HI all,

I was wondering if anyone knew why Murray decided on 17 inch wheels rather then 18's or 19's.... IIRC, weren't 17's and 18's all the rage back then... I guess I am just confused why they didn't go with a taller wheel to lower the center of gravity a bit more......

Murray wasn't in to 'all the rage', he was focused on weight reduction; I am sure a higher diameter wheel would have been heavier than the one he chose

... I guess I am just confused why they didn't go with a taller wheel to lower the center of gravity a bit more...... Making something taller raises the center of gravity...:wink::shakehead:screwy::nono::banghead:

Making something taller raises the center of gravity...:wink::shakehead:screwy::nono::banghead:

Hi all,

You've heard what you've heard as I in a vice versa, but since you had to add all that stupidy too, PROVE IT!? Or can you....? I will seek my answer and post it right here..........

Hi all,

You've heard what you've heard as I in a vice versa, but since you had to add all that stupidy too, PROVE IT!? Or can you....? I will seek my answer and post it right here..........

Sorry, but that sentence didnt make much sense to me :screwy::shakehead

HI all,

Yes, I am aware of what I can be about this car, yes, I also know there are things that I don't know about this car.... I do know that while this is a definate car for the masses, there is alot more into this then all the rage... That was just an idea to get the idea that 18 inch wheels were already done back then too, ;)

I also have some thoughts I can share about this particular question...
Disclaimer: These are my ideas surround this issue, which in the last point I will make, I think, my strongest arguement to the contrary of taller height being a higher center of gravity, when it comes to wheels on cars that is....

A forum I frequent alot more than this one, a thread topic was made and this is what was gathered from there.......

1: They are probably weekend mechanics, with probably no engineering degree at all, particularly in automotive design... This isn't as bad as it seems now, just read on.

2: The easiest of answers when going to a taller wheel size is simple, raise the suspension pieces to a higher level on the frame, or do what the ricers and hot rodders do, BUY a lowering kit, lol.... MUCH cheaper option I think... Or for that matter if you know of someone you can trust to do this option then all the power to you; but, you can also cut the OEM sized springs, which it turns lowers the car......

3: The next option you have is to go with a taller rim but a smaller sidewall on the tyres, which can be the same size of your OEM wheels and tyres with enough cash on hand, lol......... I.e, custom made if neccessary, and at these prices for a car, one should think you could afford it.....

4: Now this will probably answer my question more elaborately than above...
Disclaimer: I dunno if it is possible to Now make a taller wheel size in the same category as the weight of the OEM 17 inch wheel of the F1.......... If you've been following along than the answer is most likely that of weight for the OEM sized wheels on the F1....

To elaborate: Let's think on this one a bit, can you see a bodyless car driving around a track? The roaring sounds of engine and x-host, tyres screaching while coming out of the twisties, corners.... Can you feel that, live that? I hope so, or else this exercise will be in vain..... Ok, for starters let's back up a weee bit, can you see that bodyless car rolling hard into that twisty, now if you were to have a taller wheel, the sheer mass and or weight, I am no engineer, would take more weight or stress in a corner with less body roll than a smaller sized wheel..... Sure you can have stiffer springs, gas shocks, thicker anti-sway bars, and poly-bushings... Or you could just go to a larger wheel, and or both....

Does this make any sense at all to anyone here?? I am dying to know, cuz honestly, I once thought for a short while on becoming an automotive engineer.......

Sorry, but that sentence didnt make much sense to me :screwy::shakehead

Hi all,

What I am saying is that I "think" his is one of opionon, and or heard it from a friend of a friend, that sorta thing.... Now becuase I had heard the opposite, or the vice-versa I asked him to prove what he is saying, and I would try and do the same thing........

edit to add: By all that stupidy I think and or thought he was calling me an idiot, but alas, and with a sigh, for this forum thing is only in black n white.........

Quote from a friend: " If your not confused, you aren't paying attention...."

Yes, I was calling you an idiot. Hope it's clear now.

You recalled incorrectly. 18" wheels weren't the rage at the time. 17" were dominant wheels back in the early 90s. Tire manfucturers were catching up with sizes at the time. With very few even offering anything close to the shoes worn by the McLaren. Even to this day very few companies offer a 345 in 18 size.

And just because you make the wheel larger doesn't make your overal tire diameter larger. You can have a larger wheel with the same overall diameter by reducing the profile of the tire: ie. a 245/45R17 tire has the same overall diameter as a 245/40R18 tire.

You want to be a tuner. If you want to be an engineer, a lot of your thoughts are incoherent and way off base. I suggest a lot of studying ... not from forums either.

:lol: Is this the McLaren section? Or am I in the wrong place?

Making something taller raises the center of gravity...:wink::shakehead:screwy::nono::banghead:

Well not always, it depends on the car sometimes 18 inches can be better then 16's because the cars tranny etc might not be located inside the actaul structure but more or less hanging down under the body so a bigger rim might actually allow a closer height to the ground as weird as it sounds.

The F1 however it's body is so low and everything in the car is so tucked away that you can virtually get within an inch or so atleast of the road.

Well not always, it depends on the car sometimes 18 inches can be better then 16's because the cars tranny etc might not be located inside the actaul structure but more or less hanging down under the body so a bigger rim might actually allow a closer height to the ground as weird as it sounds.No. Increasing the diameter will increase the height of the center, which will raise the center of gravity. It creates more clearance, which may allow bigger things or differetn things to be packaged which were previously not possible. But all other things being equal, increasing wheel diameter will increase height which will raise the c of g.

All other things being equal is *always* assumed anytime you discuss the effect of changing one variable. So increasing wheel diameter and then decreasing tire profile is not really a valid point--of course changing to a thinner tire will pull things back down a bit. We are only talking about increasing the wheel diameter, with the axle attached to the center of the wheel. Wheel plus tire combinations would have to be examined for the overall effect to get to the final result, as would doing a million other things.

Yes, Raising the center of G up is definitely the biggest downside besides rotational mass.

NO... Increasing the diameter of the wheel alone will not increase the height.

If you do not increase the overall diameter of the tire you will not increase the height. You can go from a 14" wheel to an 18" wheel, but as long as your tire profile is reduced appropriately, you will not increase the overall diameter, which will not change the location of the center. The location of the center of the wheel is in direct proportion to the overall diameter.

You can only change the location of the hub of the wheel in relation to the car if and only if you change the springs (suspension geometry). By going with larger than stock OD, then you will change the CG.

Ie. If you have a 28" OD, with a 17"wheel, you have 5.5" of sidewall (11/2). If you get a larger wheel to 18", you would get a proper tire size which would have a sidewall of 5" (10/2), thereby maintaining your OD of 28"

When you put aftermarket wheels, you will always take into consideration the tires to go with it... trying to at least match the OD of the wheel/tire package.. so you NEVER only change one variable when changing wheels.

Monster, you are overthinking things when it comes to wheels/tires.

OK guys the reason for the smaller wheels is so that murry could use a larger sidwall tire, while keeping the same outside diameter. Using a larger sidwall tire will alow for more flex in the sidwall of the tire making for a smoother ride. However with this comes the trade off of higher performance since a taller sidwall will flex more, it will also be less responsive in the corners. Apprently this is not a big problem for the car since it still had a pretty damn good skid pad g level. If you have any more questions about the physics of the taller wheel PM me and i will go into more detail. Thanks guys, have a good one!

More sidewall is a better for topspeed because of expansion and heat.

And higher profile tires give better ride quality too. So what. Guys, this is a stupid debate. I am aware of the numerous factors that can affect the final outcone, such as tire profile, and suspension pickup points, relative density and amount and shape and position of materials used, etc., etc. The point is, when debating the effect of one variable, such as tire diameter, you assume that all the other variables stay constant. Otherwise, you include them in your model and consider the overall effect.

If you increase wheel diameter, while keeping all other things the same, then you raise the center of gravity. No two ways about it.

Couldn't of said it better myself.

OK guys the reason for the smaller wheels is so that murry could use a larger sidwall tire, while keeping the same outside diameter. Using a larger sidwall tire will alow for more flex in the sidwall of the tire making for a smoother ride. However with this comes the trade off of higher performance since a taller sidwall will flex more, it will also be less responsive in the corners. Apprently this is not a big problem for the car since it still had a pretty damn good skid pad g level. If you have any more questions about the physics of the taller wheel PM me and i will go into more detail. Thanks guys, have a good one!

:iceslolan I agree with him^^^^:iceslolan

While im here, does anyone know the size of the OZ alloys on the LM/ GTR? I assume there greater in size then "17 as they are fitted to cars designed for racing whereas the standard F1 was designed for the road.

:iceslolan I agree with him^^^^:iceslolan

While im here, does anyone know the size of the OZ alloys on the LM/ GTR? I assume there greater in size then "17 as they are fitted to cars designed for racing whereas the standard F1 was designed for the road.

18" is your answer,

Before any prat goes harping on, that this must have raised the CofG on the GTR. the two main reasons for an increase in wheel diameter on the GTR is for larger brake discs and lower profile slick tyres for greater side wall stiffness.

FACT....The centre of gravity on the GTR, is lower than on the road F1!!