Tyres - How big is too big?

indy · Post by **indy** » Tue Feb 17, 2009 12:36 pm

Hey all just wondering on what your thoughts are for tyres offroad, whats the biggest you'd put on an L-series without sacrificing much of the gearing?
as i understand the bigger the tyres the higher geared the car is? meaning itd go quicker on the flat, and be more fuel efficient. but going up hills and such it'd be harder.
I have standard 17's on at the moment, was thinking what would be the max you'd goto without throwing the speedo out too much and making it too high geared?
i wouldnt mind a nice pair of muddys on the ol' girl

Phizinza · Post by **Phizinza** » Tue Feb 17, 2009 1:53 pm

Anything over 12% original size is a bad idea IMO. On road and offroad.
Original size is 175/70R13. I've got Kumho 27x8.5R14's, or call them 215/75R14's in Metric terms and they are the limit I'd want to go. Already the hill climb ability is lacking due to lack of gearing, see here http://www.youtube.com/watch?v=PPyETl7BQBs.

Use this page to figure out what size is good http://www.miata.net/garage/tirecalc.html

Larger doesn't always mean more fuel efficient. They make Subaru's drive at 3000rpm at 100kph for a reason and that is because thats where the motor makes most efficient kW vs Nm for driving. If you up the power conciderably like swapping in a larger engine lower gearing can help because you don't need most of the power the motor has to offer to hold the speed. My dual carb EA81 with a L sereis 3.9 ratio gearbox and the Kumho's runs at around 2600rpm at 100kph, because its a dual carb (101hp from factory vs EA82 86hp) it just gets away with it but I change into 4th a fair bit to keep from flooring it.
Also larger tyres weight more, and offroad tyres aren't designed for efficiency so they normally suck a bit of fuel.

Post by **Alex** » Tue Feb 17, 2009 2:14 pm

is 17's a typo?

also, its not just gearing youd have to think about. Larger/heavier tyres place much more stress on the whole car. Gearbox, cv's, brakes, everything suffers much more.

at the moment im running 29 inch tyres on 15inch rims. this is largest id ever go on a l-series. They also arent an option if you plan on running the standard motor. You will require alot more power to get them rolling, and keep them rolling. To fit 29s it also takes alot of work to cut guards and youd need at least a 3inch lift.

Give us sum specs of your car and we can give you better advice.

alex

indy · Post by **indy** » Tue Feb 17, 2009 2:41 pm

mmm yeh i get what your saying.
Sorry i meant 17" inch tyres, yeh mines just a 88 single carby l series, pretty much everything is stock, 3.7 diff. i want to get a 3"lift just for some more clearence, and to get clearance for the diff and all i need some bigger tyres, now i have 13" wheels, and i don't really want to compromise fuel efficiency and also the low gearing of things cause she isn't the best at going up hills at the moment lol. this is just all theory for the future when i get the money to be able to get some new tyres, lift kit etc.
Itd be mainly for driving on road, but i want the clearence for when i go offroad aswell.
Should i just stick with the 17" tyres but get some offroad sorta mud tyres?
or can i go up a few sizes without compromising too much?

YouTube · Post by **El_Freddo** » Tue Feb 17, 2009 4:53 pm

Or you could get a 2 inch lift and run with the standard size rims/tyre diametre in a mud and snow tyre if you want. It won't give you the diff clearance you talk about but it will give you better approach and departure angles + more clearance under the belly in general.

Correct me if I'm wrong here fellas (i'm still getting around to a lift

)

Cheers

Bennie

Fatz · Post by **Fatz** » Tue Feb 17, 2009 5:00 pm

i have 31x10.5 on my l wags.. and IMO they are too big.. biggest id go in the future 30x9.5

Phizinza · Post by **Phizinza** » Tue Feb 17, 2009 5:26 pm

17" OD tyres??!?!!?! standard 175/70R13's are 22.6" (outside diameter) 27x8.5R14's (most common actual OD size of these is 26.6") are 11.8% larger then standard

indy · Post by **indy** » Tue Feb 17, 2009 5:52 pm

sorry mate i dont have much of a clue when it comes to tyres lol yeh i just had a look they are 175/70R13's.
yeh that sounds like the g-o el-freddo, i'll probaby just get a 2-3inch lift and stick with the size tyres i have now but maybe some nice offroad pattern

My old man foiund a suby wheel and a mud/snow tyre at a job he was working on, i want to find another similiar then ill put those two babys on the front, which then means its puddle time lol.

Phizinza · Post by **Phizinza** » Wed Feb 18, 2009 8:35 am

For 13" your pretty limited.

Toyo 720F is the one I know of, but have been told maybe its not in production anymore.

And BnS Brat said Bridgestone might have one..

stinky · Post by **stinky** » Wed Feb 18, 2009 8:42 pm

27's like the Wrangler TGs are perfect for a MY or L series with 2" lift ( and some creative hammering )

AndrewT · Post by **AndrewT** » Wed Feb 18, 2009 9:55 pm

This is too big...

http://www.youtube.com/watch?v=c2nqPASxWek

heh but yeh seriously....around 29" is about the max u would want to go. I have 6" body lift and I won't be going any bigger than 29s.

vincentvega · Post by **vincentvega** » Wed Feb 18, 2009 10:13 pm

why do you guys insist on reminding people that you have 29" or 31" tyres on your hacked to pieces cars.

why even mention it? the guy has a stock ea82. personally i wouldnt advise much more than a 26" tyre on the thing... they are slow enough with stock tyres.

if you want a chunky tread pattern - a goodyear wrangler TG is the go. 26ish inch and very aggressive pattern