Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Which wheels?

Are there noticeable differences between the smaller and larger diameter wheels (comfort, ground clearance, road holding)? Thanks!

Trad Morgan's rely on the tyres as part of the suspension so reducing the depth of sidewalls gives a harsher ride but possibly sharper steering. Obviously increasing rolling radius of wheel and tyre combination increases ground clearance but will also increase gearing reducing acceleration through gears and speedometer will no longer be accurate, although a small increase may improve it

With the lighter 4/4's narrower higher profile tyres as factory fitted seem to suit best so any changes should be of a minor nature dimension wise.

Later Roadsters came fitted with up to 205/55/16 tyres to better accomodate the power on the rear at least, but most had electric steering assistance.

You will get more specific advice if you advise what model you have with what wheel/tyre combination and what you wish to achieve, i.e. better ground clearance, handling, comfort.

As best I can remember earlier +8`s had smaller diameter (Millrace) alloy wheels, with larger aspect ratio ( higher sidewalls) tyres than later +8`s though both wheel and tyre combinations had the same rolling radius thus could be swapped without altering speedo read outs etc.. I never drove both versions to be able to provide comparative differences, however Porsche had a similar wheel tyre choice set of options on the 911, and there was a notable difference in the improved comfort levels with the higher sidewall tyre set-up, on the negative side the steering was less direct due to sidewall flex taking longer to settle into corners which was more noticeable when on a interesting twisty road... Porsche also fitted more sporting shockers to the cars with lower sidewalls which may have added to the difference in feel.... I have no idea if Morgan altered shocker types when changing from smaller to larger diameter wheels.

It seems ever larger wheels with ever lower aspect ratio tyres may be more desired option, perhaps on the basis of style than performance in many cases...I would guess that a CX Morgan may have more possibilities for compliant suspension than a Trad, thus could run more comfortably on lower aspect ratio tyres than a trad..? I guess seat padding may also be a consideration, both one`s own and that of the car..?

It seems logical that round clearance can be improved with larger diameter wheel/tyre combo`s but fitting them under the wings and avoiding fouling steering would seem to have potential to create issues..?

Good luck in your choices.

Given this is in the CX section and the other post mentions that he is spec'ing his CX I think we are talking about the modern mogs? I cannot speak for the CX suspension but for the Aero ?

I have an Aero S2 on 18's and a Coupe (slightly heavier) on 19's with the same outside diameter and a very small sidewall.

On the 18's I have more sidewall and I think the overall balance of comfort, grip and cornering is better. I am also less worried about the rim being damaged because of no sidewall and the range of potholes we have around here.
I would also say the 19's are more pressure sensitive and you can feel it through the steering and in the handling quickly.

Having said that the 19's are the Rays aeromax design and I think they match the Coupe so they are not being changed.

I can get most of the decent tyres in both sizes now so no restriction on that front.

My Plus Six rides on 19" rims that look great and do offer decent handling and a fair amount of comfort on decent roads to,.

Apologies Keith have just checked back to your previous posts and it appears you have a new Plus Six. I was told that the assymetric tyre sizes and brand were custom spec'd to this model by MMC. For this reason you may not have much choice in alternate tyres. Our local dealer did query this as a customer wanted to fit snow capable tyres to his Plus Six but not sure of the answer MMC gave.

If it's improved comfort and roadholding you are after the Morgan specialist are SSL in the UK who I know offer a suspension upgrade kit for your car.