41 replies to this topic

[Hark]

I know their lighter but have no idea by how much. EDIT (Found this now between 1.5-2.5kg I think) Do other wheel suppliers like BBS etc not do the odd fitments that the VX needs? I did a quick search but there were 280 topics...

Edited by Hark, 08 September 2010 - 09:30 PM.

[Hark]

Ok done some reading. Is it something to with different wheel sizes giving a wider variety of tyres?

[P11 COV]

I know their lighter but have no idea by how much.

Do other wheel suppliers like BBS etc not do the odd fitments that the VX needs? I did a quick search but there were 280 topics...

I think its because generally they are the only ones that fit straight on and in the 16in/17in combo that is accepted as the best handling wise.

Compomotive do the same sizes in the speedline VXR design but only produce them every now and agin when there is enough interest.

Edited by P11 COV, 08 September 2010 - 09:33 PM.

[mandarinvx]

Wider tyre choice is one of the advantages (including the ability to fit semi-slick like A048's V70A's and R888's) But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

[Retset]

As above .... and they're black

[VXTyrant]

Because they can't get their hands on the rare OZ alternative

[rossma]

the vx was specified with 17" front wheels for aesthetic reasons

Does anybody know where this, often quoted, info came from ? I have seen it on the TMS website but is this actually true ?

[luke.]

My matehas some white td on his peugot 306 for some obsene reason and I cleaned them up before he put them on and they seemed a pain in the ass to clean. Maybe you guys can say what they are like to clean. I prefer compomotive 5 spokes imo but no idea on weight differences

[LazyDonkey]

But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

how does wheel diameter affect handling ?

[slindborg]

But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

how does wheel diameter affect handling ?

/me grabs the popcorn

I did it for a better selection of pikey tyres, thats it plain and simple.

[mandarinvx]

But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

how does wheel diameter affect handling ?

It's not the wheel diameter that affects the handling, it's the tyre profile

[LazyDonkey]

But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

how does wheel diameter affect handling ?

It's not the wheel diameter that affects the handling, it's the tyre profile

and the profile of an Elise 175/55 on 16" is massively different from a 175/55 on 17" ?

IIRC the profile is a percentage of the width and not the diameter.

Or am i talkign out my arse ?

Edited by LazyDonkey, 09 September 2010 - 09:01 AM.

[Retset]

^^ I agree whole heartedly with Mandarin AND Donkey! The profile is a very important part of the whole thing. Some cars use the tyre as suspension a lot (like Caterhams) and handle brilliantly with balloon type tyres. More modern ones are designed to do all the work in the suspension - a case in point is my father's Jag XF which has great ride and handling on 20" wheels with rubber band tyres. Most cars have a profile which works nicest, even though other options are available. Case in point was my BMW 540i (E39): I had 16" rims for ages and it always turned in lazily. I moved to 17" and it was a huge transformation in handling (& looks) with still great ride quality. Then I went 18" which made it look like it was on stilts, kept the same handling and reduced the ride quality a bit - luckily I hadn't yet sold the 17s!! Most keen drivers also know that the E46 M3 is a better steer on the unfashionable 18s rather than the ubiquitous 19s. Lotus obviously think the car handles nicely with higher profile (55) tyres and if we stick to 17's and widen the width then we lower the profile and so change the characteristics. Wider tyre on a 16" wheel keeps things about the same (I ran 205/50s).

Edited by Retset, 09 September 2010 - 09:09 AM.

[siztenboots]

But also for handling (the vx was specified with 17" front wheels for aesthetic reasons - the Lotus varients came with 16" fronts as standard

how does wheel diameter affect handling ?

It's not the wheel diameter that affects the handling, it's the tyre profile

and the profile of an Elise 175/55 on 16" is massively different from a 175/55 on 17" ?

IIRC the profile is a percentage of the width and not the diameter.

Or am i talkign out my arse ?

ass ?

the xxx / yy are pretty much approximate numbers, but you are correct. usually you can find the exact dimension on the tyres company website if you need more accurate info

but for example , say you switched to much cheaper and lighter wheels and tyre combo

for this it was considered that the smaller rear tyre contact patch was not significant

RE040 , size, diameter mm, rolling radius mm , rim width
front 175/55/17 , 624 , 1903 , 5.5J
rear 225/45/17 , 634 , 1933 , 7.5J

KU31 , size, diameter mm, rolling radius mm , weight lbs, cost ( camskill )
front 195/45/15 , 557 , 1699 , 16.9 , £39
rear 205/50/15 , 587 , 1790 , 19.6 , £45

change in static ride height assumes standard f 140/r 140 to f 107/r 117
front 624-557= 33mm drop
rear 634-587= 23mm drop
rake = 10mm fr to back
rear rolling radius change , 1933/1790 = 8% , also effective 8% more gearing / torque advantage / speedo adj.

[LazyDonkey]

Yes but we're not talking about changing to lighter wheels with wider tyres. The statement was that the elise runs 16" wheels and thus handles better. My question was how is the wheel diameter relevant ? I can buy the less unsprung weight thing but I simply can't beleive that an S2 elise on 175/55 Re040s on 16"s is in anyway different from a vx on the same combo on 17"s if all other things are equal. I'm not against moving to 16"s by any means, i just dont want people to think that the fact the VX runs 17"s means it handles worse than the lizzy.

Edited by LazyDonkey, 09 September 2010 - 09:14 AM.

[spuk87]

Theoretically wheel diamater would make a difference, but in reality I don't know if it would be noticeable. It could only be tested if you had the exact same wheel pattern in 16" and 17" though I think. The 17" wheel would have more moment of inertia so would theoretically take more effort to change direction when it is spinning, as well as more effort to increase/decrease rotation speed. However in reality with all the other factors involved I seriously doubt the significance of that.

[JohnTurbo]

12.7mm reduced ride height without affecting wishbone angle.

[SteveA]

Even if it does make a difference, the actual amount is negligable. Fifth gear VXT vs 111r test speaks volumes. There was literaly nothing in it, a few 10th's tops and I recon that's more down to the 111r's higher power to weight ratio.

Edited by SteveA, 09 September 2010 - 10:08 AM.

[theolodian]

One of my 17" fronts wouldn't balance. TDs with Kumhos are cheap, and seemed like the best value long-term. For instance I only paid £50 more for new Kumhos delivered than I got for my used OE tires.

[VXTyrant]

Even if it does make a difference, the actual amount is negligable.

Fifth gear VXT vs 111r test speaks volumes. There was literaly nothing in it, a few 10th's tops and I recon that's more down to the 111r's higher power to weight ratio.

And the fact that they always send one car off the racing line for the photo finish. The VX came out the corner ahead, is quicker at accelerating then lost it when veering offline for the finish… the VX would have won had the lotus moved to the right; of that I have no doubt!