purely on the fact that tyre replacement costs are going to be significantly higher with the larger diameter. Depending upon tyre choice, this figure can be as much as 50% greater than the equivalent tyre for a 15" rim.

Therefore, the only reason I'd replace wheels for 16" is for aesthetics (something I seem prone to do every couple of years to spruce the car up! ;o) or if tyre regulations in the Abingdon trophy start to be clamped down on as threatened in the last year.

Rob
Rob Bell

Remember! When you go from 15-16 inch wheels your speedo will be incorrect. It will read low, so your speedo may say 30mph, but you will be going faster. How much faster depends on the tyre size as well. You can work it out, there are several sites on the net that have tyre size calculators.
Steven

I have recently changed to 16" wheels from 15" and immediatley noticed the difference.
At the same time I had the car lowered and a non rover spec tracking setup. I can not say what parts give the difference but overall the car now drives fantastic as well as looks fantastic.

I will though still be using 15" wheels for sprints due to not wanting to buy new tyres regularly and it means I don't care what happens to the sprint tyres, lock ups, spins etc soon wear the tyres out.

Tom
Tom Randell

A very good tyre page can be found at http://www.geocities.com/MotorCity/2195/tyre_bible.html

Everything you wanted to know about tyres and were afraid to ask.

Regarding rolling radii of 15 and 16" wheels, what Steven says is quite right, but the problem can be largely solved by choosing the correct tyre side wall height (explanations on the above URL).

Incidently, if you get the Elite parts catalogue the tyre section includes useful info on rolling radii of various tyre choices, so you can easily avoid speedo calibration problems.

Rob
Rob Bell

Go with F1 Eagle 16 inch. I got them with the car and they are great. Used them during the winter here in Germany and they stuck to ice roads nicely. Plus they just look great!

Best of luck
Adrian
Adrian Ferrer

Hi,

With standard tyre sizes there's no need to worry about speedo readings, as the 215/40 16" tyres are fractionally smaller in diameter than the 205/50 15" tyres, but not enough to worry about. There's some comment on the General board about the 16" F1's being a vast improvement in the wet, which must be a benefit. I have 16" F1's and I've never lost it in either wet or dry, but that may have something to do with it being my £20k I'm driving. (OK, £10k now, but you know what I mean). As mentioned above there's some good offers going on the 16" Abbi wheels: besides, they just look so good!

Regards, Kes.
Kes

>A very good tyre page can be found at <snip>

There's also a link to another tyre related web site on the links page of my site - I would look and tell you the URL but I'm feeling lazy (sorry!)

http://www.dotcomoff.demon.co.uk

Home of the F'ers Gallery, MG Dealer Guide and that link to the tyre website. ;-)
Paul Lathwell

Steven, the tyres on the 16" rims are 215x40 and on the 15" rims are 205x50 on the rear. As I understand it, the diameters of these two combinations is almost exactly the same. As it is only the driving wheels that relate to the speedo, gearing etc. this is not a problem.

As I understand it the profile(50 or 40) is based on a percentege of the width of the tyre, Roger could tell you more. So different wheel sizes use different profiles which keep the wheel and tyre diameter the same.

Not sure what difference we have between 185x55, 195x50, 205x50 or 215x40 on the front, but this is not so important.

My personal ideal is 195x50x15 front and 205x50x15 rear. The 205's I have now on the front tend to follow the ruts a bit too much. Anyone tried 195x50x15 front 215x40x16 rear, who was it had some spare 15" wheels. What's good enough for Lotus..... :-)

Rob, nice to hear you got some decent tyres :-)

Tony Smith

Hi

Sorry, I should have made that clear. Moving to bigger wheels will effect your speedo, but not so if you use the proper tyre size. If you go for bigger tyres as well then your heading for errors.

Steven
Steven

Thanks Tony! :o)

Thinking of the different diameter wheels front to rear, it could be done with standard MG rims of the same style- the square spoke wheels come in both 15 and 16" rim diameters...

An interesting idea/ experiment, but I do not know what advantage (if any) there would be for this kind of set up?

Rob
Rob Bell

Ok, thanks for the info everybody, i think it backed up what i was thinking, not to bother with the 16, just get the beter tyres, and save some money in the long run. but..... what does teh f look lik lowered with 15", i can see it not looking quite right, any pics anywhere..opinions etc?

cheers again
Matt

Matt, as the total wheel diameter is the same it should not make too much difference in look when lowered, just more black and less silver, the same as at standard height :-)

Using bigger profile tyres on the 16" wheels would defeat the object of using the 16" wheels in the first place :-).
Tony Smith

A ride height of 340mm looks the bees-knees for 15" wheels, but lower looks a little silly. For 16" wheels, a ride height of 320mm looks real mean. I suspect the difference is largely down to the visual illusion by the light coloured alloy- the larger diameter wheel simply looks bigger although the rolling diameter with tyres is actually no different as we've already discussed.

All IMHO ofcourse!

Rob
Rob Bell

Matt wrote:
---------begin---------
Ok, thanks for the info everybody, i think it backed up what i was thinking, not to bother with the 16, just get the beter tyres, and save some money in the long run.
---------end-----------

and I thought I opened this thread.

anyway, I am not really convinced to stick with the 15". A benefit for the 16" will be the look, but the global size of wheel and tyre must be kept the same as for a 15" (if you wanna avoid the speedo recallibration). So... there goes the better look.
And not mentioned in postings above (I think) is the impact on performance. The few extra bhp's gained with the installation of K&N (or other) and sports exhaust system is thrown away. Hmmm.....

cheers,

Erik

OK I had a BIG scare today driving on the Autobahn. Was driving from Heidelberg, Germany to Stuttgart,Germany. It was drizzling rain all day long. I was coming up on this 18 wheel flat bed truck, when all of a sudden it started to swerve all over the road! I slammed on the brakes because I was almost next to him and wanted to get out of his way. Once he past me, he swerved over onto my side and slammed on his brakes;(really stupid to do that in a truck on a wet road.) I braked and went onto the other lane. Please remember when all this started I was doing about 190 KPM. My tires never lost their grip on the road. The trucker finnaly gained control and pulled to the side and so did I, wanted to check if he was ok, then kill him. He apoligiezed and said good thing I had a good car with good tires.

Thank god for F1 Eagles, 16 inch.
Adrian" when is the sun coming out" Ferrer
Adrian Ferrer

OK I had a BIG scare today driving on the Autobahn. Was driving from Heidelberg, Germany to Stuttgart,Germany. It was drizzling rain all day long. I was coming up on this 18 wheel flat bed truck, when all of a sudden it started to swerve all over the road! I slammed on the brakes because I was almost next to him and wanted to get out of his way. Once he past me, he swerved over onto my side and slammed on his brakes;(really stupid to do that in a truck on a wet road.) I braked and went onto the other lane. Please remember when all this started I was doing about 190 Kph. My tires never lost their grip on the road. The trucker finnaly gained control and pulled to the side and so did I, wanted to check if he was ok, then kill him. He apoligiezed and said good thing I had a good car with good tires.

Thank god for F1 Eagles, 16 inch.
Adrian" when is the sun coming out" Ferrer
Adrian Ferrer

Erik - you did, sorry

Can somebody give me a quick recap of 'standard' ride height range

cheers

ps, i'm gona stick with the 15" lower it to 320 and paint the indide bit of the tyres silver, hows that sound
Matt

Here's the little calculation I use for wheels height / diameter.
It's only based on my reasoning, but I suspect it's (almost ?) true.

The height of a rim + tyre is :
(height of rim) + (2 x height of tyre)

- height of the rim is its diameter in inches (so multiply it by 25.4 mm)
- height of tyre = width of tyre x profile (example = 215/40 : height = 215 x 0.4)

so, 205/50-15 gives a height of : (15 x 25.4) + 2x(205 x 0.5) = 586 mm
215/40-16 : (16 x 25.4) + 2x(215 x 0.4) = 578.4 mm

That means the outer diameter with 215/40-16 is 1.3% smaller than with 205/50-15 ... better acceleration ? ;o))

Keep in mind the difference in diameter between brand new and worn tyres can go up to 17 or 18 mm !! (hello speedo !!)

That's easy to make an Excel sheet with different tyre widths, profiles and rims diameters ... and see the suitable combinations

Fabrice
Fabrice

Hi,

Erik, I think that we're repeating ourselves now: there are enough posts to show that there are no problems with speedo calibration or performance with the 16" wheels on 215/40 tyres.

What you eventually choose is of course up to you: there are still a couple of points to confuse you further..

The 16" F1's are generally considered to be exceptional in the wet. This means far more to me than the ultimate dry weather performance (but the 15" F1's are probably as good).

The 16" wheels and tyres were available from B&G for £850 a set. If you subtract their £500 cost as a new car option that leaves the tyres - which you have to get anyway - as £350, which is a pretty good price, and you could always sell the old wheels for a few quid. They're a bargain. I'm sure B&G will mail to Antwerp.

Fabrice, what tyres do you use? The F1's (and other tyres I've measured) have 7mm of tread when new, so at 5mm wear - just about the limit - the tyre diameter is reduced by 10mm. Numbers, it's all numbers!

Regards, Kes.
Kes

Kes,
it was a rough approximation...
new : 10 mm thread
worn : 1.6 mm thread (legal limit in Belgium)
Anyway, that's no big deal.
I only tried to highlight that was not negligible ...
Your numbers should me more accurate

Fabrice
Fabrice

>>Can somebody give me a quick recap of 'standard' ride height range<<

Okay, here's the summary: ride height is measured on the front axle between the centre of the wheel to the tip of the wheel arch vertically above it.

Measurements should be performed at 17 celcius- if lower, then an adjustment of -0.4mm per degree needs to be made; if above then add 0.4mm per degree change.

The ride height range is 368mm plus or minus 10mm (or to put it another way, 358mm to 378mm).

HTH Matt

Rob
Rob Bell

Matt,
Robs instruction can be also found in my even under construction web 'desert':
http://members.tripod.de/MGF/technik.htm

click on ride hight or print out directly this one.
http://members.tripod.de/MGF/ebhoe.htm

Please notice, the measurement looks simple but its vital to bounce the front and rear once to get a kind of settled position.

Dieter
Dieter

Fabrice, B&G are going to appear in Arnhem (Holland) in May at the big MGCC bash, give them a call, maybe they will bring a set over for you.

B&G at

http://www.ukmgarts.com
Tony Smith

Thanks Tony for the input, but I don't think Fabrice will go for another set... ;-)

Dieter, could you bring the B&G catalogue with you on Saturday? Then I can have a look at it, and see if it's interesting to take some further steps in obtaining the 16".

Thanks guys !!!
you're all wonderfull
Erik

>Thanks guys !!! you're all wonderfull

We Know :-)
Tony Smith

While we're here on this wheels thread, does anyone know of someone who has put wheels larger than 16" on an MGF? I'm curious to know the implications (ride height, tyre rubbing, handling etc.)

thanks,
Rich
rich

This thread was discussed between 03/04/2000 and 06/04/2000

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