FAQ. All you need to know

Hello. I'm Boo9's CEO, David White.  I hope that the following will answer any questions you might have about our products or regarding tyre safety. If not, please use the contact page on this site and I'll be ready to help.  Also please look at our 'Safety' page.

This page is separated into three sections:

• General questions

• Questions relating to WiCaps

ASAP, I'll make it easier to find the information you need . . .

it's probably in here somewhere!

Before anything else, you might reasonably ask "why is there  so much to read on in this section? I thought your products are fit-and-forget".


Our products are indeed very easy to fit and use. WiCaps have user guides that explain everything very clearly. BUT, tyres are a big safety issue and that topic is unfortunately a very complicated one and our mission is to promote tyre safety. Also, you might like to have in-depth information about how our products work. So this section is intended as a source that you can refer to if you need to. Don't feel you have to read every word before using our products!



have become concerned about  issues with pairing WiCaps  to the  Android app – something that seems to have occurred late this November (2019) due to a change in software by the Chinese app developer. I have therefore withdrawn support for the Android app. If you are an existing user of WiCaps with an Android device – and you have concerns – please contact me via this website.


Q. Can your products help prevent tyre blow-outs on my vehicle?

A.  Yes. Both under-inflation and over-inflation of tyres is the most common cause of blow-outs. The damage that leads to a blow-out can sometimes occur over days or weeks of the tyre being running at the wrong pressures.

The solution is to prevent internal tyre damage happening by checking tyre pressures constantly. WiCaps let you do just that with no effort.


Q. What causes a blow-out and what is a blow-out?

A. Under-inflation is one cause: the rim starts to run on the inner liner of the tyre, progressively destroying it. This eventually causes further loss of pressure.

   Also, when a tyre is-under inflated, all the components of the tyre – rubber, fabric, steel, composites – flex more. When the pressure gets too low and the tyre is running under load, these components get flexed beyond their design limits. What happens then is much like the effect of bending a length of steel wire: manipulate the metal long and far enough and it will become very hot and fracture.

In the same way, tyre cords (which effectively hold the tyre together) progressively break until a point where the tyre explosively splits. 

   When under-inflation is accompanied by over-loading of the vehicle or trailer (more common with the latter), this destructive process is accelerated.

   The message here is not only to check and correct pressures frequently but also to ensure that loadings are not exceeded for the particular tyres being used. My other message is don't hesitate to talk to the manufacturer of your tyres if you have any doubts or concerns.

Q. What should I do if I discover that I have been driving with an under-inflated tyre for some time?

A. Reduced / reducing pressure is generally an indicator of a slow puncture if tyre, wheel and valve appertains to be in good condition. Take a good look to see if you have a damaged wheel, valve or tyre wall. Check the tyre rubber is not showing signs of perishing. As best you can, check for a puncturing object in the tyre tread (easier said than done).

   Also, I suggest you take the opportunity to check the date of manufacture of the tyre (it's on the tyre wall). There are mixed opinions on whether tyres should be replaced every five years or so, regardless of tread wear.

   If all looks OK, inflate the tyre to its normal cold inflation pressure (only when the tyre is cold). Then drive with caution and check the tyre pressure after a while – by checking the LED is not flashing if you have FlashCaps fitted, by the pressure  reading displayed on your phone if you have WiCaps fitted or by using a gauge.

   If you are worried about anything you have seen, I recommend you call a mobile tyre service to check the tyre.

   Finally – and this is critical –if your tyre has been run 10% or more under-inflated for a significant time, it could have unseen internal damage – a possible precursor to a blow-out later. In this case, you should have the tyre internally inspected by a tyre professional as soon as possible.


Q. I know your products are about safety and avoiding under-inflation but can they save me money?

A. Yes. Comparing a correctly-inflated tyre with one that's 25% under-inflated*, it will cost you up to 4% in extra fuel and 25 to 30% more in tyre wear. Plus your chance of a tyre-related accident increase by a factor of 3*. That could add up to an incalculable cost, of course. If your tyres are 40% under-inflated (which is very, very dangerous), tyre life is reduced by 65%. Message: our products can save you a significant amount of money – as well as time and grief. * Source: NHTSA research

Q. For what vehicles can I use your products?

A.  In two words: 'any vehicle'. However, our speciality is vehicles that are used for recreation, namely, motorhomes, caravans, boat trailers, horse trailers, horse boxes, motorbikes, even e-bikes. For many of these applications, high pressure tyres are needed. WiCaps are accurate to 180 psi  (12.4 bar).

  Anything that's towed carries extra risk with tyres. Simply because you generally can't see, hear, feel something going wrong with tyres on something you're towing. Also, there's the issue of loading: it varies a lot with recreational vehicles. We're finding it's all too common to find that caravans and motorhomes have the wrong pressures or even tyres for their laden weight. Because WiCaps  monitor your tyre pressures on the move, you can see if pressures are changing abnormally. In particular, you can see if pressures are increasing significantly because your pressures started too high, too low or because you have the wrong tyres.

Q.  Are your products suitable for bikes?

A.  For motorbikes, most certainly. For regular bikes, our products are probably a bit 'over the top'. Notwithstanding, e-bikes are an exception. They are heavy and therefore difficult to push and very difficult to carry over the shoulder if they end up with a flat tyre. If you get prior warning of reducing pressure, you have more options to deal with the problem. Also, it's easy to start a journey not realising a tyre is a bit soft – which generally indicates a slow puncture. If your bike has Presta valves you need a Schrader adapter. Contact us if you need an adapter.

Q. Are there particular vehicles where you see your products as a 'must have'.

A. Yes. Obviously, I'd suggest – wouldn't I? – that our products should be fitted to ALL vehicles other than those that don't already have TPMS fitted as standard (a legal requirement for cars since 2014 in many countries). However, I strongly feel TPMS is a ‘must-have’ for all caravans and trailers because it is virtually impossible to tell when a tyre has gone soft on a trailer while you are towing it. (In contrast, with a car, the change in handling due to a soft tyre is generally noticeable). 

   The consequences of a trailer tyre failing can be catastrophic and this is particularly so if the trailer is a valuable caravan, or you are moving horses or towing an expensive boat.

   The big risk with a trailer tyre failure is that the trailer causes the tow vehicle to swerve or over-turn.

    I also recommend TPMS for motorhomes because, with heavier vehicles, it's also more difficult to detect a soft tyre by noticing a change in handling. 

   Wheelchairs are 'vehicles' where we don't tend to consider tyres to be an issue. In fact, it is an issue because wheelchair tyres are easily punctured. And it's essential that a puncture (as indicated by lower than normal pressure) be addressed before the wheelchair is used.


Q. Can WiCaps be used on vehicles that have original equipment TPMS?

A.  This is a question I never thought I'd be asked.However, increasingly drivers are getting fed up with systems that often have just a red light that warns of major under-inflation. And often the system needs resetting if it triggers.

What you see of a TPMS valve looks very similar to a normal Schrader valve. As a result, WiCaps can screw straight on. With the low-cost of WiCaps, we are increasing see customers fitting them to TPMS-equipped vehicles so they get readings of actual pressure readings. 


Q. Can your products cause tyre imbalance?

A.  This is a a somewhat difficult question to answer. A WiCap weighs 10g plus 2.5g for its optional lock nut. We've only experienced slight front-wheel vibration issues at higher than the legal limit with some cars. Personally, I would take the fitting of WiCaps as an opportunity to have your vehicle or trailer tyres professionally checked and balanced. To be clear, don't waste money on having our products professionally fitted – it's a quick and easy DIY job. 


WiCap-specific questions


Q. Before fitting a WiCap, I've realised there is not enough space for it to fit on the valve. What do I do?

A.  As long as the product hasn't been used, you can return it for full refund. However, often there is a solution: have your tyre professional fit longer valves. You can also use a valve extender – which doesn't involve demounting the tyre. Only use an extender if a tyre professional agrees it's OK for your wheels. I suggest that if an extender is used, it should be fitted using liquid thread lock.  In some cases, hub caps can make fitting difficult. Temporary or even permanent removal of the hub caps may be a solution.

Q. Before fitting a WiCap, I've realised that it will extend the tyre valve beyond the outer wall of the tyre. What do I do?

A.  As long as the product hasn't been used, you can return it to us for a full refund. However, often there is a solution: have your tyre professional fit a shorter valve (which involves demounting the tyre).

Q. What is the wireless range of a WiCap?

A. We, at BOO9, have tested WiCaps with various recreational vehicles and have found the app works reliably and accurately in all normal situations. In short, the range is adequate for use with caravans, trailers and motorhomes.

   In technical terms . . . WiCaps use an international wireless standard called Bluetooth (BLE). The transmitted power is regulated to a fixed strength. The signal received varies, of course, with range as well as a number of other factors.

  Objects between receiver and transmitter reduce signal strength depending on their consistency and size. For instance, a brick wall may totally block out a signal.

I mention this because it's often possible to see your tyre pressures from inside your house with the WiCap system. 

I don't promise that however!

   If a transmitter and receiver are very close, yet blocked or partly-blocked by a human body, the signal can be reduced significantly, even at this short range. A typical example is when Bluetooth headphones work intermittently.

   At longer ranges, the omni-directional radio waves from the WiCap can generally go round the side of an object between it and the receiver (your mobile device). Hence, our tests demonstrated that a WiCap fitted to a wheel can successfully communicate with a mobile device hand-held in the passenger seat of a van – when the range is up to 28 metres. Clearly, this is not an absolute figure – it's influenced by many factors such as rain and radio interference. 

Q. How does the WiCap system work?

A. In simple terms, the WiCap, when fitted to a tyre valve, radios information from the various sensors it incorporates to a mobile device such as a smart phone or tablet. This information is then translated by an app, running on the mobile device, so that tyre pressures etc can be displayed on screen.

   In technical terms . . . WiCap incorporates a MEMS (micro solid-state) pressure sensor which sends pressure information to the WiCap's microprocessor. 

   This processor is incorporated within a large chip that also integrates a radio transmitter/receiver and other electronics that turn information from the pressure sensor into digital data that can be transmitted and error-checked.

   Once fitted, the Wicap communicates, wirelessly, with an app running on smartphone or tablet.

   The communication method is low energy Bluetooth (BLE), a wireless standard used by  smartphones and tablets.

   The communication is  one-way, from WiCap to app as digital data, eg pressure, which is passed to the app for display on the mobile device's screen. 

   WiCaps use state-of-the art technology to pack a lot of electronics into a very small and light package to deliver very accurate information. The package works with high pressures, can cope with high temperatures and is waterproof to the IP67 standard.  

   WiCaps are designed to use minimal power such that the (replaceable) battery can last two to three years. WiCaps switch on when they are pressurised and sense pressure or temperature changes.

Q. What is pairing?

A. Pairing is a process you only have to do ONCE. WiCaps need to associate themselves with the app such that the app can permanently  'memorise' their IDs. This means the app only searches for and listens to the intended WiCaps. It can then ignore the dozens, even hundreds, of other Bluetooth devices that may be in range at any given time. The app can then also ignore any other WiCaps that might come within range. This process of association is called 'pairing' or sometimes 'binding'. It's a one-time process.

   Once achieved – it's a near instant process – the app will be able to associate wheel positions (as displayed on-screen) with the particular ID of the WiCap on that wheel.      Pairing process is a one-time process  . . . removing a WiCap from its valve never affects the pairing. 

Q. How is pairing achieved?

A. The user initiates the app to pair one sensor at a time.

Once initiated, the app searches for a WiCap with an ID format it recognises. It also looks for an identifier for the wheel position.

   WiCaps are numbered 1 through 4. The user starts with WiCap 1 and decides which wheel position will be associated with 1. The user taps the screen of the smartphone to start pairing with 1 and the app starts searching for an ID prefixed with 1.

   When WiCap 1 is fitted to the tyre, it becomes pressurised, which in turn switches on its electronics. It then immediately transmits a pairing signal to the smartphone. Within seconds, the pairing is achieved and the user can continue fitting the rest of the WiCaps in numerical order.

   Once pressurised, WiCaps transmit every three minutes to 'advertise' their presence to the app. Transmissions are kept minutely short so that power consumption is minimal – thus allowing WiCap batteries to last for several years. 


Q. What happens if I only want to use two WiCaps for my single axle trailer?

A. WiCaps come in packs of two and four. With 2-cap packs, you may receive WiCaps numbered 1 and 2 or numbered  3 and 4.

   For the former, you start pairing with WiCap 1. For the latter you start pairing with sensor 3. The app allows for four WiCaps by displaying four dials on the screen. With caps numbered 1 and 2, pair the WiCaps with the 'front' two dials. With WiCaps numbered 3 and 4, pair them with the 'back' dials.

Q. Why does the app offer several means of pairing?

A. The app is third-party software which is multi-purpose: hence it offers pairing to suit, for instance, sensors that fit inside the tyre.


Q. I think I've followed the user guide but I haven't achieved pairing. Why?

A. If you follow the steps given in the printed user guide supplied with the WiCap kit, it will be unusual if you have a problem. One cause of non-pairing is radio interference, although WiCaps use sophisticated 'frequency hopping' to circumvent interference.


Here are other reasons why pairing fails first time:

• You initiated pairing for, say, wheel 1 but did not fit

WiCap 1. (If you have been supplied with WiCaps numbered 3 and 4, you'd start with 3.


• You didn't pair / fit the WiCaps in numeric order.


• You didn't fully screw the WiCap on to the valve stem.


• The tyre wasn't inflated.


We all know that phone apps can sometimes not do what the programmer intended. So if pairing still is not

achieved . . . so here are some solutions.

Solution 1. Use the automatic pairing method which is described in a  separate instruction sheet with your kit. With this method, you instruct the app to 'listen' for a WiCap. The app displays a count-down. Within that time, you fit a WiCap to the tyre valve. Then the WiCap instantly transmits its ID to the app and pairing occurs.


Solution 3. Close the app, restart it and repeat the pairing process.


Solution 4. Turn your smartphone off and back on again.


Solution 5. Finally, if all else fails, delete the app and download it again. Remember you should download the app from the 'app' page of this site.


If you still have a problem, contact us. 

Q. The WiCaps don't seem to be transmitting to the app Why?

A. The range of WiCaps is exceptionally good, so that factor shouldn't be an issue. Remember that the WiCaps only transmit every 3 minutes (to save power), so you may have to wait 3 minutes or more for all WiCaps to have transmitted to your mobile device.


Q. What does the rotation of the dials (on the smartphone's screen), when the app is running, signify?

A. The dials rotate only when the app has  received a transmission from any one of its paired WiCaps – typically this will be when the WiCaps come within range of your smartphone.

   I suggest you wait for 3 minutes after approaching your vehicle / trailer / caravan before checking your tyre pressures. You may find it more convenient to start driving your vehicle and have your 'co-pilot' check pressures when all the WiCaps 'wake up'. Thereafter, you can check the pressures inside your vehicle whenever it is safe to do so. As the driver, don't use your phone while driving.  

Q. Why does the app indicate that tyre pressures have increased once I have been driving a while ?

A. As tyres warm up, pressure increases.

Q. Sometimes pressures appear higher on one side of the vehicle to the other. Why?

A. Particularly with caravans and trailers, the nearside or kerbside tyres can heat up if the edge of the road is uneven. The nearside tyres then flex more than the offside ones and heat up more, thus increasing the pressure.

Q. I don't get an alarm, visual or audible, when the tyre pressure has dropped significantly. Why?

A. The dials turn red and a speech message is given when pressure drops to the level set in the Settings page of the app. The threshold for the app to warn of low pressure has a maximum of 36 psi (this adjusted in the Settings page of the app. As a result, for example, with a 60 psi tyre, the alarm trigger point is lower than I like – but of course tyre pressures are always on display. We are addressing this issue with a new, very advanced  app of our own which has multiple speech alarms suitable for tyres at any pressure and capable of monitoring up to  eight wheels. This will be available to our customers free of charge as soon as we have completed it. 

Q. The dials on the app are permanently red. Why?

A. This means either that your tyre pressures are below the low threshold you have set in the app or the pressures are above the the maximum threshold you have set in the app. The maximum threshold is 93 psi. 


Q. How do I turn of the audible warning?

A. Tap the speaker symbol top right of the screen.


Q. Are WiCap batteries replaceable?

A. Yes. Typical battery life is up to 3 years. It's quick and easy to change a battery – the user guide on this shows you how. WiCaps use single, low-cost CR1632 button / coin cells

Q. Can WiCaps corrode or can their threads jam on the valve stem?

A. WiCap electronics are protected by seals conforming to the IP67 standard. The only metal component of the WiCap is the valve thread, which is brass – the metal used for virtually all valve stems. Whilst corrosion can occur with different metals in contact, brass on brass is generally OK. Notwithstanding, it's not a bad idea to lubricate the valve stem with a light oil or silicone spray before fitting the WiCap.

Q. Can I use WiCaps with boat trailers that get immersed in water?

A. Yes. WiCaps are totally sealed when fitted to the valve stem. They are rated to IP67, which means they can be immersed in up to 1.5 metres of water for up to half an hour if necessary. Do watch out for your wheels if they get immersed in water, especially salt water. Wash them thoroughly after immersion.


Q. Where's the best place to get information on tyres and tyre safety? Here are two good sources:


www.theAA.com/tyres     (click 'tyre advice' on the AA page)

Also, always read the user manual supplied with your vehicle, trailer or caravan.

More questions?

Use the contact page and ask away. We're here to help!


Enjoy your world

While we look out for your tyre safety