Spare tyre - shoot down my logic!?

[WHSE]

I'm still pondering on the best thing to do with having staggered 20 inch wheels and dealing with a puncture....(same sized tyres, but 8.5j front and 10j rear).

If the puncture is on the rear then the spare can be used but the dead wheel/tyre will have to be carried inside the vehicle to then be repaired/replaced. You then have to hope the nearby tyre businesses have that brand/size in stock otherwise you risk a mismatched brand on the same axle.You also have to carry the original bolts with you since the new wheels use a different bolt type to the factory spare. You also have to carry the jack.

If it's the front then you can't use the spare without it being detrimental to the diff. You can't swap a rear to the front because they are staggered.

So in that case you use tyre foam but really you should be heading fairly quickly to a nearby tyres business and again you risk a mismatched tyre.

In both cases you could try a mobile repair but it may be unrepairable, or even so bad that the foam isn't an option.

This leaves me thinking that in the absence of a full sized spare and tyre that would be usable front and back, would it be ridiculous (and physically possible) to carry just a spare tyre in the carrier which is a match for your other 4? You then can use foam for a minor puncture and then drive somewhere to swap it for you, or use a mobile service to do the same.

This then guarantees you end up with the same tyre across the axle and you don't have to carry a wheel and bolts just for one specific scenario. I'm guessing you can squeeze a 20 inch tyre into the spare carrier but you would have to mod it if it was a 20 inch wheel and tyre fitted?

Now tell me I'm talking a load of *&£^ before I order myself a tyre!

Thanks people

 

[huw169]

Lol. That’s what a differential does, it allows two wheels on the same axel to rotate at differing speeds. Rear doesn’t matter if it’s not 4 motion.
Foam kills the tyre and can it be repaired.
I run staggered and just have standard spare. I think you don’t have enough other genuine stuff in your life to worry about.

 

[WHSE]

I think there's probably a lot of people on here that have some pretty tough genuine things going on in their lives which worry them a lot, but they interact on here to take their mind of it or to focus on something they enjoy, i.e. their van.

Appreciate your thoughts on the diff. The design of the components within it are there to handle transient wheel slip and difference in wheel speed when turning corners. They aren't designed to handle two wheels and tyres of different sizes rotating at different speeds for many miles. On a T32 the nearest recommended 20 inch tyre still gives you approximately 2cm difference in diameter, or 9cm in circumference versus the spare, that's a big difference from one to the other which the diff was never designed to handle. I would assume it would get very hot. Likely it wouldn't fail immediately but heat tends to shorten the lifespan of mechanical components (and the lubricant) so it's not something I'd want to risk.

Appreciate it might be a level of detail/risk you're not worried about so don't take this as me saying your view is wrong, more that I'm of the view it's enough of an issue that I'd want an alternative way of dealing with it and not using the original spare.

 

[Paynewright]

Every time you turn slightly, one front wheel is travelling further that the other so the diff will be moving constantly to compensate for this. It is only when you are travelling straight is the diff still. Even then I wonder if road camber means the diff isnt perfectly still.

I wouldn’t be concerned about fitting a (slightly) smaller wheel in an emergency.

Have you looked at going taller on the tyre profile of a 17” wheel to get the same rolling radius, and drive as if it were a space saver?

Willtheyfit is a good website for wheel/tyre comparisons.

 

[WHSE]

That's a great idea, upsize the spare tyre so its radius is closer to the new wheels. Could probably squeeze that in the carrier under the van if it was deflated and keep a compressor onboard if you ever need to use it. Thanks @Paynewright

 

[Rarebit]

It's quite common for space savers to be a smaller diameter than the running wheels, so running a smaller diameter spare for a short distance can't be too bad for the diff.

 

[scotti]

I was going to post a similar question as only really just remembered that the new unused Devonports in my garage are a different diameter to my Vossens/tyres - hence the spare is also. I have a T32 4 motion, and am concerned not only about any diffs but the connecting parts between the front and back. I love the idea about trying to increase the spare profile and am interested to know if any other have done the same and whether this is a clean safe option for the short term, until main tyre is fixed/replaced. Thanks

 

[sdlnet]

I wont mention that the bolts on your current wheels might be different to those required by the spare lol

 

[scotti]

x

I wont mention that the bolts on your current wheels might be different to those required by the spare lol

This is a mega top tip. Thanks.

The added bolts will be in the van today.

 

[Bigsidavies]

I’ve got the original 17” spare with staggered 20’s and in the UK I’d just get recovery to turn up.
When I’m abroad I put my Devonports back on just to make life easy, but the idea of putting a bigger tyre on the spare looks like a great idea.
Has anyone done it and can confirm that you can fit a larger tyre in the holder?

 

[WHSE]

Yep, after posting this I managed to get a larger tyre onto the spare which is much closer in diameter to my 20s. I also carry 5 original bolts. I can now run the spare without it throwing a load of warning lights for ABS etc.

 

[Drive Wayne]

Yep, after posting this I managed to get a larger tyre onto the spare which is much closer in diameter to my 20s. I also carry 5 original bolts. I can now run the spare without it throwing a load of warning lights for ABS etc.

May I ask what size spare tyre you put on an R17? I think this is my future! Currently running with a spare tin of goop! Anyone near the Isle of Walsall with a 17 wheel for sale?

 

[T6Paul]

Personally I’d sell the over sized wheels and get 4 wheels and tyres that match the spare. Problem solved!

 

[Drive Wayne]

Yes but they look lovely, and Linden from Renaissance Rims near Merry Hell is a lovely guy to buy another wheel from when the need arises AGAIN! Plus the spare that I extracted from under the van was not in a healthy state, like a rusty thing on rust tablets...

 

[WHSE]

May I ask what size spare tyre you put on an R17? I think this is my future! Currently running with a spare tin of goop! Anyone near the Isle of Walsall with a 17 wheel for sale?

I keep meaning to get under and have a look but the weather is shocking! I'll dig the invoice out this weekend and see what it was.

 

[Drive Wayne]

I keep meaning to get under and have a look but the weather is shocking! I'll dig the invoice out this weekend and see what it was.

Thank you @WHSE , the invoice is the sensible thing! I will obviously be eternally grateful!

 

[WHSE]

Thank you @WHSE , the invoice is the sensible thing! I will obviously be eternally grateful!

Sorry for the slow reply @Drive Wayne !

I've found the invoice and it was a 215/65/17 that went on, so 5% bigger than the standard tyres the van came on and much closer in overall circumference to my 265/40/20s.

I reckon you may be able to squeeze something slightly bigger than that in if you needed to and it was deflated (i.e. you carry a pump on board), or I have heard of modded brackets for the spare cradle which allow a bigger wheel, but the 215/65/17 is ideal for me.

 

[Drive Wayne]

Sorry for the slow reply @Drive Wayne !

I've found the invoice and it was a 215/65/17 that went on, so 5% bigger than the standard tyres the van came on and much closer in overall circumference to my 265/40/20s.

I reckon you may be able to squeeze something slightly bigger than that in if you needed to and it was deflated (i.e. you carry a pump on board), or I have heard of modded brackets for the spare cradle which allow a bigger wheel, but the 215/65/17 is ideal for me.

Top man @WHSE think a 17 with that tyre is a no real grief option!
Thank you for coming back to me

 

[scotti]

225/65/17 looks the closet @ circumference 2275.5mm
215/65/17 is pretty close @ circumference 2234.6mm

265/40/20 = 2261.9mm

Does the 215 fit in the cage OK?

 

[WHSE]

225/65/17 looks the closet @ circumference 2275.5mm
215/65/17 is pretty close @ circumference 2234.6mm

265/40/20 = 2261.9mm

Does the 215 fit in the cage OK?

Yep, fits fine, no issues.