× A place for general chat about the Jimny. Please make sure you post in the correct section on the site, this way it keeps the site tidy AND ensures you get a more relevant answer.

Suppliers/Dealers or anyone selling with a commercial view in mind CANNOT post here unless responding to a specific request of a member in a "wanted" post.

Suppliers include people "breaking for spares" on a regular basis, when purchasing spares members should ask a supplier what they contribute to the running of the forum particularly if contacted by a Private Message

Suppliers or Members who have contributed to the forum can be identifed by the
logo.

235/75R15 on JB74....

More
26 Jun 2021 00:03 #236153 by Navigator
Propose putting Cooper Discoverer AT3 4S 235/75R15's on a new JB74. Interested to hear any observations on this - especially from real life experience of the size if not the brand. Considerable chatter on various blogs suggest this is a bridge too far. Others say it's fine, and suggest impact on performance and fuel economy, while clearly evident, are manageable/acceptable. These tyres do not have a particularly aggressive tread but they are obviously considerably larger, and heavier, than the standard issue ( in Oz) of 195/80R15. The vehicle is about to have a 45mm lift, so about 2 inches, more for GVM impact than the lift per se, so the tyres will certainly fit - on 7" aftermarket rims - but the principal concern is whether the increased weight/rolling resistance is too much to ask of the motor and other components. Appreciate any input.

Please Log in or Create an account to join the conversation.

More
27 Jun 2021 00:44 #236169 by Navigator
Replied by Navigator on topic 235/75R15 on JB74....
Navigator again on this. Subsequent to post came across a considerable discussion on this precise size for JB 74 on BigJimny - and it only heightens my interest in informed input: Various views expressed in the discussion that mirror what I have said in post above: Some say regearing needed. Others say not. Prepared to put up with need to be more mindful of tyre influence when in low range - and when tackling, especially, steep gradients. Also relatively content with some reduction in fuel efficiency - but remain much interested in feedback on whether this proposal likely to have significant negatives for vehicle overall.

Please Log in or Create an account to join the conversation.

More
28 Jun 2021 08:22 #236198 by 300bhpton
Replied by 300bhpton on topic 235/75R15 on JB74....
I'm running a 215/75R15 AT's on mine. I'd say it has had a significant knock on performance and mpg vs the factory fit tread and size.

I don't think I'd want to go bigger without potentially re-gearing and maybe a bit more power. Although it is hard to know if the next size up would have much more of an impact or not. But I suspect it would.

I think with a 235 your low 1st crawl speed would suffer too.

Please Log in or Create an account to join the conversation.

More
28 Jun 2021 08:58 #236202 by saxj
Replied by saxj on topic 235/75R15 on JB74....

Navigator again on this. Subsequent to post came across a considerable discussion on this precise size for JB 74 on BigJimny - and it only heightens my interest in informed input: Various views expressed in the discussion that mirror what I have said in post above: Some say regearing needed. Others say not. Prepared to put up with need to be more mindful of tyre influence when in low range - and when tackling, especially, steep gradients. Also relatively content with some reduction in fuel efficiency - but remain much interested in feedback on whether this proposal likely to have significant negatives for vehicle overall.

I have 235/75R15 Muddies on mine. Off-road they are great, and wouldn't change them for anything, they handle even the steepest gradients without any issues. I drove home from a trail yesterday at 75mph,  with no issues at all, except for the fuel consumption which is around 20mpg . 

Please Log in or Create an account to join the conversation.

More
28 Jun 2021 09:05 #236204 by Roger Fairclough
Everything you will read will be negative except possibly the aesthetics and/or the ground clearance.
Is this why you want to do it?
Aesthetics are personal and not open for discussion. Ground clearance increase will be nominal and only you can decide if the cost outweighs the benefit.
The negatives are legion, reduced braking efficiency, acceleration, top speed. Probability of bodywork touching, need to re-gear, extra wear on mechanical items, desire for more power to compensate for reduced performance, reduced stability.
There is a lot to consider.

Roger

Please Log in or Create an account to join the conversation.

More
28 Jun 2021 10:41 #236207 by saxj
Replied by saxj on topic 235/75R15 on JB74....

Everything you will read will be negative except possibly the aesthetics and/or the ground clearance.
Is this why you want to do it?
Aesthetics are personal and not open for discussion. Ground clearance increase will be nominal and only you can decide if the cost outweighs the benefit.
The negatives are legion, reduced braking efficiency, acceleration, top speed. Probability of bodywork touching, need to re-gear, extra wear on mechanical items, desire for more power to compensate for reduced performance, reduced stability.
There is a lot to consider.

Roger

20mm may not sound like much, but in real terms it makes a massive difference. 

Please Log in or Create an account to join the conversation.

More
28 Jun 2021 13:34 #236212 by Roger Fairclough
That's why I asked the question, is ground clearance important?

From my own experience, 20mm extra clearance under the diffs is not a major issue, especially when compared to the possibility of a roll over.

If you ground out, you can back out and try another line - no problem, but if your extra clearance leads to instability, then your chance of recovery are very slim.

Trust me, been there and done it.

Roger

Please Log in or Create an account to join the conversation.

More
01 Jul 2021 05:27 #236273 by Navigator
Replied by Navigator on topic 235/75R15 on JB74....
Thank you all for the input. In the meantime - committed. The 235's are on the vehicle. The main prompt was a perceived lack of quality in the alternative sizes (they all seemed to be trying to look tougher than each other) and, ultimately, an indication that in the "outback," if there is tyre trouble, the 235 size much more available - because much more common. May be an expensive mistake. Will report after a couple of major on/off-road journeys, and also plenty of urban zipping about. Am hopeful the relatively conventional tread will reduce the inevitable impact on fuel consumption and drive train etc.

Please Log in or Create an account to join the conversation.

More
24 Jul 2021 23:52 #236941 by Navigator
Replied by Navigator on topic 235/75R15 on JB74....
Very early days (1000 clicks) but vehicle delivering, almost precisely, the claimed fuel consumption figures of 8.2 litres per 100 kilometres for urban driving and 6.1 on the highway - at 100Km/h and 3000 revs - despite the increased tyre size/circumference/weight over OEM. The greater circumference (5.8% greater than OEM's) is also delivering, serendipitously, a speedo reading that is virtually spot on. (Assume the UK is the same as here in that manufacturers have built in an overestimate of speed.) As some reviewers have suggested, the feel on the open road is pretty "agricultural", and suspect I will settle for a pretty modest 90Km/h on long trips, which will need to be undertaken with good rest breaks: 100% concentration, while always at play in any vehicle, takes on a new meaning in the Jimny. You are "driving" it every inch of the way.

Please Log in or Create an account to join the conversation.

Time to create page: 0.087 seconds
Powered by Kunena Forum

I hope you enjoy using this forum. Please consider making a donation towards the upkeep of this forum website.

We use cookies to give you the best online experience. Please let us know if you agree to all of these cookies. Accepting the Cookies also accepts the Disclaimers for the website.