17' Series First post! 185R14 to 245/70R16!!

[TassieDowls]

Hi everyone! Thanks for having me on the forum. I’ve learnt a ton already. This is my first post and I hope it’s not a question that has been asked a lot! (I’ve researched as much as I can)
I have a 2012 Jayco Expanda Tourer which we just purchased a week ago. I was really hoping to get an Outback but had to stick to a $30k ish budget. My question is - it currently has 185R14 (piddly things) 45mm axles and 10” brakes. I have some 245/70/16 Outback wheels & tyres I would like to install. From my research to make these fit I will need to undersling the axles to under the leaf suspension, upgrade axles to 50mm and install 12” brakes. Has anyone done this before and could offer any advice on their experience??? Thanks in advance! Ash. PS- the reason I am wanting to do the upgrade is that was anticipate going to some isolated locations, nothing hectic but the clearance would be very helpful. We also have a large 4WD.

 

[Drover]

Welcome to the mob, if you look around there is a thread on putting the axle under the spring, I think you may only be able to go to 15" rims and maybe 225 or 235 due to room available, easy way to check is measure from bead of rim to inner side of hub flange on rim then measure from chassis rail to outer edge of hub, the rim should be at least 25mm less than the hub measure, depends on the off set for that rim though and the width of the wheel arch, do the axle then sort the wheel .................. Rolling the axle to under the spring will give you 80mm thats if you have a straight axle, you haven't said what size you rig is, if its an off set axle I would chuck it and get a 50mm straight job anyway but as for rim/tyres get the axle then do a measure, I can see no real need to go from 10" to 12" brakes as the braking area is the same on both actually.... My rig is 22 ft and 10" brakes with 265 75 16's ..............

Don't go using muddies or other off road tyres on van, best tyre is a mild ATR tread, better all round for a lazy wheel..... wears longer and better tracking.

 

[TassieDowls]

Thanks @Drover ! I appreciate your advice! I have a 17.56 and it has offset axle (overlay). I picked up some 16” rims from a 2012 outback which has 245/70/16 AT LT tyres from the caravan they came off, so these are what I’d like to try fit. Only reason I say 12” brakes as that’s what ALKO specify with 16” rims and 50mm axle from what I could see on their website…….would love to not have to replace the brakes!
….Thanks for the advice on the axles, I think I’ll go a straight axle as you say and do away with the overlay axle. If I get a straight axle and undersling the axle I should gain a lot more height as well?? Thanks again for your reply. Photo of my expanda attached

 

[TassieDowls]

@Drover also mate I did dummy fit the 245/70/16 wheels and they fit perfectly width and offset wise, I just need at least 100mm clearance from factory to get the clearance from the top of the wheel well especially for when going over bumps etc…

 

[Drover]

I can see you have a bum dragger there for sure, you can source a 50mm axle from any trailer shop for a reasonable price of course new U bolts and fish plate, make sure you measure the width and height of your spring pack so you get the correct size, I like using HT washers and nyloc nuts on the U bolts.

Its also an ideal time to check the spring shackle bolts, if they aren't greasable then now is the time to fit greasable bolts, far better in the long run....
Before you pull stuff off measure and score mark the position of the axle as you will want to fit the new one in the same alighnment even though under the spring, so need to carefully transcribe the mark, of course 2 x 10mm spacers for each axle as well.

Check the bearings on the current set up so you get the right axle for the bearings fitted, 2 types of bearings are available usually, the ideal way and really the only reliable way to check is to pull a hub off and have a look, take down the bearing number, if the inner and outer bearings are the same size then its a parrellel bearing so the inner and outer will be the same size otherwise the outer will be bigger than the inner...... its not a biggy to pull off the innner seal to check the bearing number, in fact take them to a bearing shop and you will get the right bearing first time, a good set of Jap bearings inner, outer and seal is only about $30 from a bearing shop compared to $50 or more from a RV shop.... so popping a seal and buying a spare set along with a new seal isn't big $$$ but saves a lot of pain in the end... and don't forget to measure the width of the axle needed usually either from tip to tip or from the face of the hub, check with the supplier you choose, get it wrong and they often won't exchange...

If your axle stub is located inline with the spring pack a straight axle under the spring pack will add 50mm to your height, new wheels will add a little bit more use this calculator and it will give you the difference in wheel sizes.... https://www.wheel-size.com/calc/

Here's a thread I did for underslinging an axle, should be close enough for starting from scratch with a straight axle I would think........... https://expandasdownunder.com/threads/underslinging-a-straight-axle.10987/

You will certainly need decent jake stands placed in the proper spots or you could bend things and never do any wheel adjusting with the jockey wheel fitted, very dangerous.

 

[TassieDowls]

Thanks @Drover this is awesome insight and advice mate! all notes take. I have a friend with a hoist so may even talk him into giving me a hand! I appreciate you taking the time to write back.