Rob you're 1000 percent correct about the Diameter once you go up to larger wheel. But the parts guy at mountain motorsports said they would reach out to rep to make sure it won't throw off traction control etc....Will keep you all posted.
Traction control & all the other 'wheel speed based' computer controlled features encompassed by the VSS/Nanny are readily up to handling 'minor' changes in wheel rolling diameter (about 20mm max) or rotational circumference (no idea of what a 20mm dia inc works out to in circumference variation) because they hafta be able to cater for different loadings &/or tire pressures; so going up a rim size and down a profile shouldn't make any difference, simply because neither the rolling diameter nor the rotational circumference should have changed much, if anything! :lecturef_smilie:
That said,
if you DO make changes that mean variations in either the rolling diameter or the rotational circumference on one end of your Spyder/Ryker (front or rear), you will generally need to adjust the other end about the same amount or risk VSS/Nanny intervention at some stage. However, I'm not alone in having run tires on my Spyder that actually
DID increase the rolling dia by 20mm without any issues at all - but when I had a 20mm larger tire fitted to the rear and before changing the fronts to suit, the Nanny got pretty upset whenever I pushed things hard thru the twisties!! :shocked: So if you
DO actually change the rolling dia on one end (& not just go up a rim size & down a profile size!) it's highly recommended that you
ALSO change the tires on the other end by about the same amount too!! :thumbup:
Aaannnd, at the risk of explaining to some what they probably already know, but simply trying to make it clear to those who don't
yet know....
On a side note Ryker2020, the
'proper term' you are looking for when you mention '
thinner tires' is actually '
Lower Profile'!! '
Thinner' implies
narrower, ie, a
195/55R15 instead of a
215/55R15.... which I'm sure is not what you mean!! :shocked: When you mention 'thinner', I take it that you are actually talking about the height of the sidewall that you can see between the rim and the tread, which is the 'sidewall height', and that's referenced in the tire's nominal size by the Profile, which is expressed as a Percentage of the tire's tread width - ie 215/
55R15, where the sidewall height is only 55% of the tire's 215mm width.
So if you want to increase the rear rim size from 15 inch to 16 inch dia, you'll need to fit a '
Lower Profile' tire not a 'thinner tire' - say, a 215/
50R16 or possibly even something like 215/
45R16 - but you should really compare the actual 'rolling diameter' or 'revs per mile' figures from the actual tire sdpecs rather than just comparing the 'Nominal Sidewall Size', which can be more than 20mm different from what the tire REALLY is!! :shocked:
Anyhow, if you have a 215/55R15 tire fitted now, and you ask for a 'thinner tire' on a 16" rim, you'll possibly end up with a 205/55R16 or maybe a 195/55R16, both of which are thinner in width and therefore have less sidewall height too, and as a result will most likely also have somewhat smaller rolling diameters than the OE spec tire! And that is most likely not going to work too well, as the smaller of those will
almost certainly be pushing that 20mm rolling dia difference and so could cause problems with the Nanny unless you change the fronts by about the same amount! :gaah:
Make sense now?! :dontknow: You really want to be:
"leaning towards the bigger rim, lower profile tire, and more customizable options." :thumbup: