Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 05-24-2012, 08:26 AM   #1 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,747

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,328
Thanked 749 Times in 476 Posts
Taller tires or lower RR?

Since my tires may need to be replaced within the next 1-2 years I'm starting to look around for the next set, just to know what is available. My car came with 195/65R15's (205/65R15's were an option) and this is what I use for most of the year. Winter tires are 185/65R15 and won't be replaced any time soon.
I haven't found low RR models any taller than what I have, and the only widely available tire with a higher profile is 185-195/80R15, but these are mostly for delivery vans. There is no mention as to what their RR is.

Switching to 185/80R15 should lower engine rpm by ~6%, and maybe slightly better comfort on bumpy roads, but will raise the car by ~20mm. I would benefit from the larger wheel only when cruising, not when coasting in neutral (which I do more often).

If van tires turn out to have worse RR than normal tires, then is the switch to taller a bad idea? And how much worse can their RR be to still allow me to switch to 80's?

__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell


[Old] Piwoslaw's Peugeot 307sw modding thread
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 05-24-2012, 08:45 AM   #2 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,203

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)

Daox's Volt - '13 Chevrolet Volt
Thanks: 2,501
Thanked 2,587 Times in 1,554 Posts
I'd stick with the stock tire size and get a LRR tire. I don't like the idea of the 20mm raise in height and I also like my speedometer to be accurate. Also, I haven't ever seen any testing that shows taller tires give nearly the gain that LRRs give you.
__________________
Current project: A better alternator delete
  Reply With Quote
The Following User Says Thank You to Daox For This Useful Post:
Piwoslaw (05-24-2012)
Old 05-24-2012, 12:12 PM   #3 (permalink)
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,266

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
How about taller LLR tires?
With most vehicles made after the late 90s you should be able to go to the dealer and have them correct the speedo with nothing more than ECU programing change.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Old 05-24-2012, 02:18 PM   #4 (permalink)
herp derp Apprentice
 
Join Date: Oct 2008
Location: Lawrence, KS
Posts: 1,049

Saturn-sold - '99 saturn sc1
Team Saturn
90 day: 28.28 mpg (US)

Yukon - '03 GMC Yukon Denali
90 day: 13.74 mpg (US)
Thanks: 43
Thanked 331 Times in 233 Posts
Changing the speedo might be as easy as an ecu reprogram, but the last time I saw one done ( on an '01 Tahoe ) tech spent about 2hrs between calls to Gm and various points waiting in the process just to get the special reprogram setup in gms system. Then he still needed to do the actual programming. Aside from the techs time, Gm also charges to do their side of it. The tech was doing this on his own vehicle, but for a customer the cost might be prohibitive. I'm sure there are vehicles out there easier to do this on. There also might be an aftermarket programmer for your vehicle that might allow you to adjust your speedo as you please. I guess I'm sayin check with your dealer first if you're going that route.
  Reply With Quote
Old 05-24-2012, 02:34 PM   #5 (permalink)
Master EcoModder
 
Join Date: Nov 2010
Location: Atlanta
Posts: 403

Sweetie - '11 Hyundai Sonata GLS
90 day: 39.35 mpg (US)

My Miles - '03 Combo GLS/KLX/Ninja
90 day: 40.49 mpg (US)

Sipper' - '04 Kawasaki Ninja 250
90 day: 74.98 mpg (US)
Thanks: 1
Thanked 37 Times in 28 Posts
I forget which post it was, but it was here, and the two tires with the least RR are the Conti VancoContact with an RR of .0064 and the Nokian Hakka C Van with a .0064 also.

The Honda Insight tires were at .0062!
__________________
This ain't a war, anymore than a war between men and maggots. Or, dragons and wolves. Or, men riding dragons, throwing wolves at maggots!
  Reply With Quote
Old 05-24-2012, 02:35 PM   #6 (permalink)
The Dirty330 Modder
 
Gealii's Avatar
 
Join Date: Dec 2011
Location: North East Ohio, USA
Posts: 642

CruzeRS - '15 Chevy Cruze LT RS
90 day: 41.29 mpg (US)
Thanks: 10
Thanked 67 Times in 59 Posts
if your gunna adjust ur speedo and tach go with taller lrr tires ( and drive over 75% hw) , if not just go with lrr tires
__________________



"The only real mistake is the one from which we learn nothing."
- Henry Ford
  Reply With Quote
Old 05-24-2012, 02:57 PM   #7 (permalink)
Mechanical engineer
 
Vekke's Avatar
 
Join Date: Jan 2009
Location: Kitee (Finland)
Posts: 1,272

Siitin - '98 Seat Cordoba Vario
90 day: 58.56 mpg (US)

VW Lupo 3L --> 2L - '00 VolksWagen Lupo 3L
Diesel
90 day: 104.94 mpg (US)

A8 luxury fuel sipper - '97 Audi A8 1.2 TDI 6 speed manual
90 day: 64.64 mpg (US)

Audi A4B6 Avant Niistäjä - '02 Audi A4b6 1.9tdi 96kW 3L
90 day: 54.57 mpg (US)

Tourekki - '04 VW Touareg 2.5TDI R5 6 speed manual
90 day: 32.98 mpg (US)

A2 1.4TDI - '03 Audi A2 1.4 TDI
90 day: 45.68 mpg (US)

A2 1.4 LPG - '02 Audi A2 1.4 (75hp)
90 day: 24.67 mpg (US)
Thanks: 270
Thanked 841 Times in 414 Posts
I will give a suggestion for 175/80R14 Toyo 350. Same diameter and 20mm narrower. Worked very well on my old Seat. Seat stock size was 185/65R14 so they were taller on my seat.
__________________


https://www.linkedin.com/in/vesatiainen/

Vesa Tiainen innovation engineer and automotive enthusiast
  Reply With Quote
Old 05-24-2012, 03:21 PM   #8 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,525 Times in 1,126 Posts
...*IF* you can easily correct for the increased tire/wheel diameter, then I'd say go for both taller and LRR tires, because the taller tires will help lower your engine RPMs at road speeds, getting you closer to the BSFC "sweet spot" if you're not already there.

  Reply With Quote
Reply  Post New Thread






Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com