TR3a Spare wheel wont fit in cubby

[boggie]

Evening all,

 

Quick question for you: Whilst we now run 72 spoke 15" wheels with Fulda Y2000 185/70R15 tyres, Dad and I have retained one of the original 60 spoke wheels with a Kumho 155R15 tyre as a spare wheel. This should be fine, even across the rear diff as the rolling radius is close enough to not be a problem. However it doesn't want to fit in the spare wheel cubby or rather it cannot be easily pushed in through the opening without a good few very hefty kicks to get it in there and once inside it is then a bugger to get back out.

 

We have a workaround in that if we deflate the tyre it slides in easily but that defeats the object so for now I have borrowed the portable air compressor out of my car (which has a spare that needs to be inflated) but we need a more sensible solution. Any suggestions please?

 

Thanks,

Ian

Edited August 31, 2014 by boggie

[Motorsport Mickey]

A problem many users have, deflated spare often is the way most go, however a cautionary word. If you fit two different size tyres onto the same axle you are leaving yourself open to prosecution.

The vehicles were never type approved either with or without two different wheels/tyres and so using two differing sizes contravenes the catchall which is "Construction and Use" legislation. C&U states that the wheels and tyres used across an axle or on one "end " of a vehicle must be the same size and tyre configuration (I'm paraphrasing here, Alec will be along in a minute with the correct passage quoted and highlighted).

 

Certain high performance cars have differing size wheels and tyre configurations between their front and rear axles, this means when carrying one size spare wheel when they use it at one end (the wrong one) they will be contravening Construction and Use legislation...however they have a derogation (get out of jail card). The wheel and tyre supplied by the manufacturer is normally of a higher specification as regards rating or ply and as such the police turn a "blind eye" to it's use. An owner using a smaller tyre or wheel as a "space saver" is in danger that it won't be accepted by the police, only manufacturers can designate a non standard supplied wheel or tyre as a space saver, not a car owner or even your local or national tyre company.

I understand If you use a smaller tyre to get you out of trouble on the road, however be aware that if the law spots you it may lead to other problems.

 

Mick Richards

Edited August 31, 2014 by Motorsport Mickey

[boggie]

Thanks but I am pretty sure this is not the case. My daily driver car rear tyres are 305 wide, the 'spare' is 145, IE less than half the width of the rears (but the rolling radius is the same). NB There is a sticker on the spare to say I should not exceed 80KMH.

 

I got a puncture last year but as the tyre fitter had tightened the nuts with an air wrench I could not get the nuts off with the standard brace. An RAC guy helped me out with his extendible bar. I asked him re the width difference and he said the rules allow for temporary use of space-saver spare wheels in an emergency, IE to get you home as long as you do not exceed the maximum speed allowance indicated

 

Ian

Edited August 31, 2014 by boggie

[boggie]

Is anyone able to recommend a narrower profile tyre that does fit into the TR3a spare wheel well, inflated?

 

Thanks

[Alec Pringle]

Hi Mick, Ian,

 

we've been through this one on Forum before, repeatedly.

 

It is not possible to legally drive any TR on a 'space saver' of any description. End of. Period. Finito.

 

See section C

 

http://www.legislation.gov.uk/uksi/1986/1078/made

 

and follow on from the reference to ECE 64

 

http://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/r064e.pdf

 

Sorry, but I can't be bothered to highlight the most relevant paras - in any case you really need to read through to understand the logic.

 

The RAC man was talking bollocks if he was referring specifically to our cars . . . . nothing new there, then.

 

Caveat emptor - and bear in mind just how many points can gross up if the Bobbies throw the book at you. Not to mention potential bankruptcy if you smack some poor innocent sod whilst driving uninsured on your ad hoc space saver . . . .

 

Cheers

 

Alec

Edited August 31, 2014 by Alec Pringle

[Motorsport Mickey]

Hi Ian,

 

You seem to have missed reading the line on my post which says "only the car manufacturer can designate a non standard wheel or tyre as a space saver ".

 

Nobodies arguing that a car that has a space saver supplied by the said car manufacturer is legal for use IT HAS A DEROGATION, ie the authorities have been notified that the car may have at some time differing wheel or tyre sizes fitted across an axle, this wheel or tyre is normally of a higher rating (regarding ply or whatever) and it's use on that particular car and for that purpose has been approved . But only that car manufacturer can designate a wheel or tyre as a space saver for that car, car owners, tyre companies, your insurance company and anybody else cannot.

The C&U regulations do not allow the fitting of Radial tyres and crossply tyres on the same axle, almost everybody is aware of that and uses matched pairs (even the RAC !), but because the regs allow the fitting of a cars manufacturer mismatched wheels and tyres under certain defined circumstances (ie the manufacturer says it's a space saver and its ok) the assumption is that somehow the law is changed and an owner fitting a skinny wheel and tyre to any car (even one which is actually of a size and capacity which in a complete set is ok) meets the regulations...it doesn't.

 

As I said in my previous post I understand why some owners may decide the risk is worth it, if you do a search on the forum under Space saver you'll find ample previous discussion on the subject, after reading you may still think that the risk is worth it, it's up to you and how you think any court case might go.

 

Mick Richards

Edited September 1, 2014 by Motorsport Mickey

[Rodbr]

Boggie,

At the risk of repeating what ever has been said on the subject I would be intrigued to know what you will do with your now deflated 72 spoke and flat or trashed tyre. Have you tried fitting a deflated 185 and wheel into the spare hatch? Either your passenger is going to have to wear it or your luggage will have to go.

185 x 15 are too wide for a side screen TR. When it lets go unexpectedly I doubt you will catch it time. There is much written about "overtyring" a car just a bad idea!!!!!!!!!!!!!!!!!!!!!!!!

 

You have two alternatives

1. Sell the 72 spoke to a TR6 owner and return to 60 spoke with a max width of 165. Fitting partially deflated spare in the hatch around 12 -15 psi should fit. You may need to jack the floor and also empty the boot to get it out.

2. Cut the boot floor and make a hatch to fit a 72 with your chosen same pattern tyre.

 

Choices:

Go to jail,

Go to jail,

Go to jail.

Drive without insurance, - go to jail. Insurance companies will resist like crazy to avoid paying out and if you serve your head on a platter they will be delighted. Expert witness "Yes, your honour, the Tr3a never had 185x 15 tyres as an option and we were not notified of the change or we would have advised against or loaded the premium. Yes the over size tyres contributed to the accident.

Go to jail as you have just been found guilty of driving without insurance.

Sell your assets, keep them readily available to pay compensation to the other party or parties.

Drive without a spare and carry a can of foam inflate gunge.

 

Don't get me wrong a side screen car would look fabulous with a nice set of Borranis but would I drive it, not a chance.

 

Hopefully you get my drift, you would run a great risk, potentially loose your house, hurt yourself or someone else. The police would look more favourably on a partially deflated spare than what you propose. Please rethink this bad idea or cut a hole in the boot floor and fit the correct spare in to hole at worst.

 

Been there, done that, and even fitting an XWX as a spare to XAS running tyres has been advised as a bad idea.

 

Finally a word of advice- no matter how much you rephrase the question, repeat anecdotes, the outcome will always be the same as well advised by the very people you asked for advice in the first place. Perhaps the real issue is that you spent substantial cash on the 72's even listened to bad advice. You are in good company as at one time or another we have all been there and done that. Except it, move on and take the advice you have been freely given as it's a hell of a lot cheaper than a lawyer.

Rgds

Rod

Edited September 1, 2014 by Rodbr

[boggie]

Hi Alec,

 

Thanks for the links, I will have a read through at lunch. You should get to bed earlier; lack of sleep seems to make you intolerant of lesser mortals in need of advice...

 

The RAC man was referring to my daily driver, not the TR. He said it was perfectly legal to drive on the space saver so I had assumed that this situation was general, not limited to individual manufacturers and models. The AA website provides similar advice, again manufacturer/model agnostic with no specific mention of the 'get you home' exception not being applicable to TRs or other cars over a certain age:

 

http://www.theaa.com/motoring_advice/safety/non-standard-spare-wheels.html

 

Having said that: Obviously I wasn't looking for a space saver specific to TR, apart from the fact that the car is so old it has splined hubs. I was just after a little help from the more experienced members, such as yourself, who may be aware of a tyre type/manufacturer that will actually fit, fully inflated, into the wheel well. I can't imagine Triumph built a car whose wheel cubby was not big enough. I therefore assumed that the 155 Kumho tyres were to blame so needed advice on what I should replace it with.

 

All this conflicting ,advice' re different tyre sizes us very frustrating. When I get a spare minute I am going to drop in on the local Police station as they have a Traffic squad and find out the Police view. After all; regardless of what anyone says, in a situation where a tyre goes pop and I pull out a tyre 1.2" narrower spare to get me out of trouble I want to know if I stand to get three penalty points in the meantime.

 

 

Thanks again,

Ian

[boggie]

Thanks Mick, i did miss that. Makes sense.

 

Rod; the insurance company are aware of the upgraded wheels/tyres and did not change the premium. The 72s with 185s have transformed the way the car handles. I can no longer feel the wheels moving around under side loading, those extra 12 spokes presumably make the wheels stiffer. Also the lower profile tyres seem to suit the R&P steering better as feel at the wheel is much improved and the vagaries of steering gone. I appreciate your point on the risks of over-size tyres letting go at higher speeds so I will take it steady to see how she feels approaching the limit, perhaps a track day with the 60s and 72s to compare is the way to go.

[RogerH]

Hi Ian,

what have you started !!

When you spoke to your insurer did you mention a narrower (space saver) tyre. I can't imagine for one minute that they would be as happy as Larry.

What width rims do you have - this may be the problem regarding fitting into the cubby hole. A 155 tyre should fit easily on a 4.5 rim.

 

Using a wide tyre as stated above may improve straightline driving but could give interesting problems when cornering in the dry. One moment grip next moment no grip.

Whereas a narrower tyre tends to lose grip gradually.

 

60 spoke rims are more than strong enough for most tyres - honest.

 

A boot rack may give an answer to where to keep the spare and or dead tyre.

 

Good luck in sorting your problem

 

Roger

[boggie]

Thanks Roger,

 

Not sure what width our 60 spokes are, they came with the car and I know they have been on it since at least 1970. I will check next time I am at my Dad's. Do you know if the info is stamped on the wheel or do I need to measure it? If so do I measure the outer rim width or to I have to remove the tyre to measure across the inner lip?

 

I know what you mean re grip boundaries of larger tyres. My daily car has massive tyres and lots of clever electronic control of all three diffs and balancing dynamic weight using application of individual brakes etc resulting in prodigious levels of grip. However, all this electronic wizardry means that if you ever explore the limit, all four tyres let go at the same time when physics takes over. Given the levels of grip being achieved just prior to the limit being exceeded you will presumably be travelling fairly briskly so it goes very wrong very fast and with little warning. So I totally agree your point re narrower tyres; there is much to be said for low grip limits that are easy to predict.

 

Back to my original request re a tyre/wheel combination narrow enough to fit into the cubby. Interestingly I just performed a search as Alec suggested and found a topic from someone in a similar situation in which Alec posted, advocating the use of the smaller 48 spoke wheel to fit in the wheel well. Unfortunately he failed to include tyre details...

 

Cheers,

Ian

[Alec Pringle]

Hi Ian,

 

155/80 x 15 on a 48 spoke will fit . . . . . and should be marked with the relevant instruction for emergency use only, 50mph maximum . . . .

 

Anything wider, tyre wise, will need to be deflated or it's a struggle to fit.

 

Personally I wouldn't worry too much about using the narrower tyre for local journeys, but it's a pain for longer distance touring.

 

Personal risk assessment, and your own choice once you have adequate information from which to make an informed decision.

 

One solution is a spare bootlid with a full size spare mounted thereon, fibreglass bootlids are not expensive. For long haul you then have a pukka spare and extra luggage space . . . . .

 

If you do have to use a narrower fitment in emergency, better if it's on the rear than the front - in my opinion.

 

As for 185/70x15 on a sidescreen car . . . . wider than my taste, but I can't see what the problem is that Rod refers to. Over tyring is more of an issue with IRS than live axle cars. at least in my experience.

 

Cheers

 

Alec

[Rodbr]

Ian,

The fact that you make the statement about the car being so old it has splined hubs speaks volumes. Sorry but what does that have to do with age given that a Triumph Stag can be fitted with spilned hub wire wheels. Do you understand that wheels have an offset and that could be why a 155 on a 72 spoke wheel wont fit. Have you got the wheel the right way up to fit the hole, It goes inside up so the outer section fits into the slot.

Not sure why you say "After all; regardless of what anyone says", why bother asking the question if you don't like the answers given. Please advise when and where you do your "track day" as I want to avoid it.

Given the collective knowledge base of 40 + years driving and maintaining classic cars of the average owners you could be foregiven for thinking that their advice would carry some weight.

 

 

This has nothing to do with intolerence of "lesser" mortals but you asked a question, were given answers and as much information as possible so that you are well informed. Please also tell us which Insurance advised you that a space saver (o.e narrow wheel) was OK on a TR.

I'm done as can't be bothered any more.

[McMuttley]

Ian, aside from what the insurance say (ensure its recorded on your schedule) (and note a third party in an accident doesnt have to agree with your insurer); you say the 60 spokes were put on circa 1970. Does this mean that the car was last upgraded nearly 45 years ago?

 

If you drive to what you think a 185 can handle (or far less) you are exerting a significantly greater load strain through the hub/brake, axle, suspension, diff, basically all of the drive train components. Thats a vey long list of fairly important components at a greater risk of failure due to additional strain.

 

If your axle broke and you veered into me whether i am walking or driving, your insurance wouldnt get you off the hook if I spot a huge wheel tyre combo hanging off a 50 year old bit of thin rusty steel. As others have said, it would be easy to say in court that these are well beyond the design parameters.

 

Apart from risking having the replace a lot of the car to handle the pressure, we sadly live in a litigous world.

 

Put the bling in the classifieds and get 60's /165 max

[mleadbeater]

Ian

 

To answer a few questions you have

 

a 48 spoker with a 165 80 15's will fit through the aperture, this is what I shall use as a spare to my 60 spoke wheels fitted with this size of tyre.

 

My car has been modified as suggested, it has has an open boot floor to the wheel well, I will make a ply floor with a central screw to clamp the wheel in position, I much prefer this to struggling with the rear cover, and I can keep tools inside the spare.

 

Part-inflated tyre to me is not a solution, as it wont squash much unless totally deflated and not in contact with the rim ( as it would be newly fitted but not inflated.

 

Regarding rim width, its stamped into the inside of the rim, visible with the wheel removed, and generally, 48 spokes are 4 1/2", 60 spokes 5 1/2", 72 spokes 6 1/2", total width to outside of the rim, which you can measure with two straight-edges across the rim.

 

Hope this helps

Mike

Edited September 1, 2014 by mleadbeater

[boggie]

Wow Rod,

 

I am not sure why you are so hostile to me, perhaps there are issues I am unaware of? I appreciate any input but initially I received quite a negative response that took the thread away from my simple request for information on what tyres will fit in the spare wheel well, nothing more...

 

Yes I undersatand offset etc. I have built sucessfull rally cars, a Lotus seven replica from scratch, restored three classic cars from the ground up and a number of motorbikes too so, whilst no expert, I do know a little. I also have the wheel in the correct orientation for pushing it into the cubby (altgough it is obvious which way it should be)

 

I appreciate some people on forums can be quick to misinterpret, be rude and even aggressive from behind the safety and anonymity of public internet forums. What ever it was I did or said you to cause such a response I have no idea but apologise for your misunderstanding as I meant no malice. I imagine you would quite like me if we met, most people do.

 

Ian

Edited September 1, 2014 by boggie

[boggie]

Thanks Alex and Mike, very helpful and exactly what I was after. So now the search begins for a good 48 spoke wheel onto which I will fit a 155R16 tyre (only to get me home if the Tyreweld does not work)

 

McMutley: our car has been the subject of a six year, ground-up restoration. My Dad is a retired aircraft engineer, whose hobby is building steam traction engines in his fully equipped metal workshop and i am an engineer and amateur car builder / restorer with 30 years experience. This car is better than new now, shut lines are all perfect, every component has either been replaced, rebuilt or upgraded to our rather pedantic level of engineering. She doesn't even drop oil (for now). So please don't make assumptions and don't fret. I promise you are a safe...

 

Ian

Edited September 1, 2014 by boggie

[Rodbr]

Ian,

To answer you I have no hostility towards you or anyone else for that matter. If you have done all you say then I am a bit surprised you ask the question. You would be surprised how many people do try to put a wheel the wrong way up.

I presume that you mean a 155 x 15 just remember that you will need the same type of tyre as the others fitted, don't mix tyres on the same axle?

I honestly feel that using oversize tyres is wrong and if they are on a 4.5" rim I rightly or wrongly feel equally strong that it is a bad idea. What do I know I've only beed working and rebuild cars fast and slow for nearly 50 years.

This subject has been discussed at length before on the forum and a search would probably turn up the information supplied.

 

As a young man I lost a dear friend due to this very issue so I try to advise accordingly. There is always the possibility that you can take out the sidewall of the tyre on the lip of the wing, do this at speed and the result is kind of lively, wide tyres and no lip roll is a recipe for an ohh nasty.

 

The following is from Revington website

72 spoke wire wheel 5 1/2" J x 15" painted with chromed stainless steel spokes. This wheel is the standard TR6 shape and style.

The three main sizes of road wheel used on the TR range from TR2 to TR6 are 4" (TR2-3), 4½" (TR3A-5) and 5-½" (TR6)
It is not uncommon and certainly when one of our suspension packages has been fitted, highly desirable, to fit the wider and stronger 5½" wheels.

However, there can sometimes be a clearance issue on earlier cars, particularly TR2-3A where it in not uncommon to find the body far from central on the chassis, leaving lots of clearance (especially at the back) one side and a possible interference in bump (when the wheel goes up into the wheelarch), between the tyre and the lip of the wing. For this reason it is important to understand that the extra width of the wider two of the three wheels is not spaced equally about the centre line of the inner hub. This variation is identified by measuring the offset which is explained as follows.

The offset (sometimes called backspace) is the measurement from the inner face of the hub (where the spokes attach and not where the splined hub attaches) and the inner lip of the rim (not the face where the tyre sits but the turned over edge). This is not ideal as the edges being used to measure are not machines and are sometimes rough. However, this method is practical for measuring at home without the benefit of complex measuring instruments. The table below shows how much of the additional width is added to the inboard and outboard for the two wider sizes.

WW450P/C 4" wide. Back space 83mm
WW452P/C 4½" wide. Back space 87mm. Extra 4mm inboard, extra 9mm outboard
WW4572P/C 5½" wide. Back space 95.5mm. Extra 12.5mm inboard, extra 25.5mm outboard

[boggie]

Thanks Rod,

 

Glad we cleared that up! You had me worried there...

 

The 185s are on 72 spoke 5.5J and I have a tool that rolls the return lip on the arches to provide the necessary clearance. We found the body is off centre on the chassis so it turned out only one side needed rolling after testing full travel on both sides but I rolled both anyway. I have created a pair of custom rear wing stays to address the issue of symmetry so now the two rear wheels sit the same in their respective arches, at least when viewed from behind. This also serves to slightly widen the rear of the car and I have to say the subtle change of this combined with the wider tyres makes the car look more purposeful without going too far.

 

I did a lot of research before deciding to do this and I appreciate it is not to everybody's taste (especially the purists) but i like it and there are many owners who made the change and are happy with it. I fully appreciate the issue of mixing tyre size across axels but my POV is that if I get a flat, whether it be on the Motorway or a deserted country lane, I would rather use a slightly undersize tyre to get me safely home or to somewhere I can get it fixed than leave it there whilst I get help. Admittedly it is my 'fault' in opting for a tyre that doesn't fit in the cubby but neither do the 155s on 60 spokes...

 

I have to say Alec's idea of carrying a full sized spare on the boot deserves some thought. I had considered it but not sure I like the look. However, I have a spare steel boot lid that only needs a new corner welding in and I still have a couple of litres Primrose celly left. I even have an old set of hubs and spinners so could potentially attach the wheel to the boot with that, rather than straps...

 

Ian

[Geko]

What a put-off. Deflate and carry a hand-pump so you can help your fellow bikers with a flat

[boggie]

Agreed, I don't like the idea of a spare on the boot lid, a bit too Landrover for my liking. However, as a temporary solution for a long trip it might be a good thing: It would mean I have 5 identical tyres and I can probably stash about 20 bottles of good wine in the spare wheel well.... Alec, you might be onto something here

[Alec Pringle]

Hi Ian,

 

If the car is pre-60K it can be jolly difficult to wedge in a 165, but it should just fit on a 4" 48 spoke wire . . . . . with some shoving and an old seat belt around the tread to pull it out again. Post-rebuild, it isn't always quite so easy, just a whisker of depth lost and it won't go through the aperture. Post-60K cars have that wee bit more room.

 

It really is not a good idea to wedge in a semi-deflated tyre, not if it can be avoided, too likely to result in carcass stress damage. You realise that when the tread rips off at 50 . . . .

 

Bear in mind that 185/70x15 is not a size that the average tyre bay keeps on the shelf, nor is the inner tube. If one is irrepairably damaged on holiday that'll be a two day wait in this country for a replacement, and in France that could be 5 days. Not always convenient !

 

The extra luggage space can make all the difference as to whether or not SWMBO takes to the idea of a TR tour . . . .

 

Cheers

 

Alec

[Don H.]

I have a 155/80-15 Vredestein Sprint Classic on a 4" 48-spoke wheel as my spare, and it JUST fits in the compartment on my post 60k shell. My road tires and wheels are 165/80-15 Vredesteins on 4.5" 60 spoke.

 

The rolling diameters are close enough that I'm not worried about limited use of the spare. I'd rather have an inflated tire and 8 mm sidewall height seems a reasonable tradeoff.

[Motorsport Mickey]

I don't think the technical small variation in rolling diameter is an issue Don, over here our vehicle "bibles" for construction of all vehicles say no different size wheels or tyres on the same axle, if involved in an accident "the law" and VOSA (Vehicle enforcement agency) will jump all over the driver, and then look out for your insurer heading for the hills.

 

Mick Richards

[mleadbeater]

Ian,

 

just collected my wheels fitted with Toyo 165 80 15's on 60 and 72 spoke wheels, both of which go thro the spare wheel door.

 

I have a spare 48 spoke wheel if you need one, let me know by PM.

 

Cheers

 

Mike