Internal -vs- external sensors (FOBO-vs-Orange)

T_C

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Did a little experiment this morning. I put my new FOBO bluetooth TPMS sensors (external) on my bike that has the Orange (internal) TPMS installed. I wanted to see how things compared.

Starting with the main dispaly. The Orange has a hardwired unit that is weahterproof, mounts somewhere of your choice on the dash. Two buttons and combinations of presses let you do programing of high/low temperature warnings, over temperature warning and the normally blue background flashes red when you exceed one of your pre-sets. Mating the sensors to the unit is not too hard, just lower tire pressure to 10-20 psi and it'll pick it up and assign it to the slot you choose. You can measure in bar, kpa, psi, ˚F, ˚C. The FOBO uses your smart phone. So any and all setting are customizable and the pairing sequence is easy and similar to many other bluetooth devices.

For myself, I prefer the fixed and hardwired display of the Orange. A little harder to program and customize, but it's always there, always ready to go. Can't leave it behind. But the reality, I rarely go anywhere on the bike with out my phone. It has a dedicated mount on the bike. Big easy to read display and can pump audible messages of tire events into my headset.

The tire pressure was right on equivalent level between the two. The FOBO unit will allow for temperature compensated pressure (but read below for the design flaw). I more fear the the external sensors will allow some air leakage. The internal sensors have the old reliable valve core to keep things sealed. The FOBO unit pushes the valve core out of the way and relies on it's seal to your valve stem to remain airtight.

Both displayed the same readings (give or take), the FOBO was displaying in one-tenth increments, the Orange rounds it off to the whole number.

Temperature readings, both units do it. But one reads from the end of a inch long metal stem while swinging around in the ambient air. The other is sitting insulated from teh outside air inside the tire cavity. Guess where the reading are more accurate.

Rolling out of the garage they were both reading about the same. Good news I though. Ambient air temperature was around 30˚F. After 42 miles of highway blasting at 70 (give or take judge) I was measuring 34/55 on the FOBO, Orange was measuring 62/75 (Front rear respectively). Plenty of time for the warm air to get to the FOBO units, but the metal valve stem and sensors swinging in free air will prevent them from every really seeing it. In less extreme cold the sensors may be more accurate, but they will always be less then idea for monitoring the tire carcass' true temperature.

So if the FOBO unit is doing temperature compensated pressure how can it be reliable when it's temperature sure is not.

Another issue.. if the tire a FOBO unit develops a catastrophic failure you will possibly not be alerted. Now if this is on your bike I think you will realize it anyway, but if it on a trailer you are pulling, you may not. If the pressure drops to zero in under 8 seconds the FOBO unit just thinks it was removed from the valve stem and this is SOP.

Two strikes against FOBO, but one up for it. You can program the nominal reading and it will alert you if you deviate, outside of the alerts it gives if you are at the extreme levels. Also the FOBO unit can put the sensors into a high-power mode. If you are pulling a trailer and the distance/interference is preventing the signal from coming through, kick the sensors up in power (with a reduction in battery life) and all might be good.

Speaking of reduction in battery life, the batteries on the FOBO units can be changed, the Orange can not. And that might be the death of my love of my Orange unit. I can buy a whole FOBO kit for less then the cost of a pair of replacement Orange sensors.

Hmmm...
 

MrB

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Nice comparison T_C!
Was just talking to our buddy Tim about this, I'm going with less reliance on cellphone as it puts too much importance in one device. I used to ride with my phone flapping in the breeze but after considering how important it would be to have after a boo-boo I've decided to keep it locked up safely in one of my storage areas. My previous position was Bluetooth everything but tire pressure is too critical a function for me to rely on a separate device.
The temperature function on the FOBO is useless, as expected. Don't know what they were thinking...
Got the new M203 on order with fresh batteries, if Orange is still around in 3 or 4 years I'll bite the bullet and buy new ones. If not, I'm sure there will be something else to take their place.
 
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Back when I had a SmartTire (internal sensors), I was impressed with the temperature function, but after while, it just doesn't matter much (still nice to have if accurate)...... using a Doran now that does not report temperature, but having the previous experience, I understand the rise in pressure as the tires heat up. It is more important IMHO that the system recognize a loss of pressure in a timed period or below your set threshold, and trigger the alarm. But you should be able to just forget you have TPMS and the whole idea was to ride with the confidence it will alert you to a problem.
The Doran is going with the bike when I sell it, I'm going to give the Hawkshead a shot on the new bike because I like the replaceable battery idea. Doran sensors are about $75 for a pair which will last over 2 years (they now have improved batteries, so that should get better), and Orange sensors are kinda pricey too. All are good, pick one of these I don't think you can go wrong.
 
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T_ C As stated in another recent post here , I just replaced both my sensors for my M 202 unit. By email I contacted the company in Taiwan and the sales rep sold me both sensors for $25. each, which I thought was very reasonable.
 
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One question here. Beyond academic interest, when would we (riding as most of us do with a TPMS - i.e. off the racetrack) have a need to know that the tire temp is increasing beyond what is safe? As the temp increases, the pressure goes up, and that will show up on the readout and sound the alarm. So, why do we care if the temperature reading is inaccurate as long as the pressure is monitored correctly.
 

Andrew Shadow

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One reason would be that if the system is displaying temperature compensated pressure readings and the temperature is being incorrectly monitored then the compensation would be equally inaccurate. This would make the pressure reading displayed inaccurate and the alarms questionable.
 
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IMHO, it's confusing to bring temperature into it...... unless you have a calculator to know what the corresponding pressure should be at a given temperature....... or, what temperature is deemed 'unsafe'........ I say keep it simpler, you know your tires have higher pressure when hot, you started out at 42, it's a really hot day out, you ride and later it's 50 psi. Happens all the time with me, normal, and (currently) I don't know what the tire temperature is. It does depend on ambient temperature too.

Back in the day of SmartTire, the theory was if a tire got real hot (unsafe hot), the reason it was likely doing so is because the pressure went down and a blowout might be imminent......... made sense, but the pressure alarm was on anyway......

I just view the temperature as interesting information. I wouldn't want compensated pressure readings, because that's just confusing information....... need to ride more, worry less about gawking at my TPMS.
 

skipcurt

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I've been researching a TPMS recently and I decided on the Hawkshead like Uncle Phil mentioned. I like the idea of the internal system but what made the decision easy for me was that the internal unit does not have replaceable batteries. You would then have to buy new units which in the long run will be more expensive. Also, since I don't have a tire changer at home, I then have to go to my tire guy to remove the tires to get the units which of course will cost more money. The current group buy is very sweet.

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Uncle Phil

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Personally, I think the idea of a TPMS is to get a heads up before the tire gives up - at least for me. The accuracy of the temperature or pressure to the exact degree or pound is not nearly as important as detecting movements in direction, especially the 'downward' one for pressure. If I had one when I had my sudden front tire failure, I would have know that the front tire was leaking before it suddenly came loose from the rim. That knowledge would have saved me close to the cost of a system and a lot of 'puckertude' when I considered the time and effort it took to come to an orderly halt, then to get someone to come with a trailer and the destruction of the front tire. I think the legitimate ones all work well, it's just a matter of what features/size/battery replacement, etc. we prefer. ;-)
 
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T_C

T_C

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T_ C As stated in another recent post here , I just replaced both my sensors for my M 202 unit. By email I contacted the company in Taiwan and the sales rep sold me both sensors for $25. each, which I thought was very reasonable.
That is a reasonable price, mine were bought in January of '15 and were double the price. More money then I spent on the whole FOBO unit. One thing I did like about teh FOBO was the ability to monitor my trailer. The orange sensors will not fit in my trailer rims. Well when my Orange sensors die I will see what happens. They are just at one year old so I should be set for awhile.

Beyond academic interest, when would we (riding as most of us do with a TPMS - i.e. off the racetrack) have a need to know that the tire temp is increasing beyond what is safe?
Correct, most of us do not have the knowledge to really understand the high points and their extened run limits. But if you occasionally monitor it you can get a feel for the normal. Then if you see deviations you can consider something may be wrong.
 

ST Gui

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it's confusing to bring temperature into it...... unless you have a calculator to know what the corresponding pressure should be at a given temperature....... or, what temperature is deemed 'unsafe'........ I say keep it simpler, you know your tires have higher pressure when hot, you started out at 42, it's a really hot day out, you ride and later it's 50 psi. Happens all the time with me, normal, and (currently) I don't know what the tire temperature is. It does depend on ambient temperature too.

Back in the day of SmartTire, the theory was if a tire got real hot (unsafe hot), the reason it was likely doing so is because the pressure went down and a blowout might be imminent......... made sense, but the pressure alarm was on anyway......

I just view the temperature as interesting information. I wouldn't want compensated pressure readings, because that's just confusing information....... need to ride more, worry less about gawking at my TPMS.
+1 on all of that and especially on the bold stuff. I only want to know what I need to know. Do I have enough air in my tires or not. I don't know about a TPMS' ability to predict catastrophic failure. Maybe. I dunno.

I got a TMPS for one reason: I want to know if my tires have enough air before I drive off. The compressor is right next to the bike. If the tire's low it can be topped off before I even turn a key. This is particularly useful and convenient since finding air at a gas station is pretty hit or miss and mostly miss around these parts. I turned off the temperature display. It's of no interest at all.

If it weren't for the recent group buy of a cost effective TPMS I wouldn't have bothered with one at all.
 

ibike2havefun

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In your experience, where is the "normal" pressure range when you are riding on a day where the temperature is between 85 and 90F, if you've started from a "cold" pressure of 42?

I'm new to the TPMS arena, having installed my first set yesterday. (Also still relatively new to riding, so everything I "know" about tire pressure management comes from what you and others have written.)

What I've not seen anywhere is what the "normal" pressure range is. I target 42 psi cold pressure as the baseline, as per the Honda manual, but have no feel for where to set the low and high warning limits.

So I arbitrarily selected 40 psi as the low, knowing that even a little bit low is a Bad Thing, and 50 psi as the high because I have absolutely no idea what it "should" be.

On yesterday's ride with ambient air temperatures in the mid-60s, I was seeing pressures around 47-48 psi, and higher on the rear than the front. That front/rear differential makes sense (to me, at least) given the weight distribution and the fact that the rear wheel is propelling the bike. So I can see where it might get warmer than the front, despite having a larger volume of air (and tire mass).

Here in the mid-Atlantic, it can get quite a bit warmer than it was yesterday which I would anticipate means I'd see somewhat higher pressures when the tires are really warm. Have I set myself up for the thing to cry "wolf" on a warm day?

One side note: after sitting idle for two months (almost to the day) in an unheated storage unit, my tire pressures had dropped by only three psi, to 39 from the 42 they were at when I started my previous ride two days after Christmas. That was a very pleasing discovery, since my previous tires / stems tended to lose 5 psi/week, meaning I had to be really diligent about checking them before every ride.

Thanks!
 
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On the hottest of days, I have seen 51 psi, but never higher than that. Oddly enough, starting out at 44, same thing as (I think) the slightly stiffer tire doesn't heat up as much. I have seen 48 on the front. I don't think upper limits are as important as lower limits..... it will vary a little with conditions, tires and bike.... One of the TPMS I had did not have you set an upper limit, but would trigger an alarm at +/- 12.5% which seems reasonable. Even so, I set my lower limit to 39 and figure if it triggers when I start out, I need to add some air before my ride.
 
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T_C

T_C

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Now I am Double Dark, so take this with a caveat of YMMV.
During the cool winter time (ambient 46? F) I am running about 30? and 40? over ambient (front and rear respective).
This is after a 45 mile run of slab at 70-80 speeds. But I am usually up to operating pressure after about 10 miles.
Pressure climbed 3 psi in the front and 6 psi in the rear. (Started 42 and 36 respectively.)
I have seen 48 front and 51 rear when doing extended high-speed running with a full loaded bike.
 
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T_C

T_C

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Onr thing I did notice, never thought of before.

The FOBO dates and time stamp it's last update. So when you are staring at the tire pressure screen you instantly know if it is current readings or something in cache.

The Orange unit does time out after 20 minutes and puts an error code on screen... but if you wanted to confirm a valid reading after 'potentially' hitting something on the road you would have to either shut the Orange off and restart or wait 20 minutes to see if anything timed out. Actually both in reality.

The FOBO also writes it to a log... but the usefulness and exploit capability of that has yet to be investigated and evaluated.

Still thinking I prefer the internal and always on, hardwired and permanantly mounted to bike capability capacity of the Orange TPMS.
But the price of the FOBO, audible warning, replaceable batteries... dang!
 
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I've had two rear flat tires over the last 35 years. Both times I asked myself "why does my bike feel like someone loosened my swingarm pivot bolt?" and pulled over to the side of the road. I'm guessing that qualifies as an "external" sensor?
 

wjbertrand

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I've had two rear flats before installing TPMS too. The ST13 and the ST11 are remarkably stable on an under-inflated tire (at least running straight) so much so that by the time I realized there was a problem it was now urgent to stop. immediately. Since installing TPMS in my ST1300, I've twice received warnings early enough for me to find a more appropriate place to address them. Once when leaving work, just exiting the parking lot I noticed the alert. Instead of getting on the freeway, I made my way to a gas station with an air hose, got out my plug kit and carried on. Similarly on the way to San Diego once, running down the 405 at 70+ MPH, I noticed an alert allowing me to get off the freeway and find a gas station where I could safely perform the repair.

In both cases without TPMS, I would probably have been stuck on the side of the freeway, with traffic whizzing by, trying to repair my tire.
 

Uncle Phil

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I run 42 in the rear and it usually gets up around 51, the front at 36 gets up to around 47.
Just had a similar experience - my Hawkshead TPMS let me know my rear was low as I rolled backwards out of my parking spot at work. It still had enough air to ride safely and I only live 10 miles from work. So I headed on back roads at a leisurely pace (instead of the slab) near gas stations and kept an eye on the monitor. When I saw that it was holding, I just headed on home figuring I'll picked up a nail. Turned out it was screw dead center in the brand new Z6 I'd just installed. But it was nice to know what the pressure was and whether I needed to address it immediately or ride it to the house carefully. It was lot easier to fix at the house than in the parking lot for sure! ;-)
 
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T_C

T_C

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Both times I asked myself "why does my bike feel like someone loosened my swingarm pivot bolt?" and pulled over to the side of the road. I'm guessing that qualifies as an "external" sensor?
Wehn the front gets low the the external sensor (handlebars) will let you know too, the tire rolls over since the sidewall is not stiff and feels like it's flopping. But it only happens when you corner... so it's just a part time TPMS. ;)
 
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