GenVibe - Community for Pontiac Vibe Enthusiasts

Just a quick question about upgrading from 16's to 17 inch wheels. If you upgrade from 16 inch wheels to 17 inch wheels, won't that slow down your acceleration a bit because of the bigger wheels and tires? Also, do you have to have your speedo recalibrated when going to a larger size wheel? Just curious.

acceleration can vary...factors are weight, distance from center of hub, and diameter.Generally your aftermarket wheels will be lighter....my 17's are lighter than the stock 16's....lighter is faster....sometimes....i'll explain. Having lighter wheels may mean faster but remember now your wheels are bigger some of that weight is further from the center of the wheel hub so it has more rotational mass.....therefore it takes more power to accelerate. so if you get bigger rims that are light enough to offset the additional rotational mass then your faster but i think they'd have to be pretty damn light! light=$$$$$$$ So you will most likely get a lighter rim, that makes you faster and more rotational mass that makes you slower ....so you wont really gain or lose any speed at all....at least nothing noticeable and probably not even measureable. The whole rotational mass thing is overlooked by a lot of people but usually on the subject of brakes....the big brake kits can be = weight to stock or sometimes heavier....they can really suck horsepower. a big brake kit on our car would probably suck 5-10+ horsepower. the tricky part is that w/ the big brake kit...on drag strip the car would be slower but on the road course it would be faster...hehe! When you go up in wheel size, you will go down in tire sidewall height to compensate so that your diameter doesnt change. >> 205-55-16 is stock...the 55 is your sidewall height. with aftermarket 17's you might go to a 205-50-17....i dont even know if that size is readily available...in reality the aftermarket wheels would be a little wider so you would be in a 215 tire or a 225-45-17 But basically your diameter will stay the same if you do this....its probably the easiest way to go....so your speedo wont be off or anything like that.I'm tired....i hope my ramblings above made some sense...i'll re-read them tomorrow and correct the errors... -Phil

Yes, reducing unsprung weight is one good way to get better acceleration times. Good answers, Phil.

I have also noticed in a couple of threads (don't remember them) that You should also consider the tire weight. I have spent all morning looking online for different tire weights and only only store has them, that I found. This is a copy and paste of hte site from my browser's toolbar.http://www.hptire.net/index.cfm?fuseaction=homeI hope it works for you

I wouldn't worry so much about tire weight...a light weight tire is likely to have less build to it and therefore is likely to have softer sidewalls resulting in poor handling. I forgot to mention that the way to actually improve your acceleration is to go to a smaller diameter.....but be cautious, you vehicle will look kinda funny. Going to smaller wheels reduces weight and rotational mass (closer to hub) and then putting smaller tires on too will make your overall diameter very small....this reduces your gear ratios to the ground and makes acceleration quite a bit quicker. Eh...I don't think its practical though....your speedo will be way off and on the highway your REVs will be higher for a given speed.....less gas milage too. But if your looking for race/track wheels then its a good way to go for using them only on the track.-Phil

So....basicaly most folks upgrade to 17's to get the better handling and for the fact that they look better correct? Thanks for the explination on the wheel size. My general thought was that it would just take more power to turn the larger wheels..thus slowing down your acceleration. Good point about wheel weight. Going along with your statement about smaller wheels, would larger wheels lower your rpms on the highway a bit?Jim

When going from 16" to 17" you will need to decrease the sidewall of the tire. The best match to the P205/55R16 is P225/45R17. The difference is VERY little. I went P215/45R17 for mine. The % is still small but the P225 is the best size.

Quote, originally posted by Kissfan79 »So....basicaly most folks upgrade to 17's to get the better handling and for the fact that they look better correct? Going along with your statement about smaller wheels, would larger wheels lower your rpms on the highway a bit?JimYeah...Looks are the main reason...not too much to be had in performance...but sometimes being able to put a wider tire on is the biggest performance advantage. Not larger wheels, but a larger overall diameter would certainly reduce your RPMs on the highway. You could do this w/ your stock wheels if you wanted too....simply buy tires w/ a taller sidewall and poof you have a larger diameter. Be advised that your speedo would be off and also that you dont want to go too much bigger b/c you'll lose torque to the ground (higher gear ratios).....torque is nice to have especially when passing or doing those highway speeds into a strong wind....even more so if you carry anything on the roof such as bikes etc.-Phil

So, in your opinions, a lighter tire does not really help any in terms of performance, when looking at performance as straightline speed plus turning ability?

Quote, originally posted by noginsk »So, in your opinions, a lighter tire does not really help any in terms of performance, when looking at performance as straightline speed plus turning ability? Yeah...I wouldn't waste your time searching for weights and trying to find a light tire....anything you gain in acceleration, you'll miss in cornering. I would just buy a good quality tire thats built well. I'm a Kumho fan myself, but many others are great tires too.-Phil

Quote, originally posted by philndz »acceleration can vary...factors are weight, distance from center of hub, and diameter.Generally your aftermarket wheels will be lighter....my 17's are lighter than the stock 16's....lighter is faster....sometimes....i'll explain. Having lighter wheels may mean faster but remember now your wheels are bigger some of that weight is further from the center of the wheel hub so it has more rotational mass.....therefore it takes more power to accelerate. so if you get bigger rims that are light enough to offset the additional rotational mass then your faster but i think they'd have to be pretty damn light! light=$$$$$$$ So you will most likely get a lighter rim, that makes you faster and more rotational mass that makes you slower ....so you wont really gain or lose any speed at all....at least nothing noticeable and probably not even measureable. The whole rotational mass thing is overlooked by a lot of people but usually on the subject of brakes....the big brake kits can be = weight to stock or sometimes heavier....they can really suck horsepower. a big brake kit on our car would probably suck 5-10+ horsepower. the tricky part is that w/ the big brake kit...on drag strip the car would be slower but on the road course it would be faster...hehe! When you go up in wheel size, you will go down in tire sidewall height to compensate so that your diameter doesnt change. >> 205-55-16 is stock...the 55 is your sidewall height. with aftermarket 17's you might go to a 205-50-17....i dont even know if that size is readily available...in reality the aftermarket wheels would be a little wider so you would be in a 215 tire or a 225-45-17 But basically your diameter will stay the same if you do this....its probably the easiest way to go....so your speedo wont be off or anything like that.I'm tired....i hope my ramblings above made some sense...i'll re-read them tomorrow and correct the errors... -PhilHoly crap!!! Thank you Mr. Wizard!!! Great explanation

Quote, originally posted by Mr. Poopypants »Holy crap!!! Thank you Mr. Wizard!!! Great explanation Hehe...yeah...looking back on it there, i guess i got a little carried away....well I hope I was able to pass some knowledge on. -Phil