sometimes its fun to ask the forums. So many opinions on the internet. Everything from:
A. Drivewheels are 70% more important than non-drive wheels.
To
B. All wheels are equally significant.


Is weight reduction in the drive wheels more effective/important than weight reduction in rear wheels or is all equal?

 

Reducing rotating mass of the drive wheels would probably be more noticeable coming out of the hole.. There is so much more that is improved besides acceleration by changing to lighter wheels all the way around that you would be missing out on a lot by not doing it... Kraftwerks Oscar Jackson Sr. said that next to boost lighter wheels and tires is the best thing you can do to improve the performance of the Fit.. I have experienced noticeably better performance on many vehicles with small and mid sized engines starting with very tweaked air cooled VWs in the early 70s I have posted a bunch here and started a thread that is among the most read on the other Fit Forum... The RPF1 15x7 41 Enkeis and Swift springs completely changed the way my car feels and handles as well as improving acceleration at any speed.. Removing the rear seats helped a considerably but still only a fraction of what the wheels did even though the seats weighed well over twice the amount of weight of what I dropped off of the axle ends Put 20 pounds of weight on your back and go for a run, then take it off and put 5 pounds of weight on each ankle and you will understand... Think of how much less strain there is on your entire drive train, suspension, steering, brakes and engine mounts with the weight reduction in terms of rotating mass and unsprung weight.. It is phenomenal.

 

The two of you above likely know all of this so it's more fyi for others.

Drive wheels would be more important in acceleration as well as cornering while all wheels would be equally significant in stopping utilizing the brakes. When accelerating, the axle is turning the drive wheels which means the torque is applied to the center of the wheels. The rear wheels are being rotated by the forward movement of the car where force is applied to the outside edge of the tire (this takes much less effort)

As far as turning is concerned, the heavier the wheel, the more gyroscopic effect is in play. This will make the wheel harder to turn and also apply more force when turning to the rest of the car.

Stopping using the brakes... all about the same given that equal force/pressure is used at all corners the same distance away from the center of the wheel. (that isn't at play here due to the lack of rear disc but probably is a miniscule difference).

My $.02

~SB

 

Testify to that! I dropped a lot of weight (36#'s) when I changed shoes and it is a better car all the way around because if it. MPG up from average 28 to 34 and I realize I did this at the same time that winter gas was changin to summer blend but this is around town mpg's, I can't wait to see what the trip to ECHS will be.
Big Mike

 

Should have made it a poll.

There may be some minor differences but my vote is all wheels are equally important.

Whether they are drive wheels or "just along for the ride" energy is still required to change their momentum. The less mass the better.

 

just curious, how did you save 70 pounds by changing wheels? thats 17.5lb per corner

 

I mean...he could have shed weight with the tires too? lol

 

I bet he uses helium in his tires... lol

 

what is the lightest '16 rims?
the lightest i saw at tire rack is 13.7

 

Or lower the recommended 33 pounds pressure. Lets say 10 pounds per wheel makes a huge 40 pounds difference!

Edit: or even remove the 60 from the spare... lol

 

My 15" rims weigh in at 13 pounds each. Very happy with the change!

https://www.fitfreak.net/forums/tire...er-wheels.html

Tirerack goes lower with the Enkei's...
Enkei Racing RPF1 (Silver)
Size: 15x7
Price: $199 (each)
Offset: 41mm
Backspacing: 5.55"
Bolt Pattern: 4-100
Rec. Tire Size:195/60-15

Weight: 9.5lbs.

 

Ya these are 15" rims with the sp31 donlops vs. the stock 15" 08 sport rims w/ 1" spacers. The stock rims have Eagle GT A/S 195/60/15 weight is 39 lbs. setup. The rims I bought are Jet 15x 6.5 -40mm w/ donlops are 31lbs setup. and the spacers weight something like a pound a peice. It adds up x4 corners, fast!

 

unless im missing something, im going to have to say math fail. 8lb x 4 corners = 32lb. still a ton of weight, but no where near 70lb

 

Actually, I redid the math as well and it looks like you are missing the spacers as well. Drop another 4lbs off of that for 28lbs.

the Stock 16" alloy on the 09+ sport with the Bridgestones comes in at 36.5lbs with about 20K miles. (let's say 37lbs new) My 15" alloys with snows were around 34lbs and those tires were taller than OEM 15" Probably would have been around 33 if I went with stock height.

~SB

 

I made a mistake it's (4x8)+4= 36 Not 70 your right,
But thanks for your comments I think we got it now.

 

All the wheels are equally important. True, the fronts are being turned by the engine and the rears dragged in turning the effect is the same for resistance to rotation. but if the rear tires are lighter its a different matter; and useful on tuning Fits handling.
But note that the weight of the wheels is not nearly so important as the weight of the tires. Though both wheels and tires have their mass centered close to their OD the OD of the tire is much farther from the hub center so the tire weight offers greater resistance to turning (torque); ergo the more important. If you compare the difference in performance between wheels of different weights the probability that one is better than the other will almost always be masked by weights of tires even when the tires are identical. It takes statistics to prove the difference.

 

Is the resistance to rotation the same for the front and rear? The fronts are attempted to be rotated by the axles which are at the center of the hub, while the rears are being turned by the most outward part (where it contacts the road) turning a wheel by it's outward edge is much easier than at the center. This would require more work to rotate the fronts.

I disagree only because I'm trying to figure out the physics behind it and it isn't sitting right in my head. (been a few too many years since I took physics... CRAP it's been like 18 or 19 years.)

~SB

 

Think of the acceleration and resistance to wheel rotation as two separate things. The resistance to the wheel rotation (torque) is separate from the engine overcoming the inertia and weight of the vehicle. The resistance to rotation from the wheels/tires is the same sum for all four wheels and results from drag at the ground and changes in roation velocity. The resistance to changes in wheel/tire rpm may be different for all four wheels but the sum is the same and thats why there is little difference which axle they are on.
The engine, in order to accelerate, must overcome both the drag from the inertia of wheels/tires and the vehicle weight and of course aero drag from the bodywork. The work required to turn all four wheels is the same regardless where the lighter wheels/tires are. Lighter wheels on one axle vs the other makes some difference to the acceleration; but lighter wheels or especially tires really makes that difference as any reduction in weight aids acceleration and any lighter tires especially makes those wheels easier to turn even if they are only on one axle because there is less resistance to changes in angular velocity (changes in rotation rpm).
Make sense?
The comp Fits all use a lighter and narrower rear tire and wheel than on the front. I think most are usins 5" wide rims with 165 or 175 tires rear and 6" rims and 195 or 205 fronts with a slight diameter bias toward the front, perhaps a quarter-inch diameter smaller in front where allowed (some comp orgs require all 4 tires the same size so only the narrower rims are allowed. A pound or two matters even then. What they are doing is increasing rear oversteer to balance the large unsteer in the front end. Some even disengage the front antisway bar.

 

It requires greater force to accelerate the wheel from the center, but the work is the same as the outer edge of the wheel has to move farther even with less force to get the same acceleration (force over distance equals work or some such thing. It's been even longer for me...).

 

The problem I see here is if this were true (exaggerating greatly here) having 200lb wheels on the front and 20 lb wheels on the rear, acceleration would be the same as if you had the reverse (20lb wheels on the front and 200lb wheels on the rear. To me, the engine would need to work many times harder to rotate the 200lb wheels on the front vs "dragging" them if they were on the rear. On the rear, it's little/no different than having an extra passenger while I hate to think of the L15 struggling to rotate massively heavy front wheels.

If this was a "gravity" racer with no engine and no need to rotate the front wheels from an axle, I'd agree that it doesn't matter.

see this to me is the difference, the work isn't actually applied to the same points on the wheel so there is less force needed to begin rotating the tires. For example, Flip a bike over and tape a small weight -fishing weight- to the tire and watch the wheel rotate. move that to the closest point to the hub on one of the spokes and it probably won't rotate. It takes less work to rotate the tire from the outside than it does from the hub (axle on the fit).

It just doesn't sit right with me from a logic standpoint.

To me, my brain says lighter wheels on the front would be more beneficial. (not like too many would opt for different weight wheels on the Front VS the back but...)

DAMNIT LYON... you made me think. now my brain won't stop.

Sometimes it's fun to ask the forums... sometimes it's fun... DAMNIT

~SB