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[gregwho]

Happily (but also sadly because of the cost!) its time for my Jeep to get a new set of tyres all round!  Its got the OEM Wrangler's on at the moment, but I am looking at an AT tyre to do a bit of offroading.  Seems the WJ's have a weird tyre size (235 65 17) and its difficult to get a good AT for them.  So, ive been checking out the Toyo Open Country ATR (seem to be top choice at the moment), Yokohama Geolander AT and tried to find some Kingpin's, but they dont do any tyre in this size.  Can anyone recommend a good (and cheap if possible!) AT tyre for the WJ's?  Are re-treads a good idea if i can find them in the size?

On a totally separate thing, i've been thinking about a chip upgrade (mines the 2.7 CRD) - anyone have any experience with them - are they any good?  Do they up the mpg etc?  Any recommendations?

Cheers all

[Nosebolt]

others will have to confirm if it posible, but my first step would be to investigate the chance of fitting 16" rims, much wider range of tyres and you could prob buy a set of 16" rims with what you save on the tyres

[sprintagogo]

Chipping! There are two opinions on this and, hypocrite that I am, I agree with them both.

I know the 5 cylinder merc 2.7 CDI engine personally as I had one in my LWB Sprinter van. This van was fitted with a luton body that stood around 10½ft tall and I ordered it from the factory with 4.111 axle ratio instead of the 4.375 standard as I did a lot of motorway work. The body size and higher gearing might have resulted in a sedate performance but the power from that superb engine meant the performance was always exciting all the way up to 95mph when wind resistance eventually got the better of it.



I think that the engine should be more than adequate to move your GC around at illegal speeds with gusto and you would be mad to consider upsetting it by going away from the manufacturers spec.

Now for the Hypocrisy. I wanted more, more, MORE! I wanted to hit the 100mph electronic speed limiter every time. To do this I went straight to the company with pedigree, Superchips. I was too worried by all the new on the scene diesel remappers that had exploded onto the market at the turn of the millennium and I knew Superchips had been trading for decades. For £500 (ouch) they worked their magic on my 90k engine that I had owned from new and serviced by the book with genuine parts and Mobil 1 to the recognised Merc spec. I also sent oil samples to two separate oil analyst labs to make sure the engine wasn't hiding any problems prior to getting it chipped and both said all appeared well. The difference after chipping was immediately noticeable and the resulting extra grunt was a welcome change. It pulled better lower down the revs so was more relaxing to drive and the semi-auto gearbox (sprintshift) worked really well with the extra power. Fuel consumption was closely monitored on this van from new and could range from 17mpg on a flat out 95 mph dash down the M1 to 30mpg if driven like a sedated pensioner at 49mph all day, so with such varied consumption it was difficult to pinpoint any improvements but I reckon there was a 5% improvement in mpg at the most. On a van that covered 40k pa this meant the chipping cost was recouped in 12-18 months.

Now the downside. At 100k, only 10k after the chip installation, the engine blew a conrod. With only 3-4 months left of the 3 year warranty Merc fitted a replacement engine. They didn't spot the chip and at a later date I got a Merc tech to go looking for it with the computer and he couldn't spot it which is reassuring. After the engine replacement the clutch had to be replaced under warranty as the dual mass flywheel was failing. This is despite the gear changes and clutch action all being computer controlled. The flywheel was then replaced again as a goodwill claim 5-6 months later and when I sold the van with just under 150k on the clock the clutch was starting to judder again.......

Now I don't know if the chip caused the engine failure, the jury is out and it could just be a coincidence. The sprintshift gearbox was renowned for problems and I could just have been a victim of these, the box was dropped from the Merc range soon afterwards but the suspicion is there that it worked perfectly before the chip.

So there you go, I have been there and done that, warts'n'all. I probably wouldn't do it again given how good these engines are to start with. In your case I reckon gearbox woes would be avoided with the proper traditional auto gearbox and I may have just been unlucky with the engine failure. The choice is completely yours.

[gregwho]

Now the downside. At 100k, only 10k after the chip installation, the engine blew a conrod. With only 3-4 months left of the 3 year warranty Merc fitted a replacement engine. They didn't spot the chip and at a later date I got a Merc tech to go looking for it with the computer and he couldn't spot it which is reassuring. After the engine replacement the clutch had to be replaced under warranty as the dual mass flywheel was failing. This is despite the gear changes and clutch action all being computer controlled. The flywheel was then replaced again as a goodwill claim 5-6 months later and when I sold the van with just under 150k on the clock the clutch was starting to judder again.......
earbox and I may have just been unlucky with the engine failure. The choice is completely yours.

Thank you sprintagogo very much for all the info and experience of your chipping!  From reading through everything you wrote, i think i'll leave the chip - although it would be nice to get a bit more mpg, I dont wanna break anything else, and the gains dont seem worth it!!  Totally agree about not wanting to use one of the newer companies selling the chips/boxes - i would much rather trust a company thats been around for a while.  Again, thank you for taking the time to put your thoughts down on it and hopefully this will help anyone else thinking the same as me too.

[gregwho]

others will have to confirm if it posible, but my first step would be to investigate the chance of fitting 16" rims, much wider range of tyres and you could prob buy a set of 16" rims with what you save on the tyres

I'm not entirely savvy when it comes to changing tyres from the original sizes (never done it before!).  I guess i'd have to find a tyre that has a similar height to the ones I've got at the moment, otherwise would I have to do anything with the speedo?  If i drop to the 16's, can I still make the truck higher?  At the moment its a totally stock GC, but as i save my pennies Im slowly making it a bit more off-road worthy, and raising it is one of the things i'd like to do.  I'd love to put some big chunky wheels on 

[sprintagogo]

although it would be nice to get a bit more mpg

As I hinted in my post, the biggest single factor in fuel consumption is the driver. I found the fuel use could be doubled by the enthusiasm of the driver. After this you can look at vehicle maintenance and tyre pressures but if these are ok then there is little you can do and chipping the vehicle will only have a marginal impact on fuel consumption. Bigger tyre could well reduce the MPG so think carefully before fitting bigger sizes.

I'd love to put some big chunky wheels on

OK, sit down and prepare to be schooled.

235/65/17. This gives you all the information you need to compare tyre sizes. 235 is 235mm wide tyre casing (tyre width). 65 is the sidewall height as a percentage of the tyre width (in this case 65% of the 235mm width = 153mm). 17 is the rim size in inches (it is a strange anomaly to quote tyre sizes in a mixture of metric, percentages and imperial measurements but that is the industry standard at present).

once you hit a calculator and do the sums you can see the overall height of your current 235/65/17 tyre.

65%x235 + 17"x25.4mm + 65%x235 = 737mm or 29"

Tyre heights are commonly quoted in inches so this is the measurement you will need to concentrate on when comparing different sizes. I am not sure what the tallest recommended height of tyre is for the WJ but is suspect you can probably fit a 30" or maybe a 31" tyre to an otherwise standard vehicle.

www.bfgoodrichtires.com/specs/all-terrain-t-a-ko/44.html

This chart could be very usefull for you and you can clearly see that a tyre such as the 235/70/16 at 29.1" tall would be a good direct swap for your current tyres if you can source a set of 16" rims (quite plentiful on eBay). Maybe a size like 245/75/16 would give you the chunkier look you are after and at only 30.5" tall might fit without rubbing. You should really avoid going wider than 235 if you can help it as wider and taller is a recipe for rubbing problems.

[Nosebolt]

we also have our own calculator page

[prophet]

Just ordered some General Grabber AT2's for my XJ.. having them fitted this week so am looking forward to an improvement over the 4 mismatched van tyres I've got at the mo. £80 a corner including fitting from Buckley Tyres. Have been going to this tyre place for years and years, they're the best in North Wales!

http://www.buckleytyre.co.uk/

[gregwho]

OK, sit down and prepare to be schooled.

Its been a right fecker of a week at work, so apologies for not having replied.  Thank you for the schooling, it was a great intro to getting some chunkier tyres.  And i'm dead excited about the much bigger choice of tyres on the 16" rims.  So, i guess i have a couple more questions from what you wrote if thats ok.

I am not sure what the tallest recommended height of tyre is for the WJ but is suspect you can probably fit a 30" or maybe a 31" tyre to an otherwise standard vehicle.

Does anyone know what the recommended max height and width is for fitting on a WJ?  Anyone ever fitted 245/75/16's or non-standard sizes without rubbing problems?  I'm worried about parting with the cash for 5 tyres and rims, to find they rub!

if you can source a set of 16" rims (quite plentiful on eBay)

Does the make/model matter of the alloy, or is it only important to make sure it has the same bolt pattern?  Do i need to worry about the hub or anything else?

Maybe a size like 245/75/16 would give you the chunkier look you are after and at only 30.5" tall might fit without rubbing

Loving the look of the BFG's!!  Any other makes/models that are recommended?

Thanks again for all your help

[Grumpy]

Look at the General Grabber AT2's as Prophet has just had fitted. Usually cheaper than BFG's and just as good. Had some on my XJ for the last 2 years, can't rate them highly enough on and off road . Oh, and in 16" as well as I have later Cherokee wheels on mine.

[Bishops Finger]

Had GG AT2s on my GC and they were good but in the end thought bollix and went M/Ts......Kumho 71's ...they are good

[sprintagogo]

Does the make/model matter of the alloy, or is it only important to make sure it has the same bolt pattern?

The best option will be to get the standard Jeep 16" wheel for your vehicle. Ebay usually has a few sets of 4 or 5 wheels listed and I think they commonly sell for around £150-£200 but I haven't been watching them too closely as they won't fit my earlier Cherokee. They are common because everyone wants to go bigger and blingy with 18" or 20" rims 

This is the type of rim you want - http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=110417343923
Typically there is only 2 individual wheels listed at the moment so keep watching to get a feel for how often they come up and how much they sell for.

As the factory size seems to be 245/70/16 I don't think the 245/75/16 size we are discussing will rub as it is only going to be 1/2" closer to the bodywork.

Does anyone know what the recommended max height and width is for fitting on a WJ?  Anyone ever fitted 245/75/16's or non-standard sizes without rubbing problems?  I'm worried about parting with the cash for 5 tyres and rims, to find they rub!

More info on tyre size options rims here -

http://www.wjjeeps.com/wheels.htm

Here's the closest I could find to a definite answer -

http://www.jeepforum.com/forum/f13/wj-tire-size-611079

Go on, do it, you know you want to. 245/75/16 is the way to go.

[gregwho]

They are common because everyone wants to go bigger and blingy with 18" or 20" rims 

I'm well chuffed that other people want to go big and blingy - means theres more choice for us lot to go and play in the mud 

I followed some of the links for the jeepforum, and did find another site with some info on WJ tyre sizes - in case any else wants to check it out its at http://www.geocities.com/jeepfaq/.  Also, stumbled across a ZJ table too (but more with lifts than stock height) at http://www.jeepforum.com/forum/attachments/f13/4798d1107180922-tire-size-v-lift-size-chart-tvlchart.gif.  Hope it helps others.

So that leads onto another important question about chunkier tyres - is it worth lifting my jeep before i get new wheels?!! At the moment, i'm totally green on what lifting involves, and how much it costs?  I'm wondering as im writing this if i should be learning to walk before i learn to run...or say screw it and go for the lift and tyres!  Is it a lot of work to lift a jeep?  I'd be doing it myself (good experience as well as saving a few pennies).  I'm going to trawl through the posts on here in a bit and see what others have done.

As the factory size seems to be 245/70/16 I don't think the 245/75/16 size we are discussing will rub as it is only going to be 1/2" closer to the bodywork.

From the link you posted yesterday and the one above looks like the 245/75/16 has minimal rubbing on the front bumper 

Go on, do it, you know you want to. 245/75/16 is the way to go.

Man, you know me well...

[gregwho]

Had GG AT2s on my GC and they were good but in the end thought bollix and went M/Ts......Kumho 71's ...they are good

If you mean a set of these http://www.kumhotire.com/tire/tire_detail.jsp?prdt_id=52, they're fricking awesome looking 

[Dave69]

what is the clearance between the caliper and the inner wheel rim ? if there isn't alot then you might not be able to fit the 16" rims. might be worth looking at before spending some money. If you can slide your fingers between the caliper and rim easily then you will be ok.



your link goes to a set of slick tyres ?

do you mean
http://www.kumhotire.com/tire/tire_detail.jsp?category_cd=003004000000000

[gregwho]

what is the clearance between the caliper and the inner wheel rim ? if there isn't alot then you might not be able to fit the 16" rims. might be worth looking at before spending some money. If you can slide your fingers between the caliper and rim easily then you will be ok.



your link goes to a set of slick tyres ?

do you mean
http://www.kumhotire.com/tire/tire_detail.jsp?category_cd=003004000000000

I'll definately check the space available, thanks for the tip.  Not sure what happened to the link, I was looking at the ones you posted in your link when I copied it!  Dont think the ones I posted would be too great at going through the mud 

[gregwho]

Just been looking at the AT2's recommended by Prophet and Grumpy, and they look like a great tyre.  Checked the reviews on google and everyone seems to be very happy with them - great on-road manners and gets through most of the off-road stuff, although seems not recommended for serious mud.  Shouldnt be a problem for me, as i'll be taking the off-road part easy to start with!  So looked at the sizes, and they come in a 245/70/17....hmmm im thinking - would these fit my current 17 rims and i can save a bit on not having to buy new wheels?  I cant find out if anyone has fitted them and if they have any rubbing problems.  I'm going to get the tape measure now and see how much space is around my current wheels!  The height difference is about 1.5", so im not sure....

[sprintagogo]

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270471974764

[gregwho]

I finally managed to get my ass outside and measure my wheels, and now i'm really confused - if my tape measure is reading right, my alloys are 18", but the tyres are def the Wrangler OEM 235/65/17.  I measured from the outside of the "rim" of the alloy, through the middle, to the other outside of the "rim".  What did i do wrong?! 

More importantly though, I measured the gap between the tyre and the front bumper, and looks like if i try to put on a 30.5", it will rub on the inside wheelarch cover (not sure of its proper name!), but not the bumper when the wheel is at full lock.  So, think i need to limit myself to a 30" tyre, at the stock height (although the 2" lifts look fairly easy to install).  That was all done with the Jeep sitting in the driveway, so i'm guessing if/when i hit the trails, that gap reduces even more when going over the bumpy stuff.

If i do decide to go with a 2" lift, are there any recommendations on the make or a good place to buy?  Also, should I replace the stock shocks?  From some searching it seems the WJ's are a bit picky about being lifted, and its not recommended to go much more than about 3.5"-4" (found some info here http://www.rocky-road.com/wjtrailblazer.html).

[tim_aka_tim]

I measured from the outside of the "rim" of the alloy, through the middle, to the other outside of the "rim".  What did i do wrong?!  

You just answered your own question. The size of the wheel is the inside diameter - the diameter of the hole in the tyre. What you measured is just the lip that stops the tyre falling off.

[prophet]

General Grabber AT2's are fantastic. With the old knackered tyres, the Jeep felt unstable on roundabouts, I guess the sidewalls on the Generals are much stronger. On tarmac they feel like road tyres and are quiet, even at motorway speeds. On the farm tracks and fields I drive around, they work well wet or dry. I don't really do extreme off roading so can't comment about that, but the tyres feel like they'd go anywhere. I'm pretty sure they come with a 60,000 mile guarentee, but I've been known to make mistakes.

Have a look here: http://www.4x4tyres.com/index.php?show=tyres&rim=R15&profile=225/75

[haslamg]

Hiya

Anyone know what Gregwho finally settled for, in the end?

G.

[scotty]

i've had some Kumho Road Venture AT KL78 on the ml for a few years on her merc ml and have been great in all but deep mud,they were very very surprising in the snow(i could only get them to slip on very hard packed ice/snow once and i really tried ) they handle and look like road tyres and have hardly worn in 20k!! i wasnt convinced they were anything but road tyres untill i decided to show her in doors that they are crap....and it drove through everything! they do them in 17's and as my dad just got a wj i'm going to get him to put them on.


scotty

[gregwho]

Hiya

Anyone know what Gregwho finally settled for, in the end?

G.

Finally went for the Cooper Discoverer ATR's in size 255/65/17 - i'm very happy with them!  They are very quiet on roads (definately quieter than the Wrangler's that were on there before).  Size wise, they look like a much much better fit than the standard 235/65/17 and there is no rubbing on full lock forwards or reverse (standard height suspension).  Grip so far has been tremendous - I had them put on about 2 months ago, and since then we seem to have had all the weather available!  They do well in the snow and ice (even when its packed), great in the wet and excellent in the dry.  Not had the chance to take them through too much off road yet.  Also, the spare tyre well just fits the new size - if i had gone any bigger on the tyre size, it wouldnt have done!

Are you looking to replace your tyres too?  I bought mine from a company called AllTyres, based in Launceston, Cornwall and they did them for £89.00 a corner all in.

Cheers

[haslamg]

Thanks for the reply.

Coopers  - a fine choice.  I've used Discoverer ATs, STs and STTs.  All have performed fantastically.

I'll likely be getting a set of 245/70R16s for my 2000 WJ (fitted to JK wheels, awaiting patiently for them, in the garage).

G.