Tyre size help.....I have read the FAQ

[smellypaddler]

Hi guys,

I have read all the strings for tyre related threads in the FAQ's and am still stuck.

I have a SXPII and want to change the wheels from the standards to 15x7 sunnies and 235/75 x 15 wrangler MTRs.

Does anyone know if these will fit without a body or suspension lift? A few people seem to reckon they'll just go onto a narrow track but I nead to know if they will fit my widetrack.

My sway bar is still on until I get around to lifting the vehicle.

Also, where do I go to get an engineers certificate in Vic and does anyone know how much it would cost just to get the tyre size certified.

[Dangerous Dave]

15x7 sunnies and 235/75 x 15 tyres will fit on a standard height Feroza no worries. I also think that size tyre is the biggest "legal" size you can go too.

[RobF300]

I put on 225x70 on my narrow track, and they look pretty illegal (hangin out about half an inch from guards), but it passed rego... Ive heard everywhere 235s will go too, so give it a shot...

You dont need to engineer for tires this big...

[murcod]

Someone on here has fitted 235/75R15 MTR's to a widetrack ages ago - there's a thread in here somewhere.... Basically the bolts on the mudflaps fouled on full lock IIRC?

225/70R15 are standard fit BTW and shouldn't stick outside the guards unless your rims are the wrong offset. You won't find much in the way of serious off road rubber in that size though.

As for getting it approved try the RTA website for Vic. Here in SA it was a joke what they wanted me to do for approval for that size. 235/70R15 can legally be fitted, but you'll be limited to what brand and pattern tyre you can get (ie none of the good off road tyres come in that size.)

Another option is the BFG Mud Terrain which comes in 215/75R15 which from memory is also a legal fittment. You can increase the overall diameter by up to 15mm over the largest size listed on the tyre placard. Tassie is the one exception to this rule, apparently you can fit anything over there!?

[murcod]

Here's the thread about the MTR's on the wide track:

http://www.outerlimits4x4.com/PHP_Modul ... hlight=mtr

[smellypaddler]

Thanks for all the help. I had already read that thread murcod but I wasn't sure if "Mudpig" was running a widetrack or narrow.

I have the car booked in for the tyres tomorrow so I'll soon find out.

Hell, if they don't fit I can always lift it hey!

Just for everyones info there was a big difference in price for the tyres depending on where you went. The most I got quoted was $312.80 per wheel (235/75x15 MT/R + 15 x 7 rims)

and the cheapest was Beaurepairs in Bentleigh at $249

Another beaurepairs wanted to charge $289. The moral of the story is shop around before you buy.

[murcod]

Tip - don't buy CSA Ranger RV steel rims (they look like sunraysias with a red and blue stripe around the rim edge.)

$249 for the MTR including the rim sounds like an excellent price. Does that include the centre caps, they're normally extra with steel rims?

[smellypaddler]

Yeah I was pretty happy with the price as well. I made him repeat what I had asked for twice just to make sure.

I doubt that it includes centre caps but I'll find out tomorrow once they're on.

Although on this post it has been said that they will be legal size I am sure they are not due to the fact that it is a 37.5mm increase in size.

There is a thread about legal sizes on the FAQ's if anyone needs to check the rules. I have emailed all the engineers on the VASS list and so far have had 1 reply saying: "An engineers certificate can only be issued to state that the whole vehicle is roadworthy and they don't issue certifiate's for ovrsize tyres or body lifts"

If anyone needs the list just go to the stupidly hard to navigate vicroads website and type in VASS in the little search box.

Does anyone know of an engineer in Vic who is 4wd and pocket money friendly as I want to lift my feroza as well?

[murcod]

You're right, they aren't legal.

15mm is the largest legal increase in all states except Tassie. I went through the same process trying to get 235/75R15 approved here in SA. Only one engineer responded and said I'd have to get all sorts of tests done including emissions, drive by noise, slalom, brakes etc etc. Gave up on it as a bad idea.

235/70R15 is spot on the legal limit and what I ended up fitting. Coopers seem to be about the only tyres sold in this size though? And only their A/T and ATR patterns IIRC. They're a very good tyre IMHO, but certainly not something you'd choose for serious off road use.

[murcod]

As far as lifts go are you talking suspesnion or body?

You can do small suspension lifts by fitting new rear springs and won't need it engineered. I think ADR's state something along the lines that you must maintain a certain amount of up vs down travel? Extended shackles are illegal- so if you want to stay legal springs are the only way.

I think Lovells website catalogue has an extract with the blurb from ADRs regarding lifts? Try www.lovells.com.au and open their PDF spring catalogue.

[smellypaddler]

I will probrably be looking at a body lift to start with as I don't have the finances to do a suspension lift at the mo.

It looks pretty cheap to do a body lift. $350 from big balls and a lot of beer and swearing. It'll probrably take me while to get it done though as I have limited mechanical knowledge. If there are any victorians who want to help out I'll be happy to sort them out with beer or some camping gear (I manage a camping store).

Anyway I was looking at the engineers cert for the body lift as I was a bit confused with the ADR's. Some people say that you can do a 50mm body lift without an engineers and yet on the big balls website it says that all body lifts require a certificate.

I moved here from the U.K 4 years ago and have only had the feroza (my frrst 4wd) for the past 12 months so please forgive my dumb questions.

[smellypaddler]

Just got off the phone with a VASS engineer. He said that to run bigger tyres he would have to check the stability of the vehicle. His main concern was that running bigger tyres would decrease the braking capacity by approx 15-20%.

Because of this I would need either my brakes redone or would need new brakes.

His fee for the certificate once the work was done would be around $600.

Has anyone else had any problems with braking capacity when running bigger tyres on their Feroza. He also said that it would handle likea marshmallow and I'd hate it and that I should just run the risk of using the big tyres off road and using my standard rims the rest of the time. He said if you get canaried just put the std's back on.

[smellypaddler]

Thanks for everyones help on this matter.

For those of you thinking about doing the same the 235/75 x 15's went on yesterday and look awesome.

They scrubbed on the bolts connecting the mudguard so they were removed.

ALSO, they scrubbed on the plastic end units to the front bumber assembly. I have removed these and will be cutting them back and sanding them tonight. After reading the FAQ's I will also be removing the sway bar tonight.

Great site you have and I appreciate all the friendly advice.

[murcod]

So what's it like to drive in comparison? Are you getting it engineered?

[rocknferoza]

Just got off the phone with a VASS engineer. He said that to run bigger tyres he would have to check the stability of the vehicle. His main concern was that running bigger tyres would decrease the braking capacity by approx 15-20%.

Because of this I would need either my brakes redone or would need new brakes.

His fee for the certificate once the work was done would be around $600.

Has anyone else had any problems with braking capacity when running bigger tyres on their Feroza. He also said that it would handle likea marshmallow and I'd hate it and that I should just run the risk of using the big tyres off road and using my standard rims the rest of the time. He said if you get canaried just put the std's back on.

I had my feroza engineered a few years ago. I had a 3 link coil conversion fitted and needed 2 get that engineered. The engineer asked about the tyres and I said they were bigger (235/75r15). The only problem he had with the tyres was the speedo being out which is only about 5%.
He passed the lot without any problems and the certificate only cost $220. That is in NSW though.

[smellypaddler]

Feels good but I won't be sqealing around the corners anymore. Braking is definately affected so I have to be mindful of that. I'm pulling off the sway bar when I get home tonight and taking it for a run in the snow next week. I have only done about 10km in them so far so haven't really got to know how they handle.

I won't be getting them engineeered though. I have the old wheels that I'll put on if I get canaried otherwise a bit of rubber on the trim should see me right. (they stick out a bit)

The engineer wanted to test: Stability, rolling resistance, brakes, emissions, speedo etc, etc. Then he started talking about all the things that can go wrong with a body lift. I thought it was just undo the bolts, jack it up and slap n the new blocks + new bolts, watch for stretch and jobs a goodun. Now I am doubting my ability do it.

I'll post pics when I get home tonight if I get the chance.