[joel]

so i have fitted the 215's to the jim,
and even with this little increase in size, im having a very hard time being able to sit on 100kmh.
it hit over drive around 95 and just cant hold it and drops back a gear, and just keeps doing that, so i have to sit at 85 to 90, not much of a problem, right.... until you travel 500km to go shooting. fuel economy is out the window and its a snail now.

the help im after is, will trailjimny 25% vvt reduction gears help me, or be to low and i would be red lining at 100??
trying to use the gearing calculator but im out of my depth.
any help and advice welcome
cheers
joel

[303zuke]

So when it changes up into overdrive, what revs are you doing then?

Multiply those revs by 125% to decide if you will be red lining!

Also, check your actual speed with a GPS. After fitting the larger tyres, you might find that the indicated 95km/h is actually over 100, meaning you will be safer sitting on an indicated 90.

[Bugsta]

215 x what? 70, 75? and on 15's I presume?

[joel]

215 x 75 r15
checked the speed on gps and its around 2km difference,
at 100km its used to sit at around 3100rpm in overdrive, no i cant hold 100kmh unless i drop it into 3rd and than its around 4000rpm

[joel]

303zuke wrote:

So when it changes up into overdrive, what revs are you doing then?

Multiply those revs by 125% to decide if you will be red lining!

Also, check your actual speed with a GPS. After fitting the larger tyres, you might find that the indicated 95km/h is actually over 100, meaning you will be safer sitting on an indicated 90.

mate, please excuse me, but i am really useless with maths, its actually embarrassing,
but why 125% when the gears reduce it by 25%??
i did the calculatio of 3000rpm x 125% and got a figure of 3750.
sound about right?
a bit revvy but has to be better than flogging the auto or sitting on 85.

[Dan85]

I have a stupid scoop jimny auto with 215/75/15 muddies and dont have this problem. obviously it struggles at a whiff of an incline but its not much worse than it was stock. perhaps its something you need looked at? I found my fuel economy went from approx 7-8l/100km to a pretty consistent 9l/100km for normal driving and a little less than that for highway driving if you just let the cruise control run at about 100kph. it takes a while to get there but in gentle rolling hill country will for the most part sit comfortable at 100. My missus being the lead foot she is drove 1800kms in 3 days sitting on 110 for most of it but thats the flat WA country. if you have 215/75/15 i think its about 7-8% difference? but someone smarter will confirm. All the rough numbers ive used are speedo based numbers so factor in the larger tyres and it all looks a little better in corrected numbers. not a solution to your gearing question but similiar cars without the same issue. although maybe im just traveling at a slower pace of life hahaha

[joel]

What cruise control?
It's running fine but just won't hold 100, the slightest incline or strong head breeze has it drooping back. If my calculation is correct 3750 rpm at 100 I can live with.

[Dan85]

I had an aftermarket cruise control installed. just seems strange it doesnt hold 100 when ours does. 3750 at 100 isnt to bad maybe you will just have to go the 225/75 or 235/75 if you get the gears. Im keen to hear how you go anyway if you get the gears.

[atari4x4]

joel wrote:

trying to use the gearing calculator but im out of my depth.
any help and advice welcome
cheers
joel

hey joely, i know just the person who would have been able to help you...

joel wrote:

Gwagensteve wrote:

A) that hardtop hurt my eyes
B) that was worth a video?
C) I. Like LJ's, but not enough to hide in the bushes and breathe heavily as they go past.

will you please fuck off.

but after this outburst i do wonder if he'd bother

[want33s]

joel wrote:

at 100km its used to sit at around 3100rpm in overdrive,

3100 x 125% = 3875

[zukenutter]

First anyone has had a complaint like this when they've added larger rubber to an auto. Sounds like somethings wrong with the auto shift timing.

I think the auto's transfer ratio would make a WT Sierra transfer an almost perfect option to sort your gearing.

[shep]

If you want a sierra transfer I gave a good condition one I would trade in on ya auto transfer

[Dan85]

ZN. So a WT transfer is about that 7-8% different ratio than an auto vvt? or does it go a bit further like 8+%?

[joel]

atari4x4 wrote:

joel wrote:

trying to use the gearing calculator but im out of my depth.
any help and advice welcome
cheers
joel

hey joely, i know just the person who would have been able to help you...

joel wrote:

Gwagensteve wrote:

A) that hardtop hurt my eyes
B) that was worth a video?
C) I. Like LJ's, but not enough to hide in the bushes and breathe heavily as they go past.

will you please fuck off.

but after this outburst i do wonder if he'd bother

he may, hey may not,
either, or, i can do without the 4 paragraphs on all the things wrong with a jimny and the belittling narrow minded view of one over zealous pretentious member of a community thats holding on by a thread.

i like the guy, his knowledge is second to joeblow, its the belittling holier than thou attitude in every reply that pisses me off.
i would rather find out the hard way than be spoken down to, as will many.
viewtopic.php?f=4&t=38169&p=741094&hilit=you+are+a+seagull#p741094

[joel]

zukenutter wrote:

First anyone has had a complaint like this when they've added larger rubber to an auto. Sounds like somethings wrong with the auto shift timing.

I think the auto's transfer ratio would make a WT Sierra transfer an almost perfect option to sort your gearing.

it started the second the larger rubber went on,
the kid at work has 205's on his sierra at work, so i threw them back on for a test run, holds 100 fine, just seems the bigger rubber and a bit of a hill or stiff head breeze has it shifting back ,
doesnt seem to be a problem, oil is new, same grade as specifies, no fault codes... maybe im just expecting to much??

[joel]

Dan85 wrote:

I had an aftermarket cruise control installed. just seems strange it doesnt hold 100 when ours does. 3750 at 100 isnt to bad maybe you will just have to go the 225/75 or 235/75 if you get the gears. Im keen to hear how you go anyway if you get the gears.

i like that train of thought!!
sounds like a good cure to me

[Mike57]

This does seem a bit unusual.

The manual has a 1:1 ratio in the transfer in high range and I fitted 215/75/15's and only saw about a 5% difference, just enough to correct for the speedo. Certainly I have to drop out of 5th gear on the hills to maintain 100kph and sometimes down to third gear and this is normal. I certainly don't have any trouble maintaining 100 or 110 kph on flat ground. I understand that the auto has lower gearing in the transfer case by about 30%? but then the auto transmission gearing is probably different as well. Bottom line is I would not have expected the new tyres to cause you this sort of trouble. 3000 rpm at 100 kph seems a bit low though and in this rev range you might expect to be down on torque. We would need to hear from someone else with an Auto. Do you still have the old wheels and can you swap back to do a comparison.

Dan85 is yours an auto?

[christover1]

Zooks are happy to rev.
Less strain on auto, too, as it don't have to slip the converter as much.
Less heat produced also.
I'd do the gearing, but I'm me

[shep]

Next time you are in town mate stick my stock tyres on and see if it makes a difference.

[joel]

Mike57 wrote:

This does seem a bit unusual.

The manual has a 1:1 ratio in the transfer in high range and I fitted 215/75/15's and only saw about a 5% difference, just enough to correct for the speedo. Certainly I have to drop out of 5th gear on the hills to maintain 100kph and sometimes down to third gear and this is normal. I certainly don't have any trouble maintaining 100 or 110 kph on flat ground. I understand that the auto has lower gearing in the transfer case by about 30%? but then the auto transmission gearing is probably different as well. Bottom line is I would not have expected the new tyres to cause you this sort of trouble. 3000 rpm at 100 kph seems a bit low though and in this rev range you might expect to be down on torque. We would need to hear from someone else with an Auto. Do you still have the old wheels and can you swap back to do a comparison.

Dan85 is yours an auto?

think i may have mislead you all, i can hold 100 if i put it intop 3rd, but i cant hold 100 if i have it in "D" and it drops into overdrive.
mike i think your on the money with the torque.
cheers
will look at my options, have emailed trailjimny to see what they reckon.

[Dan85]

Mike mine is an auto with 215/75/15 and as I said I have no issues sitting on 100. Sits at about 3100 for 100 but it seems happy enough there.

[joel]

response from trail jimny
will order them tomorrow




Hello,
with your 215/75/15 tyres and our 25% reduction gears you would be
a little lower than with stock tyres and stock gears combo, but
with the auto transmission I think this wouldn't be an issue in the
on-road drive and it would definitely be a huge improvement in off-
road.
Time of delivery of this kit is approx 20 days from your order
becaue we build it only on demand.
The price would be 750 EUR + 80 EUR for shipment to your address.
Feel free to contact us anytime.

Cordiali saluti/Best regards
trialjimny.com

[zukenutter]

I think the Trial Jimny gears would be too low. I think the WT transfer would be roughly 12% lower (high range) which would be like stock if you ran 235s. 215s would be lower of course.

[jdk81]

Using jimny stats from this link
http://www.globalsuzuki.com/automobile/lineup/jimny/spec/
Some of the info there seems a little questionable, but ill work with it.
EDIT:Changed all diff ratios to be 4.09 based on info from joeblow, except for 4.3 in VVT manuals
EDIT2: Changed non VVT manual 4th and 5th ratio, to be 1 and 0.86 respectively

With stock tyres (being a true 205/70R15)
I get
non VVT manual at 3501rpm@100km/h
auto at 2984rpm@100km/h
VVT manual at 3415rpm@100km/h
auto at 2984rpm@100km/h

With your 215/75R15 tyres
in 3rd I get 4071rpm@100km/h
In 4th I get 2834rpm@100km/h

If the manual is factory designed to sit at 3415rpm I dont see why the auto would have any issues.
Itll be easier on the auto.

As someone mentioned above, I'd suspect the auto in factory spec has the motor just on the tail end of useable torque. Fuck knows why, id guess economy/emission reasons. So the slightest bump in tyre sizes and you get the slight change, which is hugely annoying.

As per your gearing
215/75R15
A 1.0L or 4.16 high range would give you 3387 rpm@100km/h with 215/70R15
The 25% reduction gears from trial jimny would give you 3542 rpm@100km/h

235/75R15
A 1.0L or 4.16 high range would give you 2900 rpm@100km/h with 215/70R15
The 25% reduction gears from trial jimny would give you 3397 rpm@100km/h

I would suspect the trialjimny stuff would be a pretty decent option, the slight increase in revs isnt a concern for me, as the manual cruises near those rpm anyway, and it opens up a wealth of tyre size options down the track.

[zukenutter]

Global Suzuki info definitely seems a bit incorrect. For a start, I know for sure that a non VVT and VVT gearbox are different ratios.
Further to that I'm a bit doubtful about the accuracy of those final drive RPM figures, I'm running 1.3 Sierra Transfer with 30s and my RPM at 100 (around 3800RPM) is definitely higher than the 1.0L figures above.

Not dissing you just worried that your info will mislead those reading this thread.

[jdk81]

well provide me the correct ratios and i will revise

It was why I linked where i got the info from because i know almost nothing about Jimny's, yet the info seemed dubious

zukenutter wrote:

Global Suzuki info definitely seems a bit incorrect. For a start, I know for sure that a non VVT and VVT gearbox are different ratios.
Further to that I'm a bit doubtful about the accuracy of those final drive RPM figures, I'm running 1.3 Sierra Transfer with 30s and my RPM at 100 (around 3800RPM) is definitely higher than the 1.0L figures above.

You manual or auto?

[zukenutter]

Manual

[jdk81]

Suzuki Aus has same specs as I linked for VVT manual and auto.
However ZN if I take your tyre size (true 30"), rpm, using stock 1.3 WT ratio, and your diff ratios, I get a 5th gear ratio for nonVVT manual of approx 0.87.

0.864 for coilys on this site
http://www.suzuki-forums.com/suzuki-jimny-sierra-samurai-forum/47262-2001-jimny-gear-ratios.html
0.86 for jimny on this site
http://www.suzukiclubuk.co.uk/forum1/viewtopic.php?f=12&t=3495

Info from this review of g13bb jimny
110km/h = 4200 rpm works out to be a 5th gear of 0.87 if the diff ratios are 4.09
Obviously its fairly close, as we dont know how true all the tyre sizes are.
BUT this also works with the info provided by global suzuki (a diff ratio of 3.416 gets the 5th gear ratio of 1:1)
http://www.4wdonline.com/Suzuki/Jimny/1999.html

So until there is a bit more confirmation etc, Ill leave it as is.

This thread is about VVT jimny, which the info I have for that is correctish...

[Mike57]

The info from jdk does seem to line up with Joel's experience. It would appear that a lower ratio transfer is what you need Joel. The question is just how much.

Curious though that Dan85 drives OK at 100kph and at 3,100 rpm without experiencing the same issue of having to drop a gear. Joel mentions an overdrive on his auto so that is effectively a 5th gear? That is four speed auto plus overdrive? I would have thought there would be no difference between Dan85 and his 2012 model and Joel with a 2011 model. Both auto, both with 215/75/15's. Anyway I can see that anywhere around 3,000 to 3,100 is probably a bit marginal for torque.

Something that I might mention is that a few weeks ago I changed my muffler from stock to a tripple flow model and despite my scepticism I have noticably more low end torque. A $200 muffler might be worth trying first? Might just be enough to get you up the torque curve a little. Just a thought.

[zukenutter]

Joel, what end result are you after?
(A) retain 215s and make gears reflect the ratios you had with 205s

Or

(B) lower than what you had with 205s but with your 215s

Or

(C) as B but get bigger tyres