TPMS – a good idea

Tubeless Conversion Index Page

flatIt’s not impossible to get a bit cynical about the flood of gimmicky gadgets, products or optional features which modern technology has enabled, not least when associated with ‘adventure’ + ‘motorcycling’. But I believe that for the
• price
• ease of fitting and
• non-interferring redundancy
a wireless Tyre Pressure Monitoring System is a smart idea for your travel bike. 

For as long as I’ve been on the road, tyre makers and road safety tsars have harped on about the importance of maintaining correct tyre pressures. They’re right of course: doing so is a major contribution to road safety for the reasons illustrated vividly in the videos below. But modern bike tyres are so good that I’ve often inadvertently ridden on drastically under-inflated tyres for weeks and not even noticed. 

nureyevAdd the fact that on some bikes the valves can be awkward to access with tyre gauges which themselves are hard to read or flakey. Plus it’s all grubby down there and your knees/back are no longer like Nureyev in his prime. Unless you’re a certain type of ATGATT swot, for day-to-day riding it’s all a bit of a faff to check tyre pressures as regularly as they advise. And yet your bike’s other vital signs: oil pressure, battery charge, temperature, lights and even which gear you’re in – are all conveniently lit up right there on the dash.

Tyre Pressure Monitoring System
tpms4The problem has always been how to read the pressure inside a tyre that’s spinning around at 1050rpm. Solution: the advent of inexpensive wireless technology. A TPMS is ingeniously composed of two replacement valve caps fitted with pressure sensors which pair and communicate wirelessly with a small watch-sized display mounted where you can see it (or beamed to your indispensable smartphone; right).smartpms The TPMS display is either powered off the bike’s battery or is rechargeable in some way, so it’ll work on anything else with a regular Schrader valve.
Result: real-time tyre pressure and even temperature monitoring (right), either full-time if hardwired, or displayed on demand at the press of a button. And best of all, the rechargeable ones don’t interfere with thetpms-temp bike’s systems in any way. If the caps play up, just refit regular ones. They weigh as little as 8 grams so are unlikely to cause tyre-balancing issues at normal road speeds.
Over the years I’ve found DIY as well as other tubeless conversions like Tubliss and BARTubeless have lost air pressure  faster than a regular tyre, tubed or otherwise. And this is even when not run at very low psi where the tyre could conceivably ‘burp’ out some air over a bump. With any sort of DIY tubeless conversion, I highly recommend fitting a TPMS; certainly in the early days until you know how good the seal is.

86-tin-taradjeliRiding Off Road
As we all know, lowering tyre pressures greatly improves traction on loose surfaces and can transform a bike from a mindless shopping trolley into a hyper-sapient roller blade. But when you lower tyre pressures, temperatures in the tyre carcass soar as it flexes and unflexes on each rotation, just as you get hot exercising because your muscle tissue is rubbing. And as tyres heat up pressure readings climb. (This is why cold tyre pressures should be your baseline).  In this hot, rubber-softened state a tyre is much more prone to punctures 82~up-creekand other woes.
Off-road I tend to keep pressures as low as necessary but as high as possible. Usually   erring on the high side at the cost of a comfy ride, so weary am I of repairing flats on tubed tyres in the middle of nowhere (left).

A TPMS won’t stop punctures but at least you’re able to observe how pressures climb from a cold start and what they’re actually doing on the dirt, so helping eliminate the guesswork of ‘press the valve for 2-3 seconds’ or the nagging feeling of ‘should stop and inflate a bit?’.

michelin-tpmsThis is one worthwhile gadget I wish I’d had on my Tenere back in 2007, if not all my desert bikes over the years. I’ll be fitting one to the Enfield Himalayan running Tubliss all round.
You can buy obscure-brandMichelin-TPMS TPMS kits for your bike off ebay from £30 for the smartphone-only ones.
In the UK and presumably elsewhere, Michelin licencee Fit2Go have released a USB-rechargable kit (£79.95) which I’ll be testing on the Himalayan. 

This entry was posted in AMH News, Project: Enfield Himalayan, Tyres and tagged , , , , , , , . Bookmark the permalink.

4 Responses to TPMS – a good idea

  1. Andrew Metcalfe says:

    Vested interest here because I sell TPMS for trucks. The retrofit ones have two problems. First the cheap ones suffer valve failures. Second, the valve neck can be too weak. A metal replacement neck or internal sensor and standard valve is best. There is a good reason it will be mandated on all vehicles within 10 years, it will save lives.

    • Chris S says:

      Thanks for the tip, Andrew. I can imagine cheap TPMS valve caps failing (tho’ a mate has had no probs with his, afaik).
      By neck I realise you mean the metal valve body as used on inner tubes andpictured here
      as opposed to black rubber/plastic ones you get on cars
      Internal sensors, so much the better – presume most easily inside TL wheels.
      Anyway, I am reassured Michelin have put their name to a self-fit set.
      Happy to see TPMS become a standard feature. Much more useful on a travel bike than TC, leaning ABS etc, etc.

  2. muppix says:

    Neat idea, but that looks like a fairly hefty chunk to screw onto a standard (and in this case vertical) valve. Any issues with balancing? Safe to use on angled valves?

    • Chris S says:

      Good reminder about balancing, but I suspect they’re just a few grams heavier than a regular cap.
      I guess a fully perpendicular valve on a slim rim will always be more vulnerable on rocky terrain.
      At worst it will bash and break the cap. You can buy replacements, or just remove it.

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