Volkswagen GTI Forums - My Fast GTi banner
1 - 11 of 11 Posts

·
Registered
Joined
·
300 Posts
Discussion Starter · #1 ·
I couldn't bear to keep on "Three gauges....i need you're help!", so I'm starting a new thread...

Many interesting things were said on that thread, so I'm curious. Can anyone speak to the difference in performance of a 17" rim with 45 series tires, and an 18" rim with a smaller series tires, resulting in the same actual diameter at the road? I would assume there's a difference, but I'm not sure which one would be better?
 

·
Registered
Joined
·
274 Posts
deviltailedfast said:
I couldn't bear to keep on "Three gauges....i need you're help!", so I'm starting a new thread...

Many interesting things were said on that thread, so I'm curious. Can anyone speak to the difference in performance of a 17" rim with 45 series tires, and an 18" rim with a smaller series tires, resulting in the same actual diameter at the road? I would assume there's a difference, but I'm not sure which one would be better?
A smaller series tire is going to give you a stiffer sidewall. Handling will be better. Bumps will be harsher.
 

·
Registered
Joined
·
749 Posts
In most cases (that is, any case where the wheel has a higher average density than the tire that's wrapped around it), the additional weight of the larger wheel and the fact the weight is distributed further from the hub will reduce acceleration because heavier wheels are harder to turn.
 

·
Registered
Joined
·
300 Posts
Discussion Starter · #5 ·
BlueFrogPosse said:
In most cases (that is, any case where the wheel has a higher average density than the tire that's wrapped around it), the additional weight of the larger wheel and the fact the weight is distributed further from the hub will reduce acceleration because heavier wheels are harder to turn.
I never considered that. I bet it's a fairly small effect, but still an interesting point.
 

·
Registered
Joined
·
749 Posts
Generally it'd be hardly noticeable, but if you were to go from relatively light, aluminum 17" rims to heavy, chromed 19's, you'd probably think something was wrong with your car the first couple times you tried to launch.

Another problem that comes with increasing the overall weight of your wheel/tire combination is the reaction of your springs and shocks/struts. The car's suspension system is built to hold up a 3000+ lb car so 5 to 10 pounds on each corner might not seem like a big deal. However, your wheels of course are not held by the car's suspension. Your shocks/struts are designed to control the rebound of the wheels when the springs compress and expand. If you start with a 21 lb wheel and 22 lb tire (typical stock 17-inch setup), then swap them out for a blingin' set of 19" (and 32 lb) chromes and wrap them with 20 lb tires, you will have increased your unsprung weight by 21%. Some of this difference can be mitigated by proper suspension tuning but with that much additional weight, you're always gonna feel it. Even with a ~3 lb overall increase on each corner, you might not feel it, but your dyno and timeslips will show it.

You just can't get away from the fact that excess mass is bad almost anywhere on a car, but the two places you'll feel it most is on anything that rotates (or reciprocates, like pistons) or anything that's not held up by the car's suspension system. And your wheel fall into both categories.
 

·
Registered
Joined
·
749 Posts
But don't get the idea that I don't like bigger wheels. Jgo had a good point about sidewall flex, and to a certain extent, I am willing to go a little heavier in favor of wider (for better grip). The problem is it's hard enough to find 19 X 8.5 wheels that weigh under 20 lbs; even harder to find any that look good; and downright impossible to find them in my modest price range.
 

·
Registered
Joined
·
1,629 Posts
cant picture that helping the GTi at all except giving it more weight but alright... maybe if you put those on the front it would help with traction... but on the back.... just more weight to lug around.
 

·
Registered
Joined
·
277 Posts
GTfly said:
cant picture that helping the GTi at all except giving it more weight but alright... maybe if you put those on the front it would help with traction... but on the back.... just more weight to lug around.
+1

Ebay has a some reasonable 19''s (399 - 599 for 4) that are staggared like this....if you email the guy (I did) you can get them no staggered. I was look'n for rims for My girls Nitro which is why I know this.
 
1 - 11 of 11 Posts
Top