Club 80-90 Forums

Hi,

1983 westy pop top. Orginal height springs. Bilstein B4 on front and Gas Gr2 shocks on back. Used for family camping, london roafs with endless speed humps and glastonbury / other trips with band and equipment.

I run carat alloys with 205 70 14 nexen at 's and am considering new springs and possible wheel / tyre changes. I quite like to be able to crawl underneath the van if necessary so my initial idea of -30mm avo springs does not seem great. I was wondering if and why changing to a 15 or 16 wheel might effect ride improvement? I also quite like a syncro look with mefros and AT tyres but do not want to mess up the gearing with only a 1.9dg to push it. Any suggestions for an improved ride within my parameters.....? Cheers

15 or 16 inch won't improve the ride they make it worse with less sidewall height to absorb the bumps, they also have more rolling resistance increasing fuel consumption.

I thought bigger wheels gave you a better top speed?

kit wrote:I thought bigger wheels gave you a better top speed?

Only if you increase the overall tyre diameter. Normally if you increase the rim diameter you use a lower profile tyre to keep the same overall diameter.
Standard tyres are 185/80R14 roughly 25 inches overall diameter, if you fit 15 inch wheels you would fit 185/70R15 to give you the same 25 inch overall diameter

Thanks Big Herb. If this is the case are the large numbers of people with bigger wheel/tyre combos just getting 'looks over function'. One reason I raise the question is that so many modern vehicles use larger diameter wheels and there must be some good reasons.

bigherb wrote:15 or 16 inch won't improve the ride they make it worse with less sidewall height to absorb the bumps, they also have more rolling resistance increasing fuel consumption.

I disagree and no doubt the majority of people who run 15's and 16's,with the correct size tyres,will also disagree.

Over the many years of T25 ownership I have run 15's,16',17's and 18's and I can honestly say that 16's with 215 or 225/55/16 tyres were the perfect combination for both handling and comfort.

15" wheels require 195/70 tyres or 205/65's,not 185/70's to keep the same rolling radius as 185R14's and 205/70/14's.....185/70/15's are 18mm smaller than 185R14's and 7mm smaller than 205/70/14's.

16" wheels require 225 or 215/55's to keep the same rolling radius as 185R14's and 205/70/14's.

If the tyre sizes above are adhered to there's no way whatsover that fuel consumption will increase....it can't because they give the same rolling radius.

If the tyre size is increased slightly...205/70/15 or 215/60/16...you could actually see a reduction in fuel consumption due to the taller gearing.

waltraud wrote:Thanks Big Herb. If this is the case are the large numbers of people with bigger wheel/tyre combos just getting 'looks over function'. One reason I raise the question is that so many modern vehicles use larger diameter wheels and there must be some good reasons.

Well a big wheel with low profile tyre means that the tyre distorts less during aggressive cornering, which is why sports / performance cars use them. People also put them on normal cars because they think it makes them look like sports cars. I however drive a slow, heavy campervan

The rolling resistance stuff is down to width rather then diameter isn't it? A wider tyre will be less fuel efficient.