MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: evileye_wrx on May 27, 2008, 18:36

Title: 14 inch wheels
Post by: evileye_wrx on May 27, 2008, 18:36
Would there be any benefit in using 14 inch wheels to increase performance? I was thinking if 17's are supposed to slow you down then smaller than stock will make you go quicker. I was also thinking of getting some 14's from a yaris to try out the theory.

Phil
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Post by: Anonymous on May 27, 2008, 18:56
The only benefit you'd gain is losing unsprung weight: You'd have a smaller contact patch with the road so would have reduced grip, but you'd get more feel from the tyres if you kept the ratio the same as stock. Would 14" wheels even clear the brakes properly?

Interesting idea, but you'd be better off with a lightweight set of 15/16/17s in practice I would think.
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Post by: Jaik on May 27, 2008, 19:10
Quote from: "Ekona"The only benefit you'd gain is losing unsprung weight: You'd have a narrower contact patch with the road so would have reduced grip, but you'd get more feel from the tyres if you kept the ratio the same as stock. Would 14" wheels even clear the brakes properly?

Interesting idea, but you'd be better off with a lightweight set of 15/16/17s in practice I would think.
EFA  s;) ;) s;)
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Post by: Anonymous on May 27, 2008, 19:12
So smaller then  s;) ;) s;)
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Post by: aaronjb on May 27, 2008, 19:20
Plenty of people in the US run 13" wheels for AutoX - anyone in the higher classes.  I forget the make, search on SC and there's a very recent (this week/last week) post on which 13" wheels clear the calipers and how far they have to stick out of the bodywork to do so..

Not something I'd do for the road, though, it looks a bit.. odd.
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Post by: Jaik on May 27, 2008, 19:25
Nope, at the same tyre pressure, the contact patch will be narrower but longer. The reduction in grip comes from the way the tyre material deforms on the road surface I think.

(http://www.carbibles.com/images/contactpatch1.gif)
From this superb article (http://www.carbibles.com/tyre_bible.html).
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Post by: northernalex on May 27, 2008, 19:29
Surely the moment of inertia is far less on a 14 than on a 17..
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Post by: Anonymous on May 27, 2008, 19:33
Now that is a fantastic link, nice one  s8) 8) s8)
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Post by: Chris_h on May 27, 2008, 19:46
I know when I had a RS clio, the keener track drivers went for 15's on the basis that tyres were much much cheaper and of course reduced mass etc.

Its nice to see a revolt againts the ever increasing size of wheels - but if its for road use and aesthetics matter, I cant help thinking 14 may look a little lost in the arches. From pure looks, your SP wheels look great Phil

Also, I dont think 14s go that wide (?) and availability of performance tyres is probably limited to the 185 width and 55/50 profile - think off all that power going through a Fiesta 1.25 tyre   s:shock: :shock: s:shock:
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Post by: aaronjb on May 27, 2008, 19:53
Here's the thread I was looking at on SC:  m http://spyderchat.com/forums/index.php?showtopic=52376 (http://spyderchat.com/forums/index.php?showtopic=52376) m

You can get 13x8.5 from Panasport, but if you run 13 or 14" wheels you're likely to end up running wheels that have to stick out like this:

(http://k43.pbase.com/o2/34/789434/1/96748845.zGNAd9qz.CRW_3628.jpg)

Not sure if that is running 13"s (probably), but that's the kind of look you'll end up with.  Track only, really.

Or this, definitely running 13's:

(http://www.umit.maine.edu/~richard.nye/IMG_3780.jpg)
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Post by: evileye_wrx on May 27, 2008, 20:03
It was speed for track rather than the road I was thinking. I'm more rather happy with the look of the 17's for posing about in.
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Post by: aaronjb on May 27, 2008, 20:10
Here's a checklist of what you'll need:

1) VERY stiff springs or anti-roll bars
2) Extra poly bumpstops fitted to the shocks
3) 13" wheels with tiny offsets
4) Possibly slim spacers so the calipers clear
5) Might as well run slicks or semi slicks - tyre choice will be pretty much limited to pure race tyres.
6) Large wallet (Panasports/Traklites etc are expensive)  s;) ;) s;)

You need the extra bump stops because the tyres will stick out of the arches - too much body roll will cause the tyre to hit the arch and pop..
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Post by: evileye_wrx on May 27, 2008, 20:32
Bollocks to all that then. Might see if I can pick up a cheap set of 15's at some point for all the time I am planning on spending on track. Which isn't much, not enough to justify any major cash lay out

Phil
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Post by: Anonymous on May 27, 2008, 22:17
If it's just for track use Phil, you might be better putting the money towards some A048s/R888s which will see you so much better on track than dropping a wheel size or two, and it won't look half as daft  s;) ;) s;)
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Post by: ChrisGB on May 28, 2008, 00:51
Quote from: "Ekona"If it's just for track use Phil, you might be better putting the money towards some A048s/R888s which will see you so much better on track than dropping a wheel size or two, and it won't look half as daft  s;) ;) s;)

Or V70 A Kumhos for that matter.

Chris