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Help Please - Re 2005 Jimny VVT manual, Gear Reduction advice required

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24 Jan 2023 19:27 #247155 by XTOPERMAN
Dear All, 
I appreciate that this topic has been raised on numerous occasions in the past, but after trawling through the posts I would really like some advice on the following query. Any help would be gratefully appreciated as I am sure some members will have been through the same dilema as myself. :)

Background:I have a 2005 Suzuki Jimny VVT manual gearbox  (with the electric 2wd-4wd push button on the dashboard), that I purchased recently which has been fitted with new Mud-Terrain 235/75 R15 Tyres.I’d like to keep using these larger tyres, however the Jimny struggles on the road especially up hills, and acceleration is poorer, - all to be expected with the larger tyres I know.

As the Jimny is mainly used on-road and is a daily driver, what gear reduction kit would you recommend to obtain/fit to restore the standard gearing, especially for the road? Low Range reduction is not important for me.Additionally, the speedo now appears to over-read with the larger tyres, so when I’m doing 60 mph it actually reads just over 70mph, which is very strange as I thought that with larger tyres the speedo would under-read so not sure what the issue is here?I have seen the following kits which differ in the amount of high ratio reductions, my dilema is which one would suit a daily road driver the best to help restore to some degree the standard high range driving?

1. Jimnybits 17% gear reduction for high ratio:- 
www.jimnybits.com/jimny-17-high-87-low-r...on-transfer-box.html which also comes with a speedo correction gear.
2. Protrack do a gear reduction of 7% High and 77% low   protrack.gr/en/gears/jimny-vvt-ddis-redu...gears-high-27-low-97 which may be a better solution than the Trail Gear (17% and 87%) respectively as the overall difference in gearing (when comparing the standard 205/70 R15 with 235/75R15 sizes on www.tyresave.co.uk/tyre-size-calculator/  equates to around 9.88%. The Protrack kit also comes with a speedometer correction gear.I’m still confused as to which will be the best kit for on-road use only.Low range reduction is irrelevant for me as the Jimny will only be used on road, so I guess it’s a choice of either going for the 17% high reduction kit or the 7% high ratio reduction kit considering the 9.88% difference between 205/70 and 235/75 size tyres.Given the slightly wider width of the tyres (235 v 205) and the larger rolling diameter/height of the 235's combined with their more aggressive mud profile and the 2” suspension lift that I have,  I’m erring more towards the Jimny Bits Trail Gear kit but am undecided. Will the 17% high ratio reduction be too much for highway driving and cause the revs to be too high at 50-60 mph? Or would the 7% reduction be more appropriate?
Any suggestions or thoughts on these two kits?
  1. Will the 17% high ratio reduction be too much for highway driving and cause the revs to be too high for say fifth gear cruising on the highway/motorway? (i dont thrash the Jimny and on long drives dont go above 60mph anyway).
  2. Would I be better considering a 7% high ratio reduction kit that Protrack offer?
  3. I have heard that on some gear reduction kits, they can produce some transmission whine? Does the Trail Gear or the Protrack kit make any noise/whine that is noticeable when driving on the road? Does anyone have experience of either kit? Which is the best quality and most reliable?
Any impartial help, suggestions and recommendations would be very much appreciated.

My other Jimny's have 215/75 BFG tyres and having covered over 350,000 miles in Jimny's on these tyres thay are highly recommended however I do want to keep the 235's fitted to this particualr Jimny, as they came with the car and are brand new, so please no suggestions on going down a size.Many thanks in advance, I'm really hoping for some recommendations, ideally from members who have used either the TG or Protrack kits in similar circumstances or can advise on the best option from experience. Kit quality and reliabilty are important. 
The Jimny has done 40k road only miles and the T/F Box chain should be fine as i've heard the VVT manual chains are stronger than the A/T or mk1 Jimny chains. 
Many thanks. 

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24 Jan 2023 20:51 #247158 by yakuza
Hi
I got the 17/87% gears in my 2005 Jimny with 235/75 BFG.
I got the tires and lift first and the 1.6 and the gears after. However my catalytic converter was congested so I had horses like less than a 1.3. When driving highway with the 235 and no gearing i kind of liked it, but not for towing and steep hills however. with the 1.6 it would be ok i guess without the 17% reduction for highway use. But Now with the gears i got a very "fast" jimny at least for accelerating. Driving on highways with my trailer i follow traffic easily but 110kmh is not doable for long distances. I usually cruise along around 90-100kmh easy and for longer periods. even with my trailer at 90kmh.
I drive down to Denmark and south of Norway and on other longer trips now and then and sometimes do long stretches like 8-9 hours of driving as well. My car has extra sound insulation and a good sound system so the 3500 to 4000rpm do not bother me, and the engine just have to cope or it will get fired.

As long as I only drive around here where I live and I must drive 3-4 hours in 80kmh to find a 110kmh speed limit highway, I am ok with the gears.
If I where to drive for hours in 110kmh once a week, i guess i would keep the gears and buy another car to commute. :)

I regret swapping the speedo gears. for 235 tires they got my speedo way off so if i have to service my tranfsfer case it is definately coming out.
Unless I have ordered the 1100€ iceland flares and put on my 325-65-15 tires. :)

But offroad the the 87% is just awesome. I love crawling around in first, and also use 2nd gear alot for faster driving offroad. 87% is so nice I will cope with the 4000rpm for a long long time.
And there is the 30 or 31" tire possibility also..

Norway 2005 Jimny M16A VVT, 235 BFG MT, 2" Trailmaster, ARB rear lck, 17%/87% high/low gears.
The following user(s) said Thank You: XTOPERMAN

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25 Jan 2023 13:56 #247166 by XTOPERMAN
Many thanks Yakuza, did you experience any of the whine noise that a number of people have mentioned after fitting the reduction gears?
Was yours the Trail Gear make?
After you had fitted the speedometer correction gear, did your speedo under read or over read? How much out is your speedo now at say 30mph and 60mph? and was your speedo gear calibrated for 29”-30” [736-762mm] tyres?
Many thanks for your help it is much appreciated.

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26 Jan 2023 06:42 - 26 Jan 2023 06:49 #247177 by yakuza

Many thanks Yakuza, did you experience any of the whine noise that a number of people have mentioned after fitting the reduction gears?
Was yours the Trail Gear make?
After you had fitted the speedometer correction gear, did your speedo under read or over read? How much out is your speedo now at say 30mph and 60mph? and was your speedo gear calibrated for 29”-30” [736-762mm] tyres?
Many thanks for your help it is much appreciated.
Yes, I have the whine when taking off hard in first at high gear and under load or steep hill also a bit in second.. Yes it is Trail Gear.
It is louder going uphill or at more load but still at the same rpm or so, so I suspect it is the chain that hits a whirling spot going into resonance.
www.britannica.com/science/resonance-vibration
It has not gotten much worse over the years so I am not very worried, but I try not to apply too much power at the spot.
I did not service or change the chain when I replaced the gears. But the original setup was silent.
There is also a road speed connected buzz kind of noise. this was terrible at first but after an oil change and the running in period it is better now.
But not at all possible to ignore the fact that this is an offroader now. Sounds more like an old SJ  :)

My speedo was more or less correct before the gear swap. Now it shows approx 15% too much. 
 I do not remember what tire size it was supposed to be good for but I did not expect it to be this much off.
I thought at first that the speedo gear set would compensate for 17% high reduction but after installing when i got to think about it, I found that it is before the the gears so it is just for the tires. (isn't it?)

Norway 2005 Jimny M16A VVT, 235 BFG MT, 2" Trailmaster, ARB rear lck, 17%/87% high/low gears.
Last edit: 26 Jan 2023 06:49 by yakuza.

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26 Jan 2023 10:59 #247184 by XTOPERMAN
Many thanks Yakuza for your very helpful advice. Yes the speedo gear should compensate for larger tyres. It is strange as you say that your speedo now over-reads following the installation.

When I bought the car it had recently been fitted with 235/75 r15 tyres and strangely it also over-reads by approx 15%. I'm sure no reduction gears were fitted, as it is very lethargic and I have to drop 2 gears when going up hills compared to a standard car.

I'm tempted to get the high range 7% reduction kit offered by Protrack with a speedo gear correction to suit 28-29" tyres which I'm hoping will be appropriate. It just feels that the 17% reduction kit in high range may be too much?
Ref. www.protrack.gr/en/gears/jimny-vvt-ddis-...gears-high-17-low-87

Regarding your point " But the original setup was silent.
There is also a road speed connected buzz kind of noise. this was terrible at first but after an oil change and the running in period it is better now."
What oil change do you mean? Was this the gearbox oil that was changed?
Many thanks, David

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26 Jan 2023 23:16 #247194 by yakuza
Instructions for the gear set says to change the oli in the transfer case after 1000(?)km. And I also did a later change and is doing one again soon. First oil change the oil was very Grey from grinding gears. The production prosess of these Does not include Machine fine grinding so the gears will wear to fit.

Norway 2005 Jimny M16A VVT, 235 BFG MT, 2" Trailmaster, ARB rear lck, 17%/87% high/low gears.
The following user(s) said Thank You: XTOPERMAN

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27 Jan 2023 14:11 #247200 by me101
Hi, if not too bothered about the low range, you can look at the older gearbox / manual transfer box. This drops the high ratio by 10%, the parts are cheap, and if your R72 gearbox is in good condition you can sell that for enough to cover the swap. Cheers

2007 Little Jim with cheap mods!
www.youtube.com/channel/UCeBDekO99Qk2aOmBmSmrI9w
The following user(s) said Thank You: XTOPERMAN

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27 Jan 2023 20:21 #247208 by XTOPERMAN
Thank you Yakuza, much apprediated.

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27 Jan 2023 20:25 #247209 by XTOPERMAN
Thanks me101, to be honest I want to retain the OEM electric push button 2/4wd system but appreciate your views on options.

Has anyone any experience at all of the Protrack Gears from Greece? Are they good quality? Do they emit any whine or buzz after fitting? Are they reliable? I have mailed Protrack but still have not received any response which is a little disappointing.

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