Weight Saving / Spare Tyre...

[RobBentley]

Hi All.

I've been thinking about performance a bit of late. The W8 has pretty much reached what is possible without spending stupid amounts. Its been remapped, rev limit increased ever so slightly, the TCU settings have been tinkered with, 155mph limiter removed, the exhaust has been done and its got a K&N filter.

Now.. speaking to a mate of mine at the weekend who has an RX-8, we got talking about weight saving. First thing I notice about the RX-8, no spare tyre!! Not even a place to put one.

Is this a good idea really? He's got two cans of the squirt in get you home stuff... is this any good? Does it actually work?

I'm considering ditching my heavy pram-wheel spare...

Additionally, any other tips as to what could be changed on the B5.5 shape Passat (W8 saloon) to weight save... ? I doubt the performance companies make such things as carbon fibre boots & bonets!!


Regards,

 

[HDi fun]

Do a web search for a product call Ultra Seal. It goes into the tyre when it's fitted and, well, read for yourself.

I have used this and it DOES work extremely well.

The only problem is that if you need to rebalance 1/2 way through the tyre's life it takes ages.

 

[BAD63R]

The other downside is, that if you were to get a really good puncture, i.e. a screw through the rubber that comes back out again, you wont be able to get the puncture repaired as the wall inside the tire gets covered with the tire seal stuff. So yes, great stuff for an emercency but not if you still have some good tread on the tire as it can basically mean you have wasited one tire.

Good to have a can on board but dont use it as a permenent fix

 

[HDi fun]

The other downside is, that if you were to get a really good puncture, i.e. a screw through the rubber that comes back out again, you wont be able to get the puncture repaired as the wall inside the tire gets covered with the tire seal stuff. So yes, great stuff for an emercency but not if you still have some good tread on the tire as it can basically mean you have wasited one tire.

Good to have a can on board but dont use it as a permenent fix

It should seal a nail or tyre hole. I actually tried it with on old tyre. Drive a self tapping screw into the tread and then pulled it out with pliers. And it worked. Much to my surprise. Obviously you need to still check your tyres for sidewall damage etc

 

[charger69]

yea, that's one of the things on the process of removing weight at a car.

 

[RobBentley]

I always replace tyres after a puncture anyway - I only want to get it home.

The speeds I do sometimes and the stress I put on the tyres (drags, track days, upcoming visit to germany etc) means I really don't fancy doing 150+ on a 'repaired' tyre.

 

[turbonutter69]

Your right there Rob punctures should be replaced. As for the tyre stuff it will get you home mate with no worries.. The Clio 182 has this stuff instead of a spare wheel too...

 

[HDi fun]

I'm not talking about tyreweld. I'm talking about the stuff that is fitted when a new tyre is mounted on the rim. It's used by several police forces and ambulance services throughout the UK. And it seals punctures when they occur. And it actually works.


I do agree with RB though that if you're frequently driving at speeds in excess of 150mph you really are probably safer with a new tyre.

 

[RobBentley]

What do you guys do who've fitted larger alloys? (which I recently have)... another reason my spare is potentially not worth carrying. Its rolling radius is going to be ever so slightly different (although within acceptable tolerance for the speedo).

I don't think the torsen 4motion system would take too kindly to having a space-saver on one wheel and 225/40/18 RS-replica alloys on the other 3!

 

[HDi fun]

The 4Motion system used by VAG is a very good one. If the overall wheel diameter is the same it should not cause a problem as long as you don't expect to use all the torque.

I've heard of people having error codes from the transmission on these cars simply because of uneven tyre wear around the car.

Try the ultraseal stuff. I had very good results. The only problem is that with about 8-12 ounces going in each wheel you're increasing the unsprung mass

 

[RobBentley]

Rolling radius is very slightly different from stock (0.47%) according to the Torque Cars calcualtor.

I'm always concious that unlike most VAG 4motion systems (Haldex based) the W8 4motion is a full time all wheel drive Torsen system - not sure if that makes a hoots bit of difference.

Anyway - think i'll ditch this pram wheel.

 

[HDi fun]

I think that's a good plan.

 

[old-git]

One thing about space saver wheels has me wondering.

I believe that the law in the UK states that wheels and tyres on the same axle have to be the same size. If this is correct, then using a space saver would be illegal unless you fitted two

Or have I got this wrong?

 

[old-git]

Additionally, any other tips as to what could be changed on the B5.5 shape Passat (W8 saloon) to weight save... ? I doubt the performance companies make such things as carbon fibre boots & bonets!!Regards,

If you want a carbon fibre bonnet or boot, or anything else for that matter, I can put you on to my supplier. He will make anything He is currently making my doors and bonnet. The boot he made me last last year weighs in at 1kg as opposed to the 6kg original.

 

[HDi fun]

One thing about space saver wheels has me wondering.

I believe that the law in the UK states that wheels and tyres on the same axle have to be the same size. If this is correct, then using a space saver would be illegal unless you fitted two

Or have I got this wrong?

There must be provision in the construction and usage regulations such that an emergency spare wheel can be used. It probably contains all the usual missives (ie. shortest route to a place where proper repair can be carried out etc.). I think that the usual 50mph max speed advised with these things must be observed as well.

I had a puncture in 2008 Mondeo ST and had to drive a dozen miles or with the space saver mounted to near side rear. The standard tyres are (frankly, ridculously) sized at 245/40/ZR18.

The spare, likewise, look ridiculous but was the same diameter as a proper assembly.

Strangely, it drove quite pleasantly. Clearly I wasn't about to exploit the limits but the car did track straight ahead, something I didn't expect.

 

[obi_waynne]

I've only ever used a spare once in my entire life. As most of my journeys are near home and I can call home for the spare to be brought out to me and the fact that I have breakdown cover I can't actually see much point to having a spare.

Is a spare a legal requirement in the UK? I know a car will fail with a bald spare but pass if the spare is removed.

 

[RobBentley]

Waynne - I'll ask my mate - he's a copper. I think the answer will be no, its not, as for starters he has an RX8 and it didn't come with a spare!

 

[obi_waynne]

Cheers mate, i'd appreciate that! It might even save me a bit of fuel!

 

[turbonutter69]

Cheers mate, i'd appreciate that! It might even save me a bit of fuel!

No having a spare is not an Mot requirement. But I think you must have some of that tyre stuff instead.... I have taken cars plenty of times with no spare wheel an I think they just put it down as an advise....

 

[HDi fun]

Having a spare is not a MoT requirement but I seem to remember that if there is one it is subject to the same conditions at the road wheels.

 

[old-git]

Having a spare is not a MoT requirement but I seem to remember that if there is one it is subject to the same conditions at the road wheels.

As I understand it, the spare wheel is not part of the MOT, so the examiner won't even look for it. There is no law against carrying bald tyres in your car, only using them!

 

[old-git]

Waynne - I'll ask my mate - he's a copper. I think the answer will be no, its not, as for starters he has an RX8 and it didn't come with a spare!

Oh, crikey, don't ask a copper, they usually haven't got a clue unless they are Traffic Cops and even they aren't experts on MOT rules.

 

[HDi fun]

I haven't checked this recently but I'll take your word for it. I do actually have a fullsize spare buried in the spare wheel well in the boot. Only used it once, thankfully. I recently replaced the tyre as it was the age of the car and would be likely to perish if mounted and subsequently driven upon.

The spare is a steel rimmed assembly but is fitted with a full size Bridegstone tyre.

I assume that I could drive on this as if it was a normal alloy wheel.

 

[old-git]

I haven't checked this recently but I'll take your word for it. I do actually have a fullsize spare buried in the spare wheel well in the boot. Only used it once, thankfully. I recently replaced the tyre as it was the age of the car and would be likely to perish if mounted and subsequently driven upon.

The spare is a steel rimmed assembly but is fitted with a full size Bridegstone tyre.

I assume that I could drive on this as if it was a normal alloy wheel.

You could have lots of tyres in your car boot, it only becomes a problem if you decide to use one. The MOT is only a check to see if the car is roadworthy as it stands at the time of the test.

A more interesting fact is that the tester is not allowed to remove anything in order to check something. So, if it is hidden, he can't check it so can't fail it. For example, if you cover brake pipes with underseal he can't scape it off to check the condition of pipes. All inspection is visual only. this is becoming quite a problem with modern cars where everything is shrouded. They are now looking into using minicams for inspecting hard to get to places.

No problem in using a steel wheel, the regs only cover the tyre. Space savers are steel, are they not ?

 

[HDi fun]

My spare is steel, but it's a full size rim and is fitted with a tyre same dimensions as the running wheels.

 

[old-git]

My spare is steel, but it's a full size rim and is fitted with a tyre same dimensions as the running wheels.

Can't see anything wrong with that.

 

[charger69]

so there in uk are laws about keeping or no a spare tyre?

 

[old-git]

so there in uk are laws about keeping or no a spare tyre?

A spare tyre is not required under UK law.

 

[charger69]

A spare tyre is not required under UK law.

either here. if you go for a long trip, you'll need one, while if you wont go far away, and want performance, don't keep the spare tyre.

 

[turbonutter69]

I'm not talking about tyreweld. I'm talking about the stuff that is fitted when a new tyre is mounted on the rim. It's used by several police forces and ambulance services throughout the UK. And it seals punctures when they occur. And it actually works.


I do agree with RB though that if you're frequently driving at speeds in excess of 150mph you really are probably safer with a new tyre.

I'm sorry but Ambulances Do get punctures...

 

[pgarner]

It's used by several police forces and ambulance services throughout the UK

note the word several TN

 

[RobBentley]

If you want a carbon fibre bonnet or boot, or anything else for that matter, I can put you on to my supplier. He will make anything He is currently making my doors and bonnet. The boot he made me last last year weighs in at 1kg as opposed to the 6kg original.

Only just read this - definatly interested! Although I suspect a carbon boot/bonet is going to be mega £££s!

 

[WLBjork]

I haven't checked this recently but I'll take your word for it. I do actually have a fullsize spare buried in the spare wheel well in the boot. Only used it once, thankfully. I recently replaced the tyre as it was the age of the car and would be likely to perish if mounted and subsequently driven upon.

The spare is a steel rimmed assembly but is fitted with a full size Bridegstone tyre.

I assume that I could drive on this as if it was a normal alloy wheel.

Dunno if my car manual is accurate on this, but it claims you'll be speed-limited due to the fact that spares are "dual rotation" whereas reglar tyres are "single rotation".

It reads rather strangely, but what it seems to say is that nearside tyres are designed rotate anti-clockwise and offside tyres clockwise. As a spare needs to be able to fit any wheel, it's tyre is designed to rotate both ways, which degrades it's comparative performance.

Given the design of modern tyres, I found myself accepting this, but now you've mentioned it I wonder...

 

[Chris Green]

Dunno if my car manual is accurate on this, but it claims you'll be speed-limited due to the fact that spares are "dual rotation" whereas reglar tyres are "single rotation".

It reads rather strangely, but what it seems to say is that nearside tyres are designed rotate anti-clockwise and offside tyres clockwise. As a spare needs to be able to fit any wheel, it's tyre is designed to rotate both ways, which degrades it's comparative performance.

Given the design of modern tyres, I found myself accepting this, but now you've mentioned it I wonder...

Something we all need to bear in mind, especially when changing to a different make of tyre. Some tyres are unidirectional, e.g the ones with the sexy chevron tread patterns, but it some cases can be put on either side of the car because the pattern is symmetrical all the way to both shoulders. Others have a specific side and direction of travel. In either case, the spare needs to be a bi-directional tyre which kinda rules out the old custom of tyre rotation to even out wear. I'm not even sure if a front-back swap is advisable these days, with FrontWD cars putting so much stress on the front wheels compared to the back which just hold the car up and do a 'bit' of braking, and they probably wear to different camber angles too. My previous C4 VTS had a full sized spare with a bi-directional tread pattern, whereas my current Leon has the more usual 'moped wheel' with a 55kph sticker on it!

I have to echo HDiFun's praise of Ultraseal (not the Tireweld get-you-home stuff!). We put it in my wife's Smart from new (a 51 reg) and she never had one problem through not carrying a spare. I don't recall there even being any need to adjust pressures between services, such was the effectiveness of the seal. The liquid is a water-soluble gunge, which I imagine could be cleaned off if the tyre really did need a puncture repair. Now that we've got a spare, we didn't bother again when replacing the tyres, but it was interesting to see the Ultraseal still there as a little puddle at the bottom, but still ready to coat the insides once you start to move. I think the idea is that it stays liquid whilst kept under pressure, but as soon as it reaches the outside air it curdles or cures, call it what you like. Somebody told me that milk does the same! Don't ask me whether that's gold top or skimmed!

 

[obi_waynne]

My mums rice puddings would lead to the same effect as driving with a solid rubber tyre!

 

[MasterAuron]

If you want a carbon fibre bonnet or boot, or anything else for that matter, I can put you on to my supplier. He will make anything He is currently making my doors and bonnet. The boot he made me last last year weighs in at 1kg as opposed to the 6kg original.

Price for 5 Carbon Fibre Punto boot lids? Got to be talking mega-money and he's as busy as out so I hear?