upsize my 14" rims to 16" What can I expect?

Submitted: Sunday, Jun 29, 2003 at 20:43
ThreadID: 5728 Views:1823 Replies:6 FollowUps:2
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I am in the final stages of upgrading my Mitsubishi L300. I putting in a 2600 Astron motor,done the suspesions, heavy duty clutch, brakes, second battery etc but what I would like to do is replace my standard 14" rims with 16" rims for increased ground clearance. So far nobody can agree on the result.
Do I get better or worse economy?
How is my power effected?
What about towing?
If you can answer any of these questions I would be grateful. I would also like to know why as I have so many 'experts' with varying opinions.
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Reply By: desert - Sunday, Jun 29, 2003 at 20:50

Sunday, Jun 29, 2003 at 20:50
Going to the taller wheels is simply making the gearing taller (higher geared) than before, which equates to: slower off the mark, but less revs for a given speed;if the higher gearing causes you to use more throttle to maintain speed, then economy will suffer, despite lower revs. Towing will be like doing everything in the next higher gear. In short, I think it will be a dog to live with!
AnswerID: 23793

Follow Up By: Truckster (Vic) - Sunday, Jun 29, 2003 at 21:45

Sunday, Jun 29, 2003 at 21:45
Wouldnt make no difference if your using 31inch tires on a 11/17inch rim, since the outside diameter is still 31inch? Just less sidewall....
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FollowupID: 15948

Reply By: phil - Monday, Jun 30, 2003 at 08:32

Monday, Jun 30, 2003 at 08:32
The increased power and torque of the 2.6 Astron motor will, at least partly, cancel out the taller effective gearing from the larger tyres. Given that many older utes had rather low overall gearing the result may allow much more relaxed highway cruising. However you may find it difficult to crawl slowly over rough and steep terrain. I can not see why fuel economy should suffer , in fact if the engine is revving less at highway speeds, and has sufficient power, it should improve.
Phil
AnswerID: 23820

Follow Up By: Matt M - Monday, Jun 30, 2003 at 15:37

Monday, Jun 30, 2003 at 15:37
Phil, The original designers of the L300 would have spent months calculating the best compromise for that vehicle with engine power, gearing, revs and load.

If we change ANYTHING it effects that overall package. But as we all know... sometimes these changes are what we set out to achieve and suit our individual requirements.

If you change you gearing, be it final drives, T/case or wheel dia, then it will effect the vehicles top speed, revs at any speed and load (fuel consumption).

If the 2600 has the amount of torque output that, at that standard gearing, with 31' tyres on then your economy will most likey be better..IF... So at cruising speed, with just enough throttle to keep you there you may find you are cruising better. But usually any increase in top end gearing is ALOT more load on the engine and will cause it to use more fuel even if it is doing less revs!! But you wont know for sure without doing the sums!

You would need to compare the weight of the vehicle and what final gear ratio it operated at and the speed it used to turn at, because this is what the manufacturer would have set it for, for optimal economy at tthat speed. eg 1000kg Sigma with 3.11 reduction at diff plus 1.08 over drive in fifth doing 90km would give a rev of say 3000rpm could have been the most efficient load on the engine, but make it push harder (taller wheels) and you will increase the load even though you drop revs!!! So most likely higher fule consumption!

I dare say the L300 is heavier and the 2600 isnt all that neck snapping to allow for a decrease in load!! Its not like you have put a V8 Chev in a landcruiser!!

So there are alot of variables and heaps of different ranges and conditions to compare fuel consumption and unless you know the exact dia of the final wheels, there wont be many out htere that could give you and accurate answer. But hopefully you understabnd the complexity of the question and why there are so many different answers from EXPERTS!

ps EXPERT (EX, as in past tense) (Spurt, is a drip under pressure)

Goodluck and enjoy, I think the L300 will end up a good little rig!
Matt.
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FollowupID: 16000

Reply By: Ray - Monday, Jun 30, 2003 at 15:19

Monday, Jun 30, 2003 at 15:19
Hi Ian
Use 15 in you will have a greater range of tires to choose from. Make any further changes by changing tires Borrow some to try before you buy
AnswerID: 23861

Reply By: howesy - Monday, Jun 30, 2003 at 17:26

Monday, Jun 30, 2003 at 17:26
Got a mate that did it with 16's and it throws the ratios right out the window giving you die back on steep inclines just when you don't want it. There is a site he went to and I'm sure there are plenty who make body lifts and suspension lifts for your vehicle and the prices start from around $500. Keep the wheels and do the suspension lift (expensive one but well worth it) Think you will find you will need a body lift or other modification to fit the astron.
AnswerID: 23870

Reply By: Eric - Monday, Jun 30, 2003 at 22:38

Monday, Jun 30, 2003 at 22:38
Ian.
As I siad in a previos post I have done both the 2l and 2.6 conversion and was disapionted with the 2.6 because of gearing. I tried bigger wheels but the centre of gravity was far to high by the time the body was lifted. I ended up lowering the body and moving it forward on the chassis, this rquired cuting and reworking the back of the wheel arches. the effect was much better but on the test run it fell over and was a right off. good luck . Eric.
AnswerID: 23908

Reply By: Glen@oz - Tuesday, Jul 01, 2003 at 11:30

Tuesday, Jul 01, 2003 at 11:30
Ian,

I've had my L300(brick) for about 12 Years. It's currently in the workshop getting the 2.6 Astron replaced by a 2.6 out of a Magna. The Astron died on Frazer after UltraTune dropped something into the inlet manifold.(They refused to accept responsibility for it but I don't have to go there any more. I believe that they can change oil reeely good).
My brick's got the body lift, bigger springs and tortion bars, LSD rear, 100litre aux tank, 90Ltr LPG tank,10.5R tyres, dual batteries and a few other mods.
Off road it's towed a lot of other trucks out of the slop and sand. It hasn't been stopped itself too often.
On the road you won't get to use 5th gear too often, but you'll be able to tow a camper at highway speed up most hills and drop down to 3rd for the big hills. (with the big wheels, 4th's now an overdrive).
Aerodynamically, its like driving a block of flats. Expect no better than about 7 Klm per Litre at highway speeds. They tell me that it's better at about 80KPH, but I've never driven that slow for a full tank of fuel yet.
To fit the 10.5Rs you need to trim theback of the front guards a tad, and depending on the offset of the rims, you may have to pack out the side door sliding track by about an inch.
The other mod is to replace the speedo shaft connection on the Gearbox. Mitsubishi, in their wisdom used to sell this part in several different ratios for different tyre sizes. Dunno if they still have them.

If you need any more help drop me a line

AnswerID: 23939

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